JP5162435B2 - Rotation angle detector - Google Patents

Description

  The present invention relates to a rotation angle detection device suitable for being applied to vehicles such as passenger cars, trucks, and buses.

  2. Description of the Related Art Conventionally, in a rotating electrical machine such as a motor, a motor generator used in a hybrid vehicle or an electric vehicle, and an EPS (Electronic Power Steering) motor used in a normal passenger car, a rotation angle detection device for detecting a rotation angle of a rotor has been provided. In addition, the efficiency of the rotating electrical machine is increased by performing appropriate control according to the detected rotation angle.

  Such rotation angle detectors generally require high environmental resistance including heat resistance and vibration resistance. Therefore, instead of magnetic encoders using optical encoders or magnetoresistive elements, environmental resistance It is common to use a resolver with a high value.

  As such a resolver, there exists a thing as described in patent document 1, for example. The resolver includes an inductor-type rotor to be detected that is drive-coupled to a rotor shaft included in a rotating electrical machine, the diameter of which is periodically changed in the circumferential direction, and a stator that is positioned in an arc shape on the outer circumferential side of the rotor. And a plurality of teeth arranged at equal intervals in the circumferential direction of the stator and directed radially inward of the rotor, an excitation coil wound around the plurality of teeth, and a detection coil for detecting sine and cosine.

  In the resolver as described in Patent Document 1, when an excitation voltage is applied to the excitation coil, an air gap, that is, a magnetic resistance between each of the plurality of teeth and the rotor changes as the rotor rotates. By detecting a change in the output signal generated in the coil, the arc tangent of the quotient of the two sets of output signals of sine and cosine can be calculated by an R / D (Resolver Digital) converter to obtain the rotation angle.

  Such a resolver is referred to as a transformer type or a variable reluctance type because a rotation angle is obtained by a change in an output signal generated in a detection coil due to a change accompanying rotation of an air gap rotor.

In particular, in the resolver as described in Patent Document 1, since the stator has an arc shape, the number of teeth is the minimum necessary for excitation and detection compared to the stator having an annular shape. The volume is reduced to reduce manufacturing costs and product weight.
Japanese Patent Laid-Open No. 2002-168652

  However, in a resolver in which such a stator has an arc shape, the following problems occur as compared with an annular stator. The arc-shaped stator is provided, for example, by means such as fitting and fastening on the axial end surface or outer peripheral surface of the casing of the rotating electrical machine, and is ideal for various reasons such as assembly errors and operation play during installation. Deviation from position occurs. Further, the rotor is also provided by being fitted to the shaft of the rotor on the rotating electrical machine side, and this also deviates from an ideal position upon installation. For this reason, when the arc center of the arc-shaped stator does not coincide with or is inclined with respect to the central axis of the rotor, eccentricity occurs.

  When the stator is annular, even if such eccentricity occurs, the plurality of teeth included in the stator are provided over the entire circumference, so a pair of teeth positioned on the opposite sides in the radial direction. If the windings of the pair of detection coils wound around the teeth are connected to each other, the output voltage of the detection coil wound around the teeth due to the change in the air gap between the teeth and the rotor due to eccentricity Even if changes, the output voltage of one of the pair of detection coils becomes high, but the output voltage of the other becomes low, so the change in the total output voltage is canceled between the opposite sides in the radial direction. However, in the case of an arc-shaped stator, since such a canceling force does not act, there arises a problem that the detection accuracy decreases with a change in output voltage.

  An object of this invention is to provide the rotation angle detection apparatus which can raise detection accuracy more in view of the said problem.

In order to solve the above problem, the rotation angle detection device according to the present invention is:
A rotor, an excitation coil, a detection coil, and a stator including a plurality of teeth, wherein the plurality of teeth are positioned on an outer peripheral side of the rotor around which the excitation coil and / or the detection coil are wound. The contour shape on the radially inner side of the plurality of teeth in a cross section perpendicular to the central axis of the rotor and extending radially inward of the rotor includes a convex shape that is convex radially inward . The convex shape is a curved shape including any one of a circular shape, an elliptical shape, a quadratic curve shape, and an exponential function shape .

  Here, the rotor is an inductor-type rotor to be detected whose diameter periodically changes in the circumferential direction, and is, for example, drivingly coupled to a shaft included in a rotor of a rotating electrical machine to be detected.

