JP2015132502A - Variable reluctance-type resolver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable reluctance-type resolver in which an axis double angle allowing for reduction in oscillation of a rotor when rotated in high speed is 1X.SOLUTION: A variable reluctance-type resolver arranged inward in a radial direction further than a stator core 25 comprises: a rotor core 41 shaped to have a distance from a rotating axial line 8 to an outer peripheral surface 47 successively varying along a peripheral direction 7 in the outer peripheral surface 47; a shaft 43 inserted into the rotor core 41; and a non-magnetic body 42 externally fitted into the rotor core 41, in which an axis double angle is 1X. The rotor core 41 includes through-holes 44 and 45 along an axial direction 9, and the non-magnetic body 42 comprises: a pin section 61 that is inserted into the through-holes 44 and 45; a counter-weight section 62 that is arranged outward in a radial direction of a recess section 46 including a location where a distance to the rotating axial line 8 is the shortest in the outer peripheral surface 47; and connection sections 63A and 63B that connect the pin section 61 and the counter-weight section 62.

Description

  The present invention relates to a variable reluctance resolver.

  2. Description of the Related Art A variable reluctance resolver that is provided in a brushless motor, has a rotor and a stator, and detects the rotation angle of the rotor that rotates with respect to the stator that forms a magnetic field is known. The rotor generally has a structure in which magnetic steel plates are laminated. In the stator, an exciting coil and an output coil are wound around a plurality of teeth arranged around the rotor. When an excitation voltage is applied to the excitation coil, output voltages having different phases according to the rotation of the rotor are output from the output coil based on the excitation of the excitation coil. Based on this output voltage, the rotation angle of the rotor, that is, the rotation angle of the rotor of the brushless motor is detected. The rotation of the brushless motor is controlled based on the detected rotation angle.

  In the output signal of the variable reluctance resolver, various resolvers are referred to as “nX”, where n is a sine wave cycle of the voltage output during one rotation of the rotor. For example, a resolver that outputs two cycles of a sine wave while the rotor makes one revolution is referred to as “2X”.

  A rotor provided in a variable reluctance resolver with a shaft angle multiplier of 1X outputs one cycle of a sine wave during one rotation. The variable reluctance resolver including such a rotor has an advantage that the absolute angle of the rotor can be easily measured. A variable reluctance resolver having a shaft angle multiplier of 1 × is disclosed in Patent Document 1.

JP 2010-216844 A

  However, the rotor provided in the variable reluctance resolver having a shaft angle multiplier of 1 × has a recessed outer peripheral surface and has an asymmetric shape with respect to the rotation axis. Therefore, the center of gravity of the rotor deviates from the rotation axis. As a result, when the rotor rotates at high speed, vibration may occur.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a variable reluctance type resolver having an axial multiplication angle of 1X that can reduce vibration of a rotor when rotating at high speed.

  (1) A variable reluctance resolver according to the present invention includes a stator core in which a plurality of teeth extending radially inward from a cylindrical core yoke are arranged in the circumferential direction, and a coil wound around each of the plurality of teeth. And a rotor core having a shape in which the distance from the rotation axis to the outer peripheral surface continuously changes along the circumferential direction on the outer peripheral surface, and the rotation inserted through the rotor core. The shaft angle multiplier having a shaft and a nonmagnetic material fitted on the rotor core is 1 ×. The rotor core has a through hole along the rotation axis direction. The non-magnetic body includes a pin portion inserted through the through-hole, and a counterweight portion disposed on the radially outer side of the recess including a position where the distance from the rotation axis is the shortest on the outer peripheral surface of the rotor core, The rotor core is disposed on the outer side in the rotation axis direction of the rotor core, and includes a connection portion that connects the pin portion and the counterweight portion.

  According to the above configuration, since the concave portion is provided in the rotor core, the weight on the concave portion side with respect to the rotation axis in the rotor core is smaller than the weight on the opposite side to the concave portion with respect to the rotation axis in the rotor core. That is, the center of gravity of the rotor core is shifted from the rotation axis to the side opposite to the concave portion. Therefore, in the above configuration, the counterweight portion is disposed outside the concave portion in the radial direction. As a result, the weight on the concave portion side with respect to the rotation axis in the rotor core increases. As a result, the center of gravity of the rotor core can be brought closer to the rotation axis, so that vibration during high-speed rotation of the rotor core can be reduced.

