JP2001186700A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rotor from being vibrated and at the same time to reduce costs in an electric motor. SOLUTION: In the electric motor having a rotor inside a stator for generating a rotary magnetic field, the rotor forms a projecting part 10a inside a magnet 10 that is located at an outer periphery, forms a projecting part 12a at the outer periphery of a rotary support 12 that is fixed to a shaft 11, and inserts a buffer member 13 between the magnet 10 and the rotary support 12. A recessed part 13a where its projecting part 10a is engaged is formed at the buffer member 13, and at the same time a groove 13d where the projecting part 12a is fitted is formed. Two flywheels 14 and 15 are crimped and fixed to the shaft 11 by holding the buffer member 13 from both the directions of the shaft of axis of the shaft 11 and at the same time caulking the center side of the flywheels 14 and 15 for forming a caulking part 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor used for home electric appliances (air conditioners and the like) and industrial equipment, and more particularly to an electric motor characterized by a vibration-proof structure of a rotor.

[0002]

2. Description of the Related Art An electric motor has a rotor inside a stator for generating a rotating magnetic field. As shown in FIGS. 9 and 10, for example, the rotor is provided between a rotating support (core) 2 fixed to a shaft 1 serving as a center of rotation and a magnet 3 disposed on the outer peripheral side of the core 2. The buffer members (rubber) 4 and 5 are inserted from the axial direction of the shaft 1, and the iron plates 6 and 7 are attached from the axial direction of the shaft 1, and the pin 8 penetrates the iron plates 6 and 7 and the rubbers 4 and 5 and the stopper 9. Stopped at. Thereby, the iron plates 6 and 7 push the rubbers 4 and 5 into the inside, and the rubbers 4 and 5 expand to hold the magnet 3 on the core 2. Further, both ends (left and right directions in FIG. 9) of the magnet 3 are suppressed by the rubbers 4 and 5.

According to the configuration of the rotor, the magnets 3 can be held on the core 2 by the rubbers 4 and 5, and the vibrations caused by the rotation of the magnets 3 are absorbed by the rubbers 4 and 5. Therefore, the vibration is not transmitted to the core 2 and the shaft 1, and an anti-vibration effect and an eccentricity prevention effect are exhibited. Specifically, refer to JP-A-7-32841. According to the publication, the cushioning members of rubbers 4 and 5 are divided into two in order to insert the cushioning members from the axial direction of the shaft 1 to facilitate the insertion of the cushioning members.
The eccentricity and inclination of the rotor due to the displacement of the contact portion between the buffer member and the magnet 3 and the contact portion between the buffer member and the core 2 can be prevented by the shape of the divided buffer member.

[0004]

However, in the above-mentioned electric motor, the magnet 3 is held on the shaft 1,
Further, in order to prevent the rotor from being decentered, eccentric and inclined, two rubbers 4, 5, two iron plates 6, 7, pins 8, and stoppers 9 are required. Therefore, there is a drawback that a complicated structure having a large number of parts is required and the manufacturing cost is increased. In particular, in view of the fact that cost reduction is an extremely important factor in an electric motor, it is not preferable that the manufacturing cost be increased.

When a load is applied to a fan, a pump planner, or the like attached to the shaft 1, the natural frequency of the load matches the torsional natural frequency of the shaft 1,
When it is necessary to avoid that the natural frequency becomes the resonance frequency, a large design change may be involved, and in the worst case, it may be necessary to redesign the electric motor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to realize vibration elimination and the like by realizing vibration elimination and the like of a rotor with a small number of parts, to reduce the cost of an electric motor, and to reduce the load. An object of the present invention is to provide an electric motor in which resonance of torsional vibration of a shaft caused by the above is avoided by a simple design change, the adaptation to various products is excellent, and the reliability can be improved.

[0007]

In order to achieve the above-mentioned object, the present invention has a rotor inside a stator for generating a rotating magnetic field, the outer periphery of the rotor being a magnet, and the magnet being attached to the rotor. An electric motor held on a shaft of a rotor, comprising a rotor having a structure in which one buffer member is inserted between a rotating support fixed to the shaft and the magnet.

According to the present invention, a rotor is provided inside a stator that generates a rotating magnetic field, and an outer periphery of the rotor is a magnet,
An electric motor for holding the magnet on a shaft of the rotor, wherein one flywheel is inserted between a rotating support fixed to the shaft and the magnet, and two flywheels are provided from both directions of an axis of the shaft. And a rotor having a structure in which the center of the flywheel is crimped and fixed to the shaft by crimping.