  According to this, when an excitation voltage is applied to the excitation coil, a magnetic flux associated with the excitation voltage is released from the radially inner end face of the teeth around which the excitation coil is wound, and the released magnetic flux After entering the rotor, the magnetic flux emitted from the rotor enters the radially inner end face of the tooth around which the detection coil is wound.

  In this case, the radially inner end surface of the tooth is the convex shape in which the contour shape is convex inward in the radial direction, and thus the contour shape is convex inward in the radial direction. A saddle shape or a substantially U shape is formed continuously in the axial direction of the rotor, and the magnetic flux is intensively emitted from the vicinity of the center in the circumferential direction of the end face, and the emitted magnetic flux passes through the rotor. After that, the detection coil is intensively entered from the vicinity of the center in the circumferential direction of the end face into the tooth around which the detection coil is wound.

  By the way, the shape of the end surface on the radially inner side of the teeth of the normal resolver to which the present invention is not applied becomes a concave cylindrical surface shape toward the radially inner side formed around the central axis of the rotor. With such a cylindrical end surface, the magnetic flux that is released or enters will pass uniformly over the entire circumferential region of the cylindrical end surface.

  For this reason, the air gap between the teeth and the rotor, when the mutual positional relationship between the stator and the rotor is eccentric from an ideal position, the air gap at the circumferential end of the teeth and the teeth The air gap at the center in the circumferential direction is greatly different, and the amount of change in the air gap increases.

  However, according to the rotation angle detection device of the present invention, the end face is convex toward the inside in the radial direction, and the emitted or entering magnetic flux intensively passes near the center in the circumferential direction of the end face. It will be. For this reason, the air gap between the teeth and the rotor can be the shortest distance in the gap between the rotor and the narrow region including the center in the circumferential direction of the end surface on the radially inner side of the teeth. Even when this occurs, the amount of change in the air gap can be reduced.

  As described above, in the rotation angle detection device according to the present invention, the amount of change in the air gap can be reduced even when the eccentricity occurs by making the shape of the end surface convex inward in the radial direction. Therefore, the change in the output voltage of the detection coil can be suppressed, and the detection accuracy can be further increased.

Incidentally, in the rotation angle detecting device,
The convex shape is a curved shape including any one of a circular shape, an elliptical shape, a quadratic curve shape, and an exponential function shape .

  In any case, the convex shape can be oriented inward in the radial direction. Which of these is selected is appropriately determined based on the efficiency of the rotation angle detection device in each shape and ease of forming the teeth. can do.

Furthermore, in the rotation angle detection device,
The convex shape may be symmetric with respect to a circumferential center of the contour shape.

  In the first place, in the rotation angle detection device, the teeth are required to be installed at equal intervals in the circumferential direction with respect to the stator, and thereby an excitation voltage is applied from the teeth to the excitation coil. Is more evenly distributed to the plurality of teeth around which the detection coil is wound.

  Under this precondition, based on the fact that the convex shape is symmetric with respect to the circumferential center of the contour shape, the convex shape is made coincident with the circumferential center of the teeth, thereby mainly releasing and absorbing magnetic flux. The circumferential center of each convex shape of each of the teeth that fulfills the above function can be positioned at equal intervals in the circumferential direction, thereby generating an excitation voltage from the teeth to the excitation coil. Even in the present invention, it is possible to ensure that the magnetic flux is more evenly distributed to the plurality of teeth around which the detection coil is wound.

In addition, in the rotation angle detection device,
The convex shape may be formed in a predetermined range shorter than a circumferential length of the contour shape, and the contour shape outside the predetermined range may be a linear shape.

  As described above, a narrow region including the convex center in the circumferential direction has a function of mainly releasing the magnetic flux and absorbing the magnetic flux, and greatly contributes to the function except for the predetermined region including the circumferential center. Therefore, the contour shape other than the predetermined region can be a linear shape.

  As described above, the predetermined region including the circumferential center of the contour shape is the curved shape, and the vicinity of the circumferential end other than the predetermined region is the linear shape. Compared with the curved shape, the volume of the teeth can be more easily reduced.

Furthermore, in the rotation angle detection device,
It is preferable that the stator extends in an arc shape over a part of the rotor in the circumferential direction.

  In other words, the rotation angle detection device of the present invention is preferably applied when the stator is a so-called C-type that has an arc shape.

