JP5008274B2 - Torque detection device and rotation angle detection device - Google Patents

Description

The present invention relates to a torque detection instrumentation 置及 beauty rotation angle detecting apparatus utilizing a magnetoelastic for non-contact detection of the rotational angle of the torque and the shaft applied to the shaft.

A conventional magnetoelastic torque sensor is a magnetoelastic torque sensor that outputs a signal indicating a torque applied around an axis extending in the axial direction of a member, and is magnetically substantially inactive with a separated magnetic action region. And a single member having a substantially uniform chemical structure as a whole, and a ring formed in a ring shape in a single circumferential direction within the member, and after applying torque to the member, the torque A first magnetoelastic action that has a sufficient magnetic anisotropy to return the magnetization in the single circumferential direction when becomes zero, thereby generating a magnetic field that varies with the torque And a magnetic field sensor means for detecting the magnitude of the magnetic field and outputting an output signal in accordance with the magnitude of the magnetic field. (For example, Patent Document 1 reference.).
JP 2000-516346 A (first page, FIG. 1 (a))

  A conventional magnetoelastic torque sensor is magnetized so as to form a ring shape in the circumferential direction of a shaft, which is a single member, to form a magnetoelastic action region, and when torque is applied to this, a billiary effect (inverse magnetostriction effect) As the magnetization direction changes due to the rotation of the magnetization, an axial leakage magnetic field appears around the shaft, and since this leakage magnetic field is proportional to the torque, it is close to and close to the magnetoelastic action region. The magnetic field sensor means attached to the opposite position detects the magnitude of the leakage magnetic field and detects the torque applied to the shaft based on the output signal corresponding to this magnitude. Since the magnetic path closed in the circumferential direction is formed, it is difficult to be influenced by external energy changes such as torque. There has been a problem that it is difficult to be discriminated of the ratio.

In order to solve such a problem, a highly sensitive magnetic field sensor is required. On the other hand, since it is easily affected by an external magnetic field, a solid shield is required, which increases costs and increases the size of the apparatus. There was a problem.
In addition, as a means for forming a magnetoelastic action region by magnetizing it in a ring shape in the circumferential direction of the shaft, which is a single member, a method of bringing a magnetic pole into contact with a rotating shaft, Although a method is adopted in which the current is magnetized and magnetized by the generated magnetic field, the change in leakage magnetic field due to the application of torque is directly converted to a torque value, so torque sensitivity due to non-uniform magnetization during magnetization, etc. Nonuniformity directly affects detection accuracy. Therefore, there is a high possibility that the output is changed depending on the rotation angle, and this correction is necessary.

A torque detector according to the present invention includes a shaft formed of a composite magnetic material having two rows provided in a circumferential direction and provided with at least two magnetized portions having polarities in the circumferential direction; A magnetic field sensor for detecting a magnetic field generated in the axial direction of the shaft, two arranged for each row of the magnetized portions with a phase of an electrical angle of 45 ° in the upper vicinity of the magnetized portion of the shaft; A calculation unit that calculates a torque applied to the shaft from the detection signal of the magnetic field sensor, and the magnetized units in each row have a width of an electrical angle of 180 ° in the circumferential direction and are electrically connected in the circumferential direction. The polarities of the magnetized portions in the first row and the polarities of the magnetized portions in the second row are opposite to each other at an angle of 180 ° , and the arithmetic unit has an electrical angle of the rotation angle of the shaft. obtained twice as theta, the torque sign of one of the previous SL two magnetic field sensor of the first row A detection signal sin theta, which is the difference between the time of the torque non-application and at times, the sinθ difference when one of the torque applied among the two magnetic field sensors of the second row and at the time of the torque non-application a detection signal subtraction processing, a detection signal Sadea Ru c os theta with at the other of said torque application of the magnetic field sensor before Symbol of two single row and at the torque is not applied the second row Of the two magnetic field sensors, the detection signal of cosθ, which is the difference between the other when the torque is applied and the time when the torque is not applied, is subtracted, and the signal of each phase obtained by the subtraction process is squared Then, the signals of the respective phases subjected to the square process are added, and a torque signal that changes according to the torque is calculated.

