JP2013099161A - Stator fixing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator fixing structure capable of improving the detection accuracy of a resolver by making a magnetic flux from a motor less likely to flow into a resolver stator.SOLUTION: In the stator fixing structure for fixing the detection stator 32 of a resolver provided contiguously to a motor to the pedestal 17 of a case 16, the stator core 33 of the detection stator 32 is constituted by laminating a plurality of magnetic steel plates, at least one magnetic steel plate 33a out of the magnetic steel plates located at the axial end of the stator core 33 remote from the motor is formed in a different shape from other magnetic steel plate 33b, and the magnetic steel plate 33a of different shape has a fixing portion 54 projecting radially outward from the annular outer peripheral surface of the stator core 33 and fixing the detection stator 32 to the pedestal 17 of the case 16.

Description

  The present invention relates to a stator fixing structure, and more particularly to a stator fixing structure for fixing a resolver stator to an attachment member such as a motor case.

  Conventionally, a resolver is sometimes used to detect a rotational position of a rotor of a motor. The resolver includes a resolver rotor fixed to the rotor shaft of the motor rotor, and a resolver stator provided around the resolver rotor. The resolver stator is generally fixed to a case or housing that houses the motor, for example, by bolting.

  As a prior art document related to this, for example, Japanese Patent Laid-Open No. 2003-23761 (Patent Document 1) discloses a resolver fixing structure for a brushless motor, which can be fixed accurately without applying excessive stress. ing. In this resolver fixing structure, the resolver detection stator is accommodated in an annular recess formed in the end plate, and the flange portion of the resin-made locking member fixed to the end plate by press-fitting is provided on the axial end surface of the detection stator. It is described that the detection stator is pressed and fixed to the end plate by pressing the outer peripheral portion. Here, as 3rd Embodiment in patent document 1, the latching | locking part (73) which protrudes to a radial direction outer side in the steel plate located in the edge part by the side of the drive rotor of a motor among the steel plates which comprise the detection stator of a resolver. It is described that the detection stator is fixed to the end plate by forming it in a bent shape and press-fitting this engaging portion into the recess of the end plate.

JP 2003-23761 A

  In the resolver fixing structure described in Patent Document 1, since the engaging portion protrudes from the steel plate constituting the stator end near the motor, the magnetic flux generated from the motor due to the magnetic antenna effect is generated by the engaging portion. Easy to flow into. As a result, the detection accuracy of the resolver is easily affected by the magnetic flux that has flowed into the resolver stator via the locking portion.

  An object of the present invention is to provide a stator fixing structure capable of improving the detection accuracy of a resolver by making it difficult for magnetic flux from a motor to flow into the resolver stator.

  A stator fixing structure according to the present invention is a stator fixing structure that fixes a stator of a resolver provided adjacent to a motor to an attachment member, and the stator is configured by laminating a plurality of magnetic plate materials, and the magnetic plate material At least one magnetic plate located at the axial end of the stator on the side farther from the motor is formed in a different shape from the other magnetic plate, and the abnormal magnetic plate is used to attach the stator to the mounting destination. A fixing portion for fixing to the member protrudes radially outward from the annular outer peripheral surface of the stator.

  In the stator fixing structure according to the present invention, the fixing portion may be a positioning portion that determines a circumferential position of the stator with respect to the attachment destination member by fitting in a positioning groove formed in the attachment destination member. Good.

  In the stator fixing structure according to the present invention, when the stator is fixed to the attachment destination member, the fixing portion is engaged with a protruding portion formed on the motor side of the positioning groove so that the tip portion engages. The movement of the stator in the axial direction may be restricted.

  According to the stator fixing structure of the present invention, the fixing portion for fixing the stator to the attachment destination member is formed on the magnetic plate material that constitutes the stator end portion on the side far from the motor. Compared with the case where the fixed portion is provided at the end portion, the magnetic flux from the motor is less likely to flow into the stator via the fixed portion, and as a result, the resolver detection accuracy can be improved.

It is sectional drawing of the resolver containing the stator fixing structure which is one embodiment of this invention. FIG. 2 is a plan view (including a shaft cross section) viewed from an axial direction, showing a detection rotor and a detection stator of a resolver attached to a case in FIG. 1. It is AA sectional drawing in FIG. It is a top view of a detection stator. It is a figure similar to FIG. 3 which shows a mode when a detection stator is fixed in steps. It is a figure which shows the example which formed the base part for stator attachment of the case as an annular recessed part.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that these characteristic portions are used in appropriate combinations.