Furthermore, in the rotation angle detection device,
It is preferable that the contour shape of the teeth around which the detection coil is wound out of the plurality of teeth includes the convex shape.

  According to this, the change in the output voltage due to the eccentricity that affects the detection accuracy has a high contribution rate due to the amount of change in the air gap between the teeth around which the detection coil is wound and the rotor. By applying the contour shape including the convex shape to the teeth around which the detection coil is wound, the detection accuracy can be improved more effectively.

  Note that the so-called C type type of the rotation angle detecting device described above is limited to the length of the stator by limiting the extension range in the circumferential direction of the stator to an arc shape compared to the annular type in the first place. The number of teeth is intended to be as short as possible, and four teeth are required to detect sin and cos that are 90 degrees out of phase. Thus, a pair of teeth exclusively for excitation provided for increasing the detection accuracy of the detection coil is required on both sides in the circumferential direction of the four teeth, and therefore, those having six teeth are mainstream.

In response to this, in the rotation angle detection device,
It is preferable that the contour shape other than the pair of teeth positioned at both ends in the circumferential direction of the stator among the plurality of teeth includes the convex shape.

  That is, the change in the output voltage due to the eccentricity that affects the detection accuracy has a high contribution rate due to the amount of change in the air gap between the tooth around which the detection coil is wound and the rotor. By applying the convex shape to the teeth other than the pair of teeth around which the detection coil is wound, the detection accuracy can be more effectively increased.

Here, in the rotation angle detection device,
Of the plurality of teeth, the contour shape of the pair of teeth positioned at both ends in the circumferential direction of the stator is preferably an arc shape centered on the central axis of the rotor.

  That is, in the C-type rotation angle detection device, the pair of teeth are teeth dedicated to excitation, and thus the effect of increasing the detection accuracy by making the contour shape the convex shape is relatively thin. For this reason, the pair of teeth can have rather high efficiency in generating magnetic flux as teeth dedicated to excitation, with the arc shape being concave with respect to the conventional circumferential inner side.

  ADVANTAGE OF THE INVENTION According to this invention, the rotation angle detection apparatus which can raise detection accuracy more can be provided.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an embodiment of a rotation angle detecting device, that is, a resolver according to the present invention. Since the general configuration of a C-type resolver is well known, the configuration according to the present invention is shown here. Only the elements are shown, and the other components are not shown.

  As shown in FIG. 1, the resolver 1 of this embodiment includes a rotor 2, an excitation coil 3, detection coils 4 s and 4 c, a pair of teeth 51 and teeth 56 around which only the excitation coil 3 is wound, Teeth 52 and 54 around which the coil 3 and the detection coil 4s are wound, teeth 53 and 55 around which the detection coil 4c is wound, and a stator 6 including the teeth 51 to 56 as parts.

  The rotor 2 is drive-coupled to a shaft of a rotor of a rotating electric machine (not shown), and has a petal shape having five petals whose outer diameter increases and decreases in five cycles per rotation around the central axis C in the circumferential direction. As the rotor of the rotating electrical machine (not shown) is formed, the air gap between the stator 61 and the teeth 51 to 56 is rotated in the circumferential direction so that the air gap with the teeth 51 to 56 per rotation is five cycles. Change.

  The stator 6 has a diameter of the rotor 2 from an arcuate portion 6a having an arcuate shape that forms a part of an annular shape centering on the central axis C, and an inner circumferential surface of the arcuate portion 6a located on the outer peripheral side of the rotor 2. A plurality of teeth 51 to 56 extending inward in the direction is included. The teeth 51 to 56 and the arc-shaped portion 6a are integrally configured by laminating, for example, silicon steel plates integrally formed by machining such as press working in the central axis C direction. In addition, the teeth 51-56 are attached | subjected the code | symbol in the clockwise order in FIG.

  The exciting coil 3 is formed by winding a winding around an insulating resin such as a bobbin (not shown) on all the teeth 51 to 56, and an excitation voltage is applied to the winding by an exciting circuit (not shown). Thus, a magnetic flux is generated, and the magnetic flux is released from the radially inner end surfaces of the respective teeth 51 to 56, and the released magnetic flux enters the rotor 2 through the air gap. The magnetic flux that has entered the rotor 2 again enters the teeth 52 to 55 from the radially inner end face of the teeth 52 to 55 through the air gap.