  As described above, the present invention provides a shaft formed of a composite magnetic material having at least two magnetized portions that are provided at substantially equal intervals in the circumferential direction and have polarity in the circumferential direction, and magnetization of the shaft. Two magnetic field sensors that detect the generated magnetic field in the axial direction of the shaft, and are applied to the shaft from the detection signal of the magnetic field sensor. Since it is configured to include a calculation unit that calculates torque, it is easier to form a magnetized part on the shaft than when a conventional magnetic path closed in the circumferential direction is formed. Since the magnetization of the magnetized part is also strong, the magnetic field sensor has high sensitivity to the leakage magnetic field generated by the magnetized vector by applying a large torque vector to the magnetized part when torque is applied to the shaft. To detect Since it is, or using a magnetic field sensor of high sensitivity, never increase is manufacturing costs of the detection apparatus to less need for shielding, detection device nor large.

  In addition, two magnetic field sensors are arranged near the upper part of the magnetized portion of the shaft with a phase of about 45 ° in electrical angle, and the calculation unit calculates the torque applied to the shaft from the detection signal of the magnetic field sensor. Therefore, the two magnetic field sensors output sin θ and cos θ detection signals corresponding to the torque applied to the shaft, and the calculation unit calculates the torque based on the sin θ and cos θ detection signals of the magnetic field sensors. Can be easily obtained.

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing a configuration of a torque detection device according to a first embodiment of the present invention, and (a) is a side view showing a state in which two magnetic field sensors are arranged in the vicinity of a shaft having two magnetized portions. FIG. 2B is a perspective view of a state in which two shafts having two magnetized portions and two magnetic field sensors are arranged, FIG. 2C is a development view of the shaft, and FIG. 2 is an explanatory diagram showing the configuration of the torque detection device. (A) is a side view showing a state in which two magnetic field sensors are arranged in the vicinity of a shaft having four magnetized portions, and (b) is a magnetic field sensor in the vicinity of a shaft having two magnetized portions. FIG. 3A and FIG. 3B are diagrams illustrating changes in the magnetic field of the magnetized portion when no torque is applied to the shaft of the torque detector and when a positive torque is applied. FIG. 4C is a graph showing a change in the magnitude of the magnetic field detected by the magnetic field sensor, and FIG. Explanatory drawing which shows the change of the magnitude | size of the magnetic field which two magnetic field sensors arrange | positioned in the vicinity of the shaft which has two magnetizing parts of a torque detection apparatus respectively, (b) is four magnetization of a torque detection apparatus. FIG. 5 is a waveform diagram showing the process of signal processing for torque detection of the torque detection device, and FIG. 5 is a diagram illustrating changes in the magnitude of the magnetic field detected by two magnetic field sensors arranged in the vicinity of the shaft having the magnetic part. It is.

In FIG. 1, the torque detection device according to the first embodiment of the present invention is directed to a shaft 1 having four magnetized portions 2 and four sensitivities arranged in the vicinity of the magnetized portion 2 of the shaft 1. And a magnetic field sensor 3 having a characteristic.
The shaft 1 is made of, for example, a Fe-18Cr-8.5Ni series or Fe-17.5Cr-0.5C series composite magnetic material.
The magnetized portion 2 is provided on the shaft 1 made of this composite magnetic material in the following procedure.
First, martensitic transformation is caused by heat treatment or machining to form a partial ferromagnetic portion at a partial position where the magnetized portion 2 of the shaft 1 made of a composite magnetic material is to be provided.

