Stator of angle sensor and angle sensor

Abstract

[Problem] To provide a stator of an angle sensor in which insert molding of a non-magnetic spacer member separating a shield and an insulator can be eliminated and the spacer member can be placed easily and precisely. [Solution] This stator of an angle sensor comprises a stator core 110, an insulator 0, and a shield 160 covering the stator core 110 and the insulator 120. The stator core 110 comprises a through hole 113a, the shield 160 comprises a first through hole 167 connected to the through hole 113a of the stator core 110, a ring 200 formed from a non-magnetic metal that contacts the stator core 110 is fixed in the first through hole 167 of the shield 160, and the ring 200 has a circumferentially continuous annular projection 220 that contacts the first through hole 167 of the shield 160.

Description

Angle Sensor Stator and Angle Sensor

[0001] The present invention relates to a stator for an angle sensor such as a resolver, and more particularly to a stator for an angle sensor having a structure for blocking magnetic flow from a shield.

[0002] Resolvers have been known as a means for detecting the rotation angle of a rotating electric machine such as a motor or a generator. When a current supplied to a winding of a rotating electric machine incorporating a resolver changes, part of the magnetic flux generated by the rotating electric machine is superimposed on a signal flowing through a winding wound around a stator of the resolver. This can distort the signal waveform, making it impossible to accurately detect the rotation angle of the rotating electric machine. For this reason, resolvers equipped with a shield are known to suppress the influence of the magnetic flux from the rotating electric machine (see, for example, Patent Document 1).

[0003] The stator of the resolver in Patent Document 1 includes an annular stator core 20 and an annular shield cover 30 made of resin attached to the outside of the annular stator core 20. The annular insulating cover 21 is integrally molded by using the annular stator core 20 and a face plate 40 made of a non-magnetic metal material as an insert material, and the face plate 40 is interposed between the annular stator core 20 and the annular shield cover 30 to separate them, thereby blocking the flow of magnetism from the annular shield cover 30 to the annular stator core 20.

[0004] Japanese Patent Application Laid-Open No. 2023-7102

[0005] The face plate 40 in Patent Document 1 has a U-shaped cutout that opens radially outward, and is integrated with the ring-shaped insulating cover 21 by insert molding. When using insert molding, it is necessary to ensure space in the mold for arranging the insert material, which makes the mold structure complex.

[0006] In contrast, if a spacer portion having the same function as the face plate 40 is made to protrude radially outward from the annular insulating cover 21, the positioning accuracy required for the face plate 40 will not be an issue. However, because the bolts for mounting the housing pass through the notches in the spacer portion and are fastened, there is a concern that the material (resin) of the spacer portion may deteriorate due to environmental stresses such as heat and oil, causing the bolts to loosen. Furthermore, there is a risk that the resin spacer portion may deform when the bolts are fastened.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a stator for an angle sensor that can eliminate the need for insert molding of spacer members such as the face plate 40 and can be made using a simple mold.

[0008] The present invention is a stator comprising a magnetic body, an insulator, and a cover that covers the magnetic body and the insulator, wherein the magnetic body has a hole, the cover has a hole that communicates with the hole in the magnetic body, and a ring made of a non-magnetic metal that contacts the magnetic body is fixed to the hole in the cover, and the ring has a circumferentially continuous inner edge that contacts the hole in the cover.

[0009] According to the present invention, the ring not only separates the magnetic body from the cover and blocks the flow of magnetism from the cover to the magnetic body, but also has a circumferentially continuous inner edge that contacts the hole in the cover, so the ring is concentrically positioned in the hole in the cover simply by fitting it into the hole. Therefore, the ring can be easily and accurately positioned relative to the cover. Furthermore, because the ring is made of a non-magnetic metal, it is resistant to deterioration due to environmental loads and deformation when the bolt is tightened.

[0010] 1 is a plan view showing a resolver according to an embodiment of the present invention; FIG. 2 is an exploded perspective view showing a stator of the resolver according to the embodiment; FIG. 3 is an exploded perspective view showing the stator of the resolver according to the embodiment as viewed from below; FIG. 4 is a plan view showing the stator of the resolver according to the embodiment; FIG. 5 is a side view showing the stator of the resolver according to the embodiment; FIG. 6 is a rear view showing the stator of the resolver according to the embodiment; FIG. 7 is a perspective view showing the stator of the resolver according to the embodiment as viewed from below; FIG. 8 is a cross-sectional view of a portion including a bolt of the stator of the resolver according to the embodiment, and FIG. 9 is an enlarged view of a portion indicated by arrow B in FIG. 10 is a cross-sectional view of a portion including a connecting pin of the stator of the resolver according to the embodiment; FIG. 11 is a perspective view showing a ring according to the embodiment, and FIG. 12 is a cross-sectional view of the ring.