  The detection coil 4s is configured by winding a winding around the teeth 52 and 54 via an insulating resin such as a bobbin (not shown), and is based on magnetic flux input to the radially inner end faces of the teeth 52 and 54. Thus, a sine output signal is output. In addition, although both the exciting coil 3 and the detection coil 4s are wound around the teeth 52 and 54, the exciting coil 3 is arranged on the bobbin side, that is, the inner layer side, and the detection coil 4s is opposite to the bobbin, that is, the outer layer. Placed on the side.

Similarly, the detection coil 4c is configured by winding a winding around the teeth 53 and 55 via an insulating resin such as a bobbin (not shown), and the cosine is generated based on the magnetic flux input to the radially inner end face. The output signal is output. Here, both the exciting coil 3 and the detecting coil 4c are wound around the teeth 53 and 55, but the exciting coil 3 is arranged on the bobbin side, that is, the inner layer side, and the detecting coil 4c is opposite to the bobbin, that is, It is arranged on the outer layer side.
The output terminals of the detection coils 4s and 4c are both connected to an R / D converter (not shown), and an output signal is output to the R / D converter.

  In a state where the rotating electrical machine is driven by a drive circuit such as an inverter (not shown) and the rotor is rotating, when a high-frequency excitation voltage is applied to the excitation coil 3 by an excitation circuit (not shown), the rotor 2 that is drivingly coupled to the rotor. Is rotated accordingly, and the shortest distance of the gap between the radially inner end face of the teeth 52 to 55 and the petal-like outer peripheral portion of the rotor 2, that is, the air gap increases or decreases in five cycles per rotation, thereby detecting The output signal generated in the coils 4s and 4c changes. Based on the change in the output signal, the rotation angle is calculated by the R / D converter.

  In such a C-type resolver 1 of this embodiment, the shapes of the respective teeth 51 to 56 are formed as follows. FIG. 2 is a schematic cross-sectional view showing a part of an embodiment of the resolver according to the present invention. Each of the teeth 51 to 56 in the schematic view shown in FIG. 1 is perpendicular to the central axis C and in the direction of the central axis C. It is shown in a cross section at an arbitrary position.

  As shown in FIG. 1, among the teeth 51 to 56 that the stator 6 of the resolver 1 has six teeth 51 to 56 provided at equal intervals in the circumferential direction on the inner circumferential surface of the arc-shaped portion 6 a, a pair of circumferential ends at which only the exciting coil 3 is provided. 2, the contour shapes 51E and 56E in the cross section perpendicular to the central axis C direction of the radially inner end faces of the teeth 51 and 56 are centered on the central axis C conventionally used as shown by the broken line in FIG. The arc shape is a concave shape in the radial direction, that is, the direction toward the rotor 2, and the end surfaces of the teeth 51 and 56 form a partial cylindrical shape in which the arc shape extends in the central axis C direction.

  Further, among the teeth 51 to 56, the contour shapes 52E to 55E in the cross section perpendicular to the central axis C direction of the radially inner end surfaces of the teeth 52 to 55 provided with the excitation coil 3 and the detection coil 4s or the detection coil 4c. Includes convex shapes 52 a to 55 a that are convex radially inward, that is, in a direction toward the rotor 2, as indicated by a solid line in FIG. 2. The convex shapes 52a to 55a may be any curved shape such as a circular shape, an elliptical shape, a quadratic curve shape, and an exponential function shape.

  Further, the contour shapes 52E to 55E will be described in detail. 3 is a schematic cross-sectional view showing a part of an embodiment of the resolver according to the present invention shown in FIG. 2, and the contour shapes 52E-55E of the respective teeth 52-55 in the schematic cross-sectional view shown in FIG. It is only shown.

  As shown in FIG. 3, the convex shapes 52a to 55a are formed symmetrically with respect to the circumferential center φ of the contour shapes 52E to 55E, and are shorter than the circumferential length L of the contour shapes 52E to 55E. The contour shapes 52E to 55E that are formed in the range S and outside the predetermined range S are formed to be linear shapes 52b to 55b.

  According to the resolver 1 of the present embodiment described above, the following operational effects can be obtained. The operation and effect will be described below with reference to the drawings. 3 to 12 are schematic views showing the operational effects of an embodiment of the resolver according to the present invention.

