JP2018182958A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of properly fixing a rotary shaft formed with a knurling in a shaft hole of a power transmission member.SOLUTION: In a motor 1, a rotary shaft 12 is fixed in a shaft hole 32 of a power transmission member 30. A shaft portion 120 is equipped with a first shaft portion 121 which is made to be a knurling equipped with a plurality of projecting portions on an outer peripheral surface, and a second shaft portion 122 on a stator 20 side to the first shaft portion 121. An outer peripheral surface of the second shaft portion 122 is not formed with the knurling. The shaft hole 32 of the power transmission member 30 is equipped with a first hole portion 321 in which the first shaft portion 121 is fitted, and a second hole portion 322 in which the second shaft portion 122 is fitted. An outer diameter D1 of the first shaft portion 121, an outer diameter D2 of the second shaft portion 122, an inner diameter Da of the first hole portion 321, and an inner diameter Db of the second hole portion 322 satisfy the following relationships. D1<D2, Da<Db.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor in which a power transmission member is fixed to a shaft portion protruding from a stator of a rotating shaft.

  In a motor, a structure in which a rotation shaft is fitted from the tip end side and fixed in a shaft hole of a power transmission member opened toward the side of a stator is widely adopted. At that time, it is proposed to partially form a knurl provided with a plurality of convex portions on the outer peripheral surface of the rotation shaft to prevent idle rotation of the power transmission member and the rotation shaft and removal of the rotation shaft of the power transmission member. (See, for example, Patent Document 1).

JP, 2013-177972, A

  When the knurling is formed on the rotation shaft, the outer diameter of the portion where the knurling is formed is larger than the outer diameter before the knurling is formed. For this reason, when a knurl is formed in a part in the axial direction of the rotation shaft as in the motor described in Patent Document 1, the outer diameter of both sides of the knurled part (the part where the knurl is not formed) is And the outer diameter of the portion where the knurl is formed. However, in the motor described in Patent Document 1, the inner diameter of the shaft hole of the power transmission member is constant. For this reason, when the part in which the knurl is formed is press-fit into the shaft hole by press-fitting, a gap is generated between the part in which the knurl is not formed and the shaft hole, and the power transmission member is formed with the knurl. It will be in a fixed state only by the For this reason, when a load is applied to the power transmission member, there is a problem that the power transmission member is easily shaken.

  In view of the above problems, it is an object of the present invention to provide a motor capable of properly fixing a rotary shaft on which a knurl is formed in a shaft hole of a power transmission member.

In order to solve the above problems, a motor according to the present invention comprises a rotor having permanent magnets held around a rotation axis, a stator disposed around the rotor, and an axis opening toward the stator And a power transmission member in which a shaft portion of the rotary shaft protruding from the stator is fixed inside the hole, and a portion of the shaft portion positioned inside the shaft hole has a plurality of outer peripheral surfaces. And a second shaft portion provided on the side of the stator with respect to the first shaft portion, wherein the second shaft portion is not provided with the protrusion. The hole includes a first hole portion in which the first shaft portion is fitted, and a second hole portion in which the second shaft portion is fitted,
Assuming that the outer diameter of the first shaft portion is D1 and the outer diameter of the second shaft portion is D2, the outer diameters D1 and D2 have the following relationship D1 <D2
The filling,
Assuming that the inner diameter of the first hole is Da and the inner diameter of the second hole is Db, the inner diameters Da, Db have the following relationship Da <Db
Meet the requirements.

In the present invention, the first hole portion of the shaft hole of the power transmission member is press-fit in the first shaft portion of the rotary shaft, the outer peripheral surface of which is a knurling having a plurality of convex portions. For this reason, while being able to suppress idle rotation of a power transmission member and a rotating shaft, the situation that a power transmission member remove | deviates from a rotating shaft does not generate | occur | produce easily. In addition, since the shaft hole is provided with the second hole portion having a large inner diameter on the side of the stator (the opening side of the shaft hole) with respect to the first hole portion, the rotation shaft can be inserted into the shaft hole. Further, the rotary shaft is provided with a second shaft portion having a large outer diameter on the side of the stator with respect to the first shaft portion, and the second shaft portion is press-fitted in the second hole portion. Therefore, since the power transmission member is supported by the first shaft portion in which the knurls are formed and the second shaft portion in which the knurls are not formed, the power transmission member can transmit power even when a load is applied to the power transmission member. Vibration is unlikely to occur on members.

