KR20120096730A - Electric motor - Google Patents

Abstract

Electric motors with improved endurance with minimal end play are provided. The electric motor includes a stator in which a plurality of coils are disposed, a rotor positioned to face the stator in an inner space of the stator, a rotor rotating shaft coupled to the rotor and rotating integrally with the rotor, and positioned in front of the rotor. And a first bearing supporting the rotor rotating shaft, a second bearing positioned behind the rotor, a second bearing supporting the rotor rotating shaft, a pressing member pressing the second bearing, and a fixing member fixing the pressing member. do.

Description

Electric motor

The present invention relates to an electric motor that converts electrical energy into mechanical energy using electromagnetic principles to provide this mechanical energy to the outside.

When the motor is driven, end play, which is the movement in the axial direction of the rotor, affects the durability of the motor and can reduce the life of the motor. Thus, there is a study on how to minimize such end play.

Korean Patent Laid-Open Publication No. 2002-0037268 relates to a motor which is operated while the rotor is pressed by one bearing, and presses the bearing by using a spring as a pressing member to increase the positional accuracy between the rotor and the stator.

In addition, the cap-shaped fixing member is used as a component to fix the pressing member.

Korean Patent Laid-Open Publication No. 2002-0010540 relates to a motor for preventing displacement of a bearing in the axial direction, and uses an adhesive, an annular leaf spring, and a screw member to achieve this object.

First, the bearing is fixed by using an adhesive, and when the adhesive is peeled off over time, the bearing is prevented from moving in the axial direction by the annular leaf spring. Further, the screw member can be used to control the movement in the axial direction of the bearing by adjusting the tightening amount of the screw.

Looking at the Republic of Korea Patent Publication No. 2002-0037268, using a spring as a pressing member and a cap as a fixing member. However, the spring may change the elastic force over time, the positional accuracy between the rotor and the stator may be lowered over time.

In addition, by using a plurality of components, such as a spring and a cap, for positional accuracy, respective dimensional tolerances can be accumulated, and the configuration of the motor may be complicated.

In the case of Korean Patent Publication No. 2002-0010540, an adhesive is used to fix the bearing. This adhesive may require a certain time or more to cure, leading to a decrease in motor manufacturing production efficiency, and may lead to a decrease in adhesive force over time, resulting in peeling.

In addition, the stickiness of the adhesive may also cause difficulty in motor cleaning and repair.

This document describes the use of annular leaf springs to compensate for the drawbacks of such adhesives, but springs are also not a solution to the change in elastic force over time.

Additionally, the document states that screw members will be used to control the number of tightenings and to control the movement of the bearings. However, a change in the tightness of the screw may occur in the process of operating the motor may cause the screw to loosen at some moment.

There may also be difficulties in the manufacturing and repair processes in that a number of components, such as adhesives, springs and screws, are used to control the movement of the bearing in the axial direction.

The technical problem to be solved by the present invention is to provide an electric motor with improved durability by minimizing the end play.

The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

An electric motor according to an aspect of the present invention for achieving the above technical problem, a stator in which a plurality of coils are disposed, a rotor located opposite to the stator in an inner space of the stator, coupled to the rotor, and the rotor and A rotor rotating shaft that is integrally rotated, the first bearing which is located in front of the rotor, and supports the rotor rotation axis, the second bearing which is located behind the rotor, and supports the rotor rotation axis, pressurizing the second bearing And a fixing member for fixing the pressing member and the pressing member.

The present invention can provide an electric motor with improved durability by minimizing end play.

1 is a perspective view of an electric motor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1.
3 is a cross-sectional view taken along the line BB ′ of FIG. 1.
4 is a cross-sectional view of an electric motor according to another embodiment of the present invention.
5 is a cross-sectional view of an electric motor according to another embodiment of the present invention.
6 and 7 are perspective views of a pressure bolt of a polygonal shape which is one component of an electric motor according to an embodiment of the present invention.
8 is a perspective view of a cycloid-shaped pressure bolt that is one component of an electric motor according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

1 is a perspective view of an electric motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1. 3 is a cross-sectional view taken along the line BB ′ of FIG. 1. 6 and 7 are perspective views of a pressure bolt of a polygonal shape which is one component of an electric motor according to an embodiment of the present invention.

