JP7166551B2 - Torque sensor stator structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stator structure of a torque sensor, and more particularly to a stator structure of a strain detection sensor that utilizes the well-known Villari effect of a magnetostrictive portion imparted to a shaft. and arranged so that the sides face each other so that the main magnetic flux can flow obliquely with respect to the axial direction, and the strain and its direction can be efficiently detected as changes in the magnetic flux.

A configuration disclosed in Patent Document 1 can be given as a conventionally used torque sensor of this type. That is, FIG. 7 is a diagram showing the structure of the torque sensor 10, and more specifically, a cross-sectional view seen from a direction perpendicular to the axis of the rotating shaft 90. As shown in FIG.
This torque sensor 10 detects the torque applied to the rotating shaft 90 using magnetostrictive characteristics. In order to utilize the magnetostrictive characteristic, the torque sensor 10 includes a first magnetic core unit 20R on the upper side of the figure that detects +45° magnetic permeability fluctuation with respect to the axial direction of the rotating shaft 90, and a -45° magnetic permeability unit. and a second magnetic core unit 20L on the lower side of the drawing that detects fluctuations. By measuring the change in magnetic permeability in these two directions, the direction and magnitude of the torque applied to the rotating shaft 90 are detected. The rotating shaft 90 is made of a magnetostrictive material, such as nickel-chromium-molybdenum steel. This material is commonly used, for example, as crankshaft material in automobile engines.

Also, the entire first magnetic core unit 20R is housed in a general housing (not shown) and fixed using, for example, a molding material (not shown). The housing is also provided with a lead-out portion in which an external circuit is provided. An external circuit supplies power to each coil (not shown) and acquires the detected output signal. Further, the housing is fixed by passing a fixing bolt through a fixing bolt hole provided around the housing and screwing it to an external fixing location. Note that the second magnetic core unit 20L is also accommodated in the housing in the same manner.

8 is a perspective view of the magnetic core used in the torque sensor of FIG. A first tooth end surface 260 a and a second tooth end surface 260 b are provided at both ends through through holes 270 .
Each of the tooth end faces 260a and 260b has a first side 30a and a second side 30b formed by bending along the surface of the shaft 90 at its tip.
Further, in the torque sensor 10 having the configuration described above, an excitation frequency of 20 kHz, an excitation current of 50 mA, an excitation coil of 100 turns, a detection coil of 200 turns, projections (not shown) of the first and second tooth end faces 260a and 260b and The air gap (magnetic gap) on the surface of the rotating shaft was set to 1 mm. In one magnetic core unit, as shown in FIG. 9, the angle connecting the centers of the first and second tooth end faces 260a and 260b is 45 degrees, whereas in the other magnetic core unit the angle is -45 degrees. made it When one magnetic core unit and the other magnetic core unit are arranged close to each other, if the end surfaces of the magnetic cores with the same polarity are arranged close to each other (the N poles are brought close to each other, and the S poles are brought close to each other), the magnetic core It is preferable because leakage magnetic flux between units can be prevented.

Fig. 9 shows how to connect each coil and the winding direction. FIG. 9 is a developed view of the surface of the rotating shaft explaining the connection state of the coils, the winding direction of the excitation coil, and the direction of the magnetic flux component, FIG. 10 is a partial configuration diagram showing the rotating shaft, and FIG. 2 is a configuration diagram showing the relationship of

Teeth end surfaces 260a and 260b of the first magnetic core in FIG. 9 face regions S1 and N1, respectively, in FIG. It is flowed onto the shaft surface 90f. Teeth end faces 260a and 260b of the second magnetic core face regions S2 and N2, respectively, in FIG. flowed upwards. Teeth end surfaces 260a and 260b of the third magnetic core face regions S3 and N3, respectively, in FIG. flowed upwards. The end surfaces 260a and 260b of the yoke ends of the fourth magnetic core face the regions S4 and N4 in FIG. It is flowed onto the shaft surface 90f.