In the present invention, the shaft portion includes a third shaft portion in which the convex portion is not formed between the first shaft portion and the second shaft portion, and the outer diameter of the third shaft portion is D3. The outer diameters D1, D2 and D3 have the following relationship D3 <D1 <D2
The aspect which satisfy | fills can be employ | adopted. According to this aspect, since the third shaft with a small outer diameter is interposed between the first shaft and the second shaft, when the first shaft and the second shaft are adjacent to each other Unlike the case where the knurling is formed on the first shaft portion, the occurrence of burrs on the second shaft portion having a large outer diameter hardly occurs. Therefore, the rotation shaft can be easily fitted inside the shaft hole.

In the present invention, when the shaft hole has a third hole on the side of the stator with respect to the second hole, and the inner diameter of the third hole is Dc, the inner diameters Da, Db, and Dc are The following relationship Da <Db <Dc
The filling,
It is possible to adopt a mode in which a part of the second shaft part fits into the second hole part, and another part of the second shaft part is located inside the third hole part. According to this aspect, the shaft hole includes the third hole having a large inner diameter on the side (opening side) of the stator with respect to the second hole, and therefore, the rotation is performed while using the third hole as a guide. The shaft can be fitted inside the shaft hole.

  In the present invention, it is possible to adopt an aspect in which a tip end of the rotation shaft opposite to the stator protrudes from the power transmission member, and the tip is the first shaft.

In the present invention, a tip end of the rotary shaft on the opposite side to the stator protrudes from the power transmission member, and the tip is a fourth shaft portion in which the projection is not formed. When the outer diameter of the fourth shaft portion is D4, the outer diameters D1 and D4 have the following relationship D4 ≦ D1.
The aspect which satisfy | fills can be employ | adopted. According to this aspect, when the knurling is formed on the first shaft portion, even if the burr is generated at the end portion of the first shaft portion, the burr does not easily protrude from the power transmission member. Further, since the outer diameter of the fourth shaft portion is equal to or less than the outer diameter of the first shaft portion, the rotation shaft can be easily fitted into the shaft hole from the tip end side (the fourth shaft portion side).

In the present invention, the outer diameters D3 and D4 have the following relationship D3 = D4
The aspect which satisfy | fills can be employ | adopted. According to this aspect, when forming the knurled (first shaft portion) on the rotating shaft, a portion having an outer diameter D3 is provided on the rotating shaft, and the knurled is formed at an intermediate position of such a portion. The fourth shaft portion, the first shaft portion, and the third shaft portion can be efficiently formed.

  In the present invention, the power transmission member may be made of resin.

  In the present invention, the first hole portion of the shaft hole of the power transmission member is press-fit in the first shaft portion of the rotary shaft, the outer peripheral surface of which is a knurling having a plurality of convex portions. For this reason, while being able to suppress idle rotation of a power transmission member and a rotating shaft, the situation that a power transmission member remove | deviates from a rotating shaft does not generate | occur | produce easily. In addition, since the shaft hole is provided with the second hole portion having a large inner diameter on the side of the stator (the opening side of the shaft hole) with respect to the first hole portion, the rotation shaft can be inserted into the shaft hole. Further, the rotary shaft is provided with a second shaft portion having a large outer diameter on the side of the stator with respect to the first shaft portion, and the second shaft portion is press-fitted in the second hole portion. Therefore, since the power transmission member is supported by the first shaft portion in which the knurls are formed and the second shaft portion in which the knurls are not formed, the power transmission member can transmit power even when a load is applied to the power transmission member. Vibration is unlikely to occur on members.

It is a sectional view showing one mode of a motor concerning Embodiment 1 of the present invention. It is sectional drawing which shows the one aspect | mode of the motor which concerns on Embodiment 2 of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the scale of each part is different so that the features of each part can be easily understood. Further, in the following description, in the direction of the axis L of the rotation shaft, the side where the rotation shaft protrudes from the stator is the output side L1, and the side opposite to the side where the rotation shaft protrudes from the stator is the non-output side L2. explain.

