Rotation angle detection device

Abstract

A rotation angle detection apparatus is provided which can suppress the deterioration of the accuracy of the angle detection, even when differences occur in the amplitudes of the output signals of the magnetic detection elements depending on the arrangement angles of the plurality of magnetic detection elements. A rotation angle detection apparatus, where half an angle of an end-to-end angle of a bracket is defined as A degrees in an electrical angle, a value obtained by dividing A degrees by 90 degrees and rounding up to one decimal place is defined as M, an upper limit gain is defined as Gmax, and a lower limit gain is defined as Gmin, and where M is an odd number, “Gmax / Gmin > -0.0031×A+0.28×M+1.07” is specified, and where M is an even number, “Gmax / Gmin > 0.0031×A-0.28×M+1.35” is specified.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a rotation angle detection apparatus. STATE OF THE ART

[0002] A rotation angle detection apparatus is known that includes a rotor that rotates centered around a rotation axis and a stator that opposes the rotor. It detects a rotation angle (or angle of rotation) by detecting a change in the flux density between the rotor and the stator. Patent Document 1 discloses a rotation angle detection apparatus that includes a plurality of magnetic detection elements arranged circumferentially and a permanent magnet arranged radially outside the magnetic detection elements and extending in the circumferential direction. CITATION LISTPatent literature

[0003] Patent document 1: WO 2018 / 078856 A SUMMARY OF THE INVENTIONTechnical Problem

[0004] However, in the rotation angle detection apparatus of Patent Document 1, differences in the amplitudes of the output signals of the magnetic detection elements occur depending on the arrangement angles of the plurality of magnetic detection elements arranged in the circumferential direction. Accordingly, there is a problem that the accuracy of angle detection is deteriorated.

[0005] Therefore, the purpose of the present disclosure is to provide a rotation angle detecting apparatus capable of suppressing deterioration of angle detection accuracy even when differences occur in the amplitudes of the output signals of the magnetic detection elements depending on the arrangement angles of the plurality of magnetic detection elements. Solution to the problem

[0006] A rotation angle detection apparatus according to the present disclosure, comprising: a rotor that rotates centered around an axis of rotation; a stator having one or more permanent magnets, a yoke, and a plurality of magnetic detection elements; and an output adjuster that adjusts each of the output signals of the plurality of magnetic detection elements or a plurality of conversion output signals converted from the output signals of the plurality of magnetic detection elements and outputs a plurality of output signals after adjustment, wherein in an opposite surface of the rotor opposite to the stator, Q concave and convex portions (Q is an integer greater than or equal to 2) are formed, the projection height of which to the stator changes periodically in a curved shape in a circumferential direction, the one or more permanent magnets are opposite the concave and convex section and are arranged next to each other in the circumferential direction, the bracket has an arc portion arranged on a side opposite the concave and convex portion with respect to the one or more permanent magnets and extending in the circumferential direction, a first end projecting from one end of the arc portion in the circumferential direction on one side to the side of the concave and convex portion, and a second end projecting from one end of the arc portion in the circumferential direction on the other side to the side of the concave and convex portion, the plurality of magnetic detection elements are arranged side by side in the circumferential direction on the side of the concave and convex portion with respect to the one or more permanent magnets with a gap to the concave and convex portions and detect a flux density between the permanent magnet and the concave and convex portion, the output adjuster amplifies or attenuates each of the amplitudes of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals by a set gain that is set for each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals within a range from an upper limit gain that can be set to a lower limit gain that can be set, when an angle obtained by multiplying Q by a mechanical angle is defined as an electrical angle, a half angle of an end-to-end angle, which is an angle between the first end and the second end, is defined as A degrees in the electrical angle, a value obtained by dividing A degrees by 90 degrees and rounding up below a decimal point is defined as M, the upper limit gain (or upper limit of gain) is defined as Gmax, and the lower limit gain (or lower limit of gain) is defined as Gmin, and if M is an odd number, “Gmax / Gmin>-0.0031×A+0.28×M+1.07” is set, if M is an even number, “Gmax / Gmin>0.0031×A-0.28×M+1.35” is set. Advantages of the invention

[0007] According to the rotation angle detection apparatus of the present disclosure, by utilizing the upper limit gain, the lower limit gain, and the end-to-end angle so as to establish the above equations, the upper limit gain and the lower limit gain that can cancel the maximum-minimum amplitude ratio of the flux density are preliminarily set if each of two or three or more magnetic detection elements is arranged at an arbitrary arrangement angle when the yoke having a certain end-to-end angle is used.Accordingly, even if the arrangement angle of each magnetic detection element is arranged at different angles, the gain suitable for the arrangement angle of each magnetic detection element can be set within the range of the upper limit gain and the lower limit gain, the differences in the amplitudes of the output signals can be adjusted, and the calculation error of the angle can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 1; Fig. 2 is an enlarged view of a main part of the rotation angle detecting apparatus according to Embodiment 1; Fig. 3 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 1; Fig. 4 is a figure for explaining the output signals when there is no amplitude difference according to Embodiment 1; Fig. 5 is a figure for explaining the output signals when there is an amplitude difference according to Embodiment 1; Fig. 6 is a figure for explaining the angle calculation error due to the amplitude difference according to Embodiment 1; Fig. 7 is a figure for explaining the relationship between the amplitude ratio between the elements and the angle calculation error according to Embodiment 1; Fig. 8 is a figure for explaining each parameter according to Embodiment 1; Fig. 9 is a figure for explaining the magnetic paths according to Embodiment 1; Fig. 10 is a figure for explaining the magnetic paths according to Embodiment 1; Fig. 11 is a figure for explaining the arrangement angle of each magnetic detection element according to Embodiment 1; Fig. 12 is a figure for explaining the relationship between the end-to-end angle of the bracket and the amplitude of the flux density of each element according to Embodiment 1; Fig. 13 is a figure for explaining the relationship between the end-to-end angle of the bracket and the amplitude ratio of the flux density between the elements according to Embodiment 1; Fig. 14 is a figure for explaining the relationship between the end-to-end angle of the bracket and the amplitude ratio of the flux density between the elements when the angle between the elements is changed, according to Embodiment 1; Fig. 15 is a figure for explaining the relationship between the end-to-end angle of the bracket and the maximum-minimum amplitude ratio of the flux density according to Embodiment 1; Fig. 16 is a figure for explaining the output signals when eccentricity is present according to Embodiment 2; Fig. 17 is a figure for explaining the angle calculation error due to eccentricity according to Embodiment 2; Fig. 18 is a figure for explaining the relationship between the ratio of the offset difference to the amplitude and the angle calculation error according to Embodiment 2; Fig. 19 is a figure for explaining the relationship between the angular interval between the elements and the ratio of the offset difference to the amplitude, according to Embodiment 2; Fig. 20 is a schematic configuration diagram for explaining the parameter setter according to Embodiment 4; Fig. 21 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 5; Fig. 22 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 6; Fig. 23 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 6; Fig. 24 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 6; Fig. 25 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 6; and Fig. 26 is a schematic configuration diagram of the rotation angle detection apparatus according to Embodiment 7. DETAILED DESCRIPTION OF THE EMBODIMENTS 1. Embodiment 1

[0008] A rotation angle detecting apparatus 100 according to Embodiment 1 will be explained with reference to the drawings. Fig. 1 is a schematic configuration diagram of the rotation angle detection apparatus 100 according to the present embodiment. Fig. 1 is a cross-sectional view of the rotation angle detecting apparatus 100 as seen in the axial direction, and Fig. 2 is an enlarged view of a main part of Fig. 1.

[0009] The rotation angle detecting apparatus 100 is provided with a rotor 1 and a stator 4. As shown in Fig. As shown in Figure 3, the rotation angle detection apparatus 100 is provided with an output adjuster 8 and an angle calculator 9. The output adjuster 8 and the angle calculator 9 may be provided in the same housing as a magnetic detection element 7 provided in the stator 4; they may be provided separately from the magnetic detection element 7 and provided integrally with the stator 4; or they may be provided separately from the stator 4. <rotor>

[0010] The rotor 1 rotates centering around a rotation axis 2. In the present disclosure, the axial direction is a direction parallel to a rotational axial center of the rotation axis 2, and a radial direction and a circumferential direction are a radial direction and a circumferential direction around the rotational axial center.