[0011] 1. Overall Configuration of the Resolver FIG. 1 shows a resolver (angle sensor) 1 according to an embodiment of the present invention. The resolver 1 is a variable reluctance (VR) resolver. The resolver 1 includes a rotor 10 and a stator 100. The rotor 10 is fixed to the output shaft of a motor (not shown). When viewed from the axial direction, the rotor 10 has a non-circular shape with multiple protrusions 11 that protrude radially outward. The rotor 10 has a structure in which multiple thin plate-shaped rotor cores are stacked in the axial direction. In the following description, the direction of the output shaft is referred to as the "axial direction," the direction perpendicular to the axial direction is referred to as the "radial direction," and the direction of rotation around the output shaft is referred to as the "circumferential direction." Furthermore, the terms "upper" and "lower" refer to the up and down directions in FIG. 2.

[0012] The thin rotor core that constitutes the rotor 10 is manufactured by pressing a plate portion made of electromagnetic steel into the shape shown in the figure. Multiple rotor cores are stacked in the axial direction and fixed by crimping to form the rotor 10. However, this configuration is not limiting, and the rotor 10 may also be formed from a single rotor core.

[0013] The stator 100 is disposed outside the rotor 10 and fixed to the housing 20. An air gap is provided between the rotor 10 and the stator 100, allowing the rotor 10 to rotate inside the stator 100. The rotor 10 and the stator 100 form a magnetic circuit. The housing 20 is a component to which the stator 100 of the resolver 1 is attached, and is provided with threaded holes (not shown) for fixing the stator 100 of the resolver 1. The stator 100 of the resolver 1 is attached to the housing 20 by threading bolts 30 into the threaded holes. Note that although only one bolt 30 is shown in FIG. 1 , the stator 100 is attached to the housing 20 with multiple bolts 30.

[0014] As shown in FIGS. 2 and 3 , the stator 100 includes a stator core (magnetic material) 110. The stator core 110 has a structure in which multiple thin-plate cores are stacked in the axial direction. The thin-plate core includes an annular core back portion 111, multiple teeth 112 protruding radially inward from the core back portion 111, and multiple flanges 113 protruding radially outward from the core back portion 111. The flanges 113 are formed with through holes (holes) 113a arranged concentrically in the circumferential direction, through which bolts 30 are inserted. The core is fabricated by pressing a plate portion made of electromagnetic steel sheet. Multiple such cores are stacked in the axial direction and fixed by crimping to obtain the stator core 110. The diameter of the through holes 113a is such that the bolts 30 do not come into contact with the stator core 110 when inserted into the through holes 113a.

[0015] Insulators 120 are fixed to both axial sides of stator core 110. Insulator 120 is formed from an insulating resin and is injection molded using stator core 110 as an insert material. As shown in Figures 8 and 9, insulator 120 includes winding portions 121 fixed to each tooth 112 and flange portions 125 extending radially outward from winding portions 121. Insulator 120 is not limited to being injection molded, and a configuration in which a separately molded insulator is fixed to stator core 110 is also possible.

[0016] The winding portion 121 is formed to surround the entire circumference of the tooth 112 and includes a body portion 122 in the radial center, an inner restricting portion 123 extending axially and circumferentially on the inner peripheral side of the body portion 122, and an outer restricting portion 124 extending axially on the outer peripheral side of the body portion 122. The stator winding 130 is wound around the body portion 122, and the inner restricting portion 123 and the outer restricting portion 124 restrict the range in which the conductor wire is wound so that the winding of the stator winding 130 does not collapse. This provides insulation between the teeth 112 (stator core 110) and the stator winding 130.

[0017] The flange portion 125 of the insulator 120 is formed with a plurality of protrusions 126 that protrude radially outward and are arranged at equal intervals in the circumferential direction. The protrusions 126 are formed so as to overlap both side portions of the flange 113 of the stator core 110 and are disposed axially opposite the flange 113 of the stator core 110. The protrusions 126 are formed with U-shaped recesses (hereinafter referred to as cutouts 126a) that are open radially outward and overlap with the through-holes 113a of the flange 113 in the axial direction. This opens the through-holes 113a in the axial direction. The cutouts 126a are not limited to being U-shaped, and may be rectangular or formed as through-holes.

