JP2017093295A - Motor rotor and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance strength of a rotor member in a radial direction so as to prevent decentering of the rotor member.SOLUTION: A rotor 30 includes: a shaft 32; and a cylindrical rotor member 50, fixed at an outside in a radial direction of the shaft 32. The shaft 32 includes: a first part 36, being in contact with an inner circumferential surface 74 of the rotor member 50; a second part 38, disposed by being separated from the first part 36 in an axial direction, being in contact with an inner circumferential surface 78 of the rotor member 50; a third part 40, extended between the first part 36 and the second part 38, having an outer diameter smaller than the first part 36 and the second part 38; and a projection part 44, projecting from the third part 40 outward in a radial direction, being in contact with an inner circumferential surface 82 of the rotor member 50.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotor of a motor and a motor.

  In order to prevent leakage of magnetic flux, a rotor in which a gap is formed between a shaft and a rotor core is known (for example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 5-244741 Japanese Patent Laid-Open No. 5-344668

  Conventionally, during rotation of the rotor, the rotor member constituting the rotor is deformed in the radial direction by centrifugal force, which may cause eccentricity of the rotor member. In order to prevent such eccentricity of the rotor member, it is required to increase the strength of the rotor member in the radial direction.

  In one aspect of the present invention, a rotor of a motor includes a shaft that extends along an axis, and a cylindrical rotor member that is fixed to a radially outer side of the shaft so as to surround the shaft. The shaft includes a first portion that comes into contact with the inner peripheral surface of the rotor member, and a second portion that is spaced apart from the first portion in the direction of the axis and contacts the inner peripheral surface of the rotor member.

  The shaft extends between the first portion and the second portion, and has a third portion having a smaller outer diameter than the first portion and the second portion, and a diameter from the third portion. It has a protrusion that protrudes outward in the direction and contacts the inner peripheral surface of the rotor member. A gap is formed between the third portion and the inner peripheral surface of the rotor member. The protrusion may extend over the entire circumference of the shaft.

  The rotor member includes a plurality of rotor cores arranged in the direction of the axis, a nonmagnetic member disposed between two rotor cores adjacent to each other in the direction of the axis, and the plurality of rotor cores and the nonmagnetic member. And a tie rod extending so as to penetrate in the direction. The protrusion may contact the nonmagnetic member. In another aspect of the present invention, the motor includes the above-described rotor.

It is a side view of the motor which concerns on one Embodiment of this invention, Comprising: One part is shown with the cross section. It is a side view of the rotor shown in FIG. It is sectional drawing in III-III in FIG. It is sectional drawing in IV-IV in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a motor 10 according to an embodiment of the present invention will be described with reference to FIG. In the following description, the axial direction indicates the direction along the axis O ₁ of the shaft 32 shown in FIG. 1, the radial direction indicates the radial direction of a circle centering on the axis O ₁ , and the circumferential direction. , Shows the circumferential direction of a circle centered on the axis O ₁ . For the sake of convenience, the left side of FIG. 1 is the front in the axial direction.

  The motor 10 includes a housing 14 that defines an internal space 12, a stator 16 that is fixed to the internal space 12 of the housing 14, and a rotor 30 that is rotatably disposed radially inward of the stator 16. The stator 16 includes a stator core 18 and a coil 20 wound around the stator core 18.

  Next, the rotor 30 according to the present embodiment will be described with reference to FIGS. The rotor 30 is a so-called radial type rotor. The rotor 30 includes a shaft 32 extending in the axial direction, and a rotor member 50 fixed to the outer side in the radial direction of the shaft 32 so as to surround the shaft 32.

  As shown in FIG. 3, the shaft 32 includes an output part 34, a first large diameter part (first part) 36, a second large diameter part (second part) 38, and a small diameter part (third part). ) 40, a base end portion 42, and a protrusion 44. The front end of the output unit 34 is mechanically connected to an external device (for example, a spindle of a machine tool), and outputs rotation to the external device. On the other hand, the rear end of the base end portion 42 terminates in the internal space 12 of the housing 14.