  Also in the C-type resolver 1 as in this embodiment, the center of the circular ring formed by extending the arc-shaped portion 6a of the stator 6 in the circumferential direction and the center axis C of the rotor 2 are actually assembly errors. Eccentricity may occur due to various factors such as backlash and operating play. When such eccentricity occurs, if the contour shapes 52E to 55E on the radially inner end faces of the teeth 52 to 55 do not include the convex shapes 52a to 55a as described above, the amount of change in the air gap is large due to the eccentricity. Thus, the output voltage of the detection coils 4s and 4c varies, and the total detection error increases.

  In the resolver 1 of the present embodiment, the contour shapes 52E to 55E of the teeth 52 to 55 have the convex shapes 52a to 55a, respectively, so that the magnetic flux is concentrated in the vicinity of the circumferential center φ of the contour shapes 52E to 55E. It is possible to avoid an increase in the amount of change in the air gap.

  Hereinafter, this effect will be described in more detail with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing the magnetic path, that is, the flow of magnetic flux, in an embodiment of the rotation angle detecting device or resolver according to the present invention. 5 to 10 are schematic cross-sectional views showing an air gap in an embodiment of a rotation angle detecting device, that is, a resolver according to the present invention based on comparison with the prior art.

  4, the tooth 53 and the excitation coil 3, and the tooth 54 and the detection coil 4s are representatively picked up from the magnetic path configuration in FIG. That is, when the exciting tooth 53 has the convex shape 53a, the magnetic flux generated by applying the excitation voltage to the exciting coil 3 is released around the vicinity of the center φ in the circumferential direction of the convex shape 53a, and the air gap A The magnetic flux that has entered the rotor 2 passes through the rotor 2, and the magnetic flux that has entered the rotor 2 passes through the air gap B through the air gap B after being discharged from the rotor 2, for example, through one petal portion in the circumferential direction. The convex shape 54a provided on the side tooth 54 enters around the vicinity of the circumferential center φ.

  These are basically the same in other combinations of the teeth 51 to 56, but the magnetic flux emitted from the teeth 51 and 56 dedicated for excitation is emitted from the entire circumferential direction of the end portions 51E and 56E. .

  Here, in FIG. 5, the resolver which does not include the convex shapes 53a and 54a in the prior art and FIG. 5A and the radially inner tip including the convex shapes 53a and 54a according to the present embodiment are round. In both of FIGS. 5 (b) showing the resolver 1, the circumscribed circle of the rotor 2 in the ideal state, that is, when there is no eccentricity, is indicated by a broken line as the position of the normal rotor 2, and the rotor 2 is positioned relative to the position of the normal rotor 2 When the eccentricity is generated in the upper direction indicated by UP in FIG. 5, that is, in the direction approaching the teeth 53 and 54 illustrated as picked up, that is, in the same direction as the eccentric direction, the air gap narrows the circumscribed circle of the rotor 2 after the eccentricity. The center axis C of the circumscribed circle of the rotor 2 after eccentricity is shown as the rotor 2 position.

  As shown in FIG. 5A, in the prior art, the post-change air gap A after the eccentricity, that is, after the position has changed, is shortened with respect to the normal air gap A corresponding to the tooth 53 at the normal rotor 2 position. With respect to the normal air gap B corresponding to the teeth 53 at the position of the normal rotor 2, the post-change air gap B after the eccentricity, that is, after the position is changed, is also shortened.

  On the other hand, according to the present embodiment, as shown in FIG. 5 (b), with respect to the normal air gap A corresponding to the teeth 53 at the position of the normal rotor 2, the change after eccentricity, that is, after the position has changed. The rear air gap A is shortened at a lower ratio than the prior art, and the post-change air gap B after the eccentricity, that is, after the position is changed, is also the prior art with respect to the normal air gap B corresponding to the teeth 53 at the normal rotor 2 position. Shorter at a lower rate.

  As a result, the sum of the normal air gap A and the normal air gap B in FIG. 5A becomes H1 indicated by the arrow on the left side in FIG. 6, and the changed air gap A and the changed air gap B in FIG. Is the H2 indicated by the left and right center arrows in FIG. 6, and the sum of the changed air gap A and the changed air gap B shown in FIG. 5B is H3 indicated by the right arrow in FIG. , H1> H3> H2, and the magnitude relationship between these sums indicates the difference in the amount of change in the air gap. Therefore, the amount of change in the air gap is greater than that in the prior art shown in FIG. As a small amount in the present embodiment shown in (b), the amount of change in the air gap can be suppressed and alleviated.