FIG. 12 shows the relationship between the output _{voltage V} and the torque T generated when the rotating shaft 90 rotates. A certain third signal _VO1 is obtained on the negative and positive sides.

JP 2010-54236

Since the conventional torque sensor is configured as described above, there are the following problems.
That is, a configuration in which a magnetic core is arranged around a shaft having a configuration in which the magnetic permeability varies depending on the direction of rotation, with a slight gap therebetween, and the lateral torque of the rotating shaft is measured by measuring the signal output by the gap permeance. However, since the magnetic flux mainly flows in the portion where the magnetic resistance is the lowest, the main magnetic flux flows perpendicularly to the axial direction where the distance between the first tooth end surface and the second tooth end surface is the shortest, and is effective for torque detection. Since it does not contribute, the detection efficiency has deteriorated.
In addition, since the winding portion and the yoke for passing the magnetic flux to the magnetostrictive portion are separated, there is magnetic loss, and errors occur due to variations in processing and assembly.
Furthermore, since the assembled magnetic cores are separated regardless of the direction of the magnetic flux, this has been a factor in degrading the accuracy of the torque sensor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and in particular, in a stator structure of a strain detection sensor that utilizes the Villari effect of a magnetostrictive portion imparted to a shaft, the tooth end surface facing the shaft is inclined. A stator structure is provided in which sides are arranged so that the sides face each other, and the main magnetic flux can flow obliquely to the axial direction, and the distortion and its direction can be efficiently detected as changes in the magnetic flux. intended to provide

The stator structure according to the present invention is a stator structure that utilizes the well-known Villari effect of a magnetostrictive portion imparted to a shaft. A body-shaped magnetic core block and a back yoke of each magnetic core block have a plurality of tooth end faces formed via a plurality of grooves, and the tooth end faces facing each other via the shaft are formed to be inclined. and winding portions provided in the respective grooves, and when the magnetic core blocks are formed in a ring shape, the sides are arranged to face each other via the shaft. As a result, the main magnetic flux can flow in an oblique direction (larger than 0° and smaller than 90°) with respect to the axial direction of the shaft, and the strain and its direction are detected as changes in the magnetic flux. Also, the grooves are formed in a direction non-perpendicular to the axial direction of the shaft, so that magnetic fluxes in different directions flow from the winding portions provided in the grooves. Each of the magnetic core blocks has a configuration in which three tooth end surfaces and two grooves are integrally manufactured together with the back yoke, and the magnetic fluxes from the first and second magnetic flux directions are , from each tooth end surface to the axial direction in an oblique direction (larger than 0° and smaller than 90°) and vertically or horizontally symmetrical, thereby generating a plurality of signals symmetrical with respect to the strain direction obtained, and the difference is taken.

Since the stator structure according to the present invention is configured as described above, the following effects can be obtained.
That is, in a stator structure utilizing the well-known Villari effect of a magnetostrictive portion imparted to a shaft, a magnetic core block integrated with a magnetic path is provided outside the shaft and formed by connecting a plurality of cores. and the back yoke of each of the magnetic core blocks includes a plurality of tooth end faces formed through a plurality of grooves, and inclined sides formed on the tooth end faces facing each other through the shaft; and a winding portion provided in each groove, wherein when each magnetic core block is formed in a ring shape, each side is arranged to face each other through the shaft, The main magnetic flux can flow in an oblique direction (more than 0° and less than 90°) with respect to the axial direction of the shaft, and the strain and its direction are detected as changes in the magnetic flux. Since the end faces of the teeth are integrally formed, the mechanical accuracy is greatly improved compared to the conventional one.
In addition, since each groove is formed in a direction non-perpendicular to the axial direction of the shaft, magnetic fluxes in different directions flow from the winding portions provided in each groove. By forming the main magnetic flux in a direction oblique to the axial direction of the magnetostrictive portion, the detection efficiency (sensitivity) can be improved.
In addition, since each magnetic core block has a configuration in which three tooth end surfaces and two grooves are integrally manufactured together with the back yoke, a magnetic core with good magnetic efficiency can be manufactured and manufacturing errors can be suppressed. can be done.
Further, the magnetic fluxes from the first and second magnetic flux directions are formed in an oblique direction (larger than 0° and smaller than 90°) with respect to the axial direction from each of the tooth end faces and vertically or horizontally symmetrically. Thus, a plurality of signals symmetrical with respect to the strain direction are obtained, and the difference between them is obtained. By forming the magnetic fluxes vertically or horizontally symmetrically, it is possible to acquire a plurality of signals symmetrical with respect to the strain direction and improve the detection accuracy.