The first large diameter portion 36 protrudes radially outward from the axial rear end of the output portion 34 and extends over the entire circumference of the shaft 32. The first large-diameter portion 36 has a cylindrical outer peripheral surface 36a, the outer peripheral surface 36a has an outer diameter _{D 1.}

  The second large-diameter portion 38 is spaced apart from the first large-diameter portion 36 in the axial direction by a predetermined distance. Specifically, the second large-diameter portion 38 protrudes radially outward from the axially front end of the base end portion 42 and extends over the entire circumference of the shaft 32.

The second large-diameter portion 38 has a cylindrical outer peripheral surface 38a, the outer peripheral surface 38a has an outer diameter _{D 2.} In the present embodiment, the outer diameter D ₂ is substantially the same as the outer diameter D ₁ (ie, D ₁ ≈D ₂ ).

The small diameter portion 40 extends between the first large diameter portion 36 and the second large diameter portion 38. Specifically, the small-diameter portion 40 extends axially forwardly from the axial forward end 38b of the second large-diameter portion 38 to the axial rearward end 36b of the first large-diameter portion 36 has an outer diameter D _3. The outer diameter D ₃ is smaller than the outer diameters D ₁ and D ₂ (that is, D ₁ ≈D ₂ > D ₃ ).

  The protrusion 44 is disposed at the center in the axial direction of the small diameter portion 40. Specifically, the protruding portion 44 is formed integrally with the small diameter portion 40 so as to protrude radially outward from the small diameter portion 40. In the present embodiment, the protruding portion 44 extends over the entire circumference of the small diameter portion 40 and has a cylindrical outer peripheral surface 44a.

Protrusion 44 has an outer diameter _{D 4.} The outer diameter D ₄ is substantially the same as the outer diameters D ₁ and D ₂ (ie, D ₁ ≈D ₂ ≈D ₄ ). Further, the protrusion 44 has a tapered shape such that its axial thickness becomes thinner from the outer peripheral surface 40a toward the radially outer side.

  The rotor member 50 includes a first rotor core 52, a second rotor core 54, a plurality of magnets 56 and 58, a first end plate 60, a second end plate 62, a nonmagnetic member 63, and a plurality of tie rods 64. .

  As shown in FIG. 4, the first rotor core 52 has a total of eight core segments 66 aligned at equal intervals in the circumferential direction. Each of the core segments 66 is composed of a plurality of electromagnetic steel plates (not shown) stacked in the axial direction, and has an inner peripheral surface 66a.

  As shown in FIG. 3, a gap 84 is formed between the inner peripheral surface 66 a and the outer peripheral surface 40 a of the small diameter portion 40. Each of the core segments 66 is formed with a through hole 68 that passes through the core segment 66 in the axial direction.

  In the present embodiment, a total of eight magnets 56 are arranged so as to be aligned at substantially equal intervals in the circumferential direction. Each of the magnets 56 is sandwiched between two core segments 66 adjacent to each other in the circumferential direction.

  Each of the magnets 56 is a rectangular plate member having a predetermined length, width, and thickness. Each of the magnets 56 is positioned with respect to the core segment 66 such that its length direction is along the axial direction, its width direction is along the radial direction, and its thickness direction is along the circumferential direction. Each of the magnets 56 is magnetized in the thickness direction.

  The second rotor core 54 is disposed adjacent to the rear of the first rotor core 52 in the axial direction, and has the same configuration as the first rotor core 52. Specifically, the second rotor core 54 has a total of eight core segments 70 aligned at substantially equal intervals in the circumferential direction. Each of the core segments 70 is composed of a plurality of electromagnetic steel plates (not shown) stacked in the axial direction, and has an inner peripheral surface 70a.

  A gap 86 is formed between the inner peripheral surface 70 a and the outer peripheral surface 40 a of the small diameter portion 40. Each core segment 70 is formed with a through-hole 72 that passes through the core segment 70 in the axial direction. The core segment 70 is positioned with respect to the core segment 66 such that the through hole 68 and the through hole 72 communicate with each other.

  In the present embodiment, a total of eight magnets 58 are arranged so as to be aligned at substantially equal intervals in the circumferential direction. Each of the magnets 58 is sandwiched between two core segments 70 adjacent to each other in the circumferential direction.