  7 shows a resolver that does not include the convex shapes 53a and 54a in the prior art, and a resolver having a round inner tip including the convex shapes 53a and 54a according to the present embodiment. In FIG. 7B showing 1, the circumscribed circle of the rotor 2 in the ideal state, that is, when there is no eccentricity, is indicated by a broken line as the position of the normal rotor 2, and the rotor 2 is illustrated with respect to the position of the normal rotor 2. 7 in which the air gap is narrowed in the circumscribed circle of the rotor 2 after eccentricity when the eccentricity occurs in the downward direction indicated by B in FIG. 7, that is, in the direction away from the teeth 53 and 54 shown in FIG. The center axis C of the circumscribed circle of the rotor 2 after eccentricity is shown as two positions.

  As shown in FIG. 7 (a), in the prior art, the post-change air gap A after the position change after eccentricity becomes longer than the normal air gap A corresponding to the teeth 53 at the normal rotor 2 position, With respect to the normal air gap B corresponding to the teeth 53 at the position of the normal rotor 2, the post-eccentric change air gap B also becomes longer.

  On the other hand, according to the present embodiment, as shown in FIG. 7 (b), with respect to the normal air gap A corresponding to the teeth 53 at the position of the normal rotor 2, the change after the eccentricity, that is, the position is changed. The rear air gap A becomes longer at a ratio substantially equal to that of the prior art, and the post-change air gap B after the eccentricity, that is, after the position is changed, with respect to the normal air gap B corresponding to the teeth 53 at the normal rotor 2 position, It becomes longer at a ratio almost the same as that of the prior art.

  As a result, the sum of the normal air gap A and the normal air gap B in FIG. 7A becomes H4 indicated by the left arrow in FIG. 8, and the changed air gap A and the changed air gap B in FIG. The sum of the changed air gap A and the changed air gap B shown in FIG. 7B is H7 shown in the right arrow in FIG. H4 <H5≈H6, and the amount of change in the air gap can be made substantially equal to that of the prior art shown in FIG.

  Further, FIG. 9 shows a resolver that does not include the convex shapes 53a and 54a in the prior art, and a resolver having a round inner tip including the convex shapes 53a and 54a according to the present embodiment. 9B, the circumscribed circle of the rotor 2 in the ideal state, that is, when there is no eccentricity, is indicated by a broken line as the position of the normal rotor 2, and the rotor 2 is illustrated with respect to the position of the normal rotor 2. 9, the rotor 2 after the eccentricity when the eccentricity is generated in the right direction, that is, picked up and separated from the tooth 53 shown in the figure, and deviated in the direction approaching the tooth 54, that is, the direction perpendicular to the eccentric direction. The circumscribed circle is shown as the position of the rotor 2 where the air gap is narrowed, and the center axis C of the circumscribed circle of the rotor 2 after eccentricity is shown.

  As shown in FIG. 9A, in the prior art, the post-change air gap A after the change in position after the eccentricity becomes longer than the normal air gap A corresponding to the teeth 53 at the normal rotor 2 position, With respect to the normal air gap B corresponding to the teeth 53 at the normal rotor 2 position, the post-eccentric change air gap B becomes shorter.

  On the other hand, according to the present embodiment, as shown in FIG. 9B, the change after the eccentricity, that is, after the position is changed, with respect to the normal air gap A corresponding to the tooth 53 at the position of the normal rotor 2. The rear air gap A becomes longer at a lower ratio than the prior art, and the post-change air gap B after the eccentricity, that is, after the position has changed, is also the prior art with respect to the normal air gap B corresponding to the teeth 53 at the normal rotor 2 position. Shorter at a lower rate.

  As a result, the sum of the normal air gap A and the normal air gap B in FIG. 9A becomes H7 indicated by the left arrow in FIG. 10, and the changed air gap A and the changed air gap B in FIG. 9A. The sum of the changed air gap A and the changed air gap B shown in FIG. 9B is H9 shown in the right arrow in FIG. , H7> H8> H9, and the amount of change in the air gap is smaller than that in the prior art shown in FIG. This is the same when moving in the direction opposite to the direction indicated by R in FIG.

