JP2003111327A - Structure and fixing method of rotor of motor, and iron core holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate mutual fixing work between an iron core and an iron core holder while restraining an increase in manufacturing cost. SOLUTION: A spider 31, which is fixed at the outer periphery of a rotating shaft 11, is constituted of an inner tube 37 in which the rotating shaft 11 is inserted and fixed, and an outer tube 39 in which the iron core 33 is fixed on the outer peripheral side. A protrusion 41 which is provided at an axial central part of the inner tube 37 enters a recess 39a of the outer tube 39, and the outer tube 39 is expanded to the outer peripheral side and is pressed to an insertion hole 33a of the iron core 33 to be fixed at the iron core 33. The outer periphery of the outer tube 39 is formed so as to be smaller than a diameter of the insertion hole 33a before the outer tube 39 is inserted in the insertion hole 33a of the iron core 33. After the insertion, the protrusion 41 is made to enter the recess 39a with the inner tube 37 moving along a taper 39b in the outer tube 39, so that the outer tube 39 goes into a state of expansion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an annular iron core, which is formed by laminating a plurality of magnetic materials along the axial direction of the rotating shaft, on the outer periphery of an iron core holder to which the rotating shaft is fixed. The present invention relates to a rotor structure of a motor, a rotor fixing method, and an iron core holder.

[0002]

2. Description of the Related Art FIG. 5 shows a rotor structure of a conventional motor. The spider 3, which is an iron core holder fixed to the outer periphery of the rotating shaft 1, includes an inner tubular portion 3a, an outer tubular portion 3b, and a connecting portion 3c connecting the inner tubular portion 3a and the outer tubular portion 3b to each other. An iron core 5 formed by laminating a plurality of thin plates made of a magnetic material such as iron is fixed to the outer peripheral surface of the outer cylindrical portion 3b. The iron core 5 is held by two end plates 7 made of a non-magnetic material such as stainless steel or aluminum at both axial ends of the rotary shaft 1.

Conventionally, the iron core 5 is fixed to the spider 3 by heating the iron core 5 to expand it, inserting the spider 3 into the spider insertion hole 5a of the expanded iron core 5, and then cooling the iron core 5 to shrink it. , So-called shrink fitting.

[0004]

However, in the shrink fitting process, as described above, the iron core 5 is heated, the spider 3 is inserted into the heated iron core 5, and the iron core 5 is further cooled. , Causing an increase in manufacturing cost.

In order to solve this, the inner diameter of the spider insertion hole 5a of the iron core 5 is made slightly smaller than the outer diameter of the outer cylindrical portion 3b of the spider 3, and the spider 3 is press-fitted into the spider insertion hole 5a at room temperature. Can be considered. However, since the iron core 5 is formed by laminating a plurality of iron thin plates and the press-fitting distance of the spider 3 is long, there arises a problem that the thin plates of the iron core 5 are separated from each other during press-fitting.

For this reason, it is difficult to fix the iron core 5 and the spider 3 to each other while suppressing an increase in manufacturing cost.

Therefore, an object of the present invention is to facilitate the mutual fixing work of the iron core and the iron core holder while suppressing an increase in manufacturing cost.

[0008]

In order to achieve the above object, the invention of claim 1 is such that a plurality of magnetic materials are provided on the outer periphery of an iron core holder to which a rotating shaft is fixed, along the axial direction of the rotating shaft. In a rotor structure of a motor in which an iron core having an insertion hole into which the iron core holder is inserted is fixed, the iron core holder has an inner diameter larger than an outer diameter of the rotating shaft. The outer cylinder part is provided with an outer diameter smaller than the inner diameter of the insertion hole of the iron core in a state before being fixed to the iron core, and the outer cylinder part is arranged on the inner peripheral side of the outer cylinder part. An expansion member is provided for pressing the outer cylindrical portion of the lever toward the outer peripheral side to expand the outer cylindrical portion and fix the outer cylindrical portion in the insertion hole of the iron core.

According to a second aspect of the invention, in the structure of the first aspect of the invention, the iron core holder has an inner cylindrical portion into which the rotary shaft is inserted and fixed, inside the outer cylindrical portion. The expansion member is integrally provided in the inner cylindrical portion.

