JPH10127000A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water entered from the outside from entering a bearing along the shaft of a rotor by a method wherein an annular water scattering wall is provided on the outer circumference of the shaft between the rotor and the bearing so as to face the rotor. SOLUTION: An annular water scattering wall 22 is provided on the outer circumference of a shaft 6 between a rotor 5 and a bearing 7 so as to face the rotor 5. Water entered from the outside and flowing along the shaft 6 toward the bearing 7 enters the annular groove 21 of the shaft 6 on its way and flows along a tapered surface and hits the water scattering wall 22 perpendicular to the center axis of the shaft 6, so that the waterflow toward the bearing 7 is blocked. The water begins rotating with the shaft 6 by the friction between the water scattering wall 22 and the water, and is scattered radially from the water scattering wall 22 by a centrifugal force. With this constitution, the water is prevented from reaching the bearing 7 along the shaft 6 and the deterioration of the bearing 7 which is caused by the entrance of water can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electric motor,
In particular, the present invention relates to an electric motor that prevents water that has entered from the outside from traveling along a shaft of a rotor and entering a bearing.

[0002]

2. Description of the Related Art The structure of a conventional induction motor is shown in FIG.
End brackets 2 and 3 are fixed to both ends of a cylindrical frame 1, respectively. A stator 4 composed of a laminate of a number of ring-shaped members is accommodated in the frame 1,
A cylindrical rotor 5 is inserted inside the stator 4. A shaft 6 is shrink-fitted at the center of the rotor 5, and the shaft 6 is rotatably supported by bearings 7 and 8 fixed to end brackets 2 and 3, respectively. A coil winding 10 for forming an induction magnetic field is wound around the stator 4.
A part of 0 protrudes outward from both ends of the stator 4.

Although not shown, a plurality of axial slot bars are embedded in the rotor 5, and when an electric current is applied to the coil winding 10 to form an induction magnetic field, the slot bar receives a force from the induction magnetic field, This causes the rotor 5 to rotate. At this time, heat is generated in the coil winding 10 through which the current flows, so that the temperature inside the motor, particularly near the coil winding 10 protruding outward from both ends of the stator 4 is likely to become high. Therefore, openings 11 and 12 for heat dissipation are formed in the frame 1 and the end bracket 2, respectively, so as to improve the ventilation between the inside and outside of the electric motor to dissipate heat.

[0004]

However, since the openings 11 and 12 for heat radiation are provided, water may enter the motor from the outside through the openings 11 and 12. That is, depending on the installation location of the electric motor, rainwater may enter the inside, or if the electric motor is mounted on, for example, a forklift, water splashed from a puddle on the ground during traveling of the forklift may enter the electric motor. The water that has entered the motor is the shaft 6 of the rotor 5
There is a possibility that it may adhere to the top and travel along the shaft 6 to reach the bearing 7 or 8. Thus, the bearing 7
Or, when water enters the bearing 8, the life of the bearing is remarkably shortened, and the bearing must be replaced.

The present invention has been made to solve such a problem, and provides an electric motor capable of preventing water that has entered from the outside from entering a bearing along a rotor shaft. The purpose is to:

[0006]

According to the present invention, there is provided an electric motor in which a shaft provided on a rotor is rotatably supported via a bearing. It is provided with an annular water-scattering wall formed so as to be opposed. The water scattering wall can be formed from the inner surface of an annular groove formed on the outer periphery of the shaft, or the side surface of a ring member fitted on the outer periphery of the shaft.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an electric motor according to an embodiment of the present invention. End brackets 2 and 3 are fixed to both ends of a cylindrical frame 1, respectively. A stator 4 composed of a laminate of a number of ring-shaped members is housed inside the frame 1, and a cylindrical rotor 5 having a shaft 6 shrink-fitted at the center is inserted into the stator 4. The shaft 6 is rotatably supported by bearings 7 and 8 fixed to end brackets 2 and 3, respectively. A coil winding 10 for forming an induction magnetic field is wound around the stator 4, and a part of the coil winding 10 protrudes outward from both ends of the stator 4. Also, the frame 1 and the end bracket 2
Heat-dissipating openings 11 and 1 for cooling the inside of the motor
2 are formed. Note that an opening for heat dissipation can be formed in the end bracket 3.