  Each of the magnets 58 has the same configuration as that of the magnet 56, and the length direction is along the axial direction, the width direction is along the radial direction, and the thickness direction is along the circumferential direction. , Positioned relative to the core segment 70.

  The first end plate 60 is an annular plate having a cylindrical inner peripheral surface 74 and is made of a nonmagnetic material. The first end plate 60 presses the inner peripheral surface 74 against the outer peripheral surface 36a of the first large-diameter portion 36, for example, by shrink fitting, and is thereby fixed to the first large-diameter portion 36. When the first end plate 60 is fixed to the first large-diameter portion 36, the axially rear end surface 60 a of the first end plate 60 comes into contact with the axially front end surface 66 b of the core segment 66.

  The first end plate 60 has a total of eight through holes 76 aligned at substantially equal intervals in the circumferential direction. Each of these through holes 76 is disposed so as to communicate with each of the through holes 68 formed in the core segment 66 (the through holes 72 formed in the core segment 70).

  The second end plate 62 has the same configuration as the first end plate 60. Specifically, the second end plate 62 is a non-magnetic material annular plate having a cylindrical inner peripheral surface 78. The second end plate 62 is fixed to the second large-diameter portion 38 by pressing the inner peripheral surface 78 against the outer peripheral surface 38 a of the second large-diameter portion 38. An end surface 62 a on the front side in the axial direction of the second end plate 62 abuts on an end surface 70 b on the rear side in the axial direction of the core segment 70.

  The second end plate 62 has a total of eight through holes 80 aligned in the circumferential direction at substantially equal intervals. Each of these through holes 80 is disposed so as to communicate with each of the through holes 72 formed in the core segment 70 (the through holes 68 formed in the core segment 66).

The nonmagnetic member 63 is an annular plate having a cylindrical inner peripheral surface 82. The inner peripheral surface 82 abuts on the outer peripheral surface 44 a of the protrusion 44. As an example, the inner peripheral surface 82 is smaller than the inner diameter D ₅ (FIG. 4) of the core segments 66 and 70 and substantially the same as the outer diameter D ₄ of the protrusion 44 (or slightly smaller than the outer diameter D _4). (Small) inner diameter.

  The nonmagnetic member 63 has a total of eight through holes 88 aligned in the circumferential direction at substantially equal intervals. Each of these through holes 88 is disposed so as to communicate with each of the through holes 68 formed in the core segment 66 (the through holes 72 formed in the core segment 70).

  Each of the eight tie rods 64 is inserted into through holes 76, 68, 88, 72, and 80 that communicate with each other. Each of the tie rods 64 extends so as to penetrate the first end plate 60, the core segment 66, the nonmagnetic member 63, the core segment 70, and the second end plate 62 in the axial direction. The first end plate 60 is fixed to the second end plate 62 on the rear side in the axial direction.

  As described above, in the present embodiment, the protruding portion 44 that protrudes from the small diameter portion 40 is provided so as to contact the inner peripheral surface 82 of the nonmagnetic member 63. The protrusions 44 restrict the movement of the nonmagnetic member 63 in the radial direction when the rotor member 50 is about to deform in the radial direction when the rotor 30 rotates.

  As a result, the tie rod 64 can be prevented from being bent and the strength of the rotor member 50 in the radial direction can be increased. Therefore, when the rotor 30 is rotated, the rotor member 50 is deformed and the rotor member 50 is eccentric. Can be prevented.

  Further, by causing the protrusions 44 to contact the nonmagnetic member 63 in this way, in addition to preventing eccentricity of the rotor member 50, the magnetic flux generated in the rotor cores 52 and 54 leaks to the shaft 32. It can also be prevented. Thereby, it can prevent that the rotational performance of the motor 10 falls.

  In the present embodiment, the protrusion 44 is integrally formed with the small diameter portion 40. Thereby, since the intensity | strength and durability of the projection part 44 can be improved significantly, eccentricity of the rotor member 50 can be reliably prevented over a long period of time.

  Moreover, in this embodiment, the protrusion part 44 has a taper shape that the thickness of an axial direction becomes thin as it goes to radial direction outer side. According to this configuration, the strength and durability of the protrusion 44 can be further increased.

