JP2013198324A - Resolver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resolver that can be enhanced in detection precision by mak ing an error in rotational angle (angle error) small.SOLUTION: There is provided a resolver 10 including an annular resolver stator 12 where a plurality of teeth parts 46 provided with coils for excitation and output are arranged at intervals in a circumferential direction, and a resolver rotor 13 which is arranged inward in a radial direction of the resolver stator 12 while fixed to a rotary shaft 11, and has an outer peripheral surface varying in radial gap with the teeth parts 46 in the circumferential direction. A circumferential center part P1 on an inner peripheral surface 46c of each teeth part 46 is arranged on a concentric circle C0 having its center in the center of the rotary shaft 11, and an inner peripheral surface 46c of each teeth part 46 is formed into an arcuate surface having its center at a position X between the circumferential center part P1 of the inner peripheral surface 46c and the center O of the rotary shaft 11.

Description

  The present invention relates to a resolver used for detecting a rotation angle (rotation position) of a rotation shaft provided in a motor or the like.

  The resolver is one of angle detection devices used to detect the rotation angle (rotation position) of the rotation shaft, and includes a resolver stator and a resolver rotor (see, for example, Patent Documents 1 and 2). For example, as shown in FIG. 11, the resolver stator 112 is formed in an annular shape, and a plurality of teeth portions 146 each having an excitation coil and an output coil wound around its inner circumferential surface are spaced apart in the circumferential direction. Is provided. The resolver rotor 113 is disposed in a state where a gap (gap) is formed on the radially inner side of the resolver stator 112, and is attached to the rotary shaft 111 so as to be integrally rotatable. The resolver rotor 113 shown in FIG. 11 is formed in a substantially elliptical shape, and the gap between the resolver stator 112 and the resolver rotor 113 changes in the circumferential direction at a predetermined cycle. And the resolver is comprised so that the rotation angle of the rotating shaft 111 may be detected by the output change of the output coil accompanying the change of the gap.

JP-A-6-82207 JP 2009-8536 A

  In the conventional resolver shown in FIG. 11, when the maximum radius portion 113a of the resolver rotor 113 is disposed between the teeth portions 146 adjacent in the circumferential direction, the opposite ends of the adjacent teeth portions 146 are opposite to each other. The gap with the resolver rotor 113 is increased at the end portion P2 (A portion in FIG. 11). Therefore, there is a problem in that the magnetic flux from the tooth portion 146 toward the resolver rotor 113 is curved and leaks in the gap, and the detection error (angle error) increases.

In order to reduce the angle error as described above, conventionally, the number of coils has been increased or the number of turns of each coil has been increased. However, this method causes an increase in the size and weight of the resolver, which increases the manufacturing cost.
In addition, the resolver described in Patent Document 2 performs a process of correcting detection data using correction parameters acquired in real time in order to reduce the angle error. Although the angle error can be reduced to some extent by performing such correction processing, the computational load on the computer increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a resolver that can reduce a rotation angle error (angle error) and improve detection accuracy.

  The present invention relates to an annular resolver stator having a plurality of teeth provided with excitation and output coils at intervals in the circumferential direction, and a radially inner side of the resolver stator fixed to a rotating shaft. And a resolver rotor having an outer circumferential surface in which a radial gap between the teeth portions changes in the circumferential direction, and an inner circumferential surface of the plurality of tooth portions. The central portion in the circumferential direction is arranged concentrically around the axis of the rotation shaft, and the inner peripheral surface of each tooth portion is between the central portion in the circumferential direction of the inner peripheral surface and the axis of the rotation shaft. It is formed in the circular arc surface centering on the position of between.