[0011] In an opposing surface of the rotor 1 facing the stator 4, Q concave and convex portions 3 (Q is an integer greater than or equal to 2, in this example, 12) are formed, the protrusion height of which toward the stator 4 periodically changes in a curved shape in the circumferential direction. In the present embodiment, the stator 4 is arranged on the radially outer side of the rotor 1; the concave and convex portion 3 is formed at the radially outer end of the rotor 1; and the protrusion height toward the radially outer side changes in the circumferential direction. The concave and convex portions 3 of Q are formed at regular intervals in the circumferential direction. The protrusion height of the concave and convex portion 3 changes in a sinusoidal shape in the circumferential direction, so that an output signal of the magnetic detection element 7 changes in a sinusoidal shape. The concave and convex portion 3 is made of a soft magnetic material.

[0012] In the present embodiment, Q is set to 12. For each rotation of the rotor 1 at a mechanical angle, an angle θ detected by the rotation angle detection device 100 rotates 12 times at an electrical angle. The electrical angle becomes an angle obtained by multiplying Q by the mechanical angle. <stator>

[0013] The stator 4 includes one or more permanent magnets 5 (one in this example), a bracket 6, and N magnetic detection elements 7 (N is an integer greater than or equal to 2, in this example 2). The one or more permanent magnets 5 face the concave and convex portions and are arranged side by side in the circumferential direction. A magnetic field is created between the permanent magnet 5 and the concave and convex portions 3. The permanent magnet 5 is arranged radially outside the concave and convex portions 3. The magnetic poles differ in the radial direction inside and outside the permanent magnet 5, generating a magnetic flux in the radial direction. In the present embodiment, the radial direction inside the permanent magnet 5 is the N pole, and the radial direction outside the permanent magnet 5 is the S pole.The N-pole and the S-pole can be swapped.

[0014] A gap length between the concave and convex portion 3 and the permanent magnet 5 changes depending on the rotation angle of the rotor 1, and the flux density changes depending on the gap length. In the present embodiment, a permanent magnet 5 having a circular arc shape is provided, extending over a circumferential interval longer than a circumferential interval in which the N magnetic detection elements 7 are arranged. A radius of the permanent magnet 5 having the circular arc shape is maintained constant. The permanent magnet 5 may be circumferentially divided according to the circumferential arrangement of the N magnetic detection elements 7.

[0015] The bracket 6 is provided with an arc portion 10 disposed on a side opposite the concave and convex portion 3 (in this example, the radially outward side) with respect to the one or more permanent magnets 5 and extending in the circumferential direction, a first end 11 protruding from the end of the arc portion 10 in the circumferential direction on one side toward the concave and convex portion 3 side (in this example, the radially inward direction), and a second end 12 protruding from the end of the arc portion 10 in the circumferential direction on the other side toward the concave and convex portion 3 side. The bracket 6 is made of a soft magnetic material. The first end 11 is opposite to the concave and convex portion 3 with an air gap 13 (relative to a first air gap 13), and the second end 12 is opposite to the concave and convex portion 3 with an air gap 14 (relative to a second air gap 14).

[0016] The arc portion 10 is formed in a circular arc shape extending over a circumferential interval longer than a circumferential interval in which the one or more permanent magnets 5 (one in this example) are arranged. The one or more permanent magnets 5 and the N magnetic detection elements 7 are fixed radially within the arc portion 10.

[0017] The N magnetic detection elements 7 (two in this example) are arranged circumferentially on the concave and convex portion 3 side (in this example, in the radial direction inside) with respect to the one or more permanent magnets 5, with an air gap between the magnetic detection element 7 and the concave and convex portion 3; and detect the flux density between the permanent magnet 5 and the concave and convex portion 3. The gap length between the concave and convex portion 3 and the permanent magnet 5 changes in a sine waveform according to the rotation angle in the electrical angle of the rotor 1, and the flux density changes in a sine waveform according to the gap length. The magnetic detection element 7 detects the flux density that changes in the sine waveform according to the rotation angle in the electrical angle of the rotor 1.The magnetic detection element 7 outputs a signal corresponding to the detected flux density. Each magnetic detection element 7 is a magnetic sensor that detects the flux density and is a Hall element or a magnetoresistive element. The output signal of each magnetic detection element 7 is input to the output adjuster 8.

[0018] The N magnetic detection elements 7 are arranged circumferentially so that each output signal in a sinusoidal shape has a different phase in electrical angle from each other. In the present embodiment, N is set to 2, and a first magnetic detection element 71 and a second magnetic detection element 72 are provided. In the present embodiment, the two magnetic detection elements 71, 72 have an interval of 90 degrees in electrical angle (90 / 12 degrees in mechanical angle) and are arranged circumferentially. The two magnetic detection elements 71, 72 may have a distance of 90 degrees + 360 degrees × R (R is one or more integers) in electrical angle and are arranged circumferentially.

[0019] The output signal of the first magnetic detection element 71 is related to a first output signal S1, and the output signal of the second magnetic detection element 72 is related to a second output signal S2. As shown in Fig. 4, in an ideal state with no amplitude difference between the output signals, the first output signal S1 and the second output signal S2 each take the form of sine waves, and a phase difference between the first output signal S1 and the second output signal S2 is 90 degrees in electrical angle. <ausgabeanpasser>

[0020] The output adjuster 8 adjusts each output signal of the N magnetic detection elements 7, and outputs N output signals after the adjustment.

[0021] The output adjuster 8 amplifies or attenuates each of the amplitudes of the output signals from N magnetic detection elements by a set gain Gst set for each of the N magnetic detection elements 7 within a range from an upper limit gain Gmax that can be set to a lower limit gain Gmin that can be set; and outputs an output signal after the amplification or attenuation.

[0022] The set gain Gst of each magnetic detection element 7, which amplifies or attenuates the output signal of each magnetic detection element 7, can be changed within the range from the upper limit gain Gmax to the lower limit gain Gmin and is set individually. The upper limit gain Gmax and the lower limit gain Gmin are determined by the performance of the hardware or the performance of the software or the like and are fixed values. If the output adjuster 8 is configured by analog circuits, each set gain Gst is set by a resistance value and the like. If the output adjuster 8 is configured by digital circuits, each set gain Gst is stored in a storage device such as ROM.

[0023] In the present embodiment, N output adjusters 8 are provided, each corresponding to one of the N magnetic detection elements 7. As shown in Fig. As shown in Figure 3, in this example, the first output adjuster 81, which adjusts the first output signal S1 of the first magnetic detection element 71, and the second output adjuster 82, which adjusts the second output signal S2 of the second magnetic detection element 72, are provided. The first output adjuster 81 adjusts the first output signal S1 and outputs the first output signal after adjustment Sadj1. The second output adjuster 82 adjusts the second output signal S2 and outputs the second output signal after adjustment Sadj2.

[0024] The first output adjuster 81 amplifies or attenuates using the first adjusted gain Gst1, which is set in the range from the upper limit gain Gmax to the lower limit gain Gmin. The second output adjuster 82 amplifies or attenuates using the second adjusted gain Gst2, which is set in the range from the upper limit gain Gmax to the lower limit gain Gmin. <winkelrechner>

[0025] The angle calculator 9 calculates an angle θ of the rotor 1 based on N output signals after adjustment Sadj. In the present embodiment, as shown in the next equation, the angle calculator 9 calculates the angle θ in electrical angle by performing an arctangent calculation of a ratio between the first output signal after adjustment Sadj1 and the second output signal after adjustment Sadj2. Through a process of subtracting a mean value or a DC component from the output signal after adjustment Sadj, only a signal component that changes according to the rotation of the rotor 1 is extracted, and this is used for the angle calculation. The angle calculator 9 transmits the calculated angle θ to the external controller 20. [Math. 1] θ=tan−1(Sadj1Sadj2) <Problem aufgrund der Amplitudendifferenz zwischen den Ausgangssignalen>

[0026] Fig. Figure 5 shows the waveforms of the first output signal S1 and the second output signal S2 when an amplitude difference occurs. Compared to the case without an amplitude difference in Fig. 4 the amplitude of the second output signal S2 is reduced. Fig. Fig. 6 shows a comparative example when the angle θ is calculated without the adjustment by the output adjuster 8 to the output signal of Fig. 5. Due to the reduction of the amplitude of the second output signal S2, an error component of two cycles of the electrical angle is generated in the calculated angle θ.