  Moreover, according to the said structure, the nonmagnetic body is being fixed to the rotor core by the pin part being penetrated by the through-hole along a rotating shaft line direction. Thereby, when the rotor core rotates at a high speed, even if a large centrifugal force acts on the nonmagnetic material, the movement of the pin portion by the centrifugal force is blocked by the inner surface that defines the through hole. As a result, it is possible to reduce the possibility that the non-magnetic material is detached from the rotor core due to the centrifugal force.

  (2) The non-magnetic material is a resin molded product fixed to the rotor core by insert molding.

  In the above configuration, the non-magnetic material is fixed to the rotor core by insert molding. Thereby, a nonmagnetic body can be firmly fixed with respect to a rotor core rather than the structure by which the nonmagnetic body was fixed to the rotor core by inserting a rod-shaped pin part into the through-hole from the outside. As a result, when the rotor core rotates at high speed, the non-magnetic material is fixed to the rotor core by inserting the rod-shaped pin portion into the through-hole from the outside. Can be lower than the proposed configuration.

  (3) The through hole is provided at a position closer to the inner peripheral surface than the outer peripheral surface of the rotor core in the radial direction of the rotor core.

  In the said structure, since the through-hole is separated from the outer peripheral surface, the precision of the output voltage output from the coil wound by the teeth can be maintained favorable. Thereby, the rotation angle of the rotor can be accurately detected.

  (4) The nonmagnetic material bulges radially outward from a position where the distance from the rotation axis to the outer peripheral surface is the longest on the outer peripheral surface of the rotor core.

Centrifugal forces acting on the respective rotor core rotates and non-magnetic material F is expressed by F = mrω ^2. Here, r is the distance from the rotation axis in the radial direction of the outer peripheral surface of the rotor core and nonmagnetic material, m is the mass of the rotor core and nonmagnetic material, and ω is the angular velocity of the rotor core and nonmagnetic material. When the rotor core and the nonmagnetic material are rotated together, the angular velocity ω of the rotor core and the nonmagnetic material is the same. Therefore, the centrifugal force F acting on the rotor core and the nonmagnetic material is proportional to the distance r.

  Based on the above, when the centrifugal force acting on the rotor core and the nonmagnetic material is compared, the magnitude of the two centrifugal forces depends on the specific gravity of the material of the rotor core and the nonmagnetic material. For example, when the nonmagnetic material is made of resin and the rotor core is made of metal, the specific gravity of the nonmagnetic material is smaller than the specific gravity of the rotor core. In this case, the centrifugal force acting on the non-magnetic material is smaller than the centrifugal force acting on the rotor core. This difference in centrifugal force causes rotor vibration during high-speed rotation.

  The magnitude of the two centrifugal forces depends on the distance r between the rotor core and the nonmagnetic material. Thus, in the above configuration, the nonmagnetic material bulges radially outward from the position where the distance from the rotation axis to the outer peripheral surface is the longest on the outer peripheral surface of the rotor core. Thereby, even if the nonmagnetic material is a material having a specific gravity smaller than that of the rotor core, the centrifugal force acting on the nonmagnetic material can be increased. As a result, since the difference in centrifugal force can be reduced, the vibration of the rotor during high-speed rotation can be reduced.

  (5) The connection portion is provided with a pair so as to sandwich the rotor core.

  In the above configuration, the nonmagnetic material can be stably fixed to the rotor core.

  According to the variable reluctance resolver having a shaft angle multiplier of 1 × according to the present invention, vibrations of the rotor core when rotating at high speed can be reduced.

FIG. 1 is a front view of a resolver 10 according to an embodiment of the present invention. FIG. 2 is a perspective view of the rotor core 41 and the nonmagnetic material 42. FIG. 3A is a front view of the rotor core 41 and the nonmagnetic material 42, and FIG. 3B is a side view of the rotor core 41 and the nonmagnetic material 42. FIG. 4 is a perspective view of the rotor core 41 and the nonmagnetic material 42 according to a modification. FIG. 5 is a perspective view of the rotor core 41 and the nonmagnetic material 42 according to a modification.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment is only an example of this invention, and it cannot be overemphasized that an embodiment can be changed in the range which does not change the summary of this invention.