According to a third aspect of the present invention, in the configuration of the second aspect of the invention, the expansion member is composed of a convex portion projecting toward the outer tubular portion, while the inner peripheral surface of the outer tubular portion is , A concave portion into which the tip of the convex portion is inserted is formed, and the concave portion has an inner diameter smaller than an outer diameter of the convex portion in a state before the iron core holder is fixed to the iron core. The inner peripheral surface of the tubular portion is formed such that the inner diameter of the axial end portion is larger than the outer diameter of the convex portion and the inner diameter gradually decreases from the axial end portion toward the concave portion. .

According to a fourth aspect of the present invention, in the structure of the first aspect of the invention, the iron core holder has the rotating shaft connected to the outer cylindrical portion and the connecting portion at one axial end. The expansion member has an inner cylindrical portion that is inserted and fixed,
It is arranged near the other end in the axial direction between the outer tubular portion and the inner tubular portion.

According to a fifth aspect of the present invention, in the structure of the fourth aspect, the outer cylindrical portion of the iron core holder has an outer diameter of the connecting portion before the iron core holder is fixed to the iron core. Is formed to be gradually smaller toward the other end in the axial direction.

The invention of claim 6 is based on the invention of claim 4 or 5.
In the clear structure, the expansion is provided on the inner peripheral surface of the outer tubular portion.
A recess is formed to allow the tip of the member to enter.
Thickness L of outer cylinder_FourIs the diameter of the insertion hole of the iron core.
D, the outer diameter of the expansion member is L ₅Then, D ≦ L_Four+ L
₅The outer cylinder is larger than the recess.
The inner diameter on the other end side in the axial direction of the expansion member is
It is larger than the outer diameter and faces the recess from the other end.
As a configuration in which the inner diameter gradually decreases
is there.

According to a seventh aspect of the present invention, in the structure according to any of the fourth to sixth aspects, a thin portion is provided between the outer cylinder portion and the connecting portion.

According to an eighth aspect of the invention, a plurality of magnetic materials are laminated on the outer periphery of the iron core holder to which the rotary shaft is fixed, along the axial direction of the rotary shaft, and the iron core holder is inserted. In a rotor fixing method for a motor in which an iron core having an insertion hole is fixed, an iron core holder to which the rotating shaft is fixed has an inner diameter larger than an outer diameter of the rotating shaft and an outer diameter of the iron core. An outer cylinder portion having a diameter smaller than that of the insertion hole is provided, and after the outer cylinder portion is inserted into the insertion hole of the iron core, the outer cylinder portion is expanded from the inner peripheral side toward the outer peripheral side by an expansion member to expand. Then, it is a method for fixing the rotor of the motor for fixing the iron core holder to the iron core.

According to a ninth aspect of the invention, the rotary shaft is fixed on the inner peripheral side, and the iron core formed by laminating a plurality of magnetic materials along the axial direction of the rotary shaft is fixed on the outer peripheral side. In the iron core holder according to the present invention, the outer cylindrical portion has an inner diameter larger than the outer diameter of the rotating shaft, and in the state before the outer diameter is fixed to the iron core, the outer cylindrical portion is smaller than the insertion hole of the iron core. Is configured to include an expansion member that presses and expands from the inner peripheral side toward the insertion hole on the outer peripheral side.

[0017]

According to the invention of claim 1, in a state where the iron core holder provided with the outer cylinder portion is inserted into the insertion hole of the iron core, the outer cylinder portion is expanded to the outer peripheral side by the expansion member to form the iron core. Since it is fixed, it is not necessary to press fit the iron core holder into the insertion hole of the iron core, so it is possible to prevent peeling of multiple thin plates that make up the iron core, and also to work steps such as cooling the iron core after heating. The iron core and the iron core holder can be easily fixed to each other while the manufacturing cost is suppressed as unnecessary.

According to the second aspect of the present invention, the core member can be fixed to the iron core by expanding the outer cylinder portion to the outer peripheral side by the expansion member integrated with the inner cylinder portion.

According to the third aspect of the present invention, the convex portion is axially moved along the inner surface of the outer cylindrical portion whose inner diameter is changed so as to be inserted into the concave portion, so that the outer cylindrical portion is located on the outer peripheral side thereof. The core holder is expanded toward the core, so that the core holder can be securely fixed to the core.