Then, the shaft 1 has both the ferromagnetic part and the nonmagnetic part. For example, the maximum magnetic permeability of the ferromagnetic part is μm ≧ 100, and the magnetic permeability of the nonmagnetic part is μ ≦ 1.01.
Next, a permanent magnet or an electromagnet is brought close to the partial ferromagnetic portion formed on the shaft 1 for a predetermined time and then moved away from it, so that the ferromagnetic portion becomes a magnetized portion 2 having N and S polarities.
In the first embodiment, two magnetized portions 2 having N and S polarities are provided in the circumferential direction at intervals of a mechanical angle of 180 ° in the circumferential direction of the first row of the shaft 1. In the circumferential direction of the second row, which is located away from the circumferential direction of the two, two pieces having a polarity opposite to that of the first row in the circumferential direction are spaced apart by a mechanical angle of 180 ° as in the first row. The magnetized portion 2 is provided.

Two magnetic field sensors 3 are arranged in the vicinity of the upper part of the circumferential direction of the magnetized portion 2 in the circumferential direction of the first row of the shaft 1 with a mechanical angle of 22.5 ° (electrical angle of 45 °) and the second row. Torque is applied to the shaft 1 by arranging two magnetic field sensors 3 at an interval of a mechanical angle of 22.5 ° (electrical angle of 45 °) in the vicinity of the upper part of the magnetized portion 2 in the circumferential direction of In this case, each magnetic field sensor 3 outputs a detection signal of sin θ.
In order to detect the torque, it is sufficient to provide two magnetized portions 2 in the circumferential direction of the first row in principle in the shaft 1, but the direction opposite to the first row in the circumferential direction of the second row is sufficient. The reason why the two magnetized portions 2 having polarity are provided is to cancel the extraneous magnetism including geomagnetism by reversing the direction of magnetization, as shown in FIG. .

In FIG. 2, four magnetized portions 2 having N and S polarities are provided in the circumferential direction at intervals of a mechanical angle of 90 ° in the circumferential direction of the first row of shafts 1. Four magnetizations having polarities opposite to those in the first row in the circumferential direction at intervals of a mechanical angle of 90 ° in the circumferential direction in the second row in the circumferential direction away from the circumferential direction. Portion 2 is provided, and two magnetic field sensors 3 are spaced apart by a mechanical angle of 11.25 ° (electrical angle of 45 °) in the vicinity of the upper part of the vicinity of the circumferentially magnetized portion 2 in the first row of the shaft 1. An example is shown in which two magnetic field sensors 3 are arranged at a mechanical angle of 11.25 ° (electrical angle of 45 °) in the vicinity of the upper portion of the second row in the vicinity of the magnetized portion 2 in the circumferential direction. Yes.
As described above, when the four magnetized portions 2 are provided in the circumferential direction of the first row of the shaft 1 with a mechanical angle of 90 °, the two magnetic fields provided in the vicinity of the shaft 1 are provided. By arranging the sensors 3 with a mechanical angle of 11.25 ° (electrical angle of 45 °), when the torque is applied to the shaft 1 as in FIG. Can be output.

Next, when torque is applied to the shaft 1 having two magnetized portions 2 provided at intervals in the circumferential direction, the torque of the two magnetic field sensors 3 provided in the vicinity of the shaft 1 is applied. The principle that can be detected from the detection signal will be described with reference to FIGS.
First, as shown in FIG. 3A, the sensitivity direction of the magnetic field sensor 3 provided in the vicinity of the shaft 1 is perpendicular to the line connecting the N pole and the S pole of the magnetized portion 2. Arrange as follows.
Then, the magnetic field direction of the magnetized portion 2 and the sensitivity direction of the magnetic field sensor 3 are orthogonal to each other, and when no torque is applied to the shaft 1, the magnetization direction of the magnetized portion 2 does not change. Does not detect the magnetic field, the output of the magnetic field sensor 3 is zero.
Next, when a torque is applied to the shaft 1, as shown in FIG. 3B when a positive torque is applied, an easy axis of magnetization is generated in the magnetized portion 2 in an oblique 45 ° direction, and the magnetization direction changes. An oblique magnetization vector is generated.