1 to 3, 6, and 7, the electric motor 100 according to an embodiment of the present invention includes a stator 500, a rotor 600, a rotor rotation shaft 300, and bearings 400 and 450. ), A pressing member 200, a fixing member 800, and a shock absorbing member 1000.

First, the electric motor 100 is a device that converts electrical energy into mechanical energy by using a force that a current flowing conductor receives in a magnetic field. According to the type of power, it is classified into DC motor and AC motor, and AC motor is divided into three phase exchange and single phase exchange.

The stator 500 may be referred to as a stator and may be a kind of electromagnet. The stator 500 includes an iron core and an electric winding (or coil), which may be wound around the iron core and disposed of. If current flows through the winding for energization, the stator 500 may become magnetic.

The rotor 600 may also be referred to as a rotor and may be a kind of permanent magnet. The rotor 600 may be positioned to face the stator 500 in the internal space of the stator 500.

When power is supplied to the winding for energization of the stator 500, the rotor 600 is rotated by the action of the rotor field formed between the rotor 600 and the stator 500, and the rotational torque of the rotor 600 is a rotor rotation shaft. The 300 can be rotated.

The rotor shaft 300 is coupled to the rotor 600 and may rotate integrally with the rotor 600. For example, the rotor rotation shaft 300 may be coupled to the rotor 600 while penetrating the rotor 600. In this binding, the rotor rotation shaft 300 may be rotated by the rotation torque of the rotor 600, and may provide mechanical energy to the outside.

For example, when a gear is connected to the rotor rotation shaft 300, the gear also rotates as the rotor rotation shaft 300 rotates.

The bearing may include a first bearing 400 and a second bearing 450. The bearing may be a ball bearing, but the bearing of the present invention is not limited to the ball bearing.

A bearing is a mechanical element that plays a role of rotating the shaft while fixing the shaft of a rotating machine at a fixed position and supporting the weight of the shaft and the load applied to the shaft. Put in between.

The ball bearings fix the rotor shaft 300 at a constant position, and as a result, the rotor 600 may always serve to maintain a fixed position and safely rotate at high speed.

The first bearing 400 may be positioned in front of the rotor 600 opposite to the pressurizing bolt, which is a pressing means, and may serve to support the rotor rotation shaft 300. The second bearing 450 may be located at the rear of the rotor 600, and one end of the pressing bolt, which is the pressing member 200, and the outer ring of the second bearing 450 may be in contact with each other. This will be described in detail below.

The pressing member 200 may serve to apply pressure in the axial direction to the second bearing 450, and the pressing bolt 200 may be used in the present invention. The pressing bolt 200 may be located at the rear of the second bearing 450 which is the rear of the rotor 600.

The pressing bolt 200 may be hollow, and the rotor rotation shaft 300 may penetrate the hollow. The pressurizing bolt 200 may include a threaded portion in which a bolt head and a thread are formed. The illustrated bolt head may be hexagonal in shape but the shape of the bolt head may vary, as will be described in detail below. The thread is threaded like any bolt.

A protrusion 700 may be formed circumferentially in one cross section opposite to the bolt head, and the protrusion 700 may serve to press the outer ring of the second bearing 450. In addition, an empty space may be formed between the inner ring portion of the second bearing 450 and the pressure bolt 200.

In the process of tightening the pressurizing bolt 200 to the electric motor 100, the pressurizing bolt 200 may be tightened such that a strong binding is made between the pressurizing bolt 200 and the housing of the electric motor 100.

By tightening the pressure bolt 200 to the housing of the electric motor 100, the protrusion 700 of the pressure bolt strongly presses the outer ring of the second bearing 450, and a preload is applied to the second bearing 450. Can be. This preload can prevent the creep from being cracked under prolonged loads, which can extend the life of the bearing.

In the case of a motor, end play, which is a phenomenon in which the rotor 600 rotates in the axial direction, may occur during the operation. In this case, when the rotor moves in the axial direction, a force (stress) is applied to adjacent components, which may cause wear of the components, thereby reducing the life of the motor.

In addition, noise may be generated by the contact between the components, and a part of the energy generated by the motor may be dissipated as sound energy, resulting in waste of energy and deterioration of the working environment.