  FIG. 1 is a sectional view in the axial direction showing a resolver 10 to which the stator fixing structure of this embodiment is applied. FIG. 2 is a sectional view of the detecting rotor and the detecting stator of the resolver 10 attached to the case in FIG. FIG. 3 is a plan view (including a shaft cross section). In this embodiment, an example in which the stator fixing structure is applied to the resolver 10 that is a rotor rotational position detection sensor will be described. However, the stator fixing structure may be used as a stator fixing structure constituting a rotating electric machine such as a motor or a generator.

  As shown in FIG. 1, the resolver 10 is provided adjacent to the motor 12. The motor 12 is accommodated in a substantially bottomed cylindrical housing 14. The open end of the housing 14 is closed by a case (attachment member) 16 that houses the resolver 10. The housing 14 and the case 16 are preferably made of, for example, aluminum die cast.

  The motor 12 includes a motor stator 20 and a motor rotor 22. The motor stator 20 has a cylindrical shape formed by laminating magnetic steel plates in the axial direction, and a plurality of teeth 24 formed so as to protrude radially inward are provided in the circumferential direction at equal intervals. A stator coil 26 is wound around the teeth 24.

  The motor rotor 22 includes a substantially cylindrical rotor core 22a, and a rotor shaft 22b fixed through the central hole of the rotor core 22a. The rotor core 22a is disposed inside the motor stator 20 with a predetermined gap therebetween. Further, the rotor shaft 22b can rotate the rotor shaft 22b of the motor 12 via a bearing 18 disposed at the center of the case 16 and a bearing (not illustrated) disposed at the center of the bottom of the housing 14 (not illustrated). It is supported by.

  The resolver 10 includes a detection rotor 30 and a detection stator 32. The resolver 10 functions as a sensor for detecting the rotational position of the motor rotor 22. The detection rotor 30 of the resolver 10 is configured, for example, by laminating a plurality of magnetic steel plates punched into a substantially elliptical or oval shape in the axial direction and integrally connecting them by caulking, welding, or the like.

  A rotor shaft 22 b extending from the motor 12 is inserted into the center hole of the detection rotor 30. A key 34 protrudes from the edge of the center hole of the detection rotor 30, and the key 34 is fitted into a key groove 36 formed in the rotor shaft 22b so that the periphery of the detection rotor 30 with respect to the rotor shaft 22b. The direction position is determined.

  In addition, when the detection rotor 30 is assembled with the end portion (left side in FIG. 1) of the rotor shaft 22b being inserted, the key 34 of the detection rotor 30 abuts on the end surface of the key groove 36 extending in the axial direction. Thus, the axial position of the detection rotor 30 with respect to the rotor shaft 22b can be determined.

  In the above description, it has been described that the circumferential position of the detection rotor 30 is determined by the fitting of the key and the key groove. However, the present invention is not limited to this, and the detection rotor is press-fitted into the rotor shaft, interference-fitted, or the like. Accordingly, the circumferential position and / or the axial position of the detection rotor with respect to the rotor shaft may be fixed.

  The detection stator 32 of the resolver 10 is provided around the detection rotor 30 via a gap. The detection stator 32 includes a stator core 33 formed by laminating magnetic plate materials. The stator core 33 is configured, for example, by laminating magnetic steel plates (magnetic plate materials) punched into a substantially annular shape in the axial direction and integrally connecting them by caulking, welding, or the like.

  The stator core 33 includes an annular yoke portion 38 and a plurality of teeth portions 39 that protrude radially inward from the inner peripheral portion of the yoke portion 38. The teeth part 39 is provided at equal intervals in the circumferential direction. A detection coil 40 is wound around these teeth portions 39. The detection coil 40 includes coil end portions 42 that protrude outward from both axial end surfaces of the stator core 33.

  As shown in FIG. 2, the detection coil 40 is preferably covered with an annular resin cover member 44. The cover member 44 is provided so as to cover the detection coil 40 over the entire circumferential direction with the end face of the teeth portion 39 exposed at the inner periphery of the detection stator 32. In addition, illustration of the cover member 44 is abbreviate | omitted in FIG.