When the shaft 1 rotates with the application of torque, the magnetic field sensor 3 outputs a detection signal of sin θ as shown in FIG.
Two magnetized portions 2 are provided at intervals of a mechanical angle of 180 ° in the circumferential direction of the first row of the shaft 1, and the two magnetic field sensors 3 are arranged on the circle of the shaft 1 as shown in FIGS. Since a mechanical angle of 22.5 ° (electrical angle of 45 °) is disposed in the vicinity of the upper part of the vicinity of the magnetized portion 2 in the circumferential direction, two magnetic field sensors are applied when a positive torque and a reverse torque are applied. The output of No. 3 has a waveform as shown in FIG.
As described above, the shaft 1 is provided with two magnetic field sensors 1 in the vicinity of the circumferentially magnetized portion 2 in the first row and the circumferentially magnetized portion 2 in the second row. In the case where the outputs of the two magnetic field sensors 3 in the vicinity of the magnetized portion 2 in the circumferential direction of the first row and the inverted signal of the output are used, Only two magnetic field sensors 3 in the vicinity of the magnetized portion 2 in the direction are required.

When detecting the torque from the detection signal of the magnetic field sensor 3, the output of the square of the magnetic field output detected by one magnetic field sensor 3 × 4 times can be obtained by calculating the detection signals of the four magnetic field sensors. However, the reason will be described below.
The output waveforms detected by the two magnetic field sensors 3 disposed in the vicinity of the magnetized portion 2 in the circumferential direction of the first row of the shaft 1 are proportional to the magnitude of the torque, as shown in FIG. It becomes a 90 ° phase difference 2-phase signal with an amplitude of ± 1. In addition, the output waveforms detected by the two magnetic field sensors 3 in the vicinity of the magnetized portion 2 in the circumferential direction of the second row are inverted signals of the respective phase signals as shown in FIG. Then, when these four signals are calculated, as shown in FIG. 5C, a signal E is obtained, and the torque value can be calculated.

These four signals are calculated as follows.
The outputs detected by the two magnetic field sensors respectively arranged in the vicinity of the circumferentially magnetized portion 2 in the first row of the shaft 1 are denoted by Ea and Eb, respectively, and in the vicinity of the magnetized portion 2 in the circumferential direction in the second row. If the outputs detected by the two arranged magnetic field sensors are Ec and Ed, Ea to Ec can be expressed by the following equations.
Ea = B0 + Acos θ
Eb = B0 + Asinθ
Ec = B0−Acos θ
Ed = B0−Asinθ
Here, B0 is an external magnetic field component that becomes noise, and A is a magnetic field component that depends on torque.

Next, a double amplitude of each phase signal is obtained by subtraction processing.
This can be expressed as an expression:
Eac = 2A cos θ
Ebd = 2 Asin θ
It becomes.
Further, the signs of the respective phase signals are aligned by the square process, and the respective phase signals are added to obtain a voltage signal having a quadruple amplitude independent of the angle, that is, a torque signal. This can be expressed as an expression:
E = Eac ² + Ebd ² = 4A ²
It becomes.
And the calculating part (illustration omitted) can obtain | require the torque applied to a shaft by performing the calculation mentioned above from the detection signal of the magnetic field sensor 3. FIG.
A Hall IC element can be used as a magnetic field sensor having sensitivity directionality. The reason is that since the strength and direction of the magnetic field can be understood, forward and reverse torque can be detected.