  In the conventional resolver, the inner peripheral surface of each tooth portion of the resolver stator is formed as an arc surface centering on the axis of the rotation shaft. On the other hand, in the present invention, the central portion in the circumferential direction of the inner peripheral surfaces of the plurality of tooth portions is arranged on a concentric circle with the axis of the rotation shaft as the center, and the inner peripheral surface of the inner peripheral surface It is formed in the circular arc surface centering on the position between the center part of the circumferential direction and the axial center of the said rotating shaft. Therefore, when the radius of curvature of the inner peripheral surface of the teeth portion is smaller than before and the maximum outer diameter portion of the resolver rotor is located between adjacent teeth portions, the opposite side of the adjacent end portions of both teeth portions The gap generated between the end of the rotor and the resolver rotor can be reduced. Therefore, the leakage magnetic flux resulting from the gap can be reduced and the angle error can be reduced.

  The ratio of δ2 to δ1 (δ2 / δ1) is δ1, where δ1 is the minimum gap between the central portion in the circumferential direction of the inner peripheral surface of the teeth portion and the outer peripheral surface of the resolver rotor, and δ2 is the maximum gap. 6.0 ≦ δ2 / δ1 ≦ 9.0 may be set.

  In addition to appropriately setting the shape of the inner peripheral surface of the tooth portion as described above, the inventor of the present invention can reduce the angle error of the resolver by reducing the inner peripheral surface of the resolver stator and the outer peripheral surface of the resolver rotor. It has been found that it is effective to consider the ratio of the maximum gap δ2 to the minimum gap δ1. That is, it has been found that by increasing the ratio of the maximum gap δ2 to the minimum gap δ1, the amplitude of the output signal can be increased and the angle error can be reduced. Conventionally, the ratio of the maximum gap δ2 to the minimum gap δ1 is approximately δ2 / δ1 = 4.0, but in the present invention, 6.0 ≦ δ2 / δ1 ≦ 9.0 is set, which is larger than the conventional ratio. . As a result, the angular error can be efficiently reduced without increasing the size and weight of the resolver and increasing the calculation load.

The minimum gap δ1 is preferably set to 0.2 (mm) ≦ δ1 ≦ 0.8 (mm).
Conventionally, the minimum gap δ1 between the inner peripheral surface of the resolver stator and the outer peripheral surface of the resolver rotor is usually 1 mm or more, but in the present invention, δ1 is set to 0.2 mm to 0.8 mm. In this way, the output signal can be increased by reducing the minimum gap δ1. Further, by making the minimum gap δ1 smaller, the ratio of the maximum gap δ2 to the minimum gap δ1 can be easily increased. That is, if the minimum gap δ1 is large, the maximum gap δ2 must be increased in order to maintain the above ratio, but in order to increase the maximum gap δ2, it is necessary to reduce the minimum outer diameter of the resolver rotor. There is. However, the minimum outer diameter of the resolver rotor cannot be made smaller than the outer diameter dimension of the rotating shaft, and is limited by the outer diameter dimension. Therefore, by setting the minimum gap δ1 as described above as in the present invention, the ratio of the maximum gap δ2 to the minimum gap δ1 can be appropriately set without being limited by the outer diameter of the rotating shaft.

  According to the resolver of the present invention, the rotation angle error (angle error) can be reduced, and the detection accuracy can be increased.

It is side surface sectional drawing which shows the resolver which concerns on embodiment of this invention. It is a front view which shows a part of resolver. It is a side view which shows a part of resolver. It is a perspective view of a case member. It is a front view which shows a resolver stator and a resolver rotor. It is a front view which expands and shows a part of resolver stator. It is a graph which shows roughly the output waveform (SIN wave) of the coil for output. It is a graph which shows roughly the output waveform (COS wave) of the coil for output. It is a graph which shows the angle error of an Example and a prior art example. It is a schematic front view explaining the shape of the teeth part of a resolver stator. It is a front view which shows the conventional resolver schematically.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side sectional view showing a resolver according to an embodiment of the present invention.
The resolver 10 of the present embodiment is used for detecting the rotation angle (rotation position) of the rotation shaft 11 of a motor generator used in a hybrid vehicle, for example, and includes a resolver stator 12 and a resolver rotor 13. I have. Furthermore, the resolver 10 of the present embodiment constitutes a rolling bearing device with a resolver together with a rolling bearing 14 for rotatably supporting the rotating shaft 11, and the resolver stator 12 and the rolling bearing 14 are interposed via a case member 15. It is assembled as one unit.