  The cover member 44 can be formed, for example, by performing insert injection molding of the stator core 33 around which the detection coil 40 is wound in a molding die. The cover member 44 preferably covers the coil end portions 42 of the detection coil 40 on both axial sides of the detection stator 32. Thus, by covering the detection coil 40 with the cover member 44, the cooling oil used for cooling the motor rotor 22 and the stator coil 26 of the motor 12 is not applied to the detection coil 40 of the resolver 10. It is possible to prevent the insulation performance of the detection coil 40 from being deteriorated due to adhesion of conductive foreign matters such as metal powder contained in the metal, and the detection accuracy of the resolver 10 can be maintained well.

  In the stator core 33 constituting the detection stator 32, at least one magnetic steel plate located at one end in the axial direction of the laminated magnetic steel plates is formed in a shape different from other magnetic steel plates. Specifically, at least two fixing portions that protrude radially outward from the outer peripheral surface 33c of the stator core 33 are formed on the magnetic steel plate positioned at the one end portion. This fixing portion is for fixing the detection stator 32 to the case 16. When the detection stator 32 is fixed to the case 16 and assembled to the housing 14, the magnetic steel plate with the fixed portion formed as described above is positioned at the axial end of the detection stator 32 on the side far from the motor 12. Will be. Details of the stator fixing structure will be described later.

  In the resolver 10 configured as described above, when the motor 12 is driven and the motor rotor 22 rotates, the detection rotor 30 rotates together with the rotor shaft 22b. At this time, the gap length between the detection rotor 30 having a substantially elliptical outer peripheral surface and the inner peripheral surface of the detection stator 32 (that is, the radially inner end surface of the tooth portion 39) changes. Therefore, when an alternating current is passed through the detection coil 40, an output corresponding to the change in the gap length is superimposed on the alternating current. The rotational position of the motor rotor 22 can be detected based on the alternating current on which this output is superimposed.

  Next, the stator fixing structure of this embodiment will be described in detail with reference to FIGS. 3 to 5 in addition to FIGS. 3 is a cross-sectional view taken along line AA in FIG. FIG. 4 is a plan view of the detection stator 32. FIG. 5 is a view similar to FIG. 3, showing the state when the detection stator 32 is fixed step by step.

  Referring to FIGS. 1 and 2, a pedestal 17 is projected from the inner surface 19 of the case 16 that houses the resolver 10. The pedestal portion 17 has, for example, a column shape having a substantially trapezoidal cross section. The pedestal portion 17 extends in the axial direction indicated by the arrow X, and the protruding length of the pedestal portion 17 is the cover member 44 when the detection stator 32 is mounted on the pedestal portion 17 (the coil end portion when there is no cover member). 42) is set so as not to contact the inner surface 19 of the case 16.

  Furthermore, as shown in FIG. 2, a plurality of pedestal portions 17 are provided at intervals in the circumferential direction along the outer periphery of the detection stator 32. In this embodiment, an example in which four pedestal portions 17 are provided at equal intervals is shown. The intervals in the circumferential direction of the pedestal portions 17 may be equal intervals or unequal intervals. When the circumferential interval of the pedestal portion 17 is set to be unequal, the mounting direction of the detection stator 32 is uniquely defined in relation to the fixed portion of the detection stator 32, so the mounting direction of the detection stator 32 is uneven. There is an advantage that can be surely prevented.

  In the present embodiment, the pedestal portion 17 for fixing the detection stator 32 is provided so as to jump in the circumferential direction. However, the present invention is not limited to this. For example, a pedestal portion extending in an annular shape may be used. By doing so, there is an advantage that the contact area between the end surface of the pedestal portion and the outer peripheral portion of the axial end surface of the stator core of the detection stator is increased, and the detection stator 32 is fixed more stably.

  Referring to FIGS. 2 and 3, each pedestal portion 17 is formed with an inlay step portion 17 a and an outer peripheral wall portion 17 b. The inlay step portion 17 a is a portion that contacts and supports the axial end surface of the stator core 33 when the detection stator 32 is disposed inside the four pedestal portions 17.