The torque detection device according to the first embodiment includes a shaft 1 formed of a composite magnetic material having at least two magnetized portions 2 provided at substantially equal intervals in the circumferential direction and having polarity in the circumferential direction; Two magnetic field sensors 3 for detecting a magnetic field generated in the axial direction of the shaft, arranged near the upper portion of the shaft 1 near the magnetized portion 2 and having an electrical angle of approximately 45 °, and detection of the magnetic field sensors And a calculation unit that calculates the torque applied to the shaft from the signal, so that the magnetized portion 2 is formed on the shaft 1 as compared with the case where a magnetic path closed in the circumferential direction is formed. It is easy and the magnetization of the formed magnetized portion 2 is strong. Therefore, a large magnetization vector is generated in the magnetized portion 2 when torque is applied to the shaft 1 and is generated by the magnetization vector. Magnetic field sensor 3 It is possible to sensitively detect, or using a magnetic field sensor of high sensitivity, never increase is manufacturing costs of the detection apparatus to less need for shielding, detection device nor large.
In addition, two magnetic field sensors 3 are arranged in the vicinity of the upper portion of the shaft 1 near the magnetized portion 2 with a phase of about 45 ° in electrical angle, and a calculation unit is applied to the shaft 1 from the detection signal of the magnetic field sensor 3. The two magnetic field sensors 3 output sin θ and cos θ detection signals corresponding to the torque applied to the shaft 1, and the calculation unit detects sin θ and cos θ detection signals of the magnetic field sensors. Based on the above, the torque can be easily obtained by calculation.

Next, an industrial mixer in which the torque detection device according to the first embodiment of the present invention is installed will be described with reference to FIGS.
FIG. 6 is an explanatory diagram showing the configuration of an industrial mixer provided with a torque detector, and FIG. 7 is a block diagram showing the circuit configuration of the torque detector.
As shown in FIG. 6, the industrial mixer is attached to the motor 11, the speed reducer 12 that decelerates the rotation of the motor 11, the two shafts 13 connected to the speed reducer 12, and the tip side of each shaft 13. And a stirrer 14. Reference numeral 15 denotes a container in which the bread dough 16 is put.
The torque detection device 10 includes a magnetic field sensor 3 and a controller 20, and the magnetic field sensor 3 is disposed in the vicinity of one shaft 13 of the industrial mixer.

The output of the magnetic field sensor 3 of the torque detection device 10 is output to the controller 20, and the output of the controller 20 is output to the motor 11.
The controller 20 is based on an A / D converter 21 that performs A / D conversion on the output signal of the magnetic field sensor 3 of the torque detector 10, and an output signal of the magnetic field sensor 3 that is A / D converted by the A / D converter 21. A torque is calculated by the above-described calculation formula, a calculation unit 22 that calculates a motor current according to the torque, and a D / A conversion of the motor current signal output by the calculation unit 22 and output to the motor 11 It is comprised with the converter 23. FIG.

  In the industrial mixer in which the torque detection device 10 is installed in this way, the magnetic field sensor 3 of the torque detection device 10 detects the torque generated in the shaft 13 having the stirrer 14 that stirs the bread dough 16 in the container 15, and the magnetic field sensor In response to the detection signal 3, the controller 20 calculates torque based on the detection signal of the magnetic field sensor 3, calculates the viscosity of the bread dough 16 from the calculated torque, and the torque change amount, change speed, etc. The motor current is calculated in consideration of these parameters, and the rotation speed, rotation stop, etc. of the motor 11 are controlled by the calculated motor current.

Embodiment 2. FIG.
FIG. 8A is an explanatory diagram showing the arrangement of the rotational speed detection devices and the magnetic field sensors of the rotation angle detection devices according to the second and third embodiments of the present invention, and FIG. 8B is the torque detection according to the first embodiment of the present invention. FIG. 9A is an explanatory view showing the arrangement of the magnetic field sensors of the apparatus, and FIG. 9A shows two magnetic field sensors arranged in the vicinity of the shaft having the two magnetized portions of the rotational speed detection apparatus according to the second embodiment of the present invention. FIG. 6B is an explanatory diagram showing a change in the magnitude of the magnetic field detected by, and FIG. 5B shows the magnitude of the magnetic field detected by the two magnetic field sensors arranged in the vicinity of the shaft having the four magnetized portions of the rotational speed detection device. It is explanatory drawing which shows a change.
The rotational speed detection device according to the second embodiment of the present invention has substantially the same configuration as the torque detection device according to the first embodiment, but differs in the sensitivity of the magnetic field sensor 3 disposed in the vicinity of the shaft 1. The direction is different.

