JP5696642B2 - Stator fixing structure - Google Patents

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, referring to paragraph 0025 of Patent Document 1, the detection stator of the resolver has a key groove that fits into a key embedded in the end plate, and the circumferential position with respect to the end plate is determined by this key fitting. It is described that

JP 2003-23761 A

  In the resolver fixing structure described in Patent Document 1, it is necessary to process a groove or a hole for embedding a key in the end plate and a key assembling work, which increases the processing cost and is complicated.

  An object of the present invention is to provide a stator fixing structure capable of easily and accurately fixing a stator to an attachment member without using a key with a simple structure.

The stator fixing structure according to the present invention includes a mounting member to which a stator made of a steel sheet laminate having an annular outer peripheral surface is fixed, and a state in which a part of the circumferential direction protrudes from a pin hole of a base portion of the mounting member. And at least two knock pins standing by being press-fitted in, and a stator having a notch that does not penetrate in the axial direction formed by rolling of a steel plate at the edge facing the outer peripheral surface, The stator has a circumferential position determined by engaging a part of the knock pin protruding to the notch portion with respect to the attachment member, and the axial end surface of the part of the knock pin protruding from the stator. axial position and nipped between the non-through portion of the cutout portion and the spigot stepped portion of the base portion are determined, the radial direction portion protruding of the knock pin is against the notch Radial position of the stator is a shall be determined by the action of inner pressure.

  According to the stator fixing structure of the present invention, at least two knock pins are driven into the pedestal portion of the attachment member and engaged with the notch portion, so that the stator is in a state where the circumferential position and the axial position are determined. Can be fixed to the attachment member. Therefore, the stator can be easily and accurately fixed to the attachment member with a simple structure. Further, it is not necessary to adjust the circumferential position after the stator is assembled to the attachment destination member, and the assembly work of the stator becomes quick and easy. Further, it is not necessary to form a through hole for inserting a bolt in the stator, and accordingly, the stator can be reduced in diameter and the material cost can be reduced.

It is sectional drawing of the resolver containing the stator fixing structure which is one embodiment of this invention. It is a perspective view which shows the detection stator of the resolver attached to the case in FIG. It is an enlarged view which shows a part of knock pin and detection stator seen from the arrow A direction in FIG. It is BB sectional drawing in FIG. It is a top view of a detection stator. It is CC sectional drawing in FIG.

  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 an axial sectional view showing a resolver 10 to which the stator fixing structure of the present embodiment is applied, and FIG. 2 is a perspective view showing a detection stator of the resolver attached to the case in FIG. In this embodiment, an example in which the stator fixing structure is applied to the resolver 10 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 detection rotor 30 is configured, for example, by laminating a plurality of magnetic steel plates punched into a substantially elliptical 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 (not shown) protrudes from the edge of the center hole of the detection rotor 30, and a key groove (not shown) recessed on the rotor shaft 22b is fitted into the key so that the rotor The circumferential position of the detection rotor 30 with respect to the shaft 22b is determined.

  Further, when the end portion (the left side in FIG. 1) of the rotor shaft 22b is inserted and assembled to the detection rotor 30, the end surface in the axial direction is in contact with a projecting portion (not shown) provided on the rotor shaft 22b. By abutting, 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, for example, a stator core 33 configured by laminating magnetic steel plates 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 and a plurality of teeth portions 39 projecting radially inward at the inner peripheral portion of the yoke portion. 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 circumference in a state where the end surface of the tooth portion 39 is exposed on the inner circumferential surface 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 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 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 the present embodiment will be described in detail with reference to FIGS. 3 to 6 in addition to FIGS. FIG. 3 is an enlarged view showing a part of the knock pin and the detection stator as seen from the direction of arrow A in FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a plan view of the detection stator 32. 6 is a cross-sectional view taken along the line CC in FIG.

  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 and an end surface. Further, the pedestal portion 17 extends in the axial direction indicated by the arrow X, and the protruding length of the pedestal portion 17 when the detection stator 32 is mounted on the pedestal portion 17 is that the cover member 44 (or the coil end portion 42) is attached to the case 16 It is set to such an extent that it does not come into contact with the inner surface 19.