According to the fourth aspect of the invention, the outer cylinder portion is formed by the expansion member arranged near the other end portions of the outer cylinder portion and the inner cylinder portion, one end portion of which is connected to each other at the connection portion. By expanding from the inner peripheral side toward the outer peripheral side, the iron core holder can be fixed to the iron core.

According to the invention of claim 5, the outer cylindrical portion can be easily inserted into the insertion hole of the iron core.

According to the sixth aspect of the present invention, the expansion member is moved axially from the end along the inner surface of the outer cylinder portion whose inner diameter is changed to be inserted into the recess, so that the outer cylinder portion has its outer periphery. It is expanded toward the iron core on the side, whereby the iron core holder can be securely fixed to the iron core.

According to the seventh aspect of the present invention, the outer tubular portion can be easily expanded to the outside by the thin wall portion, and the iron core holder can be securely fixed to the iron core.

According to the invention of claim 8, in a state in which the iron core holder provided with the outer cylinder portion is inserted into the insertion hole of the iron core, the outer cylinder portion is expanded to the outer peripheral side by the expansion member and fixed to the iron core. Therefore, it is not necessary to press-fit the iron core holder into the iron core insertion hole, and thus it is possible to prevent peeling of multiple thin plates that compose the iron core, and manufacturing without the need for work steps such as heating and cooling the iron core. It is possible to easily fix the iron core and the iron core holder to each other while suppressing the cost.

According to the ninth aspect of the present invention, when the outer cylinder portion is inserted into the insertion hole of the iron core, it can be easily performed while preventing the plurality of thin plates constituting the iron core from peeling off. Since it is expanded toward the outer peripheral side by the expansion member, it is possible to easily fix the iron core holder to the iron core while suppressing manufacturing steps by eliminating work steps such as heating and cooling the iron core.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a motor having a motor rotor structure showing a first embodiment of the present invention. The motor housing 9 includes a rotating shaft 11 and two bearings 1
Left and right end plates 17, which are rotatably supported by 3, 15
19 and a cylindrical tubular body 21 fixed to the outer peripheral portion of each of the end plates 17 and 19. A cooling water passage 23 is formed at the center of the cylindrical body 21 in the axial direction.

On the inner wall of the cylindrical body 21 in the portion provided with the cooling water flow path 23, a stator 29 composed of an annular stator core 25 and a coil 27 attached to the stator core 25 is mounted.

Inside the stator 29 described above,
A rotor 35 including a spider 31 as an iron core holder fixed to the rotary shaft 11 and an annular iron core 33 fixed to the outer peripheral portion of the spider 31 is arranged.

The spider 31 is made of a magnetic material such as iron, and has an inner cylinder portion 37 into which the rotary shaft 11 is inserted and fixed, and an outer cylinder portion 39 having an inner diameter larger than the outer diameter of the rotary shaft 11. It has and. Then, the outer cylinder portion 39
Is inserted and fixed in the insertion hole 33a of the iron core 33 described above.

A convex portion 41 as an expansion member is formed at the central portion of the inner cylindrical portion 37 in the axial direction so as to project outward in the diametrical direction. The convex portion 41 enters the concave portion 39 a formed on the inner peripheral surface of the outer tubular portion 39, and the outer tubular portion 39 is
The core 33 is pressed and expanded from the inner peripheral side toward the outer peripheral side.
Is pressed against the insertion hole 33a. The outer cylinder portion 39 is formed with a tapered portion 39b whose inner diameter gradually decreases from both ends in the axial direction toward the recess 39a.

The iron core 33 is a thin plate (for example, a plate thickness of 0.5 mm) made of a magnetic material such as iron as in the conventional core.
A plurality of layers) are laminated along the axial direction of the rotating shaft 11. Although not shown, a plurality of magnet insertion holes, into which permanent magnets extending in the axial direction of the rotary shaft 11 are inserted and fixed, are formed on the outer peripheral side of the iron core 33 in the circumferential direction.

Next, the shape of the spider 31 before being attached to the iron core 33 will be described with reference to FIG. Note that, in FIG. 2, the three members, that is, the iron core 33, the inner cylinder portion 37, and the outer cylinder portion 39 are illustrated in a state where the axial center lines are aligned.