Embodiment 1
(overall structure)
FIG. 1 is a cross-sectional view showing one aspect of a motor 1 according to Embodiment 1 of the present invention. A motor 1 shown in FIG. 1 is a stepping motor and has a rotor 10 provided with a cylindrical permanent magnet 11 on the outer peripheral surface of a rotary shaft 12, and a cylindrical shape disposed around the rotor 10 so as to surround the permanent magnet 11. And the stator 20 of FIG. In the rotating shaft 12, a power transmission member 30 such as a worm gear, a spur gear, a bevel gear, and a pulley is fixed to a shaft portion 120 that protrudes from the stator 20 to the output side L1. In the present embodiment, the power transmission member 30 is a worm gear having a spiral groove 31 formed on the outer peripheral surface. The power transmission member 30 is formed with a shaft hole 32 that opens toward the non-output side L2 (the side of the stator 20), and the shaft portion 120 is fitted with the power transmission member 30 in a state of being fitted into the shaft hole 32 by press fitting. It is fixed. In the present embodiment, the rotating shaft 12 is made of metal, and the power transmission member 30 is made of resin such as PBT (polybutylene terephthalate) or POM (polyoxymethylene).

  In the rotor 10, N poles and S poles are alternately arranged in the circumferential direction on the outer peripheral surface of the permanent magnet 11. On the end face of the output side L1 of the permanent magnet 11, a recess 111 which opens while reducing the diameter from the output side L1 toward the non-output side L2 is formed so as to surround the rotation shaft 12. The permanent magnet 11 and the rotating shaft 12 are fixed by the provided adhesive 113.

  The stator 20 has a pair of stator sets 21 and 22 arranged so as to overlap in the direction of the axis L, and the stator sets 21 and 22 are coils wound around insulators 211 and 221 and insulators 211 and 221, respectively. 213, 223, stator cores 214, 224 disposed overlapping on the output side L1 of the insulators 211, 221, and stator cores 215, 225 disposed overlapping on the non-output side L2 of the insulators 211, 221. . Further, the stator core 214 has a U-shaped cross section, and the motor case 200 is configured by the outer peripheral side portion of the stator core 214.

  The stator cores 214, 224, 215, 225 each include a plurality of pole teeth 217, 227 that rise along the inner peripheral surfaces of the insulators 211, 221. With the stator set 21 configured, the pole teeth 217 formed on the stator core 214 enter between the pole teeth 217 formed on the stator core 215 and are formed on the pole teeth 217 formed on the stator core 214 and the stator core 215 The pole teeth 217 are alternately arranged in the circumferential direction. Further, in a state in which stator set 22 is configured, pole teeth 227 formed in stator core 224 enter between pole teeth 227 formed in stator core 225 and formed into pole teeth 227 formed in stator core 224 and stator core 225 The pole teeth 227 are alternately arranged in the circumferential direction.

  The output end plate 23 is fixed to the end surface of the output side L1 among the end surfaces of the stator 20, and the reverse output end plate 24 is fixed to the end surface of the non-output side L2.

  In the present embodiment, the output radial bearing 25 that rotatably supports the rotating shaft 12 at the output L1 using the output end plate 23 is held, and the output radial bearing 25 is a permanent magnet on the rotating shaft 12 A portion located on the output side L1 from 11 is rotatably supported. A hole 230 is formed in the output side end plate 23, and the diameter of the output side radial bearing 25 is increased at the output side L 1 with respect to the cylindrical portion 251 fitted in the hole 230 and the cylindrical portion 251. And a flange 252 having a large diameter. The output radial bearing 25 is a portion of the cylindrical portion 251 that protrudes from the output end plate 23 to the non-output side L2 in a state where the flange portion 252 overlaps the surface of the output L1 of the output end plate 23. It is fixed by caulking the outer edge to the surface of the non-output side L2 of the output side end plate 23. The output-side radial bearing 25 is, for example, a sintered oil-impregnated bearing.