  FIG. 1 shows the configuration of the resolver 10. The resolver 10 includes a stator 22 in which eight teeth 20 protrude in a circumferential shape toward the inner side in the radial direction, and a coil 21 is wound around each tooth 20, and a stator on the inner side in the radial direction from the stator 22. 22 and a rotor 23 that is rotatably arranged with a space therebetween. The resolver 10 is a so-called variable reluctance type in which the rotor 23 does not have a winding.

  The stator 22 includes a stator core 25 and a coil 21. The stator core 25 includes a core yoke 24 and teeth 20.

  The stator core 25 is formed, for example, by pressing a steel plate having a predetermined thickness into a plan view shape shown in FIG. 1, laminating a plurality of the steel plates, and fixing them together by caulking or the like.

  The core yoke 24 has a substantially cylindrical outer shape as a whole. Eight teeth 20 protrude radially inward from the inner peripheral surface of the core yoke 24. The teeth 20 are arranged at intervals in the circumferential direction 7. The number of teeth 20 may be other than eight.

  A coil 21 is configured by winding an exciting coil, a SIN output coil, and a COS output coil around each of the eight teeth 20 by a predetermined winding method. In FIG. 1, the exciting coil, the SIN output coil, and the COS output coil are all shown as a coil 21.

  The SIN output coil and the COS output coil are wound around the tooth 20 so as to have a phase difference of 90 °. By applying a predetermined voltage to the excitation coil, a SIN output voltage (output signal) is obtained from the SIN output coil, and a COS output voltage (output signal) is obtained from the COS output coil. The voltage applied to the exciting coil, the SIN output voltage, and the COS output voltage are transmitted between the resolver 10 and a control unit (not shown) that controls the resolver 10 through a sensor cable (not shown).

  The rotor 23 shown in FIGS. 1 to 3 has a substantially cylindrical shape. The rotor 23 is externally fitted to the rotor core 41 having a shaft hole 40 opened substantially along the axial direction 9 in the center, the shaft 43 (an example of the rotating shaft of the present invention) inserted through the shaft hole 40, and the rotor core 41. A non-magnetic material 42 is provided.

  2 and 3 show the configuration of the rotor core 41 and the nonmagnetic material 42 provided in the rotor 23, but the shaft 43 is omitted. The shaft 43 is shown in FIG. The shaft 43 is rotatably supported by a housing (not shown).

  The rotor core 41 is formed by laminating a plurality of magnetic steel plates having a predetermined thickness and fixing them together by caulking or the like. As shown in FIG. 1, the shaft 43 is inserted through the shaft hole 40 described above. The rotor core 41 is fixed to the shaft 43. Thereby, the rotor core 41 is integrated with the shaft 43 around the rotation axis 8 (see FIG. 3) passing through the center of the shaft 43 extending in the axial direction 9 (see FIG. 2, an example of the rotation axis direction of the present invention). Rotate. The inner diameter and shape of the shaft hole 40 can be appropriately changed according to the diameter and shape of the inserted shaft 43.

  As shown in FIG. 3A, the rotor core 41 has an outer peripheral surface 47 in which the distance from the rotation axis 8 in the radial direction continuously changes along the circumferential direction 7. The outer peripheral surface 47 has a shape in which the gap permeance between the rotor core 41 and the stator 22 (see FIG. 1) changes in a sinusoidal shape with respect to the angle θ (see FIG. 1) in the rotation direction of the rotor core 41 (the same direction as the circumferential direction 7). Is formed.

  As shown in FIG. 3A, the rotor core 41 is formed with one concave portion 46 defined by a curved outer peripheral surface 47. The recess 46 is recessed from the outer peripheral surface 47 of the rotor core 41 toward the rotation axis 8. The recess 46 extends from one end surface 48 (see FIGS. 2 and 3) of the rotor core 41 in the axial direction 9 to the other end surface 49 (see FIG. 3B) that is the surface opposite to the one end surface 48. Is formed. The distance from the rotation axis 8 to the outer peripheral surface 47 in the radial direction is the shortest at the bottom of the recess 46.

