JPH11356001A - Bearing device of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent foreign matter such as dusts from penetrating into a bearing box through the through-hole of a bracket satisfactorily. SOLUTION: A bell-shaped blockade cylinder 16 comprises a cylindrical part 16a through which a rotor shaft 4a is inserted and a base end which enters a bearing box (a) through the through-hole (a1 ) of a bracket 6. The leading end of the cylindrical part 16a has a small diameter. The base end has a flat part 16b with a large diameter. The rotor shaft 4a is rotatably inserted into the cylindrical part 16a of the blockade cylinder 16. The flat part 16b of the base end is held between the back wall of the bearing box (a) and ball bearings 5 to block the through-hole (a1 ) of the bracket 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a bearing device for an electric motor, and more particularly to a bearing device capable of effectively preventing intrusion of dust or moisture containing salt.

[0002]

2. Description of the Related Art Conventionally, various electric motors have been used as a drive source for a blower or the like used for many home electric appliances such as heating / cooling equipment. In most motors, ball bearings are used for their bearings. That is, the rotor rotatably mounted on the stator core of the electric motor inserts ball bearings mounted on both ends of the rotor shaft into bearing housings provided on a pair of brackets sandwiched between the stator cores. This allows the stator to be rotatably supported and held on the stator core. The rotor is rotated in a predetermined direction via the ball bearing by energizing a coil wound around the stator core.

[0003]

However, in the configuration in which the rotor is rotatably supported by using a ball bearing, the bearing housing provided on one side of the bracket has a closed back wall and the rotor shaft projects outside. Since it is possible to prevent dust and foreign substances that adversely affect the ball bearing from entering the bearing housing, the bearing housing provided on the other bracket side includes, for example, a fan of a blower. A through hole is provided for allowing the rotor shaft of the rotor to be axially projected to the outside, and the rotor shaft projects through the through hole to the outside with a small gap. For this reason, for example, when the electric motor is used as a drive source of a blower that supplies air to a combustion unit (burner unit) of a heating device to improve combustion efficiency, a ball that rotatably supports a rotor is used. Since the bearing is sealed only by the shield plate, it has been difficult to properly prevent the intrusion of dust or foreign matter that flows when air is introduced into the blower.

That is, since the ball bearing itself generally uses only a shield plate as a protection means for protecting the ball inserted between the inner and outer races from foreign matter such as dust, air is not generated when the blower is operated. Dust and salty moisture, etc., which enter simultaneously with the introduction, easily enter the bearing housing through the gaps in the through holes of the brackets from which the rotor shaft protrudes, and accumulate in the bearing housing over time. Or enter the ball bearing through a narrow gap between the shield plate of the ball bearing and the inner race surface. As a result, the inner and outer race race surfaces corresponding to the ball bearings may be roughened,
Alternatively, rusting the ball and the inside of the bearing housing, etc., significantly lowering the rotation function of the ball bearing, generating a factor of noise generation, etc., shortening the life of the ball bearing, making it difficult to operate the motor. However, there has been a problem that the reliability of the equipment using the motor is impaired.

The present invention has been made in view of the above-mentioned various problems, by closing a through-hole of a bracket from which a rotor shaft protrudes with a horn-shaped closure while the rotor shaft is rotatably inserted. It is another object of the present invention to provide a bearing device for an electric motor, in which air containing dust, salt, and the like can be satisfactorily improved to enter a bearing housing and a ball bearing, and the function of the ball bearing can be surely improved.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a pair of rotors mounted on a rotor shaft, and a pair of stators which sandwich a stator core disposed opposite to the rotor from both sides and form a bearing housing at a center position. A bracket and ball bearings attached to both ends of the rotor shaft were provided.The rotor was rotatably inserted into the stator core, and ball bearings at both ends of the rotor shaft were fitted into bearing housings from both sides thereof. A pair of brackets that rotatably support the rotor in this state are mounted on a stator core with the rotor shaft protruding from a through hole of one bracket, and the rotor shaft is inserted through the motor. A barrel-shaped closed cylinder formed by forming the distal end of the cylindrical portion into a small diameter and entering the bearing housing through the through hole of the bracket into a large-diameter flat plate portion, and rotating it to the cylindrical portion at the distal end The child shaft is inserted rotatably. The proximal end and sandwiched between the back wall and the ball bearings of the bearing housing, characterized in that so as to seal the through hole of the bracket.

In the present invention, the closing cylinder is formed by injection-molding a member made of rubber and synthetic resin, which is excellent in heat resistance, lubrication resistance and abrasion resistance, in a horn shape by injection molding means. Features.

Further, in the bugle-shaped closing cylinder, one or more protruding steps are formed on the inner peripheral surface of the small-diameter cylindrical tip through which the rotor shaft is inserted so as to be able to slide on the rotor shaft. It is characterized by the following.