[0027] Fig. Figure 7 shows a relationship between the amplitude ratio of the first output signal S1 to the amplitude of the second output signal S2 and the maximum angular error in one rotation cycle. As shown in this figure, the maximum angular error increases as the amplitude ratio increases in accordance with the amplitude difference. <Erzeugungsprinzip des Winkelfehlers aufgrund der Vergrößerung des Amplitudenverhältnisses>

[0028] The principle of increasing the angular error by increasing the amplitude ratio will be explained. Fig. Figure 8 shows the definitions of the parameters used in the following explanation. Half an end-to-end angle, that is, an angle between the first end 11 and the second end 12 of the bracket 6, is defined as A degree in electrical angle. The end-to-end angle becomes 2×A degree of electrical angle. The representative position of the first end 11 is a center position of the first end 11 in the circumferential direction. The representative position of the second end 12 is a center position of the second end 12 in the circumferential direction. Accordingly, an angle between a center line 16 between the ends and the first end 11 becomes A degree. And an angle between the center line 16 between the ends and the second end 12 becomes A degree. The center line 16 between the ends is a line passing through a center angle between the first end 11 and the second end 12.

[0029] An angle between the center line 16 between the ends and the specific magnetic detection element 7 is defined as B degrees in the electrical angle. An angle θ in the electrical angle when a center line of the concave and convex portion 3 passing through a vertex of the convex portion coincides with the center line 16 between the ends is defined as 0 degrees. In the state of the illustration, the counterclockwise direction is defined as a positive rotation direction. A, B, and θ are the electrical angles. <Kombinierter magnetischer Widerstand Rmpall aller magnetischen Wege, die durch das spezifische magnetische Erkennungselement 7 passieren>

[0030] Fig. 9 shows the first magnetic path 18 and the second magnetic path 19 of the magnetic flux passing through the vicinity of the specific magnetic detection element 7 when the apex point of the convex portion of the concave and convex portion 3 is closest to the specific magnetic detection element 7. On the first magnetic path 18, after the magnetic flux flowing from the N pole of the magnet near the specific magnetic detection element 7 in the radial direction inside the specific magnetic detection element 7 passes through the vicinity of the specific magnetic detection element 7, the magnetic flux enters the concave and convex portion 3 via the air gap 15 of the specific element. After the magnetic flux flows inside the concave and convex portion 3 in the circumferential direction of one side, the magnetic flux enters the first end 11 via the first air gap 13.After the magnetic flux flows within the arc portion 10 in the circumferential direction to the other side, the magnetic flux returns to the S pole of the magnet near the specific magnetic detection element 7. In the second magnetic path 19, after the magnetic flux flowing from the N pole of the magnet near the specific magnetic detection element 7 in the radial direction within the arc passes through the vicinity of the specific magnetic detection element 7, the magnetic flux enters the concave and convex portion 3 via the air gap 15 of the specific element. After the magnetic flux flows within the concave and convex portion 3 in the circumferential direction to the other side, the magnetic flux enters the second end 12 via the second air gap 14.Then, after the magnetic flux flows within the arc part 10 in the circumferential direction of one side, the magnetic flux returns to the S pole of the magnet near the specific magnetic detection element 7.

[0031] When the magnetic resistance of the first air gap 13 is defined as Rgp1, Rgp1 becomes a function of the angle A between the center line 16 between the ends and the first end 11, and changes in a sine waveform according to the movement of the concave and convex portion 3, that is, the rotation of the rotor 1. Accordingly, it can be expressed as equation (2). When the magnetic resistance of the second air gap 14 is defined as Rgp2, Rgp2 becomes a function of the angle A between the center line 16 between the ends and the second end 12, and changes in a sine waveform according to the rotation of the rotor 1. Accordingly, it can be expressed as equation (3). Here, a position (radius) in the radial direction inside the first end 11 is the same as a position (radius) in the radial direction inside the second end 12.Accordingly, between equation (2) and equation (3), a compensation constant β1 and an amplitude coefficient α1 are set to the same values. The compensation constant β1 changes depending on the position (radius) of each end in the radial direction. The amplitude coefficient α1 changes depending on the amplitude of the concave and convex portions 3. If the magnetic resistance of the air gap 15 of the specific element is defined as Rgps, Rgps becomes a function of the angle B between the center line 16 between the ends and the specific magnetic detection element 7 and changes in an approximately sinusoidal shape according to the rotation of the rotor 1. Accordingly, it can be expressed as equation (4). Here, βs is a compensation constant of Rgps, and αs is an amplitude coefficient of Rgps. [Math. 2] Rgp1(A−θ)=β1−α1×cos((A−θ)π180) Rgp2(A+θ)=β1−α1×cos((A+θ)π180) Rgps(B−θ)=βs−αs×cos((B−θ)π180)

[0032] As in Fig. 9, since θ = B at the time when the tip point of the convex portion of the concave and convex portion 3 is closest to the specific magnetic detection element 7, the equation (2) becomes the equation (4), the equation (5), and the equation (7). [Math. 3] θ=B, Rgp1(A−B)=β1−α1×cos((A−B)π180) θ=B, Rgp2(A+B)=β1−α1×cos((A+B)π180) θ=B, Rgp(0)=βs−αs

[0033] The combined magnetic resistance Rmpall of all magnetic fluxes passing through the specific magnetic detection element 7 becomes the series magnetic resistance of the parallel magnetic resistance of the first air gap 13 and the second air gap 14 and the magnetic resistance of the air gap 15 of the specific element, and is expressed as Equation (8). However, since the magnetic resistances within the bracket 6 and the concave and convex portions 3 are sufficiently smaller than the magnetic resistances Rmp1 and Rmp2 of each air gap, they are ignored. [Math. 4] θ=B, Rmpall=Rmp1(A−B)‖Rmp2(A+B)+Rgps(0)={β1−α1×cos((A−B)π180)}{β1−α 1×cos((A+B)π180)}2×β1−α1×cos((A+B)π180)−α1×cos((A+B)π180)+βs−αs <Maximaler Spitzenwert Mfdmax der Flussdichte, die durch ein spezifisches magnetisches Erkennungselement passiert>

[0034] When θ is equal to B and the magnetic driving force V of the permanent magnet 5 is uniform, a specific flux density Mfd detected by the specific magnetic detection element 7 becomes as given in equation (9). The specific flux density Mfd of equation (9) is the maximum peak value Mfdmax of the specific flux density when θ is B, that is, the peak value of the convex portion of the concave and convex portion 3 is closest to the specific magnetic detection element 7. [Math. 5] θ=B, Mfdmax=Mfd=VRmpall=VRmp1(A−B)‖Rmp2(A+B)+Rgps(0) <Minimalwert Spitzenwert Mfdmin der Flussdichte, die durch ein spezifisches magnetisches Erkennungselement passiert>

[0035] Fig. 10 shows the case where the rotor 1 is rotated by 180 degrees in electrical angle compared to the state of Fig. 9 rotates (θ = B + 180 degrees), and the apex of the concave portion of the concave and convex portions 3 is closest to the specific magnetic detection element 7. A combined magnetic resistance Rmpall of all magnetic fluxes passing through the specific magnetic detection element 7 becomes the series magnetic resistance of the parallel magnetic resistance of the first air gap 13 and the second air gap 14 and the magnetic resistance of the air gap 15 of the specific element, and becomes equation (10). [Math. 6] θ=B+180, Rmpall=Rmp1(A−B−180)‖Rmp2(A+B+180)+Rgps(0)={β1−α1×cos((A−B−180)π180)}{β1−α 1×cos((A+B+180)π180)}2×β1−α1×cos((A−B−180)π180)−α1×cos((A+B+180)π180)+βs−αs

[0036] When θ is B + 180 degrees and the magnetic driving force V of the permanent magnet 5 is uniform, the specific flux density Mfd detected by the specific magnetic detection element 7 is given by equation (11). The specific flux density Mfd of equation (11) is the minimum peak value Mfdmin of the flux density passing through the specific magnetic detection element 7 when θ = B + 180 degrees, that is, the peak value of the concave portion of the concave and convex portions 3 is closest to the specific magnetic detection element 7. [Math. 7] θ=B+180, Mfdmin=Mfd=VRmpall =VRmp1(A−B−180)‖Rmp2(A+B+180)+Rgps(0) <Amplitude ΔMfd der Flussdichte, die durch das spezifische magnetische Erkennungselement 7 hindurchgeht>

[0037] Accordingly, an amplitude ΔMfd of the specific flux density detected by the specific magnetic detection element 7 is a difference between the specific maximum value Mfdmax of the equation (9) and the specific minimum value Mfdmin of the equation (11), and is expressed as equation (12). [Math. 8] ΔMfd=Mfdmax−Mfdmin=VRmp1(A−B)‖Rmp2(A+B)+Rgsp(0)−VRmp1(A−B−180)‖Rmp2(A+B+180)+Rgsp(0) <Amplitude ΔMfd2 der Flussdichte, die durch das zweite magnetische Erkennungselement passiert>