In addition, when an end play phenomenon occurs in the process of operating the motor, the position tolerance between the rotor and the stator or the position tolerance between components in the motor may be a problem in driving the motor beyond an allowable value.

If the position tolerance between the rotor and the stator exceeds the allowable value, it may cause a problem in the production of the driving energy generated by the interaction between the rotor and the stator, which may shorten the life of the motor.

In the case of a motor, it is generally used in connection with a gear rather than a single product. For example, a geared motor combining a motor and a reduction gear device as one may be used.

First, when the helical gear is looked at as a gear used to be connected to a motor, the helical gear has a toothed diagonal shape, so when the gear is rotated in engagement, thrust is generated in the axial direction. This thrust acts to push the rotor backwards, resulting in end play and positional tolerances above the tolerance between the rotor and the stator.

It can also cause frequent collisions between components in the motor, which can lead to wear and noise of the components.

Hypoid gear is a kind of bevel gear, which is a gear with a staggered shaft. Hypoid gears also have a toothed oblique shape, so thrust occurs in the axial direction during driving, which can cause end play and position tolerances beyond tolerance.

Therefore, various efforts have been made to eliminate the end play phenomenon and the position tolerance beyond the allowable value, and one of the efforts is to use an adhesive material between the bearing and the housing to block the movement in the axial direction, or Washers, especially wave washers.

However, in the case of using the adhesive material, the adhesion of the adhesive material may become weaker as time passes, causing slippage and difficulty in cleaning.

In the case of using a plurality of washers, it is difficult to determine the appropriate number of washers, and the dimensional tolerances of the washers themselves may overlap, resulting in a position tolerance exceeding the allowable value.

In the case of the wave washer, it is difficult to manufacture first, and there is a risk of breaking the washer due to the thrust acting toward the wave washer while the motor is running. Wave washers also have the disadvantage of being difficult to apply to large motors.

As a result, the present invention requires only a simple process of tightening the housing using a single pressure bolt and fixing the pressure bolt, eliminating the adhesive application and curing process, and eliminating the installation of the wave washer. Simplification and efficiency can be achieved.

In the case of using a spring as an elastic member, it is also difficult to have a spring having a suitable elastic modulus and there may be a problem that the elastic force of the spring changes over time.

In the present invention, using the pressure bolt 200, which is a pressing member for providing a pressure in the axial direction to the outer ring of the second bearing 450 supporting the rotor rotation shaft 300, the pre-loading of the second bearing 450 before the motor is driven in advance. ) Can be provided.

Instead of using an adhesive material or washer, the use of the pressurized bolt 200 simplifies the construction of the motor, can provide ease of manufacture and convenience of cleaning, and above all, to minimize end play Reduce gear noise and extend life.

In addition, since the pressing member is a bolt, the position tolerance can be easily adjusted by freely selecting the tightening degree (number of times).

The fixing member 800 may be used to prevent the pressurized bolt 200 tightened to the housing from being loosened while driving the motor. That is, the fixing member 800 may serve to fix the pressure bolt 200 to the motor.

A fixing groove 850 is formed in the pressure bolt 200, and a groove corresponding to the fixing groove 850 may be formed in the motor housing. The fixing member 800 may be inserted into the fixing groove 850 and the groove formed in the housing to serve to bind the pressure bolt 200 and the housing. The fixing member 800 will be described in detail below.

The shock absorbing member 1000 may be located between the pressurizing bolt 200 and the bolt head and the screw portion, and may be an O-ring. O-rings can be circular rings used to prevent leaks, such as natural rubber, synthetic rubber, and synthetic resins. The o-ring 1000 in the present invention may be used for shock mitigation.

When the electric motor 100 is operated, the thrust described above may be applied to the pressure bolt 200. The o-ring 1000 may abut the housing when the pressure bolt 200 is tightened to the housing, and when the force including the thrust is applied to the pressure bolt 200, the o-ring 1000 may be caused by such force. It can play a role in mitigating shock.

4 is a cross-sectional view of an electric motor according to another embodiment of the present invention.