According to the present invention, the through hole of the bracket from which the rotor shaft protrudes is formed so that the distal end through which the rotor shaft is inserted has a small cylindrical shape, and the base end is sandwiched between the bearing housing and the ball bearing. With a large-diameter flat-shaped horn-shaped closed cylinder,
Since it is sealed so as not to hinder the rotation of the rotor,
During operation of the electric motor, the intrusion of dusty or salty air from the through-hole of the bracket from which the rotor shaft protrudes can be well blocked by the sealing cylinder, so that the life of the ball bearing is reduced due to intrusion of dust and the like. It is possible to surely solve the problem of lowering, and the electric motor can be driven in a stable state for a long time.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4 in which the present invention is applied to, for example, an electric motor used for a blower. FIG. 1 is a cutaway view of a main part of a blower generally used in the related art. In FIG. 1, reference numeral 1 denotes, for example, a shading coil type electric motor, and the electric motor 1 is wound with a coil (not shown). A stator core 3 having a coil bobbin 2 mounted on one side, and a rotor 4 rotatably inserted into an insertion hole provided on the other side of the stator core 3
And brackets 6, 6 a provided with ball bearings 5, 5 a rotatably supporting a rotor shaft 4 a axially mounted on the rotor 4 and mounted on the stator core 3.

The electric motor 1 is provided with, for example, a blower 7 for blowing air to a burner of a hot water supply device (not shown) or discharging combustion gas. As shown in FIG. 1, the blower means 7 includes turbofans 8, 9 disposed in two stages on a rotor shaft 4a, and first and second fan covers 10 for individually accommodating the turbofans 8, 9 respectively. , 11 are schematically configured.

The blowing means 7 has a bottom plate 12
Is fastened using a nut to a mounting bolt (not shown) screwed to the stator core 3 side, and then the first turbofan 8 is fixed to the rotor shaft 4a, and then the first turbofan 8 is circulated from above. The first fan cover 10 having the hole 13 opened at the center position is fixed to the bottom plate 12 by screws or the like. Also, the rotor shaft 4 protruding from the flow hole 13 of the first fan cover 10 is provided.
Attach the second turbo fan 9 to the end of a, and then,
A second fan cover 11 having an inlet 14 opened at a center position is fixed on the first fan cover 10 by screws.
The blower A is constructed by integrally connecting and fixing the blower means 7 and the electric motor 1 via the bottom plate 12. In addition, 15 shown in FIG. 1 is a discharge port provided in the bottom plate 12.

[0013] In FIGS. 1 and 2, 16 is blocked tube to block the through hole a ₁ of the bracket 6 drilled through holes a ₁ rotor shaft 4a protrudes, this blockade tube 16, FIG. 2, As shown in FIG. 3, a small-diameter cylindrical portion 16a is formed at the end where the rotor shaft 4a is inserted, and a large-diameter flat portion 16b is formed at a portion opposite to the small-diameter cylindrical portion 16a. Thus, the entire shape is formed in a trumpet shape.

When the horn-shaped closed cylinder 16 is formed, a synthetic resin, for example, polytetrafluoroethylene, which is excellent in heat resistance, circulation resistance and abrasion resistance, and has high elasticity, is well known in the art. It is formed by injection molding using molding means. When the sealing cylinder 16 is injection-molded, for example, as shown in FIG. 4, a cylindrical projection 17a projecting upward to form a cylindrical portion 16a of the sealing cylinder 16, and the projection 17a Is formed in a tapered shape, and the flat portion 16 is connected to the tapered portion 16c.
convex mold 17 having a flat surface 17b for forming
And a recess provided so as to be fitted and held in the projection mold 17 by providing a fitting hole 18c for fitting the projection 17a in a state of being recessed by a dimension corresponding to the thickness dimension of the sealing cylinder 16. A mold 18 is used.

In the injection molding of the sealing cylinder 16, a concave mold 18 is fitted on the convex mold 17, and a hollow is formed in the concave mold 18 so as to be recessed to form the sealing cylinder 16. Department 18
From the material supply hole 18b communicating with a, a synthetic resin pellet for molding the sealing cylinder 16 by a predetermined injection molding means (not shown) is removed by a predetermined pressure using the injection molding means (not shown). The horn-shaped closure tube 16 is formed by injection molding by injection molding in the location 18a.

Next, a case where the sealing cylinder 16 formed by the injection molding means is attached to the bracket 6 will be described. As shown in FIG. 2, a small-diameter cylindrical portion is formed through a through hole a ₁ of a rotor shaft 4 a in which the sealing cylinder 16 is bored in a back wall of a bearing housing a of a bracket 6 beforehand. to protrude 16a, and the bearing housing a a large-diameter flat portion 16b on the opposite side in a state to close the through hole a ₁
Abut against the back wall.

