CN103323158A - Brushless type torque sensor based on Hall effect - Google Patents

Abstract

A torque sensor based on the Hall effect, including a sensor shaft, a base, front and rear end covers, an excitation sleeve, an excitation core, a permanent magnet steel, an output sleeve, an output iron core, a Hall element, a toroidal transformer, a tight Firmware and matching bearings. The sensor shaft is fixed with the front and rear end covers through bearings, and can rotate relative to the machine base. The sensor shaft is concentric with an excitation sleeve. The excitation core and permanent magnet steel are fixed outside the excitation sleeve. The sensor shaft is concentric with an output sleeve. The output iron core and the Hall element are fixed inside the output sleeve, and the excitation sleeve and the output sleeve are respectively fixed on both sides of the sensor shaft through fasteners. The power supply and output leads of the Hall element are respectively connected to the inner surrounding groups of the toroidal transformer through the via holes, and the outer surrounding groups of the toroidal transformer are connected to the junction box. When in use, the two ends of the sensor shaft are coaxially connected to the load and the power source, and the sensor converts the load torque into a corresponding analog electrical signal output, which has high measurement accuracy.

Description

Brushless Torque Sensor Based on Hall Effect

technical field

The invention relates to a torque sensor, in particular to a brushless torque sensor based on Hall effect.

Background technique

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 more mature torque sensors on the market are mainly magnetoelectric and strain sensors. The magnetoelectric torque sensor obtains the torque signal through magnetoelectric induction. It is produced by HBM Company of Germany, Ono Shoki of Japan and Xiangxi Instrument Factory of China. The essence of the output signal of the sensor is two angular displacement signals with phase difference. Signals are combined and processed to obtain torque information. It is a non-contact sensor, without wear and friction, and can be used for long-term measurement. The disadvantage is that it is bulky, difficult to install, and cannot measure static torque; the strain-type torque sensor uses resistance strain gauges as sensitive components, such as the German HBM company. T1, T2, T4 series torque sensors, JN338 series sensors of Beijing Sanjing Group, etc., they install four pieces of precision resistance strain gauges on the rotating shaft or the elastic shaft connected in series with the rotating shaft, and connect them into a Whiston bridge. The torque makes the small deformation of the shaft cause the strain resistance value to change, and 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, and has the advantages of small size and light weight. The disadvantage is that the signal transmission is easily disturbed and the loss is large, resulting in low measurement accuracy.

Contents of the invention

The invention provides a brushless torque sensor based on the Hall effect. When in use, the two ends of the sensor shaft are coaxially connected to the load and the power source, and the sensor converts the load torque into an electrical signal for output. The torque directly corresponds, the precision is high, and the static torque or dynamic torque of the rotating system can be measured.

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

A torque sensor based on the Hall effect, including a machine base, a front end cover located at the front end of the machine base, a rear end cover located at the rear end of the machine base, a sensor shaft passing through the center of the front end cover and the rear end cover, and the sensor shafts pass through bearings respectively It is fixed with the front and rear end covers and can rotate relative to the machine base. In addition, it also includes:

The excitation sleeve is coaxial with the sensor shaft and placed in the machine base. There is a convex key on the outside of the excitation sleeve. The excitation core is fixed on the convex key. There is a gap between the excitation cores, and the permanent magnetic steel is installed in the gap. In the process, anaerobic adhesive is used to bond the permanent magnet steel and the excitation core, and the permanent magnet steel and the excitation core rotate with the sensor shaft at the same time;

The output sleeve is coaxial with the sensor shaft and the excitation core and placed in the machine base. There is a groove inside the output sleeve, and the output core is fixed in the groove. There is a gap between the output cores. The Hall element is installed on the In the gap, use anaerobic adhesive to bond the Hall element and the output core, the Hall element and the output core rotate with the sensor shaft at the same time, and the output sleeve is provided with a through hole;

Fasteners are used to respectively fix the excitation core sleeve and the output core sleeve to the two ends of the sensor shaft, and the fasteners are provided with through holes;

Toroidal transformers are a pair, each inner ring core is fixed to the sensor shaft, and rotates with the sensor shaft together, with winding slots, and each outer ring core is fixed to the machine base, with winding slots;

The power supply and output leads of the Hall element are respectively connected to the inner surrounding groups of a pair of toroidal transformers through the through holes of the output sleeve and the fastener through holes, and the outer surrounding groups of the pair of toroidal transformers are connected to the junction box.