  Since the rotor core 41 is configured as described above, the rotor 23 has an angle required for one cycle of the sine wave to be 360 °. That is, the shaft angle multiplier of the resolver 10 is “1X”, in which one cycle of a sine wave is output when the rotor 23 rotates once.

  As shown in FIG. 3A, the rotor core 41 has two through holes 44 and 45 formed therein. The through holes 44 and 45 are formed in the same direction as the shaft hole 40, that is, along the axial direction 9. The through holes 44 and 45 are provided in the vicinity of the shaft hole 40 in the radial direction of the rotor 23. That is, the through holes 44 and 45 are provided at positions closer to the inner peripheral surface 50 than the outer peripheral surface 47 of the rotor core 41 in the radial direction of the rotor 23.

  As described above, the positions where the through holes 44 and 45 are formed are preferably closer to the inner peripheral surface 50 than the outer peripheral surface 47 of the rotor core 41, but the outer peripheral surface 47 is more than the inner peripheral surface 50 of the rotor core 41. It may be a position close to. In the present embodiment, two through holes (through holes 44 and 45) are formed, but the number of through holes is not limited to two.

  The nonmagnetic material 42 is a resin molded product fixed to the rotor core 41 by insert molding. The non-magnetic body 42 includes three parts: a pin part 61, a counter weight part 62, and a pair of connection parts 63A and 63B that connect the pin part 61 and the counter weight part 62.

  The pin portion 61 is inserted through the through holes 44 and 45. In this embodiment, the pin part 61 is a part with which the through-holes 44 and 45 were filled in the process of insert molding. Therefore, the pin portion 61 has the same shape as the space forming the through holes 44 and 45. One end of the pin portion 61 in the axial direction 9 is continuous with the connecting portion 63A, and the other end of the pin portion 61 in the axial direction 9 is continuous with the connecting portion 63B.

  As shown in FIGS. 2 and 3, the connecting portion 63 </ b> A is disposed to face the one end surface 48 of the rotor core 41 in the axial direction 9. The connecting portion 63 </ b> A is in contact with the one end surface 48. As shown in FIG. 3B, the connection portion 63 </ b> B is disposed to face the other end surface 49 of the rotor core 41 in the axial direction 9. The connecting portion 63 </ b> A is in contact with the other end surface 49. That is, the connecting portions 63 </ b> A and 63 </ b> B are disposed outside the rotor core 41 in the axial direction 9. That is, the pair of connection portions 63A and 63B are arranged so as to sandwich the rotor core 41.

  In the present embodiment, the connecting parts 63A and 63B are shaped on the condition that they are arranged outside the rotor core 41 in the axial direction 9 and that the pin part 61 and the counterweight part 62 are connected. Is optional. For example, the connecting portion 63 </ b> A may not be in contact with the one end surface 48, and the connecting portion 63 </ b> B may not be in contact with the other end surface 49. Further, for example, the connecting parts 63A and 63B may have a shape in which a part is cut out as shown in FIGS. Thereby, the weight of the counterweight part 62 can be adjusted.

  As shown in FIG. 3A, the counterweight portion 62 is disposed on the radially outer side of the recess 46. In the present embodiment, the surface on the concave portion 46 side of the counterweight portion 62 has the same shape as the outer peripheral surface 47 defining the opposing concave portion 46, and is in contact with the outer peripheral surface 47. The surface 51 on the opposite side to the recess 46 of the counterweight portion 62 is curved along the circumferential direction 7. One end of the counterweight portion 62 in the axial direction 9 is continuous with the outer end portion in the radial direction of the connecting portion 63A. The other end of the counterweight portion 62 in the axial direction 9 is continuous with the outer end portion in the radial direction of the connecting portion 63B.