[0038] The above-explained specific magnetic detection element 7 is set to the first magnetic detection element 71, the arrangement angle B of the specific magnetic detection element 7 is set to B1, and the second magnetic detection element 72 will be explained. Fig. 11 shows the case where the apex of the convex portion of the concave and convex portions 3 is closest to the second magnetic detection element 72 arranged at an angle B2. B2 is B1 + 90 degrees, accordingly, a phase difference between the output signal of the first magnetic detection element 71 and the output signal of the second magnetic detection element 72 is 90 degrees. An amplitude ΔMfd2 of the second flux density detected by the second magnetic detection element 72 can be expressed by the following equation, which replaces B of equation (12) with B2. [Math. 9] ΔMfd2=VRmp1(A−B2)‖Rmp2(A+B2)+Rgsp(0)−VRmp1(A−B2−180)‖Rmp2(A+B2+180)+Rgsp(0)B2=B1+90 <Change in the amplitude ratio of the flux densities passing through the first and second magnetic detection elements corresponding to half the angle A of the end-to-end angle>

[0039] Fig. Figure 12 shows the amplitude ΔMfd1 of the first flux density of equation (12) and the amplitude ΔMfd2 of the second flux density of equation (13) when the half-angle A of the end-to-end angle of the bracket 6 is changed. At each half-angle A of the end-to-end angle, except for A = 90 degrees and 270 degrees, there is a difference between the amplitude ΔMfd1 of the first flux density and the amplitude ΔMfd2 of the second flux density. Fig. Figure 13 shows an amplitude ratio between the amplitude ΔMfd1 of the first flux density and the amplitude ΔMfd2 of the second flux density. The amplitude ratio is obtained by dividing the larger of ΔMfd1 and ΔMfd2 by the smaller of ΔMfd1 and ΔMfd2. When A = 90 degrees and 270 degrees, the amplitude ratio is close to one, which is the minimum. When A = 0 degrees, 180 degrees, and 360 degrees, the amplitude ratio is 1.22, which is the maximum. <Wenn zwei oder drei oder mehr magnetische Erkennungselemente 7 bereitgestellt werden>

[0040] There is not only the case where the two magnetic detection elements 7 are arranged with a phase difference of 90 degrees in electrical angle, as in the present embodiment, but also the case where the three or more magnetic detection elements 7 are arranged with a phase difference other than 90 degrees. When the two magnetic detection elements 7 are provided, the output signals of the two magnetic detection elements 7 are directly substituted into equation (1), and the angle is calculated. Accordingly, the computational burden is small. On the other hand, when three or more magnetic detection elements 7 are provided, specific harmonic noise can be removed and the deterioration of the angle detection accuracy due to the interfering magnetic field can be suppressed, while the computational burden becomes large.

[0041] As shown in equation (22) described below, when the three or more magnetic detection elements 7 are provided, the output signals S before adjustment or the output signals after adjustment Sadj of the corresponding magnetic detection elements are converted into a sine value Ssinadj and a cosine value Scosadj having a phase difference of 90 degrees in electrical angle, and the arc tangent calculation is performed.

[0042] That is, the rotation angle detection apparatus 100 of the present disclosure is not limited to the case where the two magnetic detection elements 7 are arranged with a phase difference of 90 degrees, but there is a case where three or more magnetic detection elements 7 may be provided. Accordingly, the amplitude difference that occurs when the first magnetic detection element 71 and the second magnetic detection element 72 are arranged at arbitrary angles will be explained below. <Change in the amplitude of the flux density due to changing the end-to-end angle and the arrangement angles of the elements>

[0043] As explained using equation (9), the flux density Mfd detected by the specific magnetic detection element 7 becomes the maximum peak value Mfdmax when θ = B, that is, when the peak point of the convex portion of the concave and convex portion 3 is closest to the specific magnetic detection element 7. When θ = B + 180 degrees, that is, the peak value of the concave portion of the concave and convex portion 3 is closest to the specific magnetic detection element 7, the flux density Mfd becomes the minimum value Mfdmin. The amplitude ΔMfd of the flux density is given as equation (12).

[0044] Fig. 14 shows a figure plotting the amplitude ΔMfd of the flux density when the arrangement angle B of the specific magnetic detection element 7 with respect to the center line 16 between the ends of the bracket 6 is changed from 0 degrees to 360 degrees, as a function of the half angle A of the end-to-end angle of the bracket 6. As in Fig. As shown in Figure 14, the amplitude ΔMfd of the flux density changes at each half angle A of the end-to-end angle depending on the arrangement angle B of the specific magnetic detection element 7. This also applies to the arrangement angle of other magnetic detection elements 7.

[0045] Fig. 15 shows a figure in which the amplitude ratio RMfd between the maximum value ΔMfdmax and the minimum value ΔMfdmin of the amplitude ΔMfd of the flux density (hereinafter referred to as the maximum-minimum amplitude ratio RMfd of the flux density) at each half angle A of Fig. 14. A straight approximation line is shown in Fig. 15 is shown with a dashed line. This approximate straight line is shown in equation (14). Here, M is a value obtained by dividing half the angle A of the end-to-end angle in the electrical angle by 90 degrees and rounding up to one decimal place. ROUNDUP(X, 0) is a function that returns a value rounded up to one decimal place of X. For example: ROUNDUP(0.1, 0) = 1, ROUNDUP(1.2, 0) = 2, and ROUNDUP(3.6, 0) = 4. [Math. 10] M=ROUNDUP(A90,0) 1) When M is an odd number, RMfd=ΔMfdmaxΔMfdmin=−0.0031×A+0.28×M+1.07 2) When M is an even number, RMfd=ΔMfdmaxΔMfdmin=0.0031×A−0.28×M+1.35 <Leistung des Ausgabeanpassers zur Anpassung an das Maximum-Minimum-Amplitudenverhältnis der Flussdichte>

[0046] As described above, the maximum-to-minimum amplitude ratio RMfd of the flux density due to the magnetic detection element 7 arranged at arbitrary arrangement angles B is changed by changing the end-to-end angle 2×A of the bracket 6. Even with the same end-to-end angle 2×A, the amplitude ΔMfd of the flux density is changed by the arrangement angle B of each magnetic detection element 7 within the corresponding range of the maximum-to-minimum amplitude ratio RMfd. Therefore, the amplitude of the output signal of each magnetic detection element 7 is changed differently depending on the end-to-end angle 2×A of the bracket 6 and the arrangement angle B of each magnetic detection element 7. Accordingly, if the output signal of each magnetic detection element 7 is not adjusted by the output adjuster 8, an error occurs in the calculated angle θ as calculated using Fig. 5 and Fig. 6 is explained.

[0047] In order to reduce the angle calculation error of the angle θ, it is necessary to amplify or attenuate the amplitude of the output signal of each magnetic detection element 7 individually by the set gain Gst of the output adjuster 8 set for each magnetic detection element 7.

[0048] As mentioned above, the set gain Gst of the output adjuster 8 is not infinitely adjustable to any value, but is limited by the upper limit gain Gmax and the lower limit gain Gmin, which are determined by the hardware performance or the software performance of the output adjuster 8, or both, and the like. Accordingly, the upper limit gain Gmax and the lower limit gain Gmin that can be set for the output adjuster 8 must be designed taking into account the changing range of the output signal amplitude of each magnetic detection element 7.

[0049] When the yoke 6 having a certain end-to-end angle 2×A is used, the upper limit gain Gmax and the lower limit gain Gmin can be designed to cancel the maximum-minimum amplitude ratio RMfd of the flux density corresponding to the end-to-end angle 2×A to allow the output adjuster 8 to adjust even if each of two or three or more magnetic detection elements 7 is arranged at any arrangement angle B. For this purpose, as shown in Equation (15), the upper limit gain Gmax, the lower limit gain Gmin, and the end-to-end angle 2×A can be preliminarily set so that Gmax / Gmin becomes larger than the maximum-to-minimum amplitude ratio RMfd of the flux density corresponding to each end-to-end angle 2×A.As shown in equation (16), for the maximum-minimum amplitude ratio RMfd of the flux density from equation (15), the maximum-minimum amplitude ratio RMfd of the flux density from equation (14) is used, which becomes a function of half the angle A of the end-to-end angle of the bracket 6. [Math. 11] GmaxGmin>RMfd=ΔMfdmaxΔMfdmin [Math. 12] M=ROUNDUP(A90,0) 1) When M is an odd number, GmaxGmin>−0.0031×A+0.28×M+1.07 2) When M is an even number, GmaxGmin>0.0031×A−0.28×M+1.35

[0050] According to this configuration, when using the yoke 6 having the specific end-to-end angle 2×A, the upper limit gain Gmax and the lower limit gain Gmin that can cancel the maximum-to-minimum amplitude ratio RMfd of the flux density when each of two or three or more magnetic detection elements 7 is arranged at any arrangement angle B are preliminarily set. Accordingly, even if the arrangement angle B of each magnetic detection element 7 is arranged at different angles, the set gain Gst suitable for the arrangement angle B of each magnetic detection element 7 can be set within the range of the upper limit gain Gmax and the lower limit gain Gmin, and the calculation error of the angle θ can be reduced.