  As described above, when the eccentric direction of the rotor 2 is a direction close to the stator 6, a direction perpendicular to the direction approaching or separating from the stator 6, the amount of change in the air gap is suppressed compared to the prior art, and the eccentric direction of the rotor 2 Even in the direction away from the stator 6, the amount of change in the air gap can be suppressed and alleviated when the possible eccentric directions are totaled, as in the prior art. Thereby, in the resolver 1 of a present Example, the fluctuation | variation of an output voltage can be suppressed and relieved and detection accuracy can be improved. When this relaxation effect is simulated, it becomes about 10%.

  That is, as described above, according to the resolver 1 of the present embodiment, when an excitation voltage is applied to the excitation coil 3 by the excitation circuit, for example, radially inward of the teeth 52 to 55 around which the excitation coil 3 is wound. The magnetic flux accompanying the excitation voltage is released from the end face of the coil, the released magnetic flux enters the rotor 2 and is released from the rotor 2, and the magnetic flux is radially inward of the teeth 52 to 55 around which the detection coils 4s or 4c are wound. It will enter the end face of.

  In this magnetic flux path, the radially inner end faces of the teeth 52 to 55 include convex shapes 52a to 55a in which the contour shapes 52E to 55E are convex radially inward, so that the contour shapes 52E to 55E are radially inward. It is a saddle shape formed continuously in the axial direction of the rotor 2 that is convex, and the magnetic flux emitted from the teeth 52 to 55 itself and the magnetic flux emitted and entered from the rotor 2 are both the highest. Since it has a property of traveling along a short route, it passes through the vicinity of the center φ in the circumferential direction of the end faces of the teeth 52 to 55 in a concentrated manner.

  For this reason, according to the resolver 1 of the present embodiment, the contour shapes 52E to 55E of the end surface are convex toward the inner side in the radial direction, and the magnetic flux to be emitted and the incoming magnetic flux concentrate in the vicinity of the center φ in the circumferential direction of the end surface. Will be allowed to pass through. In particular, since the incoming magnetic flux can be converged in the vicinity of the circumferential center φ, the air gap between the teeth 52 to 55 and the rotor 2 is equal to the circumferential center φ of the radially inner end face of the teeth 52 to 55. Since the shortest distance in the gap between the narrow region including the rotor 2 can be set, the amount of change in the air gap can be reduced even when the rotor 2 is eccentric with respect to the stator 6.

  Also in the C-type resolver 1 of the present embodiment, the teeth 51 to 56 are installed at equal intervals in the circumferential direction on the inner peripheral surface of the arcuate portion 6a of the stator 6, and thereby, from the teeth 51 to 56. Magnetic flux generated by applying an excitation voltage to the excitation coil 3 by the excitation circuit is distributed as uniformly as possible to the teeth 52 to 55 around which the detection coils 4s or 4c are wound.

  In the teeth 52 to 55 arranged at equal intervals in the circumferential direction as described above, the convex shapes 52a to 55a are formed symmetrically with respect to the circumferential center φ of the contour shapes 52E to 55E. ˜55a can be made to coincide with the circumferential center φ of the teeth 52 to 55, and thereby the circumferential centers of the convex shapes 52a to 55a of the teeth 52 to 55 that mainly perform the function of releasing and absorbing the magnetic flux. Can be positioned at equal intervals in the circumferential direction. Thereby, even if it has convex shape 52a-55a like a present Example, with respect to the teeth 52-55 by which the detection coils 4s and 4c were wound, the magnetic flux generate | occur | produced and discharge | released from the teeth 52-55 is radiated | emitted. More evenly distributed.

  Further, in the resolver 1 of the present embodiment, the convex shapes 52a to 55a are formed in a predetermined range S shorter than the circumferential length L of the contour shapes 52E to 55E, and the contour shapes 52E outside the predetermined range S, that is, both sides in the circumferential direction. The following advantageous effects can be obtained by setting the linear shapes 52b to 55b to -55E.

  That is, the predetermined region S, which is a narrow region including the circumferential center φ of the convex shapes 52a to 55a, has a function of mainly releasing the magnetic flux and absorbing the magnetic flux. Since it does not contribute much to the function of releasing and absorbing, the contour shapes 52E to 55E other than the predetermined region S can be linear shapes 52b to 55b that are easier to mold.

  Further, the predetermined region S including the circumferential center φ of the contour shapes 52E to 55E is formed into circular curved shapes 52a to 55a, and the linear shape 52b is formed in the vicinity of the circumferential end other than the predetermined region S, thereby forming the contour shape. Compared with making all 52E into circular curvilinear shape, the radial direction dimension of the circumferential direction both ends of teeth 52-55 can be made small, and the volume of teeth 52-55 can be reduced further.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions are made to the above-described embodiments without departing from the scope of the present invention. be able to.