  Further, the outer peripheral wall portion 17 b of the pedestal portion 17 is formed so that a slight gap is left between the outer peripheral surface 33 c of the stator core 33 when the detection stator 32 is disposed inside the four pedestal portions 17. Is preferred. In this way, when the detection stator 32 is fixed, the radial pressing force does not act on the stator core 33 from the outer peripheral wall portion 17b of the pedestal portion 17, and accordingly, due to the radial stress strain of the stator core 33. It can prevent that the detection accuracy of the resolver 10 falls.

  However, even when the detection stator 32 is arranged inside the four pedestal portions 17, the outer peripheral surface 33c of the stator core 33 and the outer peripheral wall portion 17b of the pedestal portion 17 are in contact with each other to the extent that excessive pressing force does not act. Good. In this way, the radial positioning of the detection stator 32 fixed to the case 16 can be performed easily and accurately.

  Further, as shown in FIG. 3, the outer peripheral wall portion 17 b of the pedestal portion 17 is recessed toward the radially outer side indicated by the arrow R and extends in the axial direction with a length substantially corresponding to the laminated thickness of the stator core 33. 46 is formed. The positioning groove 46 has a circumferential width W1 substantially corresponding to the width (W2) of the fixed portion described later. In addition, a protruding portion 50 that protrudes inward in the radial direction with a width W <b> 2 smaller than the recess depth D of the positioning groove 46 is formed at the tip end portion in the axial direction of the positioning groove 46. As shown in FIGS. 2 and 3, when the outer peripheral wall portion 17b of the pedestal portion 17 is viewed from the axial direction, it is the end portion of the positioning groove 46, and the overhanging portion 50 and the radially inner side surface of the outer peripheral wall portion 17b. A substantially rectangular opening 52 is formed between them.

  On the other hand, referring to FIGS. 3 and 4, the stator core 33 constituting the detection stator 32 is formed with a fixing portion 54 protruding in a rectangular shape radially outward from the annular outer peripheral surface 33 c. The fixing portion 54 is a positioning portion that determines the circumferential position (or rotational position) of the detection stator 32 by fitting in the positioning groove 46 of the pedestal portion 17 when the detection stator 32 is attached to the case 16. The protruding length of the fixing portion 54 from the outer peripheral surface 33c is such that the end portion of the fixing portion 54 that is bent and fitted into the positioning groove 46 in a state where the end surface of the stator core 33 is in contact with the spigot step portion 17a of the pedestal portion 17. It is set to engage with the overhanging portion 50 of the pedestal portion 17.

  In the present embodiment, four fixing portions 54 of the stator core 33 are provided in the circumferential direction so as to correspond to the pedestal portion 17. The number of the fixing portions 54 may be at least two as in the case of the pedestal portion 17, and the interval between the fixing portions 54 may be unequal to match the pedestal portion 17.

  As shown in FIG. 3, the fixed portion 54 includes one magnetic steel plate 33 a positioned at the axial end of the stator core 33 far from the motor 12 among the stacked magnetic steel plates constituting the stator core 33. It is formed by punching into a shape different from that of the magnetic steel plate 33b. When the detection stator 32 fixed to the case 16 is assembled to the housing 14, the motor 12 is positioned on the upper side in FIG.

  However, the fixing portion 54 is not limited to being formed on one magnetic steel plate, and may be formed on two or more magnetic steel plates positioned at the axial end of the stator core 33.

  Subsequently, an assembly process of the detection stator 32 to the case 16 will be described with reference to FIG.

  First, as shown in FIG. 5A, for example, the detection stator 32 is placed on the four pedestals 17 of the case 16 placed on a horizontal work table. At this time, the stator core 33 is disposed so that the outer peripheral surface of the stator core 33 is inside the outer peripheral wall portion 17 b of the pedestal portion 17, and the fixing portion 54 of the detection stator 32 is opposed to the opening 52 of the pedestal portion 17, that is, the positioning groove 46. The rotational position of the detection stator 32 is adjusted to the above.

  Then, in this state, as shown in FIG. 5B, the detection stator 32 is pushed into the case 16 in the direction of the arrow. Then, the fixing portion 54 is inserted into or pressed into the positioning groove 46 through the opening 52 while being bent by being pressed against the protruding portion 50.

  When the axial end surface of the stator core 33 comes into contact with the spigot step portion 17a of the pedestal portion 17, the fixed portion 54 that has passed through the overhang portion 50 engages with the overhang portion 50 by its own elastic restoring force. Thus, the detection stator 32 is fixed to the case 16. In this fixed state, the front end portion of the fixing portion 54 is engaged with the overhanging portion 50, so that the detection stator 32 is in a state where the axial position is determined without rattling in the axial direction. Will not come off.