[0051] If the end-to-end angle 2×A is designed first, the upper limit gain Gmax and the lower limit gain Gmin can be set using the already set end-to-end angle 2×A, so that Equation (16) is satisfied. If the upper limit gain Gmax and the lower limit gain Gmin are designed first, the end-to-end angle 2×A can be preliminarily set using the already set upper limit gain Gmax and lower limit gain Gmin, so that Equation (16) is satisfied. If the upper limit gain Gmax, the lower limit gain Gmin and the end-to-end angle 2×A are designed simultaneously, the upper limit gain Gmax, the lower limit gain Gmin and the end-to-end angle 2×A can be preliminarily set so that Equation (16) is satisfied.

[0052] The lower limit of Gmax / Gmin satisfies Equation (16). On the other hand, the upper limit of Gmax / Gmin is set to about 1,000,000, for example, due to limitations on the size of the device and the like. <Verarbeitung des Ausgabeanpassers>

[0053] As mentioned above, the output adjuster 8 amplifies or attenuates each of the amplitudes of the output signals S from N magnetic detection elements by the set gain Gst, which is set for each of the N magnetic detection elements 7 within the range from the adjustable upper limit gain Gmax to the adjustable lower limit gain Gmin, and outputs the output signal Sadj after amplification or attenuation. For example, as shown in Equation (17), for the output signal Si (i = 1, ..., N) of each magnetic detection element 7, the output adjuster 8 calculates the output signal after adjustment Sadji by multiplying the set gain Gsti, which is set for the output signal of each magnetic detection element 7, by the output signal Si of the magnetic detection element 7. Here, i expresses the number of each magnetic detection element 7 from one to N.Alternatively, as shown in Equation (18), the output adjuster 8 calculates the output signal after adjustment Sadji by subtracting an average value or a DC component Scnt from the output signal Si of the magnetic detection element 7 and multiplying the adjusted gain Gsti set for the output signal of each magnetic detection element 7 by a subtracted value. For the average value or the signal component Scnt, a preliminarily set value may be used, or a value obtained by performing low-pass filtering on the output signal S of each magnetic detection element 7 may be used. [Math. 13] Sadji=Si×Gsti i=1,…,N [Math. 14] Sadji=(Si−SCNT)×Gsti i=1,…,N

[0054] The adjusted gain Gst of each magnetic detection element 7 is preliminarily set within the range of the upper limit gain Gmax to the lower limit gain Gmin so that the amplitude of the output signal after adjustment of each magnetic detection element 7 is the same. If the output adjuster 8 is configured by analog circuits, the adjusted gain Gst is adjusted by a resistance value and the like. If the output adjuster 8 is configured by digital circuits, the adjusted gain Gst is stored in a storage device such as a ROM. Since Gmax / Gmin>RMfd, the adjusted gain Gst of each magnetic detection element 7 can be adjusted so that the amplitude of the output signal after adjustment of each magnetic detection element 7 is the same.

[0055] For example, the output adjuster 8 includes a current amplification circuit that increases or decreases a magneto-electric conversion coefficient of each magnetic detection element 7; a voltage amplification circuit that increases or decreases the analog output signal of each magnetic detection element 7; a processor that increases or decreases the output signal of each magnetic detection element 7 through a multiplication operation after performing digital conversion; or the like. By providing the output adjuster 8 with these features, the amplitude difference between the output signals of corresponding magnetic detection elements 7 can be reduced, and as a result, the angle detection accuracy of the rotation angle detection apparatus 100 can be improved. 2. Embodiment 2

[0056] The rotation angle detection apparatus 100 according to Embodiment 2 will be explained with reference to the drawings. Explanation of components common to those of Embodiment 1 will be omitted. The basic configuration of the rotation angle detection apparatus 100 according to the present embodiment is the same as that of Embodiment 1. However, in the present embodiment, the processing of the output adjuster 8 is different from Embodiment 1. <Einfluss der Positionierung des Stators 4>

[0057] When the rotation angle detection apparatus 100 is incorporated into the motor, the stator 4 may cause a positional shift of the rotor 1, that is, a distance between the rotational axial center of the rotor 1 and the center of the arc part 10 of the stator 4 may deviate from the design value, and static eccentricity may occur.

[0058] Fig. Fig. 16 shows the waveforms of the first output signal S1 of the first magnetic detection element 71 and the second output signal S2 of the second magnetic detection element 72 when the static eccentricity occurs. In contrast to the ideal waveforms of the first and second output signals S1, S2 of Fig. 4, an offset difference ΔSoff occurs between the mean values ​​or the DC components of the first and second output signals S1, S2. Fig. Fig. 17 shows a comparative example when the angle θ is calculated without the adjustment by the output adjuster 8 to the output signals S1, S2 of Fig. 16. If there is an offset difference in the mean values ​​or the DC components between the output signals, an error component of one period of the electrical angle will be generated in the calculated angle θ.

[0059] Fig. Figure 18 shows a relationship between the ratio of the offset difference ΔSoff between the output signals to the amplitude ΔSamp of the output signal and the maximum angular error in one rotation cycle. As shown in this figure, the maximum angular error increases as the static eccentricity increases and the offset difference ΔSoff between the output signals increases. <Auftretungsprinzip der Versatzdifferenz aufgrund der statischen Exzentrizität>

[0060] The following explains why the offset difference ΔSoff occurs between the output signals due to static eccentricity. When the stator 4 causes a positional shift in a first direction with respect to the rotor 1, an average distance of the air gap 15 between each magnetic detection element 7 and the concave and convex portion 3 varies when the rotor rotates once, depending on each magnetic detection element 7. This deviation in the average distance of the air gap 15 causes an offset difference in the combined magnetic resistance Rmpall of all the magnetic fluxes passing through each magnetic detection element 7, and the offset difference ΔSoff between the output signals occurs.

[0061] In the following, using the case of the configuration of Fig. 11 as an example, when an amount of position displacement of the stator 4 is defined as Dsft and the average distance of the air gap 15 when the rotor 1 rotates once is defined as Dave, the occurred offset difference ΔSoff between the output signals is quantitatively explained.

[0062] When the rotor 1 performs the position shift by a distance Dsft in the direction of the arrangement angle B of the first magnetic detection element 71 in Fig. 11, the air gap 15 between the first magnetic detection element 71 and the concave and convex portion 3 is reduced by Dsft, and the air gap 15 between the second magnetic detection element 72 and the concave and convex portion 3 is reduced by Dsft × cos((B2-B1) / Q×π / 180). Here, the electrical angle is converted into the mechanical angle by (B2-B1) / Q.

[0063] Accordingly, the mean value or the DC component of the flux density detected by the first magnetic detection element 71, that is, the mean value or the DC component of the first output signal S1 increases by the ratio Dsft / Dave, and the mean value or the DC component of the second output signal S2 of the second magnetic detection element 72 increases by the ratio Dsft × cos((B2-B1) / Q×π / 180) / Dave. For example, in a general motor, Dave≈1.5 mm and Dsft≈0.2 mm. At this time, since B2 = B1 + 90 degrees and Q = 12, the mean value or the DC component of the first output signal S1 increases by 13.3%, and the mean value or the DC component of the second output signal S2 increases by 13.2%. Accordingly, the offset difference of 0.1% occurs in the mean value or the DC component between the first output signal S1 and the second output signal S2.In this way, since the increase or decrease rate of the flux density due to the position shift is different depending on the arrangement angle B of each magnetic detection element 7, the offset difference between the output signals occurs.