The outer diameter d ₁ of the outer tubular portion 39 is formed smaller than the diameter D of the insertion hole 33a of the iron core 33 by L ₁ × 2. The inner diameter d ₂ of the recess 39a of the outer tubular portion 39 is smaller than the outer diameter G of the convex portion 41 by L ₂ × 2. However, L ₂ ≧ L ₁ . Further, the outer diameters of both axial ends of the tapered portion 39b on the inner surface of the outer tubular portion 39 are formed to be larger than the outer diameter G of the convex portion 41.

The above-mentioned convex portion 41 and concave portion 39 are provided.
The a may be provided continuously or intermittently in the circumferential direction, or a plurality of a may be provided in the axial direction.

Next, a method of assembling the spider 31 to the iron core 33 will be described. First, the outer cylinder portion 39 is inserted into the insertion hole 33a of the iron core 33. At this time, the outer diameter d of the outer tubular portion 39
_{Since 1} is formed to be smaller than the diameter D of the insertion hole 33a by L ₁ × 2, it is not necessary to press-fit the outer cylinder portion 39 into the insertion hole 33a, and therefore the thin plate of the iron core 33 is peeled off. Can be easily inserted without.

Next, the inner cylinder portion 37 is inserted into the outer cylinder portion 39 inserted into the insertion hole 33a. At this time, the convex portion 4
The tip of 1 moves toward the recess 39a while pressing the taper portion 39b of the outer cylinder portion 39 and expanding the outer cylinder portion 39, and enters the recess 39a. Inner diameter d _{2 of} this recess 39a
Is formed to be smaller than the outer diameter G of the convex portion 41 by L ₂ × 2, the convex portion 41 that has entered the concave portion 39a is
The outer cylinder portion 39 is expanded from the inner peripheral side toward the outer peripheral side.

As a result, the outer tubular portion 39 expands and deforms toward the outer periphery of the dimension L ₂ due to the convex portion 41, but since the gap between the outer tubular portion 39 and the insertion hole 33a is L ₁ smaller than L ₂ , The outer tubular portion 39 is pressed against the insertion hole 33 a of the iron core 33 and is securely fixed to the iron core 33. The outer cylinder portion 39
By providing a slit in the axial end portion of the outer tubular portion 3 when inserting the inner tubular portion 37 into the outer tubular portion 39.
9 easily expands to the outer peripheral side, and the iron core 33 of the outer tubular portion 39
Can be fixed more securely.

According to the above-described method of fixing the spider 31 to the iron core 33, an increase in manufacturing cost is suppressed by eliminating the work steps such as heating and cooling the iron core 33, and the mutual increase of the iron core 33 and the spider 31. The fixing work can be easily performed without peeling off the thin plate of the iron core 33.

FIG. 3 is a sectional view of a motor having a rotor structure for a motor according to a second embodiment of the present invention. In this rotor structure, the same components as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the configuration is different from that of FIG. 1, that is, the spider 4 as the iron core holder.
3 will be mainly described.

The spider 43 is made of a magnetic material such as iron as in the case of FIG.
1 is inserted and fixed, and an outer cylinder portion 47 having an inner diameter larger than the outer diameter of the rotating shaft 11. The inner cylinder portion 45 and the outer cylinder portion 47 are the right side in the drawing. The one ends in the axial direction are connected to each other at a connecting portion 49 to form a spider body 51. And this spider body 51
Is inserted into the insertion hole 33a of the iron core 33, and is fixed in a state where the outer peripheral surface of the outer tubular portion 47 is in contact with the insertion hole 33a. A thin portion 53 is formed on the entire inner periphery of the inner portion between the connecting portion 49 and the outer tubular portion 47.

In the vicinity of the other end of the spider body 51 opposite to the connecting portion 49, the outer circumference of the inner cylindrical portion 45 and
A concave portion 45a and a concave portion 47a are formed on the inner peripheral portion of the outer cylinder portion 47, and an annular expansion member 55 is fitted between the concave portions 45a and 47a. When the expansion member 55 is fitted, the outer cylinder portion 47 is pressed and expanded from the inner peripheral side toward the outer peripheral side, and is pressed against the insertion hole 33 a of the iron core 33.

Next, the shape of the spider 43 before being attached to the iron core 33 will be described with reference to FIG. Note that, in FIG. 4, the three members, that is, the iron core 33, the spider body 51, and the expansion member 55 are illustrated in a state where the axial center lines are aligned.