In this case, it is preferable that the diameter of the flywheel is set to a size such that the flywheel does not come into contact with the outer periphery of the magnet due to a dimensional change of the buffer member. Thus, the flywheel does not come into contact with the magnet, that is, the vibration damping effect is not hindered.

On the inner periphery of the magnet, a convex portion toward the center is formed, and on the outer periphery of the buffer member, a concave portion fitted into the convex portion of the magnet is formed in a groove shape up to one end of the buffer member. A groove in the center direction is formed on the inner periphery of the buffer member, and a convex portion that fits into the groove of the buffer member is formed on the outer periphery of the rotary support. The buffer member may be inserted between the magnet and the rotating support from a groove-shaped surface. Thereby, the magnet is securely held by the buffer member, and the buffer member is reliably held by the rotating support. Therefore, the magnet is securely held on the shaft fixing the rotary support, and the rotation of the magnet is reliably transmitted to the shaft.

In order to fit the convex portion of the magnet on the inner periphery of the cushioning member, a projection is formed at a predetermined portion of the groove shape of the concave portion, and the movement of the magnet is stopped on the inner periphery of the magnet. Therefore, it is preferable to form a continuous stop portion on the convex portion. Thereby, when the magnet is displaced in the axial direction of the shaft, the stop portion of the magnet is locked to the flywheel, so that the magnet can be prevented from dropping off, and the motor does not become an abnormal situation such as failure. Already
Reliability can be improved.

[0012] A plurality of convex portions of the magnet and concave portions of a buffer member fitted into the convex portions are formed at equal intervals in the circumferential direction, and the buffer members fit into the convex portions of the rotary support and the convex portions. A plurality of the concave portions may be formed at equal intervals in the circumferential direction between the convex portion of the magnet and the concave portion of the buffer member fitted into the convex portion. Thereby, the magnet is more reliably held by the buffer member, and the buffer member is more reliably held by the rotary support. Therefore, the magnet is securely held by the shaft fixing the rotating support, and the rotation of the magnet is more reliably transmitted to the shaft.

[0013]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described in detail with reference to FIG. FIG. 4 is a schematic cross-sectional view taken along the line AA of FIG. 3, and FIG.
It is a schematic sectional drawing of the BB line.

Referring to FIGS. 1 and 2, the rotor of the electric motor according to the present invention has a convex portion 10a extending toward the center on the inner peripheral side of a magnet 10 located on the outer peripheral side, and this convex portion 10a is formed into a circle. A plurality (five) are formed at equal intervals in the circumferential direction,
A cushioning member (rubber) 13 is disposed between a rotating support (core) 12 fixed to the shaft 11 and the magnet 10, and the rubber 13 is separated from the flywheel (iron disc) 14, The flywheels 14 and 15 are pressed and fixed to the shaft 11 by crimping. The rubber 13 is expanded by the flywheels 14 and 15 to hold the magnet 10 on the core 12 and the shaft 11. ing.

As shown in FIGS. 3 and 4, the side surface of the projection 10a of the magnet 10 (the surface in the axial direction of the shaft 11).
, Stop portions 10b and 10c for stopping the magnet 10 with the flywheels 14 and 15 are formed long in the axial direction. Therefore, even if the magnet 10 is shifted in the axial direction of the shaft 11, for example,
Since the motors 0b and 10c contact the flywheels 14 and 15 to stop the displacement of the magnet 10, the motor can be prevented from being in an abnormal state such as a failure and the reliability can be improved.

As shown in FIGS. 5 and 6, the rubber 13 has an inner diameter substantially equal to the outer diameter of the core 12 and an outer diameter substantially equal to the inner diameter of the magnet 10. The rubber 13 has a concave portion 13a into which the convex portion 10a of the magnet 10 fits. The concave portions 13a are formed in the same number as the convex portions 10a from the outer periphery toward the center. The recess 13a extends in a groove shape so as to reach one end face of the rubber 13, and the rubber 13 at the location of the recess 13a has an L-shaped cross section.

In the middle of the groove of the recess 13a, projections 13b and 13c are formed at positions corresponding to the axial width of the projection 10a. Thereby, when assembling the rotor, the protrusions 10a of the magnet 10 are inserted into the grooves of the recesses 13a of the rubber 13.
When the rubber 13 is fitted inside the magnet 10 from one direction, the rubber 13 can be easily fitted and the magnet 10 can be prevented from being displaced in the axial direction.

Further, a groove 13d having a predetermined depth is formed between the recess 13a from the inner circumference to the outer circumference of the rubber 13,
A plurality (five) of the grooves 13d are formed at equal intervals in the circumferential direction. And, as shown in FIG.
The core 12 has a projection 12 fitted into the groove 13d.
a are formed at equal intervals in the circumferential direction. Thereby, since the rubber 13 and the core 12 are connected, the rotation of the magnet 10 can be reliably transmitted to the shaft 11.

Referring to FIG. 7 and FIG.
The diameters 4 and 15 are such that they do not come into contact with the outer periphery of the magnet 10 even when the rubber 13 changes its size in the radial direction.
The outer diameter is smaller than the inner diameter of the magnet 10. As a result, an appropriate gap (below the space between the stator inner diameter and the rotor outer diameter) is maintained between the outer peripheries of the flywheels 14 and 15 and the inside of the magnet 10, and even if the size of the rubber 13 changes. Rotation is not hindered, and vibration of the magnet 10 is not transmitted to the shaft 11 via the flywheels 14 and 15.

The flywheels 14 and 15 have a predetermined thickness t and an inner diameter substantially equal to the diameter of the shaft 11. That is, the inside of the flywheels 14 and 15 can be caulked and fixed to the shaft 11.

In assembling the rotor having the above structure,
First, the core 12 fixed to the shaft 11 and the magnet 1
0, the rubber 13 is inserted from the groove surface direction of the concave portion 13a of the rubber 13 (the left direction in FIG. 1). At this time, rubber 1
The concave 13a of the third 3 is aligned with the convex 10a of the magnet 10, the groove 13b is aligned with the convex 12a of the core 12, and the rubber 13 is fitted between the core 12 and the magnet 10.

Subsequently, the rubbers 13 are pressed down from the flywheels 14 and 15 in the axial direction of the shaft 11 (the left-right direction in FIG. 1), and the shafts 11 of the flywheels 14 and 15 are
Is caulked and fixed to the shaft 11, for example, by providing four caulking portions 16 and fixing. As a result, the magnet 10 is held by the core 12 of the shaft 11 via the rubber 13.

As described above, since the rubber 13 is interposed between the magnet 10 and the core 12, the magnet 10
Vibration, eccentricity and inclination due to rotation of can be prevented. Also, in realizing the present invention, one rubber 13
And only the two flywheels 14 and 15 are required, and the number of parts can be significantly reduced as compared with the conventional case, so that the cost of the electric motor can be reduced. Further, assembling of the rotor is facilitated and the number of manufacturing steps is extremely small, so that the manufacturing cost can be reduced.

When the load of the motor using the rotor is, for example, a fan or a pump runner, a system in which two disks (rotor and fan) are fixed to both ends of a shaft (shaft 11). It can be. In a shaft torsional vibration system (a so-called one-degree-of-freedom system vibration) composed of this system, the natural frequency p of the shaft can be expressed by the following equation (1). In the equation (1), k is a rotational spring constant, I1 is an inertia moment of one disk (rotor), and I2 is an inertia moment of the other disk (fan or the like).

[0025]

(Equation 1)

Here, as described in the conventional example, when the natural frequency of the fan as the load matches the natural frequency p of the shaft, the natural frequency p becomes the resonance frequency, and the vibration of the electric motor, The noise increases. Therefore, when the thickness t of the flywheels 14 and 15 of the rotor is changed, and the weight of the rotor is increased or decreased to change the inertia moment I1, the natural frequency p of the shaft does not match the natural frequency of the fan. , Resonance can be avoided.

As described above, the resonance point can be avoided only by using flywheels having different thicknesses t. Therefore, resonance can be prevented without a significant design change. In addition, it is possible to cope with the case where it is used for various devices, and it is possible to increase the share of components of the rotor and the adaptability of the electric motor.

[0028]

According to the present invention described above, the following effects can be obtained. Since the electric motor of the present invention includes the rotor having a structure in which one buffer member is inserted between the rotating support fixed to the shaft and the magnet on the outer periphery, the magnet is securely held on the shaft, and the holding of the magnet is performed. By using a cushioning member (rubber), vibration of the rotor during rotation, eccentricity and inclination can be prevented, and the cost of the motor can be reduced.

In the electric motor of the present invention, one cushioning member is inserted between the rotating support fixed to the shaft and the magnet on the outer periphery, and the cushioning member is suppressed by two flywheels from both directions of the shaft axis. In addition to the above-described effects, the vibration of the shaft resonates with the vibration of the load fan, the pump runner, etc., since the rotor having the structure in which the center side of each flywheel is crimped and fixed to the shaft is provided. In this case, the torsional resonance of the shaft can be avoided by a simple design change only by changing the thickness of the flywheel, that is, by changing its weight. Therefore, there is an effect that it is excellent in adaptation to various products and that the reliability of the products can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a rotor of an electric motor according to an embodiment of the present invention.

FIG. 2 is a schematic plan view illustrating the rotor shown in FIG. 1;

FIG. 3 is a schematic plan view for explaining a magnet used for the rotor shown in FIG. 1;

FIG. 4 is a schematic sectional view for explaining the magnet of FIG. 3;

FIG. 5 is a schematic plan view illustrating a buffer member used in the rotor shown in FIG. 1;

FIG. 6 is a schematic sectional view for explaining the cushioning member of FIG. 5;

FIG. 7 is a schematic plan view for explaining a flywheel used in the rotor shown in FIG. 1;

FIG. 8 is a schematic cross-sectional view illustrating the flywheel of FIG. 7;

FIG. 9 is a schematic structural view of a rotor of a conventional electric motor.

FIG. 10 is a schematic plan view for explaining the rotor shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnet 10a Convex part (of magnet) 10b, 10c Stop part 11 Shaft 12 Rotary support (core) 12a Convex part (of core) 13 Buffer member (rubber) 13a Recess 13b, 13c Projection 13d Groove 14, 15 Flywheel 16 Caulking part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Narita 1116 Suenaga, Takatsu-ku, Kawasaki, Kanagawa Prefecture Inside Fujitsu General Co., Ltd. (72) Takashi Suzuki 1116, Suenaga, Takatsu-ku, Kawasaki City, Kanagawa F. Terms (reference) 5H002 AA04 AA08 AB05 AE08 5H605 AA04 AA05 BB05 CC03 CC05 CC10 EA02 EA06 FF08 GG03 GG04 5H621 AA04 HH01 JK02 JK15 PP01 5H622 CA01 CA05 CB04 CB06 PP04 PP10 PP11 PP12 PP14 PP16

Claims (6)

[Claims] 1. An electric motor having a rotor inside a stator that generates a rotating magnetic field, an outer periphery of the rotor being a magnet, and the magnet being held on a shaft of the rotor, the motor being fixed to the shaft. An electric motor comprising a rotor having a structure in which one buffer member is inserted between the rotating support and the magnet. 2. An electric motor having a rotor inside a stator that generates a rotating magnetic field, an outer periphery of the rotor being a magnet, and the magnet being held on a shaft of the rotor, the motor being fixed to the shaft. One cushioning member is inserted between the rotating support and the magnet, and the cushioning member is held down by two flywheels from both directions of the shaft of the shaft. An electric motor comprising: a rotor having a structure fixed by crimping to a motor. 3. The electric motor according to claim 2, wherein the diameter of the flywheel is such that it does not come into contact with the outer periphery of the magnet even when the buffer member changes in size. 4. A convex portion toward the center is formed on the inner periphery of the magnet, and a concave portion to be fitted into the convex portion of the magnet is formed in a groove shape on one end of the buffer member on the outer periphery of the buffer member. When the rotor is assembled, the groove in the center direction is formed on the inner periphery of the buffer member, and a convex portion that fits into the groove of the buffer member is formed on the outer periphery of the rotating support. 4. The electric motor according to claim 1, wherein the buffer member is inserted between the magnet and the rotary support from a groove-shaped surface. 5. 5. A protrusion is formed at a predetermined position of a groove shape of the concave portion in order to fit a convex portion of the magnet on an inner periphery of the buffer member, and the magnet is moved on an inner periphery of the magnet. 5. The electric motor according to claim 3, wherein a stop portion continuous with the convex portion is formed to stop the motor. 6. A plurality of convex portions of the magnet and concave portions of a cushioning member fitted into the convex portions are formed at equal intervals in the circumferential direction, and fitted into the convex portions and the convex portions of the rotary support. 6. The electric motor according to claim 3, wherein a plurality of concave portions of the buffer member are formed at equal intervals in the circumferential direction between the convex portion of the magnet and the concave portion of the buffer member fitted into the convex portion.