[0064] This is not limited to the case where the two magnetic detection elements are arranged with the interval of 90 degrees in electrical angle. Fig. Figure 19 shows the change in the offset difference ΔSoff between the output signals when the angular interval of C degrees in the mechanical angle between two magnetic detection elements is changed. Here, the vertical axis is expressed by a ratio obtained by dividing the offset difference ΔSoff between the output signals by the amplitude ΔSamp of the output signal. As the angular interval of C degrees between the elements increases, the ratio of the offset difference ΔSoff with respect to the amplitude ΔSamp of the output signal increases. The approximate curve corresponds to Equation (19). [Math. 15] ΔSoffΔSamp=0.11−0.11×cos(C×π180) <Leistung des Ausgabeanpassers zur Anpassung an die Versatzdifferenz zwischen den Ausgangssignalen>

[0065] As described above, as shown in Equation (19), the offset difference ΔSoff occurs between the output signals, and the offset error of the angle θ increases. To reduce the calculation error of the angle θ, it is necessary to individually adjust the output signal of each magnetic detection element 7 by the output adjuster 8.

[0066] Then, in the present embodiment, the output adjuster 8 offsets each output signal S of the N magnetic detection elements 7 by a set offset correction value Hst, which is set for each of the N magnetic detection elements 7 within a range from an upper limit of the offset correction value Hmax that can be set to a lower limit of the offset correction value Hmin that can be set; and outputs the output signal Soff after the offset. Then, the output adjuster 8 amplifies or attenuates the output signal Soff after the offset correction of each magnetic detection element 7 by the set gain Gst of each magnetic detection element 7, as explained in Embodiment 1; and outputs the output signal after the adjustment Sadj.

[0067] For example, as shown in equation (20), for the output signal Si (i = 1, ..., N) of each magnetic detection element 7, the output adjuster 8 calculates the output signal Soffi after offset correction by adding the adjusted offset correction value Hsti set for each magnetic detection element 7 to the output signal Si of the magnetic detection element 7; and calculates the output signal after adjustment Sadji by multiplying the adjusted gain Gsti set for the output signal of each magnetic detection element 7 by the output signal Soffi after offset correction. Here, i expresses the number of each magnetic detection element 7 from one to N. The output adjuster 8 can adjust the adjusted gain Gsti of each magnetic detection element 7 by the output signal Si (i = 1, ...)., N) of each magnetic detection element 7 as the equation (17) or the equation (18); then, the offset correction can be performed with the set offset correction value Hsti of each magnetic detection element 7; and the output signal after adjustment Sadji can be output. [Math. 16] Soffii=Si+HstiSadji=Soffii×Gsti i=1,…,N

[0068] The set offset correction value Hst of the output adjuster 8 cannot be infinitely set to any value, but is limited by the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin, which are determined by the hardware performance or the software performance of the output adjuster 8, or both. Accordingly, the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin that can be set for the output adjuster 8 must be designed by considering the offset difference ΔSoff between the output signals.

[0069] The set compensation Gst is multiplied by the offset component included in the output signal S of the magnetic detection element 7, and the maximum value of the set compensation Gst is the upper limit gain Gmax. Accordingly, the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin can be designed to cancel the offset difference of the output signal by which the upper limit gain Gmax is multiplied. For this purpose, the upper limit of the offset correction value Hmax, the lower limit of the offset correction value Hmin, and the maximum angular interval Cmax between the elements can be preliminarily set to satisfy Equation (21) derived using Equation (19). [Math. 17] (Hmax−Hmin)Gmax>0.11−0.11×cos(Cmax×π180)

[0070] Herein, the maximum angular interval Cmax degrees between the elements is an angle of the mechanical angle between the magnetic detection element arranged on one side in the circumferential direction and the magnetic detection element arranged on the other side in the circumferential direction among the N magnetic detection elements 7.

[0071] According to this configuration, when the maximum angular interval between two or three or more magnetic detection elements 7 is Cmax, the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin, which can cancel the maximum offset difference ΔSoffmax between the output signals, are preliminarily set. Accordingly, even if the arrangement angle B of each magnetic detection element 7 is arranged at different angles within the range of the maximum angular interval Cmax, the set offset correction value Hst, which is suitable for the offset that changes according to the arrangement angle B of each magnetic detection element 7, can be set within the range between the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin; and the calculation error of the angle θ can be reduced.

[0072] If the maximum angular interval Cmax between the elements is designed first, the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin can be set using the already set maximum angular interval Cmax so that Equation (21) is satisfied. If the upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin are designed first, the maximum angular interval Cmax between the elements can be preliminarily set using the already set upper limit of the offset correction value Hmax and the lower limit of the offset correction value Hmin so that Equation (21) is satisfied.If the upper limit of the offset correction value Hmax, the lower limit of the offset correction value Hmin and the maximum angular interval Cmax between the elements are designed at the same time, the upper limit of the offset correction value Hmax, the lower limit of the offset correction value Hmin and the maximum angular interval Cmax between the elements can be preliminarily set so that Equation (21) is satisfied.

[0073] The lower limit of (Hmax-Hmin) / Gmax satisfies Equation (21). On the other hand, the upper limit of (Hmax-Hmin) / Gmax is set to approximately 1,000,000 due to limitations on the size of the device, etc.

[0074] For example, the output adjuster 8 that performs the offset correction includes a circuit that adds or subtracts the offset voltage to the analog output signal of each magnetic detection element 7; a processor that increases or decreases the output signal of each magnetic detection element 7 through an addition operation after performing a digital conversion; or the like. If the output adjuster 8 is configured by analog circuits, the set offset correction value Hsti is adjusted by a resistance value and the like. If the output adjuster 8 is configured by digital circuits, the set offset correction value Hsti is stored in a storage device such as ROM. By providing the output adjuster 8 with these features, the offset difference of the output signal of each magnetic detection element 7 can be reduced. 3. Embodiment 3

[0075] The rotation angle detection apparatus 100 according to Embodiment 3 will be explained with reference to the drawings. Explanation of components common to those of Embodiment 1 or 2 will be omitted. The basic configuration of the rotation angle detection apparatus 100 according to the present embodiment is the same as that of Embodiment 1 or 2. Furthermore, in the present embodiment, the performance that the output adjuster 8 should satisfy is limited.

[0076] For efficient motor driving, the maximum angle error of the rotation angle detection device 100 is desirably less than or equal to 30 degrees. The amplitude ratio between the output signals that meet this requirement is less than or equal to 3 times Fig. 7. Therefore, to adjust the amplitude ratio to be less than or equal to three times, it is necessary that the set resolution of the adjusted gain Gst of the output adjuster 8 be less than or equal to three. For example, if the set resolution is 0.1, the set gain Gst can be changed by 0.1 times 0.1 (Gst= ..., 0.8, 0.9, 1.0, 1.1, 1, 2, ...).

[0077] In order for the maximum angular error of the rotation angle detection apparatus 100 to be less than or equal to 30 degrees, when the amplitude of the output signal after adjustment having the largest amplitude among the N output signals after adjustment Sadj is defined as the maximum amplitude, and the amplitude of the output signal after adjustment having the smallest amplitude among the N output signals after adjustment Sadj is defined as the minimum amplitude, the output adjuster 8 amplifies or attenuates each of the amplitudes of the output signals of N magnetic detection elements by the set gain Gst set for each of the N magnetic detection elements 7 so that an amplitude ratio obtained by dividing the maximum amplitude by the minimum amplitude becomes less than or equal to three.

[0078] A ratio (ΔSoff / ΔSamp) of the offset difference ΔSoff between the output signals with respect to the amplitude ΔSamp of the output signal that the maximum angular error becomes less than or equal to 30 degrees is less than or equal to 0.5 times of Fig. 18. The amplitude ΔSamp of the output signal normally does not exceed the maximum output signal that the output adjuster 8 can output. To adjust so that the ratio is less than or equal to 0.5, the set resolution of the set offset correction value Hst of the output adjuster 8 must be less than or equal to 0.5 times the value of the maximum output signal. For example, if the set resolution is 0.1, the set offset correction value Hst can be changed by 0.1 (Hst= ..., -0.2, -0.1, 0.0, 0.1, 0.2, ...). Here, for example, if the output adjuster 8 is a current amplifying circuit, the maximum output signal is the maximum current that can be output. If the output adjuster 8 is a voltage amplifying circuit, the maximum output signal is the maximum voltage that can be output.If the output adjuster 8 is a processor, the maximum output signal is the maximum computable value determined by the number of bits and the like.