The outer peripheral surface of the outer cylinder portion 47 of the spider body 51 is formed in a taper shape such that the outer diameter thereof gradually decreases from one end in the axial direction on the side of the connecting portion 49 toward the other end. There is. The outer diameter d ₃ of the other end is smaller than the diameter of the insertion hole 33a of the iron core 33 by L ₃ × 2. The outer diameter of the end portion of the outer tubular portion 47 on the connection portion 49 side is also formed to be smaller than the diameter of the insertion hole 33a.

Further, the distance from the bottom surface of the recess 47a in the outer cylinder portion 47 to the outer peripheral surface, that is, the wall thickness L ₄ of the recess 39a in the outer cylinder portion 47 is such that the outer diameter of the expansion member 55 is L ₅ and the iron core 33 is inserted. If the inner diameter of the hole 33a is D, D ≦ L ₄ +
It is dimensioned to satisfy L ₅ . This also leads to that the inner diameter of the recess 47 a is formed smaller than the outer diameter of the expansion member 55. Further, the inner diameter at the other end of the outer tubular portion 47 on the side opposite to the connecting portion 49 is equal to that of the expansion member 5.
5 is formed larger than the outer diameter of the tapered portion 4 and the inner diameter is gradually reduced from the other end toward the recess 47a.
7b is formed.

Next, a method of assembling the spider 43 to the iron core 33 will be described. The spider body 51 is inserted into the insertion hole 33a of the iron core 33 from the left end in FIG. At this time, since the outer diameter d ₃ of the end portion on the insertion tip side is smaller than the diameter of the insertion hole 33a, the outer cylinder portion 47 does not need to be press-fitted into the insertion hole 33a, and therefore the thin plate of the iron core 33 is not peeled off. It can be easily inserted without generating.

Next, the expansion member 55 is attached to the spider body 51.
It is inserted between the inner cylinder part 45 and the outer cylinder part 47 of the spider body 51 inserted in the iron core 33 from the direction opposite to the direction in which the iron core 33 is inserted. At this time, the outer peripheral portion of the expansion member 55 moves toward the concave portion 47a while pressing the tapered portion 47b of the outer cylindrical portion 47 and expanding the outer cylindrical portion 47, and enters the concave portion 47a. The expansion member 55 that has entered the recess 47a has an outer diameter L ₅ and the outer cylinder portion 47 in the recess 47a.
Since the total thickness of the outer cylindrical portion 47 and the wall thickness L ₄ is greater than or equal to the diameter D of the insertion hole 33a, the outer cylindrical portion 47 is expanded from the inner peripheral side toward the outer peripheral side. As a result, the outer cylinder portion 47 is attached to the spider 3
It is pressed against the insertion hole 33a of No. 3 and is securely fixed to the iron core 33.

By providing a slit from the end portion of the outer tubular portion 47 in the axial direction, the expansion member 55 is attached to the outer tubular portion 47.
When inserted between the inner cylinder portion 45 and the inner cylinder portion 45, the outer cylinder portion 47 is likely to expand to the outer peripheral side, and the outer cylinder portion 47 can be more securely fixed to the iron core 33.

According to the method of fixing the spider 43 to the iron core 33 described above, an increase in manufacturing cost is suppressed by eliminating the work steps such as heating and cooling the iron core 33, and the mutual increase of the iron core 33 and the spider 43. The fixing work can be easily performed without peeling off the thin plate of the iron core 33.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a motor having a motor rotor structure according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a shape before assembling of the spider and an assembling method to the iron core according to the first embodiment.

FIG. 3 is a sectional view of a motor having a rotor structure for a motor according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a shape of a spider before assembling and a method of assembling the spider according to the second embodiment.

FIG. 5 is a sectional view of a motor including a rotor structure of a motor showing a conventional example.