  As shown in FIG. 1, the rolling bearing 14 includes an inner ring 19 having an inner ring raceway 18, an outer ring 21 having an outer ring raceway 20 disposed concentrically on the radially outer side of the inner ring 19, an inner ring raceway 18, and an outer ring. A plurality of rolling elements 22 are provided between the tracks 20 so as to be capable of rolling. The rolling bearing 14 of the present embodiment is a ball bearing provided with balls as the rolling elements 22. The outer ring 21 of the rolling bearing 14 is fixed to the case member 15, and the inner ring 19 is fixed to the rotating shaft 11.

FIG. 2 is a front view showing a part of the resolver 10 (a part excluding the resolver rotor 13), and FIG. 3 is a side view showing a part of the resolver 10 (same as above). FIG. 4 is a perspective view of the case member 15.
As shown in FIGS. 1 to 4, the case member 15 includes an outer ring attachment portion 24 to which the outer ring 21 of the rolling bearing 14 is attached, and a fitting portion 25 to which the resolver stator 12 is attached. The outer ring mounting portion 24 is formed in a cylindrical shape, and the outer peripheral surface of the outer ring 21 is fitted and fixed to the inner peripheral surface thereof by press-fitting. The fitting portion 25 is also formed in a cylindrical shape, and the outer peripheral surface of the resolver stator 12 is fitted and fixed by press-fitting.

  The outer ring attachment portion 24 is formed to have a smaller diameter than the fitting portion 25, and a disc portion 27 disposed along the radial direction is formed between the outer ring attachment portion 24 and the fitting portion 25. Further, one end of the outer ring mounting portion 24 in the axial direction (the end opposite to the fitting portion 25 in the axial direction (the right end of the outer ring mounting portion 24 in FIG. 1)) is bent radially inward. A collar portion 28 is formed.

  At the other end portion in the axial direction of the fitting portion 25 (the end portion on the opposite side to the outer ring mounting portion 24 in the axial direction (the left end portion of the fitting portion 25 in FIG. 1)) A portion 29 is formed. And the outer ring | wheel attaching part 24, the fitting part 25, the disc part 27, the inner collar part 28, and the outer collar part 29 perform plastic processing, such as press processing (drawing process), etc. with respect to metal board | plate materials. It is integrally molded.

  The inner flange portion 28 functions as a restricting portion that restricts the position in the axial direction of the outer ring 21 fitted to the outer ring attaching portion 24. Further, the outer flange portion 29 is formed on the entire circumference of the fitting portion 25 except for the position of a connector portion 51 (see FIG. 2) described later, and serves as a rib that reinforces the fitting portion 25 from the outer peripheral side. It has a function. The outer flange portion 29 can ensure the press-fit load of the resolver stator 12 fitted to the fitting portion 25. Further, by forming the outer flange portion 29, it is possible to increase the dimensional accuracy of the case member 15 formed by press working, particularly the dimensional accuracy of the fitting portion 25. Further, the outer ring mounting portion 24, the fitting portion 25, the disc portion 27, the inner flange portion 28, and the outer flange portion 29 constituting the case member 15 are integrally formed by press working, so that the case member 15 can be easily formed. Can be manufactured.