  For example, when the convex shapes 52a to 55a in the present embodiment are curved, they are circular, but for the radius R1 of this circular curved shape, the magnetic flux is centered in the circumferential direction as the value of R1 is decreased. Since the effect of converging to φ is high, the effect of suppressing and mitigating the amount of change in the air gap can be further enhanced.

  The present invention relates to a rotation angle detection device suitable for being applied to a vehicle, and can provide a rotation angle detection device that can further improve detection accuracy, so that various vehicles such as passenger cars, trucks, and buses can be provided. It is also useful to apply to.

It is a mimetic diagram showing one embodiment of a rotation angle detecting device concerning the present invention. It is a mimetic diagram showing one embodiment of a rotation angle detecting device concerning the present invention. It is a schematic diagram which shows the effect of one Embodiment of the rotation angle detection apparatus which concerns on this invention. It is a schematic diagram which shows the effect of one Embodiment of the rotation angle detection apparatus which concerns on this invention. It is a schematic cross section which shows the variation | change_quantity of the air gap of the eccentric direction side in one Embodiment of the rotation angle detection apparatus, ie, resolver, concerning this invention based on a comparison with a prior art. It is a schematic cross section which shows the air gap of the eccentric direction side in one Embodiment of the rotation angle detection apparatus, ie, resolver, concerning this invention based on a comparison with a prior art. It is a schematic cross section which shows the variation | change_quantity of the air gap of the eccentric direction opposite side in one Embodiment of the rotation angle detection apparatus based on this invention, ie, a resolver, based on a comparison with a prior art. It is a schematic cross section which shows the air gap of the eccentric direction opposite side in one Embodiment of the rotation angle detection apparatus, ie, resolver concerning this invention, based on a comparison with a prior art. It is a schematic cross section which shows the variation | change_quantity of the air gap of the eccentric direction side side in one Embodiment of the rotation angle detection apparatus, ie, resolver concerning this invention, based on a comparison with a prior art. It is a schematic cross section which shows the air gap of the eccentric direction side in one Embodiment of the rotation angle detection apparatus, ie, resolver concerning this invention, based on a comparison with a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resolver 2 Rotor 3 Excitation coil 4s Detection coil 4c Detection coil 51 Teeth 52 Teeth 52E Contour shape 52a Convex shape 52b Linear shape 53 Teeth 53E Contour shape 53a Convex shape 53b Linear shape 54 Teeth 54E Contour shape 54b Straight shape 54b Contour shape 54b 55E Contour shape 55a Convex shape 55b Linear shape 56 Teeth 6 Stator 6a Arc-shaped part

Claims (7)

A rotor, an excitation coil, a detection coil, and a stator including a plurality of teeth, wherein the plurality of teeth are positioned on an outer peripheral side of the rotor around which the excitation coil and / or the detection coil are wound. The contour shape on the radially inner side of the plurality of teeth in a cross section perpendicular to the central axis of the rotor and extending radially inward of the rotor includes a convex shape that is convex radially inward . The rotation angle detecting device , wherein the convex shape is a curved shape including any one of a circular shape, an elliptical shape, a quadratic curve shape, and an exponential function shape . The rotation angle detection device according to claim 1 , wherein the convex shape is symmetric with respect to a circumferential center of the contour shape. The rotation angle detecting device according to claim 2 , wherein the convex shape is formed in a predetermined range shorter than a circumferential length of the contour shape, and the contour shape outside the predetermined range is a linear shape. The rotation angle detection device according to any one of claims 1 to 3 , wherein the stator extends in an arc shape over a part of the circumferential direction of the rotor. The rotation angle detection device according to claim 4 , wherein the contour shape of the teeth around which the detection coil is wound out of the plurality of teeth includes the convex shape. The rotation angle detection device according to claim 5 , wherein the contour shape other than the pair of teeth positioned at both ends of the stator in the circumferential direction of the plurality of teeth includes the convex shape. The rotation angle according to claim 6 , wherein the contour shape of a pair of teeth positioned at both ends in the circumferential direction of the stator among the plurality of teeth is an arc shape centering on a central axis of the rotor. Detection device.

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