In the case of rotation speed detection and rotation angle detection described later, since it is necessary to always detect a change in the magnetic field regardless of the torque, a magnetic field sensor provided in the vicinity of the shaft 1 as shown in FIG. 3 is arranged such that the sensitivity direction is the same as the line connecting the N pole and the S pole of the magnetized portion 2.
In the case of torque detection, when torque is applied to the shaft 1, an easy axis of magnetization is generated in the magnetized portion 2 in a 45 ° oblique direction, the magnetization direction changes, and an oblique magnetization vector is generated. As shown in FIG. 8B, the magnetic field sensor 3 provided in the vicinity of the shaft 1 has a sensitivity direction perpendicular to a line connecting the N pole and the S pole of the magnetized portion 2. To place.

In the rotational speed detection device of the second embodiment, when the shaft 1 having the two magnetized portions 2 rotates, the magnetic field changes in the circumferential direction of the shaft 1. Therefore, the change of the magnetic field is to be detected by the two magnetic field sensors 3, and the outputs of these magnetic field sensors 3 become sin θ and cos θ detection signals as shown in FIG.
Since the detection signals sinθ and cosθ of these magnetic field sensors 3 are 2 cycles per rotation of the shaft 1, the time required to obtain the sinθ and cosθ of 2 cycles per rotation of the shaft 1 is measured. The rotational speed can be detected by obtaining the reciprocal of this time.
If the rotational speed detection device of the second embodiment is installed in an electric power steering device or an industrial mixer, the rotational speed is calculated by calculating the output of the magnetic field sensor 3 by the calculation unit 22 of the controller 20 as described above. Can be sought.

In the above description, two magnetic field sensors 3 are arranged in the vicinity of the shaft 1 to obtain sin θ and cos θ and the rotational speed is detected. However, one magnetic field sensor 3 in the vicinity of the shaft 1 is detected. Needless to say, it is also possible in principle to detect the rotational speed by arranging the signals to obtain the detection signal of sinθ or cosθ.
Further, when two magnetic field sensors 3 are arranged in the vicinity of the shaft 1 having the four magnetized portions 2, the output of the magnetic field sensor 3 is a detection signal of the magnetic field sensor 3 as shown in FIG. Each sin θ and cos θ is 4 cycles per rotation of the shaft 1. Also in this case, the rotational speed can be easily obtained by measuring the time required to obtain four cycles of sin θ and cos θ per rotation of the shaft 1 and obtaining the reciprocal of this time.

Embodiment 3 FIG.
FIG. 10 is a waveform diagram showing a process of signal processing for rotation angle detection of the rotation angle detection device according to the third embodiment of the present invention, and FIG. 11 is sinωt and sin (θ + ωt) for rotation angle detection of the rotation angle detection device. This is a table for calculating an angle from the value of).
The rotation angle detection device according to the third embodiment of the present invention has substantially the same configuration as the torque detection device according to the first embodiment, except that the signal processing for angle detection is performed on the output of the magnetic field sensor 3. And the way of calculation is different.
Also, when detecting the rotation angle, the rotation angle position can be detected by signal processing and calculating the output signals of the two magnetic field sensors.

In the case of rotation angle detection, similarly to the case of rotation speed detection, as shown in FIG. 8A, the magnetic field sensor 3 provided in the vicinity of the shaft 1 has a sensitivity direction of N pole of the magnetized portion 2. Are arranged in the same direction with respect to the line connecting the S pole and the S pole.
Further, two magnetized portions 2 are provided in the circumferential direction of the shaft 1 with a mechanical angle of 180 °, and the two magnetic field sensors 3 have a mechanical angle of 22.5 ° in the vicinity of the circumferential direction of the shaft 1. It is assumed that they are arranged with an interval of (electrical angle 45 °).