[0018] As shown in FIG. 2 , a terminal block 140 is integrally molded with the insulator 120, and multiple terminal pins 141 are fixed to the terminal block 140 by insert molding. A connector housing 142 is integrally molded on the axially lower side of the terminal block 140. The terminal pin 141 is crank-shaped in the axial direction, with one end protruding axially from the terminal block 140 and the other end protruding into a space defined by the connector housing 142. This space accommodates a connector for electrical connection to the outside. A winding end 131 of the stator winding 130 is twisted and connected to one end of the terminal pin 141. At this time, the terminal pin 141 is fixed by soldering or TIG welding.

[0019] 3, an annular protrusion 127 that protrudes axially downward is formed on the insulator 120. The annular protrusion 127 extends annularly along the core back portion 111, and one end thereof is connected to the terminal block portion 140.

[0020] A terminal pin cover 150 is attached to the terminal block 140. The terminal pin cover 150 comprises a rectangular top plate 151, side plate portions 152 extending axially from three sides of the top plate 151, and a pair of arms 153 extending axially from the lower edges of the opposing side plate portions 152. Claw portions 154 that protrude toward each other are formed on the lower ends of the pair of arms 153.

[0021] 2, the upper surface of the terminal block 140 is formed with a plurality of protrusions 143 that protrude axially upward along one side, and the inner peripheral surface of the side plate 152 of the terminal pin cover 150 is in close contact with the radially outer surface of the protrusions 143. Grooves 144 are formed on both sides of the terminal block 140, and deeper steps 145 are formed at the lower ends of the grooves 144. With this configuration, when the arms 153 of the terminal pin cover 150 are inserted into the grooves 144 and pushed down, the claws 154 engage with the steps 145, and the terminal pin cover 150 is attached to the terminal block 140.

[0022] 3, a plurality of radially extending partition plates 155 are formed on the back surface of the top plate portion 151 of the terminal pin cover 150. When the terminal pin cover 150 is attached to the terminal block portion 140, the partition plates 155 are inserted between the terminal pins 141, preventing contact between the winding ends 131 of the stator windings 130 that are connected to one end of the terminal pins 141 by twisting them together, thereby preventing short circuits of the winding ends 131.

[0023] 2, a plurality of connecting pins 128 are formed on the flange portion 125 of the insulator 120 and protrude upward in the axial direction. The connecting pins 128 are located between the plurality of cutout portions 126a that are adjacent to each other in the circumferential direction. The shield (cover) 160 is connected to the insulator 120 using the connecting pins 128.

[0024] The shield 160 is annular and made of a metal material (e.g., cold-rolled steel plate), and as shown in FIG. 2 , includes a first annular portion 161 on its outer periphery. A cylindrical portion 162 extending axially downward is formed at the edge of the first annular portion 161. The axial length of the cylindrical portion 162 is set to be equal to the axial length of the stator core 110 plus the thickness of the flange portion 125 of the insulator 120, but may be longer than this dimension. A second annular portion 164 is formed on the inner periphery of the first annular portion 161 via a connecting portion 163.

[0025] The second annular portion 164 is positioned axially upward relative to the first annular portion 161, and the connecting portion 163 connecting the two has an upwardly inclined surface. A terminal block cover 166 extending radially outward is formed on one side of the connecting portion 163. The surface of the terminal block cover 166 and the surface of the second annular portion 164 are flush with each other. A circular opening 165 is formed in the center of the second annular portion 164.

[0026] The first annular portion 161 has a plurality of circular first through holes (holes) 167 formed in a row concentrically in the circumferential direction. The first through holes 167 are arranged at positions corresponding to the through holes 113a formed in the flange 113 of the stator core 110 and the notches 126a formed in the protrusions 126 of the insulator 120. The first annular portion 161 also has a plurality of circular second through holes 168 formed in a row concentrically in the circumferential direction. The second through holes 168 are arranged at positions corresponding to the connecting pins 128 formed in the flange portion 125 of the insulator 120.

[0027] A ring 200 is attached to the first through-hole 167. The ring 200 is made of a non-magnetic metal such as stainless steel, and as shown in Fig. 10, it is composed of a ring-shaped plate portion 210 and an inner edge portion (hereinafter referred to as annular protrusion portion 220) that protrudes in the axial direction from the inner peripheral edge portion of the plate portion 210. An annular groove 230 is formed at the boundary between the plate portion 210 and the annular protrusion portion 220. A tapered portion 221 whose diameter decreases toward the tip side is formed on the outer periphery of the annular protrusion portion 220.