[Explanation of symbols] 11 rotation axis 31,43 Spider (iron core holder) 33 iron core 33a insertion hole 41 Convex part (expansion member) 37,45 Inner tube part 39,47 Outer cylinder part 39a, 47a recess 39b, 47b Tapered part 49 Connection 53 Thin part 55 Expansion member

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H002 AA07 AB07 AB08 AB09 AC06                       AC08                 5H615 AA01 BB01 PP02 PP06 PP24                       SS19

Claims (9)

[Claims] 1. An insertion hole, into which an iron core holder is inserted, which is formed by laminating a plurality of magnetic materials along an axial direction of the rotation shaft, on an outer periphery of the iron core holder to which the rotation shaft is fixed. In a motor rotor structure having a fixed iron core, the iron core holder includes an outer cylinder portion having an inner diameter larger than the outer diameter of the rotating shaft, and the outer cylinder portion is fixed to the iron core. In the previous state, the outer diameter is formed to be smaller than the inner diameter of the insertion hole of the iron core, the outer diameter is arranged on the inner peripheral side of the outer tubular portion, and the outer tubular portion is pressed toward the outer peripheral side and expanded to expand the iron core. A rotor structure for a motor, wherein an expansion member for fixing the insertion hole is provided. 2. The iron core holder has an inner cylinder portion into which the rotary shaft is inserted and fixed inside the outer cylinder portion, and the expansion member is integrally provided in the inner cylinder portion. The rotor structure for a motor according to claim 1, wherein: 3. The expansion member comprises a convex portion projecting toward the outer cylinder portion, and a concave portion into which the tip of the convex portion enters is formed on the inner peripheral surface of the outer cylinder portion, This recess is
In the state before the iron core holder is fixed to the iron core,
The inner diameter is formed to be smaller than the outer diameter of the convex portion, the inner peripheral surface of the outer tubular portion has an inner diameter at the axial end portion larger than the outer diameter of the convex portion, and the concave portion from the axial end portion. 3. The rotor structure for a motor according to claim 2, wherein the inner diameter is gradually reduced toward the bottom. 4. The iron core holder has an inner cylinder part, into which the rotary shaft is inserted and fixed, which is connected to the outer cylinder part at one end in the axial direction by a connecting part. The rotor structure for a motor according to claim 1, wherein the expansion member is arranged near the other end portion in the axial direction between the outer tubular portion and the inner tubular portion. 5. The outer cylindrical portion of the iron core holder has an outer diameter gradually decreasing from the connecting portion toward the other end in the axial direction in a state before the iron core holder is fixed to the iron core. The rotor structure for a motor according to claim 4, wherein the rotor structure is formed. 6. A concave portion into which the tip of the expansion member is inserted is formed on the inner peripheral surface of the outer tubular portion, and the thickness dimension L ₄ of the outer tubular portion in the concave portion is equal to the diameter of the insertion hole of the iron core. D,
When the outer diameter of the expansion member is L ₅ , the size is set to satisfy D ≦ L ₄ + L _5, and the outer cylinder portion has an inner diameter on the other end side in the axial direction with respect to the recessed portion, 6. The motor rotor structure according to claim 4, wherein the rotor structure is formed so as to have a larger outer diameter and a smaller inner diameter from the other end toward the recess. 7. The rotor structure for a motor according to claim 4, wherein a thin portion is provided between the outer cylinder portion and the connecting portion. 8. An insertion hole, in which a plurality of magnetic materials are laminated along the axial direction of the rotary shaft, is formed on the outer periphery of the iron core holder to which the rotary shaft is fixed, and the core holder is inserted. In the motor rotor fixing method in which the iron core is fixed, the iron core holder to which the rotating shaft is fixed has an inner diameter larger than the outer diameter of the rotating shaft, and the outer diameter is larger than the diameter of the insertion hole of the iron core. A small outer cylinder portion is provided, and after the outer cylinder portion is inserted into the insertion hole of the iron core, the outer cylinder portion is pressed and expanded from the inner peripheral side to the outer peripheral side by the expansion member to expand the iron core. A method for fixing a rotor of a motor, characterized in that a tool is fixed to an iron core. 9. The rotating shaft is fixed to the inner peripheral side, and
On an outer peripheral side, in an iron core holder to which an iron core constituted by laminating a plurality of magnetic materials along the axial direction of the rotating shaft is fixed, an inner diameter larger than an outer diameter of the rotating shaft, and an outer diameter is In a state before being fixed to the iron core, an outer cylinder portion smaller than the insertion hole of the iron core is provided, and an expansion member that expands by pressing the outer cylinder portion from the inner peripheral side toward the outer peripheral side insertion hole is provided. An iron core holder characterized by being provided.