Next, when a torque is applied to the shaft 1 having the magnetized portion 2 provided at intervals in the circumferential direction and the shaft 1 is rotated, two magnetic field sensors provided with the rotation angle of the shaft 1 in the vicinity of the shaft 1 The principle of the resolver method that can be detected from the detection signal 3 will be described with reference to FIGS.
First, when a torque is applied to the shaft 1, the shaft 1 also rotates accordingly, so that the detection signal of one of the magnetic field sensors 3 becomes sin θ as shown in FIG. The detection signal is cos θ.
Next, sin θ which is the detection signal of one magnetic field sensor 3 is multiplied by cos ωt, and cos θ which is the detection signal of the other magnetic field sensor 3 is multiplied by sin ωt, respectively, as shown in FIG. sinθ × cosωt and cosθ × sinωt are generated.
Then, by adding these, sin (θ + ωt) is generated as shown in FIG.

The generated signal sin (θ + ωt) has a phase transition with respect to sinωt. By measuring this phase difference, it is possible to detect θ which is twice the electrical angle of the rotation angle of the shaft 1.
In this way, θ that is twice the electrical angle of the rotation angle of the shaft 1 can be detected, but in reality, sinθ and cosθ, which are the outputs of the magnetic field sensor 3, are assumed, and cosωt and sinωt are obtained from sinθ and cosθ. Since the values can be derived , sin θ × cos ωt, cos θ × sin ωt, and sin (θ + ωt) can be obtained by calculation, and the relationship between ω and θ can be uniquely determined. If a table as shown is created, the value of sin ωt and the value of sin (θ + ωt) based on sin θ and cos θ, which are detection signals of the magnetic field sensor 3, 2 of the electrical angle of the rotation angle of the shaft 1 corresponding thereto. It is possible to easily obtain θ which is twice.
If the rotation angle detection device according to the third embodiment is installed in the electric power steering, the rotation angle of the steering wheel can be easily obtained by calculating the output of the magnetic field sensor 3 by the calculation unit 22 of the controller 20 as described above. Can do.

Although the example which applies to an industrial mixer was shown about the torque detection apparatus of this Embodiment 1, it cannot be overemphasized that it can apply also to a drilling, a screwing machine, a lumber apparatus, etc. besides that.
Further, the rotation speed detection device of the second embodiment and the rotation angle detection device of the third embodiment can be applied to, for example, an electric power steering of an automobile together with the torque detection device of the first embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the structure of the torque detection apparatus of Embodiment 1 of this invention, (a) is a side view which shows the state by which two magnetic field sensors are arrange | positioned in the vicinity of the shaft which has two magnetizing parts, (b) is a perspective view of a state in which a shaft having two magnetized portions and two magnetic field sensors are arranged, and (c) is a developed view of the shaft. It is explanatory drawing which shows the structure of a torque detector, (a) is a side view which shows the state by which two magnetic field sensors are arrange | positioned in the vicinity of the shaft which has four magnetized parts, (b) is two magnetized. It is a perspective view which shows the state by which two magnetic field sensors are arrange | positioned in the vicinity of the shaft which has a part. (A), (b) is explanatory drawing which shows the change of the magnetic field of a magnetized part at the time of no torque application to the shaft of a torque detection apparatus, and a positive torque application, (c) is the magnitude | size of the magnetic field which a magnetic field sensor detects It is a graph which shows the change of. (A) is explanatory drawing which shows the change of the magnitude | size of the magnetic field which two magnetic field sensors arrange | positioned in the vicinity of the shaft which has two magnetized parts, respectively, (b) has four magnetized parts. It is explanatory drawing which shows the change of the magnitude | size of the magnetic field which two magnetic field sensors arrange | positioned in the vicinity of the shaft each detect. It is a wave form diagram which shows the process of the signal processing for the torque detection of a torque detection apparatus. It is explanatory drawing which shows the structure of the industrial mixer in which the torque detection apparatus was installed. It is a block diagram which shows the circuit structure of a torque detection apparatus. (A) is explanatory drawing which shows arrangement | positioning of the magnetic field sensor of the rotational speed detection apparatus and rotation angle detection apparatus of Embodiment 2, 3 of this invention, (b) The magnetic field sensor of the torque detection apparatus of Embodiment 1 of this invention. It is explanatory drawing which shows arrangement | positioning. (A) is explanatory drawing which shows the change of the magnitude | size of the magnetic field which two magnetic field sensors arrange | positioned in the vicinity of the shaft which has two magnetized parts of the rotational speed detection apparatus of Embodiment 2 of this invention, (B) is explanatory drawing which shows the change of the magnitude | size of the magnetic field which two magnetic field sensors arrange | positioned in the vicinity of the shaft which has four magnetized parts of a rotational speed detection apparatus. It is a wave form diagram which shows the process of the signal processing for the rotation angle detection of the rotation angle detection apparatus of Embodiment 3 of this invention. It is a table | surface for calculating an angle from the value of sin (omega) t and sin ((theta) + (omega) t) for the rotation angle detection of a rotation angle detection apparatus.