[0028] The annular protrusion 220 fits into the first through-hole 167, and the plate portion 210 is housed in the semicircular portion of the cutout 126a of the insulator 120. As shown in Fig. 8A, the plate portion 210 is interposed between the flange 113 of the stator core 110 and the first annular portion 161 of the shield 160, and separates the stator core 110 and the shield 160 in the axial direction.

[0029] 8(B), the thickness of the plate portion 210 in the axial direction is thicker than the thickness of the flange portion 125 of the insulator 120 in the axial direction. As a result, a gap S is formed between the first annular portion 161 of the shield 160 and the flange portion 125. Furthermore, in the radial direction, the outer peripheral surface of the plate portion 210 is spaced apart from the inner peripheral surface of the cutout portion 126a of the insulator 120. This prevents damage to the insulator 120 by the ring 200.

[0030] 2. Resolver Assembly Method First, the annular protrusion 220 of the ring 200 is fitted into the first through-hole 167 of the shield 160. In this case, the tapered portion 221 is formed on the outer periphery of the annular protrusion 220, making it easy to insert into the first through-hole 167, and once inserted, it is press-fitted and fixed in the first through-hole 167. In this state, the shield 160 is moved toward the insulator 120, and the plate portion 210 of the ring 200 is placed in contact with the core back portion 111 while being accommodated in the cutout portion 126a of the insulator 120.

[0031] As a result, the multiple connecting pins 128 formed on the flange portion 125 of the insulator 120 are inserted into the second through-holes 168 formed in the first annular portion 161 of the shield 160. The tips of the connecting pins 128 protruding from the second through-holes 168 are plastically deformed (thermally caulked) by heat, thereby connecting the shield 160 to the stator 100 (see FIG. 9 ). The method for connecting the shield 160 and the stator 100 is not limited to this, and various known methods are also possible. For example, fixing with screws, fixing with an adhesive, or fitting using a claw or protrusion are conceivable. The deformed tips of the connecting pins 128 are positioned below the second annular portion 164 of the shield 160 and do not protrude axially from the second annular portion 164.

[0032] At this time, the second annular portion 164 of the shield 160 is located above the stator winding 130 in the axial direction, and a predetermined gap is formed between the stator winding 130 and the second annular portion 164 (the back surface of the second annular portion 164), and the shield 160 faces the stator winding 130 in the axial direction via a predetermined gap.

[0033] The plate portion 210 of the ring 200 is interposed between the first annular portion 161 of the shield 160 and the core back portion 111. In this way, since the plate portion 210 is disposed between the core back portion 111 of the stator core 110 and the first annular portion 161 of the shield 160, the shield 160 does not come into contact with the stator core 110; in other words, a structure can be achieved in which the shield 160 and the stator core 110 face each other across a gap in the axial direction.

[0034] The second annular portion 164 of the shield 160 covers the stator winding 130, the first annular portion 161 of the shield 160 covers the core back portion 111 of the stator core 110, the terminal block portion cover 166 of the shield 160 covers the terminal block portion 140, and the cylindrical portion 162 of the shield 160 surrounds the entire periphery of the side surface of the stator core 110. As shown in Fig. 6 , the side surface of the stator core 110 and the inner circumferential surface of the cylindrical portion 162 of the shield 160 face each other in the radial direction with a predetermined gap (air gap) interposed between them, so that a structure can be achieved in which the side surface of the stator core 110 does not come into contact with the shield 160.

[0035] The stator 100 with the shield 160 attached is attached to the housing 20 with metal bolts 30. In this case, as shown in Fig. 8, a washer 31 can be interposed between the shield 160 and the bolts 30. The bolts 30 are inserted through a first through-hole 167 formed in the first annular portion 161 of the shield 160 and a through-hole 113a formed in the flange 113 of the stator core 110, and are screwed into the threaded holes in the housing 20.

[0036] When the motor rotates, magnetic flux is generated, and the magnetic flux directed toward the stator winding 130 is absorbed by the shield 160. In the stator 100 of the resolver configured as described above, the plate portion 210 of the ring 200 made of a non-magnetic metal is interposed between the core back portion 111 of the stator core 110 and the first annular portion 161 of the shield 160, so that the magnetic flux absorbed by the shield 160 can be prevented from linking with the stator winding 130 via the core back portion 111. This effect is achieved by fitting the annular protrusion portion 220 of the ring 200 into the first through hole 167 of the shield 160, so that the ring 200 can be easily and accurately positioned relative to the shield 160. Furthermore, because the ring 200 is made of a non-magnetic metal, it is possible to prevent deterioration due to environmental loads and deformation when the bolt 30 is tightened.