The outer flange portion 29 is further formed with a plurality (three in the illustrated example) of flange portions 31 extending outward in the radial direction at regular intervals in the circumferential direction. The flange portion 31 is formed with an arc-shaped long hole 32 centered on the axis O.
As shown in FIG. 1, the case member 15 is attached to a housing 35 such as a motor generator via a fixing ring 34. As shown in FIG. 2, the fixing ring 34 has a plurality of (three in the illustrated example) boss portions 36 at regular intervals in the circumferential direction. The boss portion 36 has a female screw hole 37. Is formed. Then, the fixing ring 34 is overlapped on the outer flange portion 29 and the flange portion 31 of the case member 15, and the bolt 38 inserted in the housing 35 and the long hole 32 is screwed into the female screw hole 37, whereby the case member 15 is It is attached to the housing 35. Further, the circumferential position of the case member 15 can be adjusted (zero point adjustment) within the long hole 32.

  As shown in FIG. 1, a mounting portion 16 is integrally formed on the rotating shaft 11. The attachment portion 16 is configured by causing a part of the outer peripheral surface of the rotating shaft 11 to protrude radially outward. An inner ring attachment portion 16 a into which the inner ring 19 is fitted is formed at one axial end portion of the attachment portion 16, and the resolver rotor 13 is fixed to an intermediate portion in the axial direction of the attachment portion 16. The attachment portion 16 may be configured as a separate component from the rotating shaft 11. In this case, the attachment portion 16 may be formed in a cylindrical shape with a metal material, a synthetic resin material, or the like, and fitted to the outer peripheral surface of the rotary shaft 11 so as to be integrally rotatable.

  FIG. 5 is a front view showing the resolver stator 12 and the resolver rotor 13, and FIG. 6 is an enlarged front view showing a part of the resolver stator 12. The resolver stator 12 is formed in an annular shape, and includes a stator core 42, a coil 43, and an insulator 44. The stator core 42 is made of a magnetic material such as a single-layered or multiple-layered silicon steel plate, and has an annular annular portion 45 and a plurality of (inwardly projecting radially inward from the inner peripheral surface of the annular portion 45). Eight teeth in the illustrated example) are integrally provided. The plurality of tooth portions 46 are formed at regular intervals in the circumferential direction. Further, as shown in FIG. 6, each tooth portion 46 includes a base portion 46a and a distal end portion 46b. The base portion 46a has a smaller width in the circumferential direction than the distal end portion 46b, and the distal end portion 46b extends from the base portion 46a to both sides in the circumferential direction. It is formed in a shape that greatly expands. The exciting and output coils 43 are wound around the base portion 46 a of the tooth portion 46.

  As shown in FIG. 5, the insulator 44 is formed in an annular shape by an insulating material such as synthetic resin. Moreover, the insulator 44 is each arrange | positioned at the surface of the axial direction both sides of the stator core 42, as FIG. 1 shows. As shown in FIG. 6, the insulator 44 has a covering portion 48 that covers the tooth portion 46 of the stator core 42, and the covering portion 48 insulates the tooth portion 46 from the coil 43.

  The covering portion 48 of the insulator 44 has a pair of wall portions 50a and 50b in the radial direction, and the coil 43 is wound between the pair of wall portions 50a and 50b. The insulator 44 disposed on one surface of the stator core 42 in the axial direction is formed with a connector portion 51 having a terminal to which the coil 43 is connected (see FIG. 5). Moreover, the cyclic | annular cover member 52 which covers the coil 43 from the axial direction outer side is attached to the axial direction edge part of both the insulators 44 (refer FIG.1 and FIG.2).

  An inner peripheral surface 46c of the tooth portion 46 is formed in an arc shape. FIG. 10 is a schematic plan view for explaining the shape of the inner peripheral surface of the tooth portion 46 in the resolver stator 12. A central portion P1 in the circumferential direction on the inner peripheral surface 46c of the tooth portion 46 is disposed on an imaginary circle C0 centered on the rotation shaft 11 and the axis O of the resolver rotor 13. On the other hand, the circular arc drawn by the inner peripheral surface 46c of the tooth portion 46 is formed on a virtual circle C1 having a radius R1 smaller than the radius R0 of the virtual circle C0. That is, the inner peripheral surface 46 c of the tooth portion 46 is formed in an arc shape having a center X at a position between the circumferential central portion P 1 on the inner peripheral surface 46 c and the axis O of the rotating shaft 11. Therefore, both end portions P2 in the circumferential direction on the inner peripheral surface 46c of the tooth portion 46 are disposed inside the virtual circle C0, and the end portion P2 of the tooth portion 46 is closer to the outer peripheral surface of the resolver rotor 13.