[0079] In order to make the maximum angular error of the rotation angle detection apparatus 100 less than or equal to 30 degrees, when an offset value of the output signal after adjustment having the largest offset value of a vibration center (or oscillation center) of the output signal after adjustment among N output signals after adjustment is defined as the maximum value, an offset value of the output signal after adjustment having the smallest offset value of the vibration center among N output signals after adjustment is defined as the minimum value, and an amplitude of the output signal after adjustment having the largest amplitude among N output signals after adjustment is defined as the maximum amplitude, the output adjuster 8 offsets each of the output signals of N magnetic detection elements by the set offset correction value Hst set for each of the N magnetic detection elements 7 so that an offset difference,which is obtained by subtracting the minimum value of the offset from the maximum value of the offset, is less than or equal to 0. 5 times the value of the maximum amplitude. 4. Embodiment 4

[0080] The rotation angle detection apparatus 100 according to Embodiment 4 will be explained with reference to the drawings. Explanation of components common to those of Embodiment 1, 2, or 3 will be omitted. The basic configuration of the rotation angle detection apparatus 100 according to the present embodiment is the same as that of Embodiment 1, 2, or 3.

[0081] In the present embodiment, as shown in Fig. 20, at the time of manufacturing or servicing the rotation angle detecting apparatus 100, the parameter setter 29 sets the set gain Gst and the set offset correction value Hst of each magnetic detecting element 7 of the output adjuster 8.

[0082] The parameter setter 29 receives the output signal of each magnetic detection element 7 when the rotor 1 rotates and calculates an amplitude value and an offset value of the output signal of each magnetic detection element 7. Then, the parameter setter 29 calculates the adjusted gain Gst of each magnetic detection element 7, which cancels an amplitude difference between the amplitude value of the output signal of each magnetic detection element 7 and a target amplitude value. Subsequently, the parameter setter 29 sets the calculated target gain Gst of each magnetic detection element 7 to the output adjuster 8. The parameter setter 29 calculates the adjusted offset correction value Hst of each magnetic detection element 7, which cancels an offset difference between the offset value of the output signal of each magnetic detection element 7 and a target offset value.Then, the parameter setter 29 sets the calculated set offset correction value Hst of each magnetic detection element 7 to the output adjuster 8.

[0083] For example, if the output adjuster 8 is an analog circuit, the parameter adjuster 29 adjusts a resistance value of a variable resistor or the like of the output adjuster 8, which corresponds to the set gain Gst and the set offset correction value Hst, respectively. If the output adjuster 8 is a digital circuit, the parameter adjuster 29 writes the set gain value Gst and the set offset correction value Hst into a memory device of the output adjuster 8, which is used by a processor.

[0084] As methods for calculating the amplitude value from the output signal, there are a method of subtracting the minimum value from the maximum value of the output signal and a method of Fourier transforming the output signal and calculating it from an order component corresponding to one cycle of the electrical angle. The parameter setter 29 calculates a ratio between the calculated amplitude value and the target amplitude value and calculates an inverse of the ratio as the set gain. To calculate the offset value from the output signal, the parameter setter 29 calculates a time-averaged value of the output signal as the offset value, calculates the difference between the calculated offset value and the target offset value, and calculates positive and negative inverses of the difference as the set offset correction value Hst. 5. Embodiment 5

[0085] The rotation angle detection apparatus 100 according to Embodiment 5 will be explained with reference to the drawings. Explanation of components common to those of Embodiments 1 to 4 will be omitted. The basic configuration of the rotation angle detection apparatus 100 according to the present embodiment is the same as that of Embodiments 1 to 4.

[0086] As in Fig. As shown in Figure 2, there is an advantage in increasing the signal strength if the permanent magnet 5 is in the form of a single fan. If a plastic magnet is used in which magnetic particles are injection-molded together with thermoplastic resin, the strength can also be ensured in the fan shape. On the other hand, as shown in Fig. 21, N permanent magnets 5 corresponding to the number of N magnetic detection elements 7 are arranged radially outside each magnetic detection element 7. If plate-shaped sintered magnets are used, the total volume of the permanent magnets 5 can be reduced, and the cost can be reduced.

[0087] The permanent magnets 5 have manufacturing-related variations in their magnetic properties. If the fan shape is as shown in Fig. 2, due to the injection molding process, differences in the flux density of the surface occur in the radial direction or in the circumferential direction. If the plurality of permanent magnets 5, as shown in Fig. 21, there may be differences in the characteristics of individual permanent magnets. When such a production deviation exists, the amplitude difference and the offset difference increase compared to the values ​​expressed in Equation (14) and Equation (19).

[0088] However, by providing the output adjuster 8 satisfying the equation (16) and the equation (21), the difference due to the deviation in the permanent magnet 5 can also be reduced by the method described in each embodiment above. 6. Embodiment 6

[0089] The rotation angle detection apparatus 100 according to Embodiment 6 will be explained with reference to the drawings. Explanation of components common to those of Embodiments 1 to 5 will be omitted. The basic configuration of the rotation angle detection apparatus 100 according to the present embodiment is the same as that of Embodiments 1 to 5.

[0090] Fig. 22 is a diagram of the rotation angle detection apparatus 100 according to the present embodiment. Although Embodiment 1 explained the angle calculation method when the number of magnetic detection elements 7 is two, as mentioned above, by providing three or more magnetic detection elements 7, specific harmonic noise can be removed and tolerance to the disturbing magnetic field can be improved. Next, an angle calculation method when providing three or more magnetic detection elements 7 and a method for reducing the amplitude difference and the offset difference using the output adjuster 8 will be explained.

[0091] The output adjuster 8 amplifies or attenuates each of the amplitudes of the output signals S of the N magnetic detection elements 7 by the set gain Gst, which is set for each of the N magnetic detection elements 7, and outputs the output signal after adjustment Sadj. If the offset correction is performed, the output adjuster 8 offsets each of the output signals S of the N magnetic detection elements 7 by the set offset correction value Hst, which is set for each of the N magnetic detection elements 7. In the Fig. In the example shown in Figure 23, N output adjusters 8 are provided, corresponding to each of the N magnetic detection elements 7. N output signals after adjustment output from each of the N output adjusters 8 are input to the angle calculator 9. One output adjuster 8 may be provided, and one output adjuster 8 may individually adjust the output signals of the N magnetic detection elements 7.

[0092] As shown in Equation (22), the N-phase / two-phase converter 28 converts the output signals of the N magnetic detection elements 7 after adjustment Sadj into a sine value Ssinadj and a cosine value Scosadj, which have a phase difference of 90 degrees. Then, the angle calculator 9 calculates the angle θ by calculating the arctangent of the sine value Ssinadj and the cosine value Scosadj after adjustment. Herein, the calculation that converts N-phase signals into two-phase signals is referred to as N-phase / two-phase conversion. The N magnetic detection elements 7 are arranged circumferentially at equal angular intervals of 360 degrees / N in electrical angle. The N-phase / two-phase converter 28 and the angle calculator 9 can be integrally configured and executed by the same processor.The output adjuster 8, the N-phase / two-phase converter 28 and the angle calculator 9 can be integrally configured and executed by the same processor. [Math. 18] [SsinadjScosadj]=[cos(2π0N)cos(2π1N)…cos(2πN−1N)sin(2π0N)sin(2π1N)…sin(2πN−1N)][Sadj1Sadj2⋮SadjN]θ=tan−1(SsinadjScosadj)

[0093] Alternatively, the N-phase / two-phase converter 28, as shown in Fig. 24, the output adjuster 8 performs N-phase / two-phase conversion of the output signals S of the N magnetic detection elements 7 and calculates a sine value Ssin and a cosine value Scos. The sine value Ssin and the cosine value Scos after conversion correspond to "a plurality of conversion output signals" according to the present disclosure. Then, the output adjuster 8 amplifies or attenuates the post-conversion sine value Ssin and the cosine value Scos, respectively, by the set gain Gst set for each sine value Ssin and the cosine value Scos, and outputs the post-adjustment sine value Ssinadj and the cosine value Scosadj. At this time, the output adjuster 8 can correct the post-conversion sine value Ssin and the cosine value Scos by the set offset correction value Hst set for each of the sine values ​​Ssin and the cosine value Scos.In this case, a similar concept can be applied in Embodiments 1 to 5 by replacing the output signals of the N magnetic detection elements 7 with the sine value Ssin and the cosine value Scos after conversion (the plurality of conversion output signals). Then, the angle calculator 9 calculates the angle θ by calculating the arctangent of the sine value Ssinadj and the cosine value Scosadj after adjustment. The N-phase / two-phase converter 28, the output adjuster 8, and the angle calculator 9 can be configured integrally and executed by the same processor.