  As described above, according to the stator fixing structure of the present embodiment, the fixing portion 54 for fixing the detection stator 32 to the case 16 is formed on the magnetic steel plate 33a constituting the stator end portion far from the motor 12. Therefore, the magnetic flux from the motor 12 is less likely to flow into the stator core 33 of the detection stator 32 via the fixed portion 54 as compared with the case where the fixed portion 54 is provided at the stator end near the motor 12. The detection accuracy of the resolver 10 can be improved.

  Further, since the detection stator 32 can be fixed to the case 16 by the fixing portion 54 formed on the magnetic steel plate 33a at the axial end portion of the detection stator 32, the pressing force is applied to the stator core 33 from the pedestal portion 17 or the case 16 when fixed. In particular, it is possible to limit or eliminate the action of a pressing force inward in the radial direction. Therefore, the detection accuracy of the resolver 10 is not deteriorated due to the stress strain of the stator core 33.

  Further, since the detection stator 32 can be fixed to the case 16 by the fixing portion 54, it is not necessary to form a fixing bolt insertion hole in the stator core 33. Therefore, the diameter of the stator core 33 can be reduced, and the material cost can be reduced by improving the yield of the magnetic steel sheet.

  Furthermore, since it is not necessary to use a bolt for fixing the detection stator 32, the stator can be easily attached to the case. At this time, the detection stator 32 can be positioned in the circumferential direction, the radial direction, and the axial direction by a one-touch operation in which the detection stator 32 is positioned and pushed into the case 16. Therefore, work such as circumferential position adjustment after assembly is not necessary, and the assembly process of the detection stator 32 becomes extremely simple.

  Note that the stator fixing structure according to the present invention is not limited to the configuration of the above-described embodiment and its modifications, and various modifications and improvements can be made within the scope of matters described in the claims and their equivalent ranges. Is possible.

  For example, in the above embodiment, the pedestal portion 17 to which the detection stator 32 is attached is provided so as to protrude from the case inner surface 19. However, the present invention is not limited to this, and as shown in FIG. An inlay stepped portion 17a that is recessed may be formed. Further, in this case, the projecting portion 50 projecting inward in the radial direction with respect to the positioning groove 46 is provided by press-fitting and fixing the ring member 56 having an L-shaped cross-section which is a separate member from the case 16 to the case 16. Also good. In this way, if the overhanging portion is constituted by another member, there is an advantage that the case 16 can be easily manufactured.

  DESCRIPTION OF SYMBOLS 10 Resolver, 12 Motor, 14 Housing, 16 Case, 17 Base part, 17a Inner step part, 17b Outer peripheral wall part, 18 Bearing, 19 Inner surface, 20 Motor stator, 22 Motor rotor, 22a Rotor core, 22b Rotor shaft, 24 Teeth, 26 Stator coil, 30 detection rotor, 32 detection stator, 33 stator core, 33a, 33b magnetic steel plate, 33c outer peripheral surface, 34 key, 36 key groove, 38 yoke part, 39 teeth part, 40 detection coil, 42 coil end part, 44 cover Member, 46 Positioning groove, 50 Overhang part, 52 Opening part, 54 Fixing part, 56 Ring member, W1 Circumferential width, W2 width, X arrow (axial direction).

Claims (3)

A stator fixing structure for fixing a stator of a resolver provided adjacent to a motor to an attachment destination member,
The stator is formed by laminating a plurality of magnetic plates, and at least one magnetic plate located at the axial end of the stator far from the motor among the magnetic plates is different from other magnetic plates. The irregularly shaped magnetic plate member has a fixing portion for fixing the stator to the attachment member projecting radially outward from the annular outer peripheral surface of the stator,
Stator fixing structure. The stator fixing structure according to claim 1,
The stator fixing structure, wherein the fixing portion is a positioning portion that determines a circumferential position of the stator with respect to the attachment destination member by fitting in a positioning groove formed in the attachment destination member. The stator fixing structure according to claim 2,
The fixing portion restricts movement of the stator in the axial direction by engaging a tip portion with an overhang portion formed on the motor side of the positioning groove when the stator is fixed to the attachment member. Fixed structure.

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