  The shape of the counterweight portion 62 is arbitrary on the condition that the counterweight portion 62 is disposed on the radially outer side of the recess 46. For example, the surface on the concave portion 46 side of the counterweight portion 62 may not be in contact with the outer peripheral surface 47. Further, for example, the counterweight portion 62 may have a shape in which a part is cut out as shown in FIG. Thereby, the weight of the counterweight part 62 can be adjusted.

  The nonmagnetic material 42 bulges radially outward from a position P (see FIG. 3A) where the distance from the rotation axis 8 to the outer peripheral surface 47 is the longest on the outer peripheral surface 47 of the rotor core 41. In other words, the distance L1 in the radial direction from the rotation axis 8 to the surface 51 of the counterweight portion 62 (the place farthest from the rotation axis 8 in the nonmagnetic body 42) is the radial distance from the rotation axis 8 to the position P. It is longer than the distance L2.

[Operational effects of this embodiment]
According to the present embodiment, since the rotor core 41 is provided with the recess 46, the weight on the recess 46 side of the rotor core 41 relative to the rotation axis 8 is on the opposite side of the rotation axis 8 of the rotor core 41 from the recess 46. Less than weight. That is, the center of gravity of the rotor core 41 is shifted from the rotation axis 8 to the side opposite to the recess 46. Therefore, in the present embodiment, the counterweight portion 62 is disposed on the radially outer side of the recess 46. As a result, the weight of the rotor core 41 closer to the recess 46 than the rotational axis 8 can be increased. As a result, the center of gravity of the rotor core 41 can be brought closer to the rotation axis 8, so that vibration during the high-speed rotation of the rotor core 41 can be reduced.

  Further, according to the present embodiment, the non-magnetic body 42 is fixed to the rotor core 41 by the pin portion 61 being inserted into the through holes 44 and 45 along the axial direction 9. Thereby, when the rotor core 41 rotates at a high speed, even if a large centrifugal force acts on the nonmagnetic material 42, the movement of the pin portion 61 due to the centrifugal force is blocked by the inner surface that defines the through holes 44 and 45. As a result, it is possible to reduce the possibility that the nonmagnetic material 42 is detached from the rotor core 41 by the centrifugal force.

  Further, according to the present embodiment, since the through holes 44 and 45 are provided closer to the inner peripheral surface 50 than the outer peripheral surface 47 in the radial direction, the through holes 44 and 45 are separated from the outer peripheral surface 47. . Therefore, the accuracy of the output voltage output from the coil 21 wound around the tooth 20 can be maintained satisfactorily. Thereby, the rotation angle of the rotor 23 can be detected accurately.

Further, the centrifugal force F acting on each of the rotating rotor core 41 and the nonmagnetic material 42 is expressed by F = mrω ² . Here, r is the distance from the rotation axis 8 in the radial direction of the outer peripheral surface of the rotor core 41 and the nonmagnetic material 42, m is the mass of the rotor core 41 and the nonmagnetic material 42, and ω is the rotor core 41 and the nonmagnetic material. The angular velocity is 42. When the rotor core 41 and the nonmagnetic material 42 are rotated together, the angular velocity ω of the rotor core 41 and the nonmagnetic material 42 is the same. Therefore, the centrifugal force F acting on the rotor core 41 and the nonmagnetic material 42 is proportional to the distance r.

  Based on the above, when the centrifugal forces acting on the rotor core 41 and the non-magnetic body 42 are compared, the magnitude of the two centrifugal forces depends on the specific gravity of the material of the rotor core 41 and the non-magnetic body 42. For example, when the nonmagnetic material 42 is made of resin and the rotor core 41 is made of metal, the specific gravity of the nonmagnetic material 42 is smaller than the specific gravity of the rotor core 41. In this case, the centrifugal force acting on the nonmagnetic material 42 is smaller than the centrifugal force acting on the rotor core 41. This difference in centrifugal force causes vibration of the rotor 23 during high-speed rotation.

  Further, the magnitude of the two centrifugal forces depends on the distance r between the rotor core 41 and the nonmagnetic material 42. Therefore, in the present embodiment, the non-magnetic body 42 bulges radially outward from the position P where the distance from the rotation axis 8 to the outer peripheral surface 47 is the longest on the outer peripheral surface 47 of the rotor core 41. Thereby, even when the nonmagnetic material 42 is made of a material having a specific gravity smaller than that of the rotor core 41 as in the present embodiment, the centrifugal force acting on the nonmagnetic material 42 can be increased. As a result, since the difference in centrifugal force can be reduced, the vibration of the rotor 23 during high-speed rotation can be reduced.