Thereafter, the rotor 4 with the ball bearings 5 and 5a mounted at predetermined positions is inserted into the rotor insertion hole 3a of the stator core 3, and then the brackets 6 and 6a are removed from both sides of the rotor shaft 4a. The fitting 6, the bracket 6 has the rotor shaft 4a protruding from the cylindrical portion 16a of the sealing cylinder 16 protruding from the bearing housing a, and the ball bearing 5 is fitted to the bearing housing a. The other bracket 6a is the rotor 6a. The ball bearing 5a is fitted to the bearing housing without projecting the shaft 4a. After the ball bearings 5 and 5a are fitted into the bearing housings of the brackets 6 and 6a, the motor 1 is rotated by tightening both brackets 6 and 6a to the stator core 3 using a fastening bolt (not shown). The assembly is completed in a state where the roller 4 is rotatably supported by the ball bearings 5 and 5a.

When the assembly of the electric motor 1 is completed, the rotor shaft 4
The bracket 6 side a is protruded, as shown in Figure 2, the rotor shaft 4 trumpet-shaped sealed tube 16 is protruded from the through hole a ₁
a is protruded from the cylindrical portion 16a in a state in which the cylindrical portion 16a is rotatably slidably contacted with the cylindrical portion 16a, and the flat portion 16b is a bearing housing a.
Is firmly held between the back wall and the outer ring of the ball bearing 5, the sealing tube 16 is reliably prevented from being pulled out from the through hole a ₁ of the bracket 6.

As a result, the through hole a ₁ of the bracket 6
Although the rotor shaft 4a protrudes outward, as shown in FIG. 2, the rotor shaft 4a is closed by a tapered portion (curved portion) 16c located between the cylindrical portion 16a and the flat portion 16b, and the bearing is closed. The space between the housing a and the outside can be completely shielded. When the assembling of the electric motor 1 is completed, the electric motor 1 and the blower means 7 are integrally connected and fixed using mounting bolts and nuts (not shown) to form, for example, a blower A. In addition,
In FIG. 1, reference numeral 20 denotes, for example, a rubber ring that closes a gap between the bracket 6 and the bottom plate 12.

Next, the operation will be described. When current is supplied to a coil (not shown) wound around the coil bobbin 2 of the electric motor 1 to rotate the rotor 4, the first
The second turbo fans 8 and 9 rotate, and supply the outside air to the blowing means 7.
The air is sucked from a suction port 14 provided in the second fan cover 11, and the sucked outside air is pressure-fed in the blowing means 7, while passing from a discharge port 15 provided in the bottom plate 12 through a flow hole 13 through a feeding pipe (not shown). The outside air is pressure-fed to, for example, a burner of a water heater (not shown). When the outside air is pressure-fed in the blowing means 7, the bottom plate 12 of the blowing means 7 has a mounting hole 12 a provided on the outer periphery of the bearing housing a of the bracket 6 of the electric motor 1.
Since the airtight sealing is performed so that no gap is formed by the zero, the outside air does not leak to the outside at all, and the outside air can be satisfactorily pumped and fed to the burner portion of the water heater.

When foreign matter such as snow or dust flows into the outside air during the feeding and feeding of the outside air, or when the outside air itself contains salt (the blower A is generally installed outdoors). , And these foreign substances and salts are not
Then, the air flows into the blowing means 7 and is supplied from the discharge port 15 to the burner together with the outside air. However, there is no particular problem if all the foreign matter and the like flowing into the blowing means 7 is discharged from the discharge port 15, but the outside air is pressure-fed by the blowing means 7 by the turbo fans 9, 8, and a part of the air is fed during the pressure-fed. The outside air tends to flow out of the mounting hole 12a of the bottom plate 12 to the outside.

However, since the mounting hole 12a is surrounded by the ring 20, it is difficult for the outside air to flow out of the mounting hole 20, and the through-hole a _{1 of the} bracket 6 from which the rotor shaft 4a of the electric motor 1 projects as it is. Trying to break into it. On the other hand, the through hole a _{1 of the} bracket 6
As shown in FIG. 2, since the rotor shaft 4 a is protruded and completely closed by a synthetic resin sealing cylinder 16, the outside air pressure-fed near the mounting hole 12 a does not although attempting to break the tapered portion 16c of the tube 16 from the pressing to the through-holes a ₁ in the bearing housing a, since blockade tube 16 is formed of a material excellent in elasticity, the tapered portion by the outside air of the wind pressure Although 16c is curved, outside air is guided along the curved surface in the radial direction of the tapered portion 16c as it is, guided to the discharge port 15 side, and discharged from the discharge port 15.