  Next, the minimum gap δ1 and the maximum gap δ2 between the tooth portion 46 of the resolver stator 12 and the resolver rotor 13 will be described in detail with reference to FIG. The minimum gap δ1 and the maximum gap δ2 described below refer to the minimum gap and the maximum gap between the “circumferential center portion P1” on the inner peripheral surface 46c of the tooth portion 46 and the outer peripheral surface of the resolver rotor 13. Shall.

  As shown in FIG. 5, the resolver rotor 13 is formed in a shape corresponding to the shaft angle multiplier. In the present embodiment, a resolver rotor 13 having a shaft multiplication angle of 2 × is used, and the outer peripheral surface of the resolver rotor 13 is formed in a substantially elliptical shape when viewed from the front (viewed in the axial direction), and is formed on the tooth portion 46 of the resolver stator 12. On the other hand, they face each other with gaps (gap) δ1, δ2.

  When the rotating shaft 11 rotates, the resolver rotor 13 also rotates integrally, and the size of the gap between each tooth portion 46 of the resolver stator 12 and the resolver rotor 13 changes. When an alternating current is passed through the exciting coil 43 of the resolver stator 12, an output voltage corresponding to the change in the size of the gap is generated in the output coil 43. The output coil 43 includes a SIN wave output coil and a COS wave output coil, which are alternately provided in the circumferential direction with respect to the plurality of tooth portions 46. And the amplitude change of the output voltage of the coil for SIN wave output and the coil for COS wave output is 90 degrees out of phase, and the rotation angle of the rotating shaft 11 is detected by signal processing this output voltage. Can do. In the present embodiment, since the shaft angle multiplier of the resolver rotor 13 is 2X, two cycles of voltage are output by one revolution of the resolver rotor 13.

  In this embodiment, the number of turns of the exciting coil wound around each tooth portion 46 is 10 to 35 turns (more preferably 25 turns), and the number of turns of the output coil is 20 to 120 turns (more preferably 80 turns). The number of turns is smaller than that of a conventionally known resolver.

As shown in FIG. 5, in the present embodiment (example), the smallest gap between the outer peripheral surface of the resolver rotor 13 and the tooth portion 46 of the resolver stator 12 (the central portion P1 in the circumferential direction of the inner peripheral surface 46c). δ1, that is, the gap δ1 between the long diameter portion (maximum outer diameter portion) 13a of the resolver rotor 13 and the tooth portion 46, and the largest gap δ2, that is, the short diameter portion (minimum outer diameter portion) 13b of the resolver rotor 13. And the tooth portion 46 is set to the following ratio (δ2 / δ1).
6.0 ≦ δ2 / δ1 ≦ 9.0

The ratio (hereinafter also referred to as “gap ratio”) is more preferably set to δ2 / δ1 = 8.0.
The minimum gap δ1 is set in a range of 0.2 mm ≦ δ1 ≦ 0.8 mm, more preferably δ1 = 0.5 mm. Hereinafter, the relationship between the minimum gap δ1 and the maximum gap δ2 will be described in detail.

  In the conventional resolver, the gap ratio between the minimum gap δ1 and the maximum gap δ2 is about δ2 / δ1 = 4.0, and the minimum gap δ1 is 1.0 mm or more. Therefore, in the present embodiment, the minimum gap δ1 is smaller than the conventional one, and the gap ratio of the maximum gap δ2 to the minimum gap δ1 is large.