[0094] Alternatively, as in Fig. 25 shown, Fig. 23 and Fig. 24 can be combined with each other. That is, similar to the case of Fig. 23, the output adjuster 8 performs adjustment processing for each of the output signals S of the N magnetic detection elements 7. The N-phase / two-phase converter 28 performs the N-phase / two-phase conversion on the N output signals after adjustment Sadj and calculates the sine value Ssinadj and the cosine value Scosadj after adjustment. Then, the output adjuster 8, similar to the case of Fig. 24, the processing of adjusting the sine value Ssinadj and the cosine value Scosadj again after the adjustment. The angle calculator 9 calculates the angle θ by calculating the arctangent of the sine value Ssinadj2 and the cosine value Scosadj2 after the second adjustment. The N-phase / two-phase converter 28, the output adjuster 8, and the angle calculator 9 can be configured integrally and executed by the same processor. If the number of processings by the output adjuster 8 is increased, the angle error can be smaller than in the case of Fig. 23 or Fig. 24. This is because in the case of Fig. 23 the N-phase signals are digitally converted by the N-phase / two-phase converter 28, but differences due to quantization errors occur in the two-phase signals during digital conversion. This is because in the case of Fig. 24 the N-phase signals are converted N-phase / two-phase with the amplitude differences and the offset differences, so that distortion occurs in the two-phase signals after the conversion and the output adjuster 8 cannot completely remove the distortion. 7. Embodiment 7

[0095] The rotation angle detection apparatus 100 according to Embodiment 7 will be explained with reference to the drawings. Explanation of components common to those of Embodiments 1 to 6 will be omitted. The basic configuration of the rotation angle detection apparatus 100 according to the present embodiment is the same as that of Embodiments 1 to 6.

[0096] In the present embodiment, as shown in Fig. 26, the stator 4 is arranged radially inside the rotor 1. If the rotor 1 has the same diameter, the diameters of the permanent magnet 5 and the yoke 6 are smaller compared to the configuration of Fig. 1 so that the stator 4 can be made smaller and more cost-effective.

[0097] The concave and convex portion 3 is formed radially inside the end of the cylindrical rotor 1, and the protrusion height in the radial direction inside changes in the circumferential direction. The protrusion height of the concave and convex portion 3 toward the radially inside changes in the circumferential direction in the shape of a sine wave. The permanent magnet 5 is arranged radially inside the concave and convex portion 3. The bracket 6 is provided with an arc part 10 arranged on the radially inside of the permanent magnet 5 and extending in the circumferential direction, a first end part 11 protruding outward in the radial circumferential direction from the circumferential end of the arc part 10 on one side, and a second end part 12 protruding outward in the radial direction from the circumferential end of the arc part 10 on the other side.The magnetic detection elements 7 are arranged radially outside the permanent magnet 5.

[0098] Although the present disclosure is described above with respect to various exemplary embodiments and implementations, it should be understood that the various features, aspects, and functions described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but may be applied alone or in various combinations to one or more of the embodiments. It is therefore understood that numerous modifications not shown by way of example may be devised without departing from the scope of the present disclosure. For example, at least one of the components may be modified, added, or eliminated.At least one of the components mentioned in at least one of the preferred embodiments can be selected and combined with the components mentioned in another preferred embodiment. LIST OF REFERENCE SYMBOLS

[0099] 1: Rotor, 2: Rotating shaft, 3: Concave and convex section, 4: Stator, 5: Permanent magnet, 6: Bracket, 7: Magnetic detection element, 8: Output adjuster, 9: Angle calculator, 10: Arc part, 11: First end, 12: Second end, 100: Rotation angle detection device, A: Half angle of the end-to-end angle of the bracket, Cmax: Maximum angle interval of the magnetic detection element, Gmax: Upper limit gain, Gmin: Lower limit gain, Gst: Set gain, Hmax: Upper limit of the offset correction value, Hmin: Lower limit of the offset correction value, Hst: Set offset correction value, S: Output signal of the magnetic detection element, Sadj: Output signal after adjustment, θ: Angle QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2018 / 078856 A

[0003] < / winkelrechner> < / ausgabeanpasser> < / stator> < / rotor>

Claims

[1] Rotation angle detection apparatus comprising: a rotor that rotates centered around an axis of rotation; a stator having one or more permanent magnets, a bracket, and a plurality of magnetic detection elements; and an output adjuster that adjusts each of the output signals of the plurality of magnetic detection elements or a plurality of conversion output signals converted from the output signals of the plurality of magnetic detection elements and outputs a plurality of output signals after adjustment, wherein in an opposite surface of the rotor opposite to the stator, Q concave and convex portions (Q is an integer greater than or equal to 2) are formed, the protrusion height of which toward the stator changes periodically in a curved shape in a circumferential direction, the one or more permanent magnets are opposite the concave and convex portions and are arranged side by side in the circumferential direction, the bracket has an arc portion disposed on a side opposite the concave and convex portion with respect to the one or more permanent magnets and extending in the circumferential direction, a first end projecting from one end of the arc portion in a circumferential direction on one side to the side of the concave and convex portion, and a second end projecting from one end of the arc portion in a circumferential direction on the other side to the side of the concave and convex portion, the plurality of magnetic detection elements are arranged circumferentially on the side of the concave and convex portions with respect to the one or more permanent magnets with a gap to the concave and convex portions and detect a flux density between the permanent magnet and the concave and convex portions, the output adjuster amplifies or attenuates each of the amplitudes of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals by a set gain that is set for each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals within a range from an upper limit gain that can be set to a lower limit gain that can be set, when an angle obtained by multiplying Q by a mechanical angle is defined as an electrical angle, a half angle of an end-to-end angle, which is an angle between the first end and the second end, is defined as A degrees in the electrical angle, a value obtained by dividing A degrees by 90 degrees and rounding up under one decimation is defined as M, the upper limit gain is defined as Gmax, and the lower limit gain is defined as Gmin, and if M is an odd number, “Gmax / Gmin>-0.0031×A+0.28×M+1.07” is set, if M is an even number, “Gmax / Gmin>0.0031×A-0.28×M+1.35” is set. [2] The rotation angle detecting apparatus according to claim 1, wherein a set resolution of the set gain is less than or equal to three. [3] Rotation angle detection apparatus according to claim 1 or 2, wherein, when an amplitude of the output signal after adjustment having a largest amplitude among the plurality of output signals after adjustment is defined as a maximum amplitude, and an amplitude of the output signal after adjustment having a smallest amplitude among the plurality of output signals after adjustment is defined as a minimum amplitude, the output adjuster amplifies or attenuates each of the amplitudes of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals by the set gain set for each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals so that an amplitude ratio obtained by dividing the maximum amplitude by the minimum amplitude becomes less than or equal to three. [4] Rotation angle detection apparatus according to one of claims 1 to 3, wherein the output adjuster offsets each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals by a set offset correction value, which is set for each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals within a range from an upper limit of the offset correction value that can be set to a lower limit of the offset correction value that can be set, when the upper limit of the offset correction value is defined as Hmax, the lower limit of the offset correction value is defined as Hmin, and an angle between the magnetic detection element arranged in the lowest circumferential direction on one side and the magnetic detection element arranged in the lowest circumferential direction on the other side is defined as Cmax degrees in mechanical angle, “(Hmax-Hmin) / Gmax>0.11-0.11xcos(Cmaxxn / 180)” is set. [5] The rotation angle detecting apparatus according to claim 4, wherein a set resolution of the set offset correction value is less than or equal to 0.5 times the value of a maximum output signal that can be output from the output adjuster. [6] Rotation angle detection apparatus according to claim 4 or 5, wherein, when an offset value of the output signal after adjustment having a largest offset value of a vibration center of the output signal after adjustment among the plurality of output signals after adjustment is defined as a maximum offset value, an offset value of the output signal after adjustment having a smallest offset value of the vibration center among the plurality of output signals after adjustment is defined as a minimum offset value, and an amplitude of the output signal after adjustment having a largest amplitude among the plurality of output signals after adjustment is defined as a maximum amplitude, the output adjuster offsets each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals by the set offset correction value set for each of the output signals of the plurality of magnetic detection elements or the plurality of conversion output signals, so that an offset difference obtained by subtracting the minimum offset value from the maximum offset value becomes less than or equal to 0.5 times the value of the maximum amplitude. [7] The rotation angle detecting apparatus according to any one of claims 1 to 6 further comprises an angle calculator that calculates an angle of the rotor based on the plurality of output signals after adjustment.

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