FIG. 4 is a perspective view showing one magnetic core block in the stator structure of the torque sensor according to the embodiment of the invention; FIG. 2 is a schematic diagram showing a magnetostrictive portion showing a state in which winding portions are mounted in grooves of the magnetic core block of FIG. 1; FIG. 4 is an explanatory diagram of an output signal when the torque sensor is in operation; FIG. 2 is a schematic diagram in which a plurality of magnetic core blocks in FIG. 1 are combined, and tooth end surfaces that form oblique magnetic fluxes are arranged vertically and horizontally symmetrically. FIG. 2 is a schematic diagram showing a configuration of a magnetic path-integrated core obtained by combining a plurality of magnetic core blocks shown in FIG. 1; FIG. 5 is an enlarged view of a part of the schematic diagram of FIG. 4; 1 is a schematic cross-sectional view showing a conventional torque sensor; FIG. 8 is a schematic enlarged cross-sectional view showing the magnetic core of FIG. 7; FIG. FIG. 4 is a developed view of a magnetic stator arranged so that the center of each yoke end of a conventional magnetic stator is inclined at an angle of 45°; FIG. 5 is a partial configuration diagram showing a conventional shaft; FIG. 3 is a configuration diagram showing the relationship between a conventional shaft and a magnetic core; FIG. 4 is a specific diagram showing the relationship between a conventional output voltage V and torque T;

A stator structure according to the present invention is a stator structure of a strain detection sensor that utilizes the Villari effect of a magnetostrictive portion imparted to a shaft, in which inclined sides are attached to tooth end surfaces facing the shaft, and the sides are arranged to face each other, To efficiently detect strain and its direction as a change in magnetic flux by allowing main magnetic flux to flow in an oblique direction with respect to the axial direction.

Preferred embodiments of the stator structure according to the present invention will be described below with reference to the drawings.
Identical or equivalent portions to those of the conventional example are denoted by the same reference numerals.
FIG. 1 shows one magnetic core block among many magnetic core blocks 10a of the stator structure of the torque sensor according to the embodiment of the present invention.
The magnetic core block 10a is made of a magnetic material and integrally formed by, for example, a metal injection molding machine. 260a, a second tooth end surface 260b, and a third tooth end surface 260c.

A first groove 101 and a second groove 102 are formed between the tooth end faces 260a, 260b and 260c, and shafts 90 shown in FIG. A first side 30a, a second side 30b and a third side 30c, which are curved surfaces facing the curved surface of the peripheral surface 91 of the shaft 90, are arranged with a slight gap from the surface of the shaft 90. As shown in FIG.

A pair of first and second winding parts 105 and 106 are arranged in each of the grooves 101 and 102 so as to form a V shape when viewed from the surface side P, and a first magnetic flux direction 107 and a second magnetic flux are provided. A direction 108 is configured to occur.
2 shows that the winding portions 105 and 106 are provided with the respective grooves 101 and 102. For example, although not shown, each tooth 260a, A configuration that wraps around 260b, 260c and passes through each groove 101, 102 is also possible.
Therefore, one magnetostrictive portion 110 is formed by the configuration of FIG.