  7 and 8 are graphs schematically showing the waveform (SIN wave, COS wave) of the output voltage of the output coil. 7 and 8, it can be seen that in the example, the maximum value of the output voltage and the amplitude of the output voltage are larger than in the conventional example. That is, the output voltage can be increased by making the minimum gap δ1 smaller than before, and the amplitude of the output voltage can be made larger by increasing the gap ratio (δ2 / δ1) than before. it can.

  When the amplitude of the output voltage is increased, the S / N ratio is increased, and a stable output can be obtained. That is, if a certain error (noise) is included in the output voltage, the ratio of the error to the output voltage decreases as the amplitude of the output voltage increases, so that the S / N ratio can be increased.

Further, when the amplitude of the output voltage is increased, the rotation angle error (angle error) can be reduced. This point will be described in detail below using mathematical expressions.
When an excitation voltage V _EX is applied to the excitation coil wound around the tooth portion 46 of the resolver stator 12, voltages V1 and V2 are induced in the SIN wave output coil and the COS wave output coil, respectively. Then, the voltages V1 and V2 can be expressed by the following equations (1) and (2), respectively.

Here, θ represents the rotation angle (rotation position) of the resolver rotor 13, and K represents the transformation ratio of the output coil.
Further, the rotation angle θ can be expressed as in Expression (3) based on Expressions (1) and (2).

Here, the main value of tan ⁻¹ is −90 ° to + 90 °. When V _EX and V1 have the same sign, θ ₀ = 0 °, and when V _EX and V1 have different signs, θ ₀ = 180 °.
If there is some variation in the components of the resolver 10, the rotation angle θ may include an error. For example, when the resolver 10 is decentered, that is, when the axial center between the resolver stator 12 and the resolver rotor 13 is deviated, the transformation ratio K between the SIN wave output coil and the COS wave output coil varies. Therefore, V1 / V2 does not coincide with tan θ. Further, if there is a variation in the electrical characteristics of the detection circuit or a variation in the elements constituting the circuit, a direct current component is added to V1 and V2, and an offset occurs.

If the error based on the transformation ratio K is β and the errors based on the voltages V1 and V2 are α ₁ and α ₂ , the rotation angle θe including the error detected from the resolver 10 is modeled as shown in Equation (4). be able to. Here, θ represents a true rotation angle that does not include an error.

  As described above, in the present embodiment (example), regarding the gap between the resolver stator 12 and the resolver rotor 13, the minimum gap δ1 is made smaller than the conventional one, and the ratio (gap ratio) of the maximum gap δ2 to the minimum gap δ1 is set. By making it larger than before, the amplitude of the output voltage is made larger than before. Here, when the ratio between the amplitude of the output voltage of the embodiment and the amplitude of the output voltage of the conventional example is C (C = (the amplitude of the output voltage of the embodiment) / (the amplitude of the conventional output voltage)> 1) In contrast to the conventional example represented by the equation (4), in the embodiment, the rotation angle θe including the error is represented by the following equation (5).

Comparing equation (4) and equation (5), the errors in the output voltages V1 and V2 were α _{1 and} α ₂ in the conventional example, whereas in the example, the error was (α ₁ / C), (α ₂ / C). Since C> 1, α ₁ > (α ₁ / C) and α ₂ > (α ₂ / C), and the error (angle error) included in the rotation angle θe in the embodiment is larger than that in the conventional example. It turns out that becomes small.

  In the above embodiment, since the resolver stator 12 and the rolling bearing 14 are integrated (unitized) by the case member 15, the center alignment of the resolver stator 12 and the rolling bearing 14 can be accurately performed. The assembling accuracy of the resolver stator 12 and the rotating shaft 11 assembled to the rolling bearing 14 and the resolver rotor 13 attached to the rotating shaft 11 can also be improved. Therefore, the gaps δ1 and δ2 between the tooth portion 46 of the resolver stator 12 and the outer peripheral surface of the resolver rotor 13 can be set accurately, and in particular, the minimum gap δ1 can be set to a smaller value. If the minimum gap δ1 can be set to a smaller value in this way, the ratio of the maximum gap δ2 to the minimum gap δ1 can be increased without increasing the value of the maximum gap δ2 so much.