As above-mentioned structure, the torque sensor based on Hall effect of the present invention, its operating principle is:

1. Measurement of static torque: the outer surrounding group of the toroidal transformer 1 is fed with alternating current, and the inner surrounding group of the toroidal transformer generates an induced potential through magnetoelectric induction. The surrounding groups are connected to form a closed loop, and then the alternating current is passed into the Hall element. The permanent magnetic steel embedded in the excitation core generates a constant magnetic field, which forms a closed loop through the excitation core, air gap and output core. The extended end of the sensor shaft is fixed, and the other end is loaded with static torque. When the static torque is zero, the sensor shaft does not deform, and the initial positions of the excitation sleeve and the output sleeve fixed at both ends of the sensor shaft remain unchanged. The permanent magnet steel fixed to the excitation sleeve and the output iron The Hall element of the sleeve has a 45° mechanical angle difference in space between its initial positions, and the direction of the exciting magnetic field formed by the permanent magnet steel is parallel to the direction of the current flowing into the Hall element, so the output voltage of each Hall element is zero; when the static torque is not zero, the sensor shaft is deformed, the initial relative position of the permanent magnet and the Hall element changes, and there is an angle between the direction of the exciting magnetic field and the current direction in each Hall element, then each Hall element The output voltage of the element is not zero and is an AC voltage. Since the output lead of the Hall element passes through the hole of the fastener and forms a closed loop with the inner surrounding group of the toroidal transformer two, there is an alternating current in the inner surrounding group of the toroidal transformer two. The current is changed, and then an induced potential is generated by the outer surrounding group of the magnetic induction toroidal transformer 2, and the induced potential corresponds to the static torque loaded by the sensor shaft.

2. Measurement of dynamic torque: the outer surrounding group of the toroidal transformer 1 is fed with alternating current, and the inner surrounding group generates an induced potential through magnetoelectric induction, because the power lead wire of the Hall element passes through the via hole of the output sleeve and the ring transformer 1 The inner surrounding groups are connected to form a closed loop, and the Hall element is fed with an alternating current. The permanent magnetic steel embedded in the excitation core generates a constant magnetic field, which forms a closed loop through the excitation core, air gap and output core. One end of the rotating shaft of the sensor is connected to the power device, and the other end is loaded with dynamic torque. When the dynamic torque is zero, the sensor shaft does not deform, and the excitation sleeve and the output sleeve fixed at both ends of the sensor shaft, and the inner ring core of the toroidal transformer rotate together with the sensor shaft, and are fixed on the excitation sleeve. The initial positions of the permanent magnetic steel and the Hall element fixed on the output sleeve have a 45° mechanical angle difference in space, and the direction of the exciting magnetic field is parallel to the direction of the current flowing into each Hall element, so the position of each Hall element The output voltage is zero; when the dynamic torque is not zero, the sensor shaft is deformed, the initial relative position of the permanent magnet and each Hall element changes, and there is an angle between the direction of the exciting magnetic field and the current direction of each Hall element. Then the output voltage of each Hall element is not zero and is an AC voltage. Since the output leads of the Hall element pass through the holes of the fastener and form a closed loop with the inner surrounding group of the ring transformer two, the inner circle of the ring transformer two There is an alternating current in the surrounding group, and then an induced potential is generated by the outer surrounding group of the magnetic induction toroidal transformer 2, and the induced potential corresponds to the dynamic torque loaded by the sensor shaft.

As above-mentioned structure, the present invention utilizes the novel torque sensor that Hall effect forms, sensor and load and power source (rotating machine) coaxial installation, load torque is converted into the electric signal output of Hall element, the electric signal of output Corresponds directly to the load torque. Therefore, the sensor is easy to use and can be used in various occasions for measuring static torque and dynamic torque.

Description of drawings

Fig. 1 is the structural representation of the novel torque sensor based on Hall effect of the present invention;

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

FIG. 3 is a schematic diagram of the working principle implemented in FIG. 1 .

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 the structure schematic diagram of torque sensor of the present invention, comprises sensor rotating shaft 1, bearing 2, front end cover 3, junction box 4, the outer ring iron core of ring transformer 1 and winding 5, the inner ring iron core of ring transformer 1 and winding 6, Fastener 7, bearing 8, output sleeve 9, output iron core 10, Hall element 11, permanent magnet steel 12, excitation core 13, excitation sleeve 14, bearing 15, fastener 16, ring transformer two Ring iron core and winding 17, toroidal transformer second outer ring iron core and winding 18, rear end cover 19, frame 20.