Therefore, dust and the like that enter with the outside air are blocked by the sealing cylinder 16 and pass through the through hole a ₁ to the bearing housing a.
Can be reliably prevented from entering. As a result, the environmental resistance to the bearing housing a and the ball bearing 5 can be maintained well, the operation of the electric motor 1 can be maintained smoothly for a long time, and the reliability of the electric motor 1 can be significantly improved.

On the other hand, a rotor shaft 4a projecting outwardly from the through hole a ₁ of the bracket 6 via the cylindrical portion 16a of the blockade tube 16 is always wear resistance upon entering the outside air of the mounting hole 12a The sliding motion is continued by slidingly contacting the cylindrical portion 16a of the sealing cylinder 16 which is excellent in the above. It is because the closure tube 16 itself is rich in wear resistance and excellent in elasticity,
Even if the outside air is pressure-fed to the mounting hole 12a, it can withstand the wind pressure and is in close contact with the rotor shaft 4a to prevent the outside air from entering the cylindrical portion 16a from which the rotor shaft 4a protrudes. By using the abrasion-resistant synthetic resin, there is no hindrance to the rotational movement of the rotor shaft 4a, and the rotor 4 is smoothly and smoothly rotated without hindering the operation of the electric motor 1. Intrusion of dust and the like can be reliably prevented.

Although the present invention has been described with reference to the example in which the rotor shaft 4a is projected from the cylindrical portion 16a of the closing cylinder 16 through which the rotor shaft 4a is inserted in a state of surface contact, the present invention is not limited to this. One or more ridges are provided around the inside of the cylindrical portion 16a, or grease is filled between the plurality of ridges, and these ridges are brought into direct sliding contact with the rotor shaft 4a, or Of course, the grease oil film may be used to prevent outside air from entering the bearing housing a. In addition, the present invention can be realized even if the sealing cylinder 16 is formed by bending a single resin flat plate into a horn shape instead of being formed by injection molding.

[0026]

As described above, according to the present invention, the through hole of the bracket from which the rotor shaft protrudes is formed into a small-diameter cylindrical tip at the end through which the rotor shaft is inserted, and the base ends are the bearing housing and the ball. The rotor shaft protrudes during operation of the electric motor because it is closed by a large-diameter flat-shaped horn-shaped closing cylinder to be sandwiched between bearings so as not to hinder the rotation of the rotor. Since the intrusion of air containing dust or salt from the through hole of the bracket can be satisfactorily shielded by the sealing cylinder, it is possible to reliably solve the problem that the life of the ball bearing is reduced due to the intrusion of dust and the like. Thus, the electric motor can be driven in a stable state for a long time.

The horn-shaped closed cylinder can be easily formed by injection molding or bending using a synthetic resin having excellent wear resistance, lubrication resistance and heat resistance. At the same time, when mounting the motor, the cylindrical part protrudes out of the bracket using the through hole from the bearing housing of the bracket when assembling the motor, and the flat part at the base end fits the ball bearing to the bearing housing. By doing so, the electric motor can be easily held between the bearing housings, so that the assembling work of the electric motor can be performed easily and economically.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of a main part of a blower showing a use state of an electric motor provided with a bearing device of the present invention.

FIG. 2 is a longitudinal sectional view showing the bearing device of the present invention.

FIG. 3 is a perspective view of a closing cylinder.

FIG. 4 is an explanatory view showing an example of a production state of the closing cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 4 Rotor 4a Rotor shaft 5,5a Ball bearing 6,6a Bracket 16 Sealing cylinder 16a Cylindrical part 16b Flat part 16c Tapered part

Claims (3)

[Claims] 1. A pair of brackets having a rotor attached to a rotor shaft, a stator core opposed to the rotor and sandwiched from both sides, and a bearing housing formed at a center position.
Ball bearings mounted on both ends of a rotor shaft, wherein the rotor is rotatably inserted into a stator core, and ball bearings at both ends of the rotor shaft are fitted into bearing housings from both sides thereof. In a motor configured by attaching a pair of brackets rotatably supporting a rotor to a stator core with a rotor shaft protruding from a through hole of one of the brackets, a cylindrical portion through which the rotor shaft is inserted The end of the bracket has a small diameter, and the base end that enters the bearing housing through the through hole of the bracket is a large-diameter flat part. A bearing device for an electric motor, wherein the bearing device is rotatably inserted and a base end thereof is sandwiched between a back wall of a bearing housing and a ball bearing to block a through hole of a bracket. 2. The closure tube is formed by injection-molding a member made of rubber or synthetic resin, which is excellent in heat resistance, lubrication resistance and abrasion resistance, into a horn shape by injection molding means. The bearing device for an electric motor according to claim 1. 3. The horn-shaped closing cylinder has one or more protruding steps formed on the inner peripheral surface of a small-diameter cylindrical tip through which the rotor shaft is inserted so as to be able to slide on the rotor shaft. 3. The bearing device for an electric motor according to claim 2, wherein: