JPH11234932A - Structure of rotor of small-sized motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely fix a shaft in a multilayer rotor iron core with high precision, without causing deformation, damage, and the like to the shaft, and remarkably lowering the performance of the shaft at the time of press-fitting the shaft in the multilayer iron core in a rotor for a rotor electric machine. SOLUTION: A metal sleeve 13 made of copper or aluminum material is inserted into a central hole of a multilayer iron core 8, and then shaft parts 7a and 7b are press-fit into the metal sleeve 13 from the directions A and B as shown by arrows in the figure and then are joined and fixed in the hole. By press-fitting the shaft parts 7a and 7b into the metal sleeve 13, the metal sleeve 13 is expanded, thereby damaging no shaft parts 7a and 7b nor deforming and surely fixing in the multilayer iron core 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized motor rotor, and more particularly to improvement in accuracy of a press-fitted and fixed rotor shaft.

[0002]

2. Description of the Related Art The general structure of a conventional small DC motor is shown in FIG. In FIG. 6, the motor shaft 7 is connected to the motor shaft 7 from the terminal 6 held by the bracket 2 via the brush 4 in contact with the commutator 3 and the commutator 3 fixed to the motor shaft 7 supported by bearings 5a and 5b. When a current is supplied to the rotor coil 9 wound around the fixed laminated core 8, the rotor 11 existing in the magnetic field formed by the magnet 10 fixed to the inner peripheral surface of the motor housing 1 is provided. Are configured to rotate.

That is, in the prior art, the rotor before the armature coil is wound, as shown in FIG.
Is press-fitted and fixed to the center hole from the direction of arrow A.

[0004] In general, the insertion force of the shaft into the laminated core is set so that the shaft has a holding force that does not easily come off from the laminated core due to impact such as dropping or vibration. This requires a somewhat strong press-fit, which is obtained by making the inner diameter of the shaft insertion hole of the laminated core smaller than the outer diameter of the shaft.

[0005]

However, a disadvantage of the prior art is that when the shaft is press-fitted and fixed to the laminated core, the shaft is forced through the central portion of the laminated core with a strong force. The through-hole of the shaft which is handled by the hole cut of the iron core, particularly the outer peripheral portion of the portion which is supported by the bearing, is torn as shown in part C of FIG. 8, and the surface roughness deterioration and size which are important elements of the shaft. Or, the roundness changes. Also, as shown in FIG. 9, the shaft may be bent in a V-shape to reduce straightness and cylindricity, which are important elements of the shaft. This induces an increase in shaft runout, noise, and vibration in the motor, and significantly reduces the performance of the motor itself.

Accordingly, an object of the present invention is to provide a method of securely and accurately fixing a shaft to a rotor laminated core without deforming or damaging the shaft.

[0007]

According to a first aspect of the present invention, there is provided a rotor structure for a rotating electric machine, wherein the shaft portion is composed of two portions in a laminated core portion around which an armature coil is wound and a shaft portion. The bonding of the book and the bonding with the laminated core are
The shaft insertion hole of the laminated core portion is used to perform the process. According to a second aspect of the present invention, in the rotor structure for a rotating electric machine, a metal sleeve is inserted into the shaft insertion hole of the laminated core, and the shafts are joined and fixed by press fitting from both sides of the sleeve. Claim 3
In the rotor structure for a rotating electrical machine, a concave portion and a convex portion are formed coaxially with the outer periphery of the shaft on the joint side of the shaft portion, and the convex side of the shaft is formed into a concave side inside the shaft insertion hole of the laminated core portion. It is characterized by being bonded and fixed by press-fitting. The rotor structure for a rotating electric machine according to claim 4, wherein a concave portion coaxial with the outer peripheral surface of the shaft is formed on the joint side of the shaft portion, and the concave portion of the shaft is formed inside the shaft insertion hole of the laminated core portion. An outer diameter dimension equal to or slightly larger than the inner diameter of the concave hole is joined and fixed by press-fitting a holding pin. The rotor structure for a rotating electrical machine according to claim 5, wherein a coaxial concave portion is formed on the joint side of the shaft portion with the outer peripheral surface, and the other shaft having a size equal to or slightly larger than the inner diameter of the concave hole is connected to the laminated core portion. The diameter of the upper and lower shafts is changed by press-fitting into the concave side of the shaft inside the shaft insertion hole to fix and join the shaft.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a shaft-fixed product of a rotor for a rotary electric machine of a small motor according to an embodiment of the present invention before an armature coil is wound. The shafts 7a and 7b are press-fitted from both sides of the laminated core 8, and are joined near the center of the center hole of the laminated core 8. If there is a concern about the strength of this joint, the outer circumferences of the laminated cores 8 may be connected by laser welding L, or the laminated cores 8 may be laminated with uneven guides so as not to be uneven. As a result, the projecting portions of the shafts 7a and 7b, especially the portions supported by the bearings, are not damaged.