The front end cover 3 is located at the front end of the machine base 20, the rear end cover 19 is located at the rear end of the machine base 20, the sensor shaft 1 passes through the center of the front end cover 3 and the rear end cover 19, and the bearings 2 are respectively placed on the sensor shaft 1 and the front end cover 3 And between the rear end cover 19.

Both sides of the sensor rotating shaft 1 are respectively fixed with the inner ring iron core 6 of the toroidal transformer 1 and the inner ring iron core 17 of the toroidal transformer 2, and can rotate simultaneously.

The outer ring iron core 5 of the toroidal transformer one and the outer ring iron core 18 of the toroidal transformer two are fixed to the machine base 20 .

The sensor shaft 1 is concentrically equipped with an excitation sleeve 14, and the excitation core 13 is fixed on the convex key outside the excitation sleeve 14. There is a gap between the excitation cores 13, and the permanent magnetic steel 12 is fixed in the gap, and anaerobic The excitation core 13 and the permanent magnet steel 12 are bonded together by glue, one end of the excitation sleeve 14 is fixed with the fastener 7, and then fixed with the sensor shaft 1 by the fixing bolt, and the other end is in contact with the sensor shaft 1 through the bearing 15 and can be opposite to each other. The sensor shaft 1 rotates.

The sensor shaft 1 is concentrically equipped with an output sleeve 9, the output iron core 10 is fixed on the inner side of the output sleeve 9, there is a gap between the output iron cores 10, the Hall element 11 is fixed in the gap, and anaerobic adhesive is used to connect the output iron core 10 and The Hall element 11 is adhered, one end of the output sleeve 9 is fixed with the fastener 16, and then fixed with the sensor shaft 1 by the fixing bolt, and the other end is in contact with the excitation sleeve 14 through the bearing 8 and can rotate relative to the excitation sleeve 14, and The output sleeve 9 is provided with through holes.

The power lead wire of the Hall element 11 first passes through the via hole of the output sleeve 9, and is connected with the inner ring core winding 6 of the toroidal transformer 1, and the output lead wire of the Hall element 11 passes through the via hole of the fastener 16, and connects with the toroidal transformer 2 The inner ring core winding 17 of the toroidal transformer is connected, and the outer core winding 5 of the toroidal transformer and the second outer core winding 18 of the toroidal transformer are connected with the junction box 4 fixed on the support 20 .

The specific implementation of the present invention is shown in Figure 2: Figure 2 is a cross-sectional view of the A-A plane of the torque sensor structure schematic diagram 1, the permanent magnetic steel 12 and the excitation core 13 are fixed on the excitation sleeve 14, and anaerobic glue is used to adhere to each other Connected, the Hall element 11 and the output core 10 are fixed on the inner side of the output core 9, and are adhered to each other with anaerobic glue. The excitation core 10, the output core 14 and the air gap constitute the magnetic circuit of the excitation magnetic field, and the excitation sleeve 14 and the output sleeve The barrel 9 is coaxial with the sensor shaft 1 .

The two ends of the sensor shaft 1 are respectively coaxially connected with the measured rotating system and the load torque. There is a corresponding relationship between the output voltage of the Hall element 11 and the measured load torque, that is, the induced current of the inner surrounding group of the toroidal transformer 2 and the measured There is a corresponding relationship between the load torque, and after the transformation of the second toroidal transformer, its outer surrounding group outputs an induced potential that has a corresponding relationship with the measured load torque.

The material of the sensor shaft 1 is carbon steel or alloy steel; the front cover 3, the fastener 7, the fastener 16, the rear end cover 19, and the base 20 are made of hard aluminum alloy; the excitation sleeve 14, the output The sleeve 9 is made of brass; the inner and outer ring iron cores of the toroidal transformer, the excitation core 13 and the output iron core 10 are composed of iron-nickel soft magnetic alloy sheets with high magnetic permeability or high magnetic permeability silicon steel sheets punched and laminated; The magnetic steel 12 is made of rare earth NdFeB sintered.

The schematic diagram of the working principle of the torque sensor in Fig. 1 of the present invention is shown in Fig. 3: when the sensor shaft is not subjected to load torque or torque, the relative position of the permanent magnet 12 and the Hall element 11 is shown in Fig. 3 (a) As shown, wherein the dotted line represents the magnetic field lines formed by the permanent magnetic steel 12, the equivalent wiring diagram of Figure 3 (a) is shown in Figure 3 (b), the direction of the magnetic field formed by the permanent magnetic steel 12 communicates with the Hall element 11 The direction of the incoming alternating current is parallel, so the output voltage of the Hall element 11 is zero at this time.