In the present embodiment, the outer diameters D ₁ , D _2, and D ₄ of the first large diameter portion 36, the second large diameter portion 38, and the protrusion 44 are substantially the same (that is, D ₁ ≈D ₂ ≈ D ₄ ).

  Thereby, when manufacturing the rotor 30, the rotor 30 can be manufactured in the order of first assembling the rotor member 50 and then inserting the shaft 32 through the rotor member 50. According to this configuration, the efficiency of the manufacturing process can be realized.

  In the above-described embodiment, the case where the rotor member 50 includes the nonmagnetic member 63 has been described. However, the present invention is not limited to this, and the rotor member does not necessarily have the nonmagnetic member 63. In this case, the protrusion 44 may be formed so as to contact the inner peripheral surface of the rotor core.

  Moreover, in the above-mentioned embodiment, the case where the protrusion part 44 extended over the perimeter of the small diameter part 40 was described. However, the present invention is not limited to this. For example, the protrusion may extend over a region around the small-diameter portion 40 or may be provided so that the plurality of protrusions are aligned in the circumferential direction. May be.

  In the above-described embodiment, the case where the rotor 30 is a so-called radial type rotor has been described. However, the present invention is not limited to this, and the rotor has an annular rotor core that surrounds the periphery of the shaft 32. The rotor core has a plurality of magnet receiving holes aligned in the circumferential direction. May be accommodated. In this case, the protrusion 44 may be formed so as to contact the inner peripheral surface of the rotor core.

  In the above-described embodiment, the case where the rotor member 50 includes the two rotor cores 52 and 54 and the one nonmagnetic member 63 and the shaft 32 includes the one protrusion 44 has been described. .

  However, the present invention is not limited to this, and the rotor member includes three or more rotor cores arranged in the axial direction and two or more nonmagnetic members disposed between two rotor cores adjacent to each other in the axial direction. The shaft 32 may have two or more protrusions.

  As an example, the rotor member includes first, second, and third rotor cores arranged in the axial direction, and a first nonmagnetic member disposed between the first and second rotor cores adjacent to each other in the axial direction. And a second non-magnetic member disposed between the second and third rotor cores adjacent to each other in the axial direction.

  On the other hand, the shaft has a first protrusion and a second protrusion formed on the small diameter portion 40 so as to be separated from each other in the axial direction. In this case, the first protrusion is disposed so as to contact the first nonmagnetic member, while the second protrusion is disposed so as to contact the second nonmagnetic member.

  As mentioned above, although this invention was demonstrated through embodiment of invention, the above-mentioned embodiment does not limit the invention based on a claim. In addition, a combination of the features described in the embodiments of the present invention can also be included in the technical scope of the present invention, but all of these combinations of features are essential to the solution of the invention. Not exclusively. Furthermore, it will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments.

DESCRIPTION OF SYMBOLS 10 Motor 30 Rotor 32 Shaft 36 1st large diameter part 38 2nd large diameter part 40 Small diameter part 44 Protrusion part 50 Rotor member 52,54 Rotor core 63 Nonmagnetic member 64 Tie rod

Claims (5)

A rotor of a motor,
A shaft extending along an axis;
A cylindrical rotor member fixed to the outer side in the radial direction of the shaft so as to surround the shaft,
The shaft is
A first portion in contact with the inner peripheral surface of the rotor member;
A second portion that is spaced apart from the first portion in the direction of the axis, and abuts against the inner peripheral surface of the rotor member;
A third part extending between the first part and the second part and having an outer diameter smaller than the first part and the second part, the third part And a third portion in which a gap is formed between the inner surface of the rotor member and
A rotor that protrudes radially outward from the third portion and abuts against an inner circumferential surface of the rotor member.   The rotor according to claim 1, wherein the protrusion extends over the entire circumference of the shaft. The rotor member is
A plurality of rotor cores arranged in the direction of the axis;
Of the plurality of rotor cores, a nonmagnetic member disposed between two rotor cores adjacent to each other in the direction of the axis,
The rotor according to claim 1, further comprising: a tie rod that extends through the plurality of rotor cores and the nonmagnetic member in the direction of the axis.   The rotor according to claim 3, wherein the protrusion is in contact with the nonmagnetic member.   A motor provided with the rotor of any one of Claims 1-4.

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