For example, consider a case where the ratio of the minimum gap δ1 and the maximum gap δ2 is set to δ2 / δ1 = 8.0. When the minimum gap δ1 is 1.0 mm as in the conventional example, the maximum gap δ2 must be set to 8.0 mm in order to satisfy the above ratio, and the minor axis of the resolver rotor 13 needs to be very small. There is. Since the short diameter of the resolver rotor 13 cannot be made smaller than the outer diameter of the rotating shaft 11, if the outer diameter of the rotating shaft 11 is large, there is a high possibility that the above ratio cannot be realized.
On the other hand, when the minimum gap δ1 is set to 0.5 mm as in the present embodiment, the maximum gap δ2 may be set to 4.0 mm, and the value of δ2 is reduced by about 4.0 mm compared to the conventional example. be able to. Therefore, it can be made difficult to be restricted by the outer diameter of the rotating shaft 11.

In this embodiment, the gap ratio is set to 6.0 ≦ (δ2 / δ1) ≦ 9.0. When the gap ratio is (δ2 / δ1)> 9.0, the minor axis of the resolver rotor 13 must be remarkably reduced as described above, and this is realized from the relationship with the outer diameter of the rotating shaft 11. Have difficulty.
On the other hand, when the gap ratio is (δ2 / δ1) <6.0, the amplitude ratio C cannot be made so large as shown in the above-described equation (5), and therefore the angle error can be made so small. Can not.

  FIG. 9 shows a comparative example in which the gap ratio is (δ2 / δ1) = 4.0 (where δ1 = 0.5, δ2 = 2.0) and (δ2 / δ1) = 6.0 (where The angle error in the example in which δ1 = 0.5 and δ2 = 3.0) is shown in the graph. In the case of the comparative example, in the whole rotation angle θ = 0 ° to 360 °, the angle error greatly protrudes and changes periodically at every small rotation angle, and the error range is −0.64 ° to 0.00. It is 75 °. This is presumably because the angle error is remarkably increased in the gap between the tooth portions 46 of the resolver stator 12 due to the small gap ratio. On the other hand, in the case of the example, the angle error gradually changes at a period for each rotation angle larger than that of the comparative example, and the error range is −0.20 ° to 0.55 °. . Therefore, by setting the gap ratio to (δ2 / δ1) = 6.0 ((δ2 / δ1) ≧ 6.0), the maximum value (absolute value) of the angle error can be reduced as compared with the comparative example. In addition, the error range can be reduced. A more suitable gap ratio range is 6.0 ≦ (δ2 / δ1) ≦ 8.0.

On the other hand, as shown in FIG. 10, the circumferential end P <b> 2 of the tooth portion 46 of the resolver stator 12 enters inward in the radial direction by a dimension s from the virtual circle C <b> 0 centering on the axis O of the rotating shaft 11. Yes. Therefore, when the long diameter portion 13a (see FIG. 5) of the resolver rotor 13 is disposed between the teeth portions 46 adjacent to each other in the circumferential direction (for example, see FIG. 11), it is opposite to the adjacent end portions of both teeth portions 46. The gap with the resolver rotor 13 at the end P2 on the side can be made smaller than before. Therefore, the leakage magnetic flux in the gap can be reduced and the angle error can be further reduced.
Further, since the inner peripheral surface 46c of the tooth portion 46 has an arc shape having a constant radius R1, the angle error can be reduced without making the inner peripheral surface 46c a complicated shape. Design and manufacture can also be easily performed.