  In this embodiment, the non-output side radial bearing 26 that supports the rotary shaft 12 rotatably on the non-output side L2 using the non-output side end plate 24 is held, and the non-output side radial bearing 26 is the rotary shaft. The portion 12 is rotatably supported at a portion located on the non-output side L2 with respect to the permanent magnet 11 at 12. A hole 240 is formed in the non-output side end plate 24, and the non-output side radial bearing 26 is enlarged by the cylindrical portion 261 fitted in the hole 240 and the non-output side L2 with respect to the cylindrical portion 261. The flange portion 262 has a diameter larger than that of the portion 261. The non-output side radial bearing 26 projects from the non-output side end plate 24 to the output side L1 of the cylindrical portion 261 in a state where the flange portion 262 overlaps the surface of the non-output side L2 of the non-output side end plate 24. The outer edge of the portion is fixed by caulking on the surface of the output side L1 of the output end plate 23. The non-output side radial bearing 26 is, for example, a sintered oil-impregnated bearing.

  A biasing member 27 is disposed between the output radial bearing 25 and the rotor 10 to bias the rotary shaft 12 to the non-output side L2. In the present embodiment, the biasing member 27 is a coil spring and is disposed around the rotation axis 12. An annular washer 28 mounted on the rotary shaft 12 is disposed between the biasing member 27 and the permanent magnet 11. The washer 28 is movable in the direction of the axis L with respect to the rotational shaft 12 or in the state of being immovable in the direction of the axial L with respect to the rotational shaft 12.

A washer 29 is attached to a portion of the rotating shaft 12 located between the permanent magnet 11 and the non-output side radial bearing 26. The washer 29 is in contact with the surface 117 of the non-output side L 2 of the permanent magnet 11. A recess 112 is formed on the surface 117 of the non-output side L2 of the permanent magnet 11 so as to surround the rotary shaft 12, and the washer 29 is a surface of the non-output side L2 outside the recess 112 of the permanent magnet 11 in the radial direction. It is in contact with 117. The outer diameter size of the washer 29 is smaller than the outer diameter size of the permanent magnet 11. As the washer 29, in addition to a metal member, a resin member may be used. The washer 29 is in contact with the surface of the output side L1 of the non-output side radial bearing 26, and is elastically pressed against the non-output side radial bearing 26 by the biasing force of the biasing member 27. The washer 29 is movable in the direction of the axis L with respect to the rotational shaft 12 or in the state of being immovable in the direction of the axial L with respect to the rotational shaft 12.

(Fixing structure of power transmission member 30 and rotating shaft 12)
In this embodiment, in fixing the power transmission member 30 and the rotary shaft 12, a knurled portion of the shaft portion 120 of the rotary shaft 12 located inside the shaft hole 32 has a plurality of convex portions on the outer peripheral surface. And a second shaft portion 122 provided on the side of the stator 20 with respect to the first shaft portion 121. The second shaft portion 122 has a convex portion (knurled). It is a straight shaft that is not formed.

Here, assuming that the outer diameter of the first shaft portion 121 is D1 and the outer diameter of the second shaft portion 122 is D2, the outer diameters D1 and D2 have the following relationship D1 <D2
Meet. In addition, since the knurls (a plurality of convex portions) are formed on the outer peripheral surface of the first shaft portion 121, the outer diameter D1 of the first shaft portion 121 is positioned on the outermost radial direction of the first shaft portion 121. It corresponds to the diameter of the part.

Corresponding to this configuration, the first hole 321 in which the first shaft portion 121 is press fitted and the second hole 322 in which the second shaft 122 is press fitted in the shaft hole 32 of the power transmission member 30. And are provided. When the inner diameter of the first hole 321 is Da and the inner diameter of the second hole 322 is Db, the inner diameters Da and Db have the following relationship Da <Db
Meet. Therefore, no gap exists between the first shaft portion 121 and the first hole portion 321 and between the second shaft portion 122 and the second hole portion 322.

In the present embodiment, the shaft portion 120 is provided with a third shaft portion 123 in which a plurality of convex portions (knurls) are not formed between the first shaft portion 121 and the second shaft portion 122, and the third shaft is formed. The part 123 is fitted in the second hole 322. Here, the outer diameter of the third shaft portion 123 is smaller than the outer diameter of the first shaft portion 121 and the outer diameter of the second shaft portion 122. Therefore, assuming that the outer diameter of the third shaft portion is D3, the outer diameters D1, D2, and D3 have the following relationship D3 <D1 <D2
Meet. Therefore, a gap is present between the third shaft 123 and the second hole 322.