When the sensor shaft is subjected to load torque or torque, the relative position of the permanent magnet 12 and the Hall element 11 is as shown in Figure 3 (c), where the dotted line represents the magnetic field lines formed by the permanent magnet 12, Figure 3 ( The equivalent wiring diagram of c) is shown in Figure 3(d). There is an angle between the direction of the magnetic field formed by the permanent magnetic steel 12 and the direction in which the Hall element 11 is fed with alternating current. Suppose that the direction of the instantaneous alternating current i is shown in Figure 3( As shown in d), according to the law of the current-carrying conductor in the magnetic field, the voltage direction generated by each Hall element 11 is shown in Figure 3 (d). In order to maximize the output voltage of the four Hall elements, each Hall element The connection line of 11 is shown in Figure 3(d). The output voltage of the Hall element is e _ab . The output lead of the Hall element 11 forms a closed loop with the inner surrounding group of the toroidal transformer 2. In the loop, due to the existence of e _ab Alternating current is generated, and according to the principle of magnetoelectric induction, the outer surrounding group of the toroidal transformer 2 generates a corresponding induced potential, which is drawn out from the junction box fixed on the sensor base.

Claims (10)

1. A brushless torque sensor based on the Hall effect, comprising a base, a front cover positioned at the front end of the base, a rear end cover positioned at the rear end of the base, a sensor shaft passing through the center of the front cover and the rear end cover, The sensor shaft is fixed to the front and rear end covers respectively through bearings, and can rotate relative to the machine base. In addition, it also includes: The excitation sleeve is placed in the machine base coaxially with the sensor shaft, and a convex key is arranged on the outside, and the excitation core is fixed on the convex key; The output sleeve is placed in the frame coaxially with the sensor shaft and the excitation sleeve, and the inner side is provided with a slot, and the output core is fixed in the slot; Fasteners are used to respectively fix the excitation sleeve and the output sleeve to the two ends of the sensor shaft; Toroidal transformer, the inner ring iron core is fixed to the sensor shaft, and rotates with the sensor shaft together, with a winding slot, and the outer ring iron core is fixed to the machine base, and has a winding slot; The two ends of the sensor rotating shaft expose the end cover, one end is connected to the power source, and the other end is connected to the load to be measured, and the two ends of the sensor rotating shaft are thicker than the middle part. 2. The torque sensor according to claim 1, characterized in that: one end of the excitation sleeve is connected with the fastener, and then fixed with the sensor shaft through a fixing bolt, and the other end is in contact with the sensor shaft through a bearing and can rotate relative to the sensor shaft . 3. The torque sensor according to claim 1, characterized in that: there is a gap between the excitation cores, the permanent magnet is installed in the gap, and anaerobic adhesive is used to bond the permanent magnet to the excitation core, The permanent magnetic steel and the excitation core rotate simultaneously with the sensor shaft. 4. The torque sensor according to claim 1, characterized in that: one end of the output sleeve is connected with the fastener, and then fixed with the sensor shaft through a fixing bolt, and the other end is in contact with the excitation sleeve through a bearing and can be opposed to the excitation sleeve. Drum turns. 5. The torque sensor according to claim 1, characterized in that: there is a gap between the output iron cores, the Hall element is installed in the gap, and the Hall element is bonded to the output iron core with anaerobic adhesive, and the Hall element is connected to the output iron core. The output iron core rotates simultaneously with the sensor shaft. 6. The torque sensor according to claim 1, characterized in that: a pair of toroidal transformers are respectively located on both sides of the sensor shaft, and the inner and outer ring groups are respectively fixed in the winding slots of the inner ring core and the outer ring core , the lead wires of each outer surround group are connected to the junction box fixed with the machine base, and are respectively used to connect the AC power supply and output the electric signal. 7. The torque sensor according to claim 1, characterized in that: the output iron core and the fastener are provided with through holes, and the output iron core through holes are used to connect the inner surrounding group of the toroidal transformer one and the power leads of the Hall element , The fastener via holes are used to connect the inner surrounding group of the toroidal transformer 2 and the output leads of the Hall element. 8. The torque sensor according to claim 1, characterized in that: the current passing through the Hall element is an alternating current. 9. The torque sensor according to claim 1, characterized in that: the excitation sleeve and the output sleeve are made of brass, and the excitation core and the output iron core are made of iron-nickel soft magnetic alloy sheets with high magnetic permeability or It is composed of punching and shearing lamination of high magnetic permeability silicon steel sheet. 10. The torque sensor according to claim 1, characterized in that: the permanent magnetic steel is made of rare earth NdFeB sintered.

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