FIG. 2 shows a sectional view of the second embodiment.
In FIG. 2, a metal sleeve 13 made of copper or aluminum is inserted into the center hole of the laminated iron core 8, and the shaft 7 a is indicated by an arrow A and the shaft 7 b is indicated by an arrow B
FIG. 3 is a view in which the core 3 is press-fitted and bonded and fixed inside the hole of the laminated core 8. In FIG. 2, the dimensions where a is the inner diameter of the shaft insertion hole of the laminated core 8, b is the outer diameter of the metal sleeve 13, c is the inner diameter, and d is the outer diameter of the shafts 7 a and 7 b, are as follows. There is. a> b, c <d Therefore, by press-fitting the shafts 7a and 7b into the metal sleeve 13, the metal sleeve 13 expands, and the shafts 7a and 7b can be securely fixed to the laminated core 8 without damage or deformation.

FIG. 3 is a sectional view of a third embodiment.
In FIG. 3, a concave shape coaxial with the outer peripheral surface is formed on the end side of the shaft 7a, and the outer diameter is coaxial with the outer peripheral surface on the end side of the shaft 7b and has an outer diameter equal to or slightly larger than the inner diameter of the concave hole. A convex shape is formed, and the shafts are press-fitted into the laminated cores 8, respectively, and simultaneously, the concave portions and the convex portions are press-fitted.
As a result, even when the laminated core 8 is not loosened, it can be securely and accurately fixed as described above.

FIG. 4 is a sectional view of a fourth embodiment. In FIG. 4, a concave shape coaxial with the outer periphery is formed on the end side of the shaft 7a and the shaft 7b, and the shaft is press-fitted into the laminated core 8, and at the same time, a metal pin having an outer peripheral size equal to or slightly larger than the inner diameter of the concave shape. 14. Press-fit simultaneously. As a result, even when the laminated core 8 is not loosened, the laminated core 8 can be securely and accurately fixed as described above.

FIG. 5 is a sectional view of a fifth embodiment.
In FIG. 5, a concave shape coaxial with the outer peripheral surface is formed on the end side of the shaft 7 a, and a shaft 7 b having an outer diameter equal to or slightly larger than the inner diameter of the concave hole is provided inside the shaft insertion hole of the laminated core 8. Press into the concave side of the shaft,
It is accurately and securely bonded and fixed to the laminated core 8. By doing so, the shaft with less side pressure can be made thinner, so that the side pressure loss can be reduced.

[0013]

The rotor structure for a rotating electric machine according to the present invention has the following features.
With the above configuration, there is an effect that the rotor can be securely and accurately fixed to the rotor laminated core without being deformed or damaged when the shaft is pressed into the laminated core.

Further, since the invention according to claim 5 is characterized in that the outer diameters on both sides of the shaft are changed, there is an effect that the bearing loss on the non-output side can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a rotor structure of a small motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part showing a rotor structure of a small motor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part showing a rotor structure of a small motor according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a main part showing a rotor structure of a small motor according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a main part showing a rotor structure of a small motor according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a conventional small motor.

FIG. 7 is a sectional view of a main part showing a rotor structure of a conventional small motor.

FIG. 8 is an explanatory diagram of a defective portion in the related art.

FIG. 9 is an explanatory diagram of another defective portion of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Bracket 3 ... Commutator 4 ... Brush 5a, 5b ... Bearing 6 ... · Terminals 7, 7a, 7b · Shaft 8 ····· Laminated iron core 9 ····· Rotor coil 10 ······················· Rotor 12 ··· ··· Thrust washer 13 ······ Metal sleeve 14 ····· Pin A ····································· ..Shaft surface scratches L ........ Laser welds

Claims (5)

[Claims] In a rotor structure for a rotating electrical machine comprising a laminated core portion around which an armature coil is wound and a shaft portion, the shaft portion is composed of two portions, and the two portions are fixedly connected and the laminated core portion. The rotor structure is fixed using the shaft insertion hole of the laminated core portion. 2. The rotor structure for a rotating electrical machine according to claim 1, wherein a metal sleeve is inserted into the shaft insertion hole of the laminated core portion, and the shafts are joined and fixed by press fitting from both sides of the sleeve. The rotor structure according to claim 1. 3. In the rotor structure for a rotating electrical machine, a concave portion and a convex portion are formed on a joint side of the shaft portion, and the convex side of the shaft is press-fitted into the concave side inside the shaft insertion hole of the laminated core portion. The rotor structure according to claim 1, wherein the rotor is bonded and fixed. 4. In the rotor structure for a rotating electrical machine, a concave portion is provided on a joint side of the shaft portion, and inside the shaft insertion hole of the laminated iron core portion, the concave portion of the shaft has a diameter equal to or equal to the inner diameter of the hole. 2. The rotor structure according to claim 1, wherein a slightly larger outer diameter is joined and fixed by press-fitting a holding pin. 5. In the rotor structure for a rotating electrical machine, a concave portion is formed on a joint side of the shaft portion, and the other shaft having a size equal to or slightly larger than the inner diameter of the concave hole is connected to the shaft of the laminated core portion. 4. The rotor structure according to claim 3, wherein the upper and lower shaft diameters are changed by press-fitting the inside of the insertion hole into the concave side of the shaft and joining and fixing the shaft.