The dimension s between the circumferential end P2 of the tooth part 46 and the virtual circle C0 depends on the dimension of the minimum gap δ1 between the tooth part 46 and the resolver rotor 13 described above, but the circumferential end of the tooth part 46. Between P2 and the resolver rotor 13, it sets so that the foreign material contained in lubricating oil etc. may not be caught.
For example, when the minimum gap δ1 between the tooth portion 46 and the resolver rotor 13 is set to 0.2 to 0.8 mm, the dimension s can be set within a range of 0.05 mm to 0.2 mm, for example. Preferably, it can be set to 0.1 mm.
The dimension s can also be set to 0.04δ1 <s <1.0δ1 in relation to the above-described minimum gap δ1, and preferably set to 0.125δ1 <s <0.5δ1. .

  In the resolver 10 of the present embodiment, the resolver stator 12 and the rolling bearing 14 are integrated by the case member 15, so that the resolver 10 and the rolling bearing 14 can be handled and compared as compared with the case where these are configured separately. The housing 35 and the rotating shaft 11 can be easily assembled.

  Since the case member 15 includes the disk portion 27 between the fitting portion 25 and the outer ring mounting portion 24, the fitting of the resolver stator 12 to the fitting portion 25 and the fitting of the outer ring 21 to the outer ring mounting portion 24 are performed. There is no mutual effect. For example, even if distortion or the like occurs in the outer ring mounting portion 24 by fitting the outer ring 21 to the outer ring mounting portion 24, the influence hardly reaches the fitting portion 25, and the teeth portion 46 of the resolver stator 12 The gap with the resolver rotor 13 does not go out of order.

The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims.
For example, the numerical values, ratios, and the like regarding the gaps δ1, δ2 between the tooth portion 46 of the resolver stator 12 and the resolver rotor 13 are not limited to those described in the above embodiment, and can be changed as appropriate.
Further, the number and shape of the tooth portions 46 of the resolver stator 12, the shape of the resolver rotor 13, and the like are not limited to the above-described embodiment, and a conventionally known configuration can be appropriately employed. The resolver rotor 13 may have a shaft angle multiplier of 3X, 4X, or the like.

  In the above embodiment, the outer ring mounting portion 24 of the case member 15 has the outer ring 21 attached by fitting the outer peripheral surface of the outer ring 21 to the inner peripheral surface thereof. The outer ring 21 may be attached by fitting. Moreover, the outer ring | wheel attachment part 24 may attach not only the outer ring | wheel 21 by fitting but welding or adhesion | attachment, and may attach only the inner collar part 28 by welding or adhesion | attachment.

  10: Resolver, 11: Rotating shaft, 12: Resolver stator, 13: Resolver rotor, 46: Teeth portion, 46c: Inner peripheral surface, O: Axis of rotating shaft, P1: Center portion in the circumferential direction of the tooth portion, P2: Teeth end in the circumferential direction, δ1: minimum gap, δ2: maximum gap

Claims (3)

An annular resolver stator having a plurality of teeth provided with excitation and output coils at intervals in the circumferential direction;
A resolver rotor fixed to a rotating shaft and disposed radially inward of the resolver stator and having an outer peripheral surface in which a radial gap with the teeth portion changes in the circumferential direction. A resolver,
The central portion in the circumferential direction on the inner peripheral surface of each tooth portion is arranged concentrically around the axis of the rotating shaft,
A resolver, wherein an inner peripheral surface of each tooth portion is formed in an arc surface centering on a position between a central portion in the circumferential direction of the inner peripheral surface and the axis of the rotation shaft. When the minimum gap between the circumferential central portion of the inner peripheral surface of the teeth portion and the outer peripheral surface of the resolver rotor is δ1, and the maximum gap is δ2, the ratio of δ2 to δ1 (δ2 / δ1) is ,
6.0 ≦ δ2 / δ1 ≦ 9.0
The resolver according to claim 1, which is set as follows.   The resolver according to claim 2, wherein the minimum gap δ1 is set to 0.2 (mm) ≤ δ1 ≤ 0.8 (mm).

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