  Further, according to the present embodiment, since the pair of connection portions 63A and 63B are provided so as to sandwich the rotor core 41, the non-magnetic body 42 can be fixed to the rotor core 41 in a stable state.

[Modification]
In the above-mentioned embodiment, although the connection part was a pair, a connection part does not need to be a pair. For example, the non-magnetic body 42 may be configured to include the connection portion 63A but not the connection portion 63B.

  In the above-described embodiment, the non-magnetic body 42 is fixed to the rotor core 41 by insert molding, but may be fixed to the rotor core 41 by other than insert molding. For example, the nonmagnetic material 42 may be attached to the rotor core 41 as follows.

  That is, the pin portion 61, which is a separate member from the pair of connection portions 63 </ b> A and 63 </ b> B, is a cylindrical member having a diameter slightly longer than the inner diameter of the through holes 44 and 45 and is fitted into the through holes 44 and 45. Further, both end portions of the pin portion 61 in the longitudinal direction protrude from the through holes 44 and 45, and the protruding both end portions are holes formed in the pair of connection portions 63 </ b> A and 63 </ b> B (the inner diameter is larger than the diameter of the pin portion 61. A little shorter). As a result, the pin portion 61, the connecting portions 63 </ b> A and 63 </ b> B, and the counterweight portion 62 can be integrated, and the integrated nonmagnetic material 42 can be fixed to the rotor core 41.

  According to this modification, the nonmagnetic body 42 is fixed to the rotor core 41 by the pin portion 61 being inserted through the through holes 44 and 45. Thereby, even if it is a case where the rotor core 41 rotates at high speed, possibility that the nonmagnetic body 42 will remove | deviate from the rotor core 41 with a centrifugal force can be made low.

  In the above-described embodiment, the nonmagnetic material 42 is a resin molded product, but may not be a resin molded product. For example, the nonmagnetic material 42 may be formed of a metal that does not have magnetism, such as aluminum.

8 ... Rotating axis 9 ... Axial direction 10 ... Resolver 20 ... Teeth 24 ... Core yoke 25 ... Stator core 41 ... Rotor core 42 ... Non-magnetic material 46 ... Recess 61 ... Pin part 62 ... Counter weight part 63 ... Connection part

Claims (5)

A stator core in which a plurality of teeth extending inward in the radial direction from a cylindrical core yoke is arranged in the circumferential direction, a coil wound around each of the plurality of teeth, and arranged inward in the radial direction from the stator core. And a rotor core having a shape in which the distance from the rotation axis to the outer peripheral surface continuously changes along the circumferential direction on the outer peripheral surface, a rotary shaft inserted through the rotor core, and a nonmagnetic material externally fitted to the rotor core A variable reluctance type resolver with a shaft angle multiplier of 1 ×,
The rotor core has a through hole along the rotation axis direction,
The non-magnetic material is
A pin portion inserted through the through hole;
A counterweight portion disposed on the radially outer side of the concave portion including a position where the distance from the rotation axis is the shortest on the outer peripheral surface of the rotor core;
A variable reluctance resolver that is disposed outside the rotor core in the rotational axis direction and includes a connecting portion that connects the pin portion and the counterweight portion.   The variable reluctance resolver according to claim 1, wherein the nonmagnetic material is a resin molded product fixed to the rotor core by insert molding.   3. The variable reluctance resolver according to claim 1, wherein the through hole is provided at a position closer to the inner peripheral surface than the outer peripheral surface of the rotor core in the radial direction of the rotor core.   The variable reluctance type according to any one of claims 1 to 3, wherein the non-magnetic body bulges radially outward from a position where the distance from the rotation axis to the outer peripheral surface is the longest on the outer peripheral surface of the rotor core. Resolver.   The variable reluctance resolver according to any one of claims 1 to 4, wherein a pair of the connection portions are provided so as to sandwich the rotor core.

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