FIG. 3 shows the number of magnetic core blocks 10a shown in FIG. 4, that is, the stator structure in which the magnetostrictive portions 110 are cylindrically arranged (FIGS. 5 and 6), and the shaft 90 is rotated. A first signal V _L1 obtained from one flux direction 107 and a second signal V _R1 obtained from a second flux direction 108 (ie, symmetrical with the first flux direction 107) are obtained, and the difference 111 is obtained.
In the conventional state, the excitation coils 214a of the winding portions 105 and 106 are excited, and the torsion of the shaft 90 is detected by the detection coils 215a. The change in the magnetic permeability of the shaft 90 is used to take out the output voltage difference in a large number of magnetostrictive portions 110 . This embodiment utilizes the well-known Villari Effect using the magnetostrictive portion 110 described above, that is, the change in magnetic permeability in a ferromagnetic material in a magnetic field under the action of stress. .

FIG. 4 is a configuration diagram in which a pair of magnetic core blocks 10a are used and arranged vertically and horizontally symmetrically by combining teeth end surfaces 260a, 260b, and 260c that form oblique magnetic fluxes. The operation of FIG. 1, which is the basis of FIG. 4, will be described below.
In the strain detection sensor 150 utilizing the Villari effect of the magnetostrictive portion 110 imparted to the shaft 90, inclined sides 30a, 30b, and 30c are attached to the teeth end surfaces 260a, 260b, and 260c facing the shaft 90, and the finished product is By arranging the sides so as to face each other, it is possible to flow the main magnetic flux inclined in a direction (more than 0° and less than 90°) with respect to the axial direction E of the shaft 90, and the distortion and the direction of the magnetic flux can be controlled. As a change, it can be efficiently detected. The efficiency is maximized when the gradient of the magnetic flux is 45°. In addition, by integrating the teeth, the winding portions 105 and 106 that connect them, and the back yoke 100, and constructing them from a continuous magnetic material, an efficient core with little magnetic loss can be manufactured as a pair. Minimize manufacturing errors. Furthermore, in the same core, by using a plurality of teeth to form a magnetic flux in an oblique direction (larger than 0° and smaller than 90°) with respect to the axial direction vertically or horizontally symmetrically, a plurality of teeth symmetrical with respect to the strain direction signals V _L1 and V _R1 can be obtained, and the detection accuracy can be improved by taking the difference 111 between them as shown in FIG.

The configuration of FIG. 5 shows a configuration in which four magnetic core blocks 10a are combined, and in reality, five magnetic core blocks 10a are further provided to form a finished product. state.
An example of a configuration for carrying out the present invention is described in FIGS. 4 to 6. FIG. The minimum unit of the magnetic core block of the embodiment is arbitrary N, and the magnetic core flocks are arranged in the axial direction.
In this embodiment, the inclined sides 30a, 30b, and 30c of the tooth end faces 260a, 260b, and 260c facing the shaft 90 face each other, and the main magnetic flux obliquely inclined with respect to the axial direction E shown in FIG. The strain and its direction can be efficiently detected as changes in magnetic flux. In addition, by integrating the tooth end surfaces 260a, 260b, 260c, the winding portions 105, 106 connecting them, and the back yoke 100 and forming a continuous magnetic material, an efficient magnetic core block with little magnetic loss can be obtained. and Furthermore, in the same magnetic core block, by combining a plurality of teeth end faces 260a, 260b, 260c that are symmetrical vertically, horizontally, or vertically and horizontally, a magnetic flux oblique to the axial direction E is formed vertically, horizontally, or vertically and horizontally symmetrically. By doing so, a plurality of signals V _L1 and V _R1 symmetrical with respect to the distortion direction can be obtained, and the difference 111 between them can be obtained to improve the detection accuracy.