Referring to FIG. 4, a plurality of fixing grooves 850 are formed in the pressure bolt 200, which is one component of the electric motor 100 according to another embodiment of the present invention. When there is only one fixing groove 850, it is difficult to match the groove formed in the housing and the fixing groove 850 corresponding to the fixing groove while tightening the pressure bolt, and the matching groove and the groove corresponding to the fixing groove Even if the pressure bolt 200 may not be sufficiently tightened in the housing.

Therefore, a plurality of fixing grooves 850 may be formed in the pressing bolt 200, and a plurality of grooves corresponding to the plurality of fixing grooves 850 may also be formed in the housing. Alternatively, one fixing groove 850 may be formed in the pressing bolt and a plurality of grooves corresponding to the fixing groove 850 may be formed in the housing.

In this case, while sufficiently tightening the pressure bolt 200 can match the groove formed in the fixing groove 850 and the housing.

5 is a cross-sectional view of an electric motor according to another embodiment of the present invention. 8 is a perspective view of a cycloid-shaped pressure bolt that is one component of an electric motor according to another embodiment of the present invention.

5 and 8, the bolt head shape of the pressure bolt 250, which is one component of the electric motor 100 according to another exemplary embodiment, has a cycloid shape. Of course, any shape may be possible if a bend is formed in addition to the cycloid shape such that the fixing member 800 can be located at this bend.

First, the part which entered the cycloid is called valley 900, and the part which came out is called the floor 950. FIG. When the fastening member 800 is positioned at the valley 900 between the floor 950 and the neighboring floor 950, the pressurizing bolts 200, 250 are moved during operation of the motor due to the fastening member 800 located at the valley 900. It may become unsolvable.

For example, after forming the bolt seat in the housing, the valley of the cycloid is placed in this bolt seat. Thereafter, when the bolt is tightened to the housing, the bolt is positioned in the valley of the cycloid, and the fixing member cannot move such as rotation.

The use of this fixing member 800 allows the pressure bolts 200, 250 tightened in the housing to continually press the second bearing 450, resulting in a reduction in end play. In addition, the positional tolerance between the rotor and the stator can also be maintained within the allowable value.

In addition, a hexagonal groove may be formed in the pressure bolt 200. When the tool is used in the process of tightening the pressure bolt 200 to the housing, the tool may be inserted into the groove to tighten the pressure bolt using the tool.

For example, when using a wrench, the wrench can be inserted into this hexagonal groove to tighten the pressure bolt as desired.

It is merely an example that the groove has a hexagonal shape, and the shape of the groove may vary depending on a tool used to tighten the pressure bolt 200.

As a result, this end play reduces the noise generated in the process of driving the motor, and can reduce the friction between components in the motor, thereby extending the life of the motor.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: electric motor 200: pressing member (polygonal bolt)
250: pressure member (cycloid bolt) 400: first bearing
450: second bearing 500: stator
600: rotor 700: protrusion
800: fixing member 850: fixing groove
900: cycloid goal 950: cycloid floor
1000: shock absorbing member

Claims (9)

A stator in which a plurality of coils are disposed;
A rotor positioned in the inner space of the stator to face the stator;
A rotor rotating shaft coupled to the rotor and integrally rotating with the rotor;
A first bearing positioned in front of the rotor and supporting the rotor rotation shaft;
A second bearing positioned behind the rotor and supporting the rotor rotation shaft;
A pressing member for pressing the second bearing; And
An electric motor comprising a fixing member for fixing the pressing member. The method of claim 1,
The electric motor further comprises a shock absorbing member integral with the pressing member. 3. The method according to claim 1 or 2,
The pressurizing member is an electric motor of a pressurizing bolt having a protruding portion circumferentially of one end. The method of claim 3, wherein
The pressing bolt presses the second bearing,
An electric motor, wherein the projecting portion presses the outer ring of the second bearing. The method of claim 3, wherein
The pressurized bolt head shape is an electric motor having a cycloid shape. 6. The method of claim 5,
The fixing member fixes the pressure bolt,
An electric motor, wherein the fixing member is located in the valley portion of the cycloid. The method of claim 3, wherein
The pressure bolt is hollow is formed, the rotor rotation shaft is an electric motor penetrating the hollow. The method of claim 3, wherein
The shock absorbing member is located between the bolt head and the screw portion of the pressing bolt. The method of claim 8,
The shock absorbing member is an O-ring electric motor.

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