[0037] The bolt 30 acts as an antenna and absorbs the magnetic flux generated by the motor, and the magnetic flux flows to the shield 160. In this regard, in the above embodiment, the annular protrusion 220 of the ring 200 is present on the inner periphery of the first through hole 167 of the shield 160, through which the bolt 30 is inserted, and therefore it is possible to prevent the magnetic flux from flowing to the core back portion 111. Furthermore, when the bolt 30 is inserted into the through hole 113a of the stator core 110, a predetermined radial gap is provided so that the bolt 30 and the stator core 110 do not come into contact with each other, and therefore it is possible to prevent the magnetic flux from flowing to the core back portion 111.

[0038] In particular, in the above embodiment, the thickness of the plate portion 210 is greater than the thickness of the flange portion 125 of the insulator 120, so the shield 160 is not in contact with the insulator 120. This prevents the insulator 120 from being caught or pinched by the shield 160, and prevents deformation of the insulator 120.

[0039] Furthermore, in the above embodiment, the outer peripheral surface of the plate portion 210 is spaced apart from the inner peripheral surface of the notch portion 126a of the insulator 120, thereby preventing the insulator 120 from being caught or pinched when the bolt 30 is screwed in, and preventing deformation of the insulator 120.

[0040] 3. Modifications The present invention is not limited to the above embodiment, and various modifications are possible as follows: i) The notch 126a formed in the protrusion 126 of the insulator 120 may be a through-hole that penetrates in the axial direction.

[0041] ii) In the above embodiment, the through holes 113a are formed in the flange 113 of the stator core 110. However, instead of the through holes 113a, U-shaped notches that are open radially outward may be used.

[0042] iii) The through-holes 113a formed in the flanges 113 of the stator core 110 may be formed separately from the stator core 110. In this case, the through-holes 113a may be formed from a material (e.g., resin) different from that of the stator core 110.

[0043] The present invention can be used in an angle sensor that detects the rotation angle of a rotating electrical machine such as a motor.

[0044] 1...Resolver (angle sensor), 10...Rotor, 11...Protrusion, 20...Housing, 30...Bolt, 31...Washer, 100...Stator, 110...Stator core (magnetic material), 111...Core back portion, 112...Teeth, 113...Flange, 113a...Through hole (hole), 120...Insulator (cover), 121...Winding portion, 122...Body portion, 123...Inner restricting portion, 124...Outer restricting portion, 125...Flange portion, 126...Protrusion, 126a...Notch, 127...Annular protrusion, 128...Coupling pin, 130...Stator winding, 131...Winding terminal, 140 ...Terminal block portion, 141...terminal pin, 142...connector housing, 143...convex portion, 144...groove, 145...step portion, 150...terminal pin cover, 151...top plate portion, 152...side plate portion, 153...arm portion, 154...claw portion, 155...partition plate, 160...shield, 161...first annular portion, 162...cylindrical portion, 163...connecting portion, 164...second annular portion, 165...opening, 166...terminal block portion cover, 167...first through hole (hole), 168...second through hole, 200...ring, 210...plate portion, 220...annular protrusion portion (inner edge portion) 220, 221...tapered portion, S...gap.

Claims

1. A stator comprising: a magnetic body; an insulator; and a cover that covers the magnetic body and the insulator, wherein the magnetic body has a hole; the cover has a hole that communicates with the hole in the magnetic body; a ring made of a non-magnetic metal that contacts the magnetic body is fixed to the hole in the cover; and the ring has a circumferentially continuous inner edge that contacts the hole in the cover.

2. The stator according to claim 1, wherein the hole in the cover has an inner peripheral surface that is continuous in the circumferential direction.

3. A stator according to claim 1, wherein the ring has an outer peripheral surface facing radially outward, and the inner peripheral surface of the hole in the cover and the outer peripheral surface of the ring are in contact with each other in the radial direction.

4. A stator as set forth in claim 1, wherein the ring comprises a plate portion extending radially from one end of the ring in the axial direction, the plate portion having one surface and another surface in the axial direction, the one surface being in contact with the magnetic body, and the other surface being in contact with the cover.

5. The stator according to claim 4, wherein the outer peripheral surface of the plate portion faces the inner peripheral surface of the insulator with a predetermined gap therebetween in the radial direction.

6. The stator according to claim 4, wherein the thickness of the portion of the plate portion facing the stator in the axial direction is greater than the thickness of the portion of the insulator facing the magnetic body.

7. An angle sensor in which a rotor connected to the output shaft of a rotating electrical machine is disposed inside the stator according to any one of claims 1 to 6.

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