Explanation of symbols

1 shaft, 2 magnetized part, 3 magnetic field sensor, 22 calculating part.

Claims (2)

A shaft formed of a composite magnetic material having two rows provided in a circumferential direction and having at least two magnetized portions having polarities in the circumferential direction;
A magnetic field sensor for detecting a generated magnetic field in the axial direction of the shaft, two arranged for each row of the magnetized portions, with a phase of an electrical angle of 45 ° near the magnetized portion of the shaft;
A calculation unit for calculating the torque applied to the shaft from the detection signal of the magnetic field sensor;
With
The magnetized portions in each row have a width of an electrical angle of 180 ° in the circumferential direction and are provided at intervals of an electrical angle of 180 ° in the circumferential direction, and the polarity of the magnetized portion in the first row and the second row And the polarity of the magnetized portion is opposite.
The calculation unit is obtained by setting twice the electrical angle of the rotation angle of the shaft as θ,
A detection signal of the difference a is sin theta and when one of the torque applied among the magnetic field sensors before two SL one row at the time of the torque is not applied one of the two magnetic field sensors of the second row Subtracting the detection signal of sin θ, which is the difference between when the torque is applied and when no torque is applied,
And Sadea Ru c detection signal os theta with at the other of said torque application of the magnetic field sensor before Symbol of two single row and at the torque is not applied in the second row the two magnetic field sensors Subtracting the detection signal of cos θ which is the difference between the other torque application time and the torque non-application time ,
A torque detection device characterized by squaring a signal of each phase obtained by subtraction processing, adding the signals of each phase subjected to square processing, and calculating a torque signal that changes in accordance with torque. A shaft formed of a composite magnetic material having at least two rows provided in the circumferential direction and provided with at least two magnetized portions having polarity in the circumferential direction;
A magnetic field sensor for detecting a generated magnetic field in the axial direction of the shaft, two arranged for each row of the magnetized portions, with a phase of an electrical angle of 45 ° near the magnetized portion of the shaft;
A calculation unit that calculates a rotation angle of the shaft that rotates by applying torque to the shaft from the detection signal of the magnetic field sensor;
With
The magnetized portions of each row have a width of an electrical angle of 180 ° in the circumferential direction, and are provided at intervals of an electrical angle of 180 ° in the circumferential direction.
The arithmetic unit is obtained twice the electrical angle of the rotation angle of the previous SL shaft as theta,
The detection signal of one sin θ of the magnetic field sensor, which is the difference between when the torque is applied and when no torque is applied, is added to the other cos θ of the magnetic field sensor, which is the difference between when the torque is applied and when no torque is applied. Multiplies cosωt corresponding to cosnθ (n is an integer equal to or greater than 2) obtained from the detected signal and sinθ ,
The detection signal before Symbol c osθ, sinnθ obtained from said said cos [theta] sin [theta (n is an integer of 2 or more) multiplied by sinωt equivalent to,
A rotation angle detection device characterized in that by adding each multiplied value to generate sin (θ + ωt), a phase difference between sin (θ + ωt) and sinωt is obtained to calculate a rotation angle of the shaft.

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