An annular groove 21 is formed on the outer periphery of the shaft 6 located between the rotor 5 and the bearings 7 and 8. As shown in FIG. 2, for example, the annular groove 21 provided between the rotor 5 and the bearing 7 has a tapered shape such that the diameter increases toward the rotor 5. An inner side surface on the side of the side 7 forms an annular water scattering wall portion 22 that is perpendicular to the central axis of the shaft 6 and faces the rotor 5. Similarly, the annular groove 21 provided between the rotor 5 and the bearing 8 also has a tapered shape such that the diameter increases toward the rotor 5, and the inner surface of the annular groove 21 on the bearing 8 side is the shaft 6.
And a ring-shaped water-dispersing wall portion 22 which is perpendicular to the central axis of the water-dispersing member and faces the rotor 5.

Next, the operation of the electric motor according to this embodiment will be described. Although not shown, a plurality of axial slot bars are embedded in the rotor 5, and the coil winding 1
When an electric current is passed through the induction magnetic field to generate an induction magnetic field, the slot bar receives a force from the induction magnetic field, and the rotor 5 rotates together with the shaft 6. Here, when water enters the motor from the outside through the openings 11 and 12 formed in the frame 1 and the end bracket 2 for heat dissipation and adheres to the shaft 6, the water may be caused by vibrations and the like due to operation of the motor. This water may travel on the shaft 6 to the bearing 7 or 8. However, the water flowing on the shaft 6 toward the bearing 7 or 8 enters the annular groove 21 on the way, contacts the water scattering wall 22 perpendicular to the central axis of the shaft 6 along the tapered surface, This blocks the movement in the bearing 7 or 8 direction. This water is
Further, it starts rotating together with the shaft 6 due to the frictional force between the water scattering wall 22 and the water scattering wall 22 due to the centrifugal force.
Sprays radially from.

Therefore, it is possible to prevent the water from reaching the bearings 7 and 8 along the shaft 6 and prevent the bearings 7 and 8 from being deteriorated due to the intrusion of water.

Incidentally, as shown in FIG.
If a plurality of annular grooves 23 and 24 are formed in the outer peripheral portion of the
And 8 can be more reliably prevented from entering the water.

Also, as shown in FIG.
The ring member 27 is fitted to the outer peripheral portion of the
7, the water scattering wall portion 28 protruding outward from the outer peripheral portion of the shaft 6 can also be formed. The ring member 27 has a tapered surface whose diameter increases toward the rotor 5 and an annular side surface perpendicular to the central axis of the shaft 6 and facing the rotor 5. A water scattering wall 28 is formed. In this way, even with the water scattering wall portion 28 protruding from the outer peripheral portion of the shaft 6, the water traveling on the shaft 6 toward the bearing 7 or 8 abuts against the water scattering wall portion 28, and the water scattering wall portion 28. Rotating with the shaft 6 due to the frictional force between them and receiving centrifugal force, they scatter radially from the water scattering wall 28. Therefore, intrusion of water into the bearings 7 and 8 can be prevented.

Although not shown, a plurality of ring members 2
7 can be fitted to the shaft 6 and water scattering walls 28 can be arranged in multiple stages between the rotor 5 and the bearings 7 or 8.

The present invention can be applied not only to the induction motor shown in FIG. 1 but also to various types of electric motors to similarly prevent water from entering the bearings.

[0015]

As described above, the electric motor according to the present invention can prevent water from entering the bearing with a simple structure at low cost. For this reason, the electric motor of the present invention can be used in an environment where water is easily splashed, for example, a forklift using marine products.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electric motor according to an embodiment of the present invention.

FIG. 2 is an enlarged front view showing a shaft of the electric motor according to the embodiment.

FIG. 3 is an enlarged front view showing a shaft of a motor according to another embodiment.

FIG. 4 is an enlarged front view showing a shaft of a motor according to still another embodiment.

FIG. 5 is a sectional view showing a conventional electric motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 2, 3 End bracket 4 Stator 5 Rotor 6 Shaft 7, 8 Bearing 10 Coil winding 11, 12 Opening 21, 23, 24 Annular groove 22, 25, 26, 28 Water splashing wall 27 Ring member

Claims (3)

[Claims] 1. An electric motor in which a shaft provided on a rotor is rotatably supported via a bearing. An electric motor comprising a wall for use. 2. The electric motor according to claim 1, wherein the water-scattering wall portion includes an inner surface of an annular groove formed on an outer peripheral portion of the shaft. 3. The electric motor according to claim 1, wherein the water-scattering wall comprises a side surface of a ring member fitted to an outer peripheral portion of a shaft.