The axial hole 32 is provided with a third hole 323 on the side of the stator 20 with respect to the second hole 322, and the inner diameter of the third hole 323 is the inner diameter of the first hole 321 and the second hole. Larger than the inner diameter of the part 322. Therefore, when the inner diameter of the third hole portion 323 is Dc, the inner diameters Da, Db, and Dc have the following relationship: Da <Db <Dc
Meet. Therefore, a portion of the second shaft portion 122 is press-fitted to a portion of the second hole portion 322 excluding the portion where the third shaft portion 123 is located, and the other portion of the second shaft portion 122 is a third portion. It is located inside the hole 323. There is a gap between the second shaft 122 and the third hole 323.

  In the present embodiment, the end portion 125 on the opposite side (output side L1) of the rotary shaft 12 to the stator 20 side (opposite output side L2) protrudes from the power transmission member 30, and in the present embodiment, the end portion 125 also The outer peripheral surface is a first shaft portion 121 which is knurled.

In the motor 1 configured as described above, the knurl formed on the first shaft portion 121 of the rotating shaft 12 is formed by knurling (knurling) such as rolling or cutting. Further, the knurl has flats in which a plurality of grooves extending along the axis L are arranged in parallel, and has eyelets formed such that grooves obliquely inclined to the axis L intersect with each other. In the present embodiment, the knurling comprises a flat formed by rolling. In this case, the outer diameter of the stem after knurling is larger than the outer diameter of the stem before knurling. Therefore, in the present embodiment, as shown by a two-dot chain line L12 in FIG. 1, in the rotary shaft 12, portions corresponding to the first shaft portion 121 and the third shaft portion 123 are used as the shaft portion 129 of the outer diameter D3. Knurling is performed only on the tip end side of the shaft portion 129 (only the portion to be the first shaft portion 121), and knurling is not performed on the portion on the stator 20 side of the shaft portion 129 (portion to be the third shaft portion 123) . As a result, the third shaft portion 123 having an outer diameter D3 is formed by the portion not subjected to the knurling, and the first shaft portion 121 having the outer diameter increased from D3 to D1 is formed at the portion subjected to the knurling Ru.

  Here, the first shaft portion 121 is provided only on the tip end side in the direction of the axis L in the power transmission member 30, and in the central portion in the direction of the axis L in the power transmission member 30, the second shaft portion 122 is the second hole 322 It is constituted by the part which is fitted by press fitting.

(Main effects of this form)
As described above, in the motor 1 of the present embodiment, the first shaft portion 121 of the rotary shaft 12 in which the outer peripheral surface is the knurling provided with the plurality of convex portions is the first of the shaft holes 32 of the power transmission member 30. The hole 321 is fitted. Therefore, idle rotation of the power transmission member 30 and the rotation shaft 12 can be suppressed, and a situation in which the power transmission member 30 is detached from the rotation shaft 12 hardly occurs.

  Further, the axial hole 32 is provided with a second hole 322 having a larger inside diameter than the first hole 321 on the side (opening side) of the stator 20 with respect to the first hole 321, and further, in the second hole 322. On the other hand, a third hole 323 larger in inner diameter than the second hole 322 is provided on the stator 20 side (opening side). Therefore, the rotary shaft 12 can be easily fitted inside the shaft hole 32.

  Further, the rotary shaft 12 is provided with a second shaft portion 122 having a large outer diameter on the side of the stator 20 with respect to the first shaft portion 121, and the second shaft portion 122 is fitted in the second hole 322. For this reason, the power transmission member 30 is supported by the first shaft portion 121 in which the knurling is formed and the second shaft portion 122 in which the knurling is not formed. Therefore, the rotation shaft 12 supports the power transmission member 30 in a wide range corresponding to the first shaft portion 121 and the second shaft portion 122. Therefore, even when a load is applied to the power transmission member 30, a shake is not easily generated in the power transmission member 30, so that power can be reliably transmitted, and power transmission of the rotary shaft 12 on which the knurl is formed It can be properly fixed to the shaft hole 32 of the member 30.

  Further, the first shaft portion 121 is provided only on the tip end side in the direction of the axis L in the power transmission member 30, and in the central portion in the direction of the axis L in the power transmission member 30, the second shaft portion 122 corresponds to the second hole 322 It is comprised by the part currently fitted by press-fit. Therefore, a worm wheel (not shown) meshing with the spiral groove 31 of the power transmission member 30 meshes with a portion of the power transmission member 30 in which the second shaft portion 122 is press-fit into the second hole 322. Therefore, even if a load is applied to the power transmission member 30 from the worm wheel, the power transmission member 30 does not easily shake.

  Further, in the rotary shaft 12, the third shaft portion 123 having a small outer diameter is interposed between the first shaft portion 121 and the second shaft portion 122, so the first shaft portion 121 and the second shaft portion 122. In the case where the knurling is formed on the first shaft portion 121, it is possible to prevent the occurrence of burrs on the second shaft portion 122 having a large outer diameter, unlike the case where the two adjacent portions are adjacent to each other. Therefore, the rotating shaft 12 can be easily fitted inside the shaft hole 32.

Moreover, since the axial hole 32 is provided with the third hole 323 having a large inner diameter on the side (opening side) of the stator 20 with respect to the second hole 322, the third hole 323 is used as a guide. The rotation shaft 12 can be fitted inside the shaft hole 32.

Second Embodiment
FIG. 2 is a cross-sectional view of a stepping motor according to a second embodiment of the present invention. Since the basic configuration of the stepping motor of this embodiment is the same as that of Embodiment 1, the same reference numerals are given to the common parts, and the detailed description thereof will be omitted.

As shown in FIG. 2, in this embodiment as well as the first embodiment, in the rotary shaft 12, the shaft portion 120 protruding from the stator 20 to the output side L1 is a shaft formed on a power transmission member 30 such as a worm gear. It is fixed to the hole 32. In this embodiment, in fixing the power transmission member 30 and the rotary shaft 12, a knurled portion of the shaft portion 120 of the rotary shaft 12 located inside the shaft hole 32 has a plurality of convex portions on the outer peripheral surface. And a second shaft portion 122 provided on the side of the stator 20 with respect to the first shaft portion 121. The second shaft portion 122 has a convex portion (knurled). It is a straight shaft that is not formed. Further, the shaft portion 120 is provided with a third shaft portion 123 in which a convex portion is not formed between the first shaft portion 121 and the second shaft portion 122. Here, the outer diameter D1 of the first shaft portion 121, the outer diameter D2 of the second shaft portion 122, and the outer diameter D3 of the third shaft portion 123 have the following relationship D3 <D1 <D2
Meet.

Corresponding to this configuration, the first hole 321 in which the first shaft portion 121 is press fitted and the second hole 322 in which the second shaft 122 is press fitted in the shaft hole 32 of the power transmission member 30. The inner diameter Da of the first hole 321 and the inner diameter Db of the second hole 322 have the following relationship Da <Db.
Meet. The axial hole 32 is provided with a third hole 323 on the side of the stator 20 with respect to the second hole 322, and the inner diameter Da of the first hole 321, the inner diameter Db of the second hole 322, and The inner diameter Dc of the three-hole portion 323 has the following relationship: Da <Db <Dc
Meet.

  In the motor 1 configured as described above, in the first embodiment, the tip 125 of the rotary shaft 12 that protrudes from the power transmission member 30 is also the first shaft 121 whose outer peripheral surface is knurled, In the present embodiment, the tip end portion 125 is a fourth shaft portion 124 in which a plurality of convex portions (knurls) are not formed on the outer peripheral surface. Therefore, when forming the knurling on the first shaft portion 121, even if a burr is generated at the end of the first shaft portion 121, the burr does not easily protrude from the power transmission member 30.

Here, when the outer diameter of the fourth shaft portion 124 is D4, the outer diameter D1 of the first shaft portion 121 and the outer diameter D4 of the fourth shaft portion 124 have the following relationship D4 ≦ D1.
Meet. Therefore, the rotary shaft 12 can be easily fitted into the shaft hole 32 from the front end side (the fourth shaft portion 121 side).