  Further, 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 the present embodiment, an example in which three pedestals 17 are provided is shown. The intervals in the circumferential direction of the pedestal portions 17 may be equal intervals or unequal intervals. When the circumferential intervals of the pedestal portions 17 are set to be unequal intervals, the mounting direction of the detection stator 32 is uniquely defined in relation to a notch portion formed on the stator outer peripheral surface described later. There is an advantage that it is possible to surely prevent the mounting direction of the from being uneven.

  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.

  A knock pin 50 is erected on the end surface of the pedestal portion 17 along the axial direction. The knock pin 50 is a fixing member for fixing the detection stator 32 to the case 16 in a state where the circumferential position and the axial position are determined. As shown in FIGS. 3 and 4, the knock pin 50 is fixed by being press-fitted into a pin hole 17 c formed in the distal end portion 17 a of the pedestal portion 17.

  The pedestal portion 17 has a tip end portion 17a, a spigot step portion 17b, and a pin hole 17c. A pin hole 17c formed in the tip portion 17a is partially open in the circumferential direction. Thereby, when the knock pin 50 is driven into the pin hole 17c, a part of the knock pin 50 in the circumferential direction, more specifically, a part facing the radially inner side of the detection stator 32 protrudes from the pin hole 17c. It is designed to be press-fitted.

Here, the pin hole 17c needs to have an inner wall surface extending over at least 180 degrees with respect to the periphery of the knock pin 50 in order to ensure press-fitting and holding of the knock pin 50. However, when the cross-sectional shape of the knock pin 50 is other than a circle, such as an ellipse, a rectangle, or a triangle, the protruding portion can be made larger than the portion into which the knock pin is press-fitted.

  The inlay step portion 17 b of the pedestal portion 17 has a function of supporting the detection stator 32 by abutting against the outer peripheral end surface of the stator core 33 of the detection stator 32. In the present embodiment, an example is shown in which the bottom of the pin hole 17c is formed flush with the spigot step 17b.

  When the detection stator 32 is accommodated and arranged inside the three pedestal portions 17 in the present embodiment, a slight gap is formed between the outer peripheral surface 33a of the stator core 33 and the tip end portion 17a of the pedestal portion 17. Is preferable. As a result, the pedestal portion 17 can be prevented from giving a radial pressing force to the detection stator 32, and the influence on the detection accuracy due to the stress strain in the radial direction of the detection stator 32 can be eliminated.

  The knock pin 50 can be suitably constituted by, for example, a metal round bar member. Further, the knock pin 50 may be a solid pin member as shown in FIG. 3, or may be a hollow pin member. Furthermore, it is preferable to form a chamfered portion on the outer peripheral portion of the end portion of the knock pin 50 in order to facilitate press-fitting. Thus, by using the knock pin 50 for fixing the detection stator 32 to the case 16 as a separate member from the detection stator 32 and the case 16, there is an advantage that the stator fixing structure can be simplified. Furthermore, if a commercially available knock pin 50 is used, a large cost reduction effect can be expected.

  In the stator fixing structure of the present embodiment, three knock pins 50 corresponding to the number of pedestal portions 17 are used. Since the detection stator 32 is fixed by the three knock pins 50 in this way, the radial position and the circumferential position of the detection stator 32 can be positioned while reducing the number of components and facilitating the assembly operation. It can be done reliably. However, of course, the number of knock pins 50 (and pedestal portions 17) may be four or more. Two knock pins 50 may be provided. In this case, the knock pins 50 may be provided so as to abut on the outer peripheral surface of the stator core 33 at a position substantially opposite to the radial direction of the detection stator 32.

  4 to 6, the stator core 33 constituting the detection stator 32 has an annular outer peripheral surface 33a, and a plurality of notches 54 that do not penetrate in the axial direction are formed on the edge facing the outer peripheral surface 33a. Is formed. More specifically, in the present embodiment, seven cutout portions 54 each having a substantially semicircular shape are formed at an equal pitch in the circumferential direction.

  The notch 54 that does not penetrate in the axial direction in the stator core 33 can be formed as follows. That is, when the stator core 33 is configured by laminating a plurality of magnetic steel plates having seven notches 54 on the outer periphery, for example, half the number of magnetic steel plates are rolled while shifting in the circumferential direction by the pitch of the notches. Then, the next magnetic steel sheet is rolled at a position shifted in the circumferential direction by a half pitch, and the remaining number of magnetic steel sheets are rolled again while shifting in the circumferential direction by the pitch. Thus, for example, as shown in FIGS. 5 and 6, half of the laminated thickness has the cutouts 54 aligned, and the remaining half is closed, resulting in the formation of cutouts 54 that do not penetrate in the axial direction. Will be. Note that the number of magnetic steel sheets constituting the notch 54 (or the number of magnetic steel sheets that close the notch 54) can be set as appropriate.