Therefore, by forming the main magnetic flux in a direction oblique to the axial direction E of the magnetostrictive portion 110, detection efficiency (sensitivity) can be improved. By forming the tooth end surfaces 260a, 260b, 260c, the winding portions 105, 106, and the back yoke 100 from an integrated continuous magnetic material, a magnetic core block with good magnetic efficiency can be manufactured, and manufacturing errors can be suppressed. .
In the same magnetic core block, by combining a plurality of tooth end faces 260a, 260b, and 260c, oblique magnetic flux with respect to the axial direction E of the magnetostrictive portion 110 is formed vertically or horizontally symmetrically. A plurality of signals V _L1 and V _R1 are acquired, and the difference 111 between them is used to improve the detection accuracy.

The present invention relates to a stator structure, and more particularly, to a stator structure that utilizes the well-known Villari effect of a magnetostrictive portion applied to a shaft. A magnetic core block integrated with a magnetic path, a back yoke of each of the magnetic core blocks has a plurality of tooth end faces formed through a plurality of grooves, and the tooth end faces facing each other through the shaft are inclined. and winding portions provided in the respective grooves, and when the magnetic core blocks are formed in a ring shape, the sides are arranged to face each other via the shaft. With this configuration, the main magnetic flux can flow in an oblique direction (larger than 0° and smaller than 90°) with respect to the axial direction of the shaft, and the strain and its direction are detected as changes in the magnetic flux. It is a configuration that

10 Stator structure of torque sensor 10a Magnetic core block (magnetic path integrated type)
30a First side 30b Second side 30c Third side 90 Shaft 100 Back yoke 101 First groove 102 Second groove 105 First winding portion 106 Second winding portion 107 First magnetic flux direction 108 Second magnetic flux direction (first symmetrical with magnetic flux direction)
110 magnetostrictive portion 111 difference between signals in first and second magnetic flux directions 150 detection sensor 214a excitation coil 215a detection coil 260a first tooth end surface 260b second tooth end surface 260c third tooth end surface E axial direction P surface side V _L1 -th A first signal derived from one flux direction V _R1 A second signal derived from a second flux direction 108 (symmetrical to the first flux direction)

Claims (4)

In a stator structure utilizing the well-known Villari Effect of a magnetostrictive portion (110) applied to a shaft (90),
a magnetic path-integrated magnetic core block (10a) provided outside the shaft (90) and formed by connecting a plurality of cores;
a plurality of tooth end faces formed via a plurality of grooves (101, 102) in the back yoke (100) of each magnetic core block (10a);
sides (30a to 30c) formed at an angle to the tooth end faces (260a to 260c) facing each other through the shaft (90);
Winding portions (105, 106) provided in the respective grooves (101, 102),
When each magnetic core block (10a) is formed in a ring shape, the sides (30a to 30c) are arranged so as to face each other through the shaft (90). The stator of a torque sensor configured to allow the main magnetic flux to flow in an oblique direction (greater than 0° and less than 90°) with respect to the axial direction (E) of the torque sensor, and to detect the distortion and its direction as a change in magnetic flux structure. The grooves (101, 102) are formed in a direction non-perpendicular to the axial direction (E) of the shaft (90), so that the windings provided in the grooves (101, 102) 2. The stator structure of a torque sensor according to claim 1, wherein magnetic fluxes in different directions flow from said portions (105, 106). Each magnetic core block (10a) has a configuration in which three teeth end faces (260a to 260c) and two grooves (101, 102) are integrally manufactured together with the back yoke (100). 3. The stator structure of a torque sensor according to claim 1 or 2 . The magnetic fluxes from the first and second magnetic flux directions (107, 108) are oblique (greater than 0° and less than 90°) from the respective tooth end surfaces (260a to 260c) with respect to the axial direction (E). and formed vertically or horizontally symmetrically to obtain a plurality of signals (VL1, VR1) symmetrical with respect to the direction of distortion, and obtain a difference (111) between them . The stator structure of the torque sensor according to any one of 1.

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