In the present embodiment, the outer diameter D3 of the third shaft portion 123 and the outer diameter D4 of the fourth shaft portion 124 have the following relationship D4 = D3.
Meet. That is, as shown by a two-dot chain line L12 in FIG. 2, in the rotation shaft 12, a portion corresponding to the fourth shaft portion 124, the first shaft portion 121 and the third shaft portion 123 is used as the shaft portion 129 of the outer diameter D3. In addition, knurling is performed only on the middle portion of the shaft portion 129 (only the portion to be the first shaft portion 121), and knurling is not performed on both end portions of the shaft portion 129. According to this aspect, the third shaft portion 123 having an outer diameter of D3 and the outer diameter D4 (D3 = D4) remain in the portion where the knurling is not performed, and the outer diameter is the portion where the knurling is performed. The first shaft portion 121 is increased from D3 to D1.

Other Embodiments
In the above embodiment, although the third shaft portion 123 of the rotary shaft 12 is positioned inside the second hole portion 322, an aspect in which the third shaft portion 123 is positioned inside the first hole portion 321 is adopted. May be

  In the above embodiment, although the third shaft 123 is formed between the first shaft 121 and the second shaft 122 with respect to the rotation shaft 12, the third shaft 123 is not formed, You may employ | adopt the aspect which the 1st axial part 121 and the 2nd axial part 122 adjoin.

DESCRIPTION OF SYMBOLS 1 ... Motor, 10 ... Rotor, 11 ... Permanent magnet, 12 ... Rotational axis, 20 ... Stator, 30 ... Power transmission member, 31 ... Spiral groove, 32 ... Shaft hole, 120 ... Shaft part, 121 ... 1st shaft part, 122 ... 2nd shaft part, 123 ... 3rd shaft part, 124 ... 4th shaft part, 125 ... tip part, 200 ... Motor case, 321 ... 1st hole part, 322 ... 2nd hole part, 323 ... 3rd hole Department

Claims (7)

A rotor having a permanent magnet held around a rotation shaft, a stator disposed around the rotor, and a shaft portion protruding from the stator of the rotation shaft inside a shaft hole opening toward the side of the stator A fixed power transmission member;
The portion of the shaft portion located inside the shaft hole has a first shaft portion whose outer peripheral surface is a knurling having a plurality of convex portions, and a side of the stator with respect to the first shaft portion And a second shaft portion provided with the convex portion not formed,
The shaft hole includes a first hole portion in which the first shaft portion is fitted, and a second hole portion in which the second shaft portion is fitted,
Assuming that the outer diameter of the first shaft portion is D1 and the outer diameter of the second shaft portion is D2, the outer diameters D1 and D2 have the following relationship D1 <D2
The filling,
Assuming that the inner diameter of the first hole is Da and the inner diameter of the second hole is Db, the inner diameters Da, Db have the following relationship Da <Db
A motor characterized by satisfying The shaft portion includes a third shaft portion in which the convex portion is not formed between the first shaft portion and the second shaft portion,
When the outer diameter of the third shaft portion is D3, the outer diameters D1, D2, and D3 have the following relationship D3 <D1 <D2
The motor according to claim 1, characterized in that: The axial hole has a third hole on the side of the stator with respect to the second hole,
When the inner diameter of the third hole is Dc, the inner diameters Da, Db, and Dc have the following relationship: Da <Db <Dc
The filling,
The part of the said 2nd axial part fits in the said 2nd hole, and the other part of the said 2nd axial part is located inside the said 3rd hole, It is characterized by the above-mentioned. Motor. The tip of the rotary shaft opposite to the stator projects from the power transmission member,
The motor according to claim 3, wherein the tip end portion is the first shaft portion. The tip of the rotary shaft opposite to the stator projects from the power transmission member,
The tip portion is a fourth shaft portion in which the convex portion is not formed,
When the outer diameter of the fourth shaft portion is D4, the outer diameters D1 and D4 have the following relationship D4 ≦ D1.
The motor according to claim 3, characterized in that: The outer diameters D3 and D4 have the following relationship D3 = D4
The motor according to claim 5, characterized in that:   The motor according to any one of claims 1 to 6, wherein the power transmission member is made of resin.

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