  Next, assembly of the stator fixing structure of the present embodiment having the above-described configuration will be described.

  First, it arrange | positions so that the outer peripheral edge part of the stator core 33 of the detection stator 32 may be mounted on the spigot step part 17b of the three base parts 17 protrudingly provided in the case 16. At this time, the circumferential position of the detection stator 32 is adjusted so that the notch portion 54 facing upward in FIG. 2 faces the portion where the pin hole 17c of the base portion 17 is opened.

  Subsequently, the three knock pins 50 are driven into the pin holes 17c of the pedestal portion 17 and are press-fitted and fixed. As a result, as shown in FIG. 4, the portion of the knock pin 50 that protrudes radially inward from the pin hole 17 c engages with the notch 54 of the stator core 33, so that the stator core 33, that is, the circumferential direction of the detection stator 32 with respect to the case 16 The position is determined.

  Further, as shown in FIG. 4, the portion protruding from the pin hole 17 c in the axial end portion of the knock pin 50 press-fitted into the pin hole 17 c of the pedestal portion 17 is the outer peripheral portion of the steel plate that closes the notch portion 54. It will contact | abut and will be in the state clamped between the spigot step part 17b of the base part 17. FIG. Accordingly, the detection stator 32 is fixed in a state where the axial position is determined with respect to the case 16.

  Further, in the present embodiment, the radial position of the detection stator 32 with respect to the case 16 can also be accurately determined by contacting the protruding portion of the knock pin 50 and the edge of the notch 54. In this case, by setting the tightening allowance of the stator core 33 so that the knock pin 54 does not apply an excessive pressing force to the stator core 33 through the notch 54, a decrease in detection accuracy due to radial stress strain is avoided. can do.

  As described above, according to the stator fixing structure of the present embodiment, at least two knock pins 50 are driven into the pedestal portion 17 of the case 16 and engaged with the notches 54, whereby the circumferential position and the axial position are adjusted. The detection stator 32 can be fixed to the case 16 in a determined state. Accordingly, the detection stator 32 can be easily fixed to the case 16 with a simple structure with high accuracy.

  Further, there is no need to adjust the circumferential position of the stator after the detection stator 32 is assembled to the case 16, and the assembly operation of the detection stator 32 becomes quick and easy.

  Further, it is not necessary to form a through hole for inserting a bolt in the outer peripheral portion of the stator core 33 of the detection stator 32, and accordingly, the diameter of the stator core 33 constituting the detection stator 32 can be reduced, and the material cost can be reduced.

  Furthermore, the region in which the radial pressing force acts on the notch portion 54 by the knock pin 50 is limited to a small size as viewed from the entire peripheral region, and the notch depth of the notch portion 54 is appropriately set, etc. It is also possible to suppress the occurrence of radial stress strain in the stator core 33 that affects the detection accuracy of the resolver 10.

  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.

  10 Resolver, 12 Motor, 14 Housing, 16 Case, 17 Base, 17a Tip, 17b Inner Step, 17c Pin Hole, 18 Bearing, 19 Inner Case, 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 outer peripheral surface, 39 teeth portion, 40 detection coil, 42 coil end portion, 44 cover member, 50 knock pin, 54 notch portion, X arrow ( Axial direction).

Claims (1)

An attachment member to which a stator made of a steel sheet laminate having an annular outer peripheral surface is fixed;
At least two or more knock pins erected by being press-fitted in a state in which a part of the circumferential direction protrudes into the pin hole of the pedestal portion of the mounting member
A stator having a notch that does not penetrate in the axial direction formed by rolling of steel plates, on the edge facing the outer peripheral surface,
The stator has a circumferential position determined by engaging a part of the knock pin protruding to the notch portion with respect to the attachment member, and the axial end surface of the part of the knock pin protruding from the stator. axial position and nipped between the non-through portion of the cutout portion and the spigot stepped portion of the base portion is defined et al is,
A radial position of the stator is determined by causing a protruding part of the knock pin to apply a radially inner pressing force to the notch,
Stator fixing structure.

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