JPH0925930A - Motor bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain any radial play of the shaft of a motor bearing by using a slant thrust bearing. SOLUTION: One end 7a of a shaft 7 supported on a bearing 5 is formed in a curved surface shape, while a thrust bearing 18 for receiving the one end 7a is constituted with a certain inclination with its contact thereto. The thrust bearing 18 is a bearing formed of sintered oil containing alloy and its surface making contact with the one end 7a is given inclination, while its other surface is tormed in a flat surface so as to be fitted to the inner bottom part of a bearing case 9. Therefore, when the one end 7a of the shaft makes contact with the thrust bearing 18 with a certain load, loads in divided x direction and y direction equivalent to the angles of inclination so that the shaft may be deviated in direction of the inclined surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor bearing structure, and more particularly to a structure of a thrust bearing for biasing a motor shaft.

[0002]

2. Description of the Related Art Sintered oil-impregnated bearings are often used as radial bearings that support motor shafts. Although this sintered oil-impregnated bearing can withstand long-term use, it is manufactured with a tolerance that causes a slight gap between the bearing inner diameter and the motor shaft outer diameter due to manufacturing restrictions. On the other hand, in the motor device, when the load rotates, as a result of centrifugal force generated by the rotation, the force of the load on the shaft in the thrust direction slightly changes, and the shaft of the motor may irregularly hit the radial bearing. For example, when the load is an impeller (blades), a force in the thrust direction is applied to the motor shaft due to the subtle difference in the flow of fluid that the impeller agitates.
The motor not only vibrates but also generates mechanical noise, shortening the life of the device.

For this reason, there is a motor device in which a lateral pressure is applied to the motor shaft in advance so as to bias the shaft to restrict the above-mentioned movement.

FIG. 4 shows an example of such a device added to the outside of the motor. In the figure, a bearing 21 made of a sintered alloy is fitted in the outer shell of the motor 1 and the center of the shield case 2, and the shaft 7 is supported by the bearing 21. The load 22 is fixed to one end of the shaft extending in the extending direction of the bearing 21. There is a lateral pressure member 20 provided to apply lateral pressure to the shaft 7 in the arrow p direction substantially in the middle of the bearing 21 and the rotating end portion. The collar 25 is made of resin or the like and is formed into a disk shape, and has a through hole 27 formed in the center thereof so that the shaft 7 can be rotatably inserted therein. Lateral pressure member 2
One end of a leaf spring 23 that fires in the horizontal direction, which constitutes 0, is screwed and fixed to the shield case 2 with a screw 30. In addition, in the vicinity of the screwed portion, a protruding portion 29 formed in a protruding shape from the shield case 2 for positioning the leaf spring.
Then, there is a fitting hole 28 formed in the leaf spring 23. An opening 24 is formed at the other end of the leaf spring fixed in this way, and a rib 26 annularly surrounding the circumference of the collar 25 that is inserted through the shaft 7 of the motor is engaged with the opening 24. As a result, the lateral pressure is applied to the shaft 7 of the motor.

The side pressure member 20 has a through hole 27 in the collar 25 prior to fixing the load 22 to the shaft end of the motor.
The shaft 7 is inserted through the shaft 7, and at the same time, the opening 24 at the other end of the leaf spring 23 is engaged with the rib 26 of the collar 25 for assembly.

The shaft 7 receives an appropriate lateral pressure by which the through hole 27 of the collar 25 is biased in a certain direction by the elastic force of the leaf spring 23. As a result, the shaft of the motor has a through hole 2 of the collar.
By sliding on the inner surface of 7, the load 22 rotates while receiving a biasing force in a certain direction. When the load 22 rotates, even if the load 22 rotates in the direction in which the scraping motion occurs, the scraping motion is blocked by a predetermined lateral pressure, so that an abnormal current increase in the motor and a rattling noise generated from the bearing on the motor side are almost eliminated.

FIG. 5 is a perspective view of another example of the lateral pressure member that gives this biasing force. In the figure, the lateral pressure member 20 is a member standing on the shield case 2 as in the case shown in FIG. 4, and applies lateral pressure in the direction of arrow p. The collar 33 is formed of, for example, a resin member having a small coefficient of friction such as Teflon, and the shaft 7 extending from the bearing 21 made of a sintered alloy of the motor is inserted into the through hole 27 formed in the central portion. A spring 32 that contracts in the arrow p direction from a hook erected on the shield case 2 (not shown) locks the one end locking portion 34 of the collar. There is a position adjusting plate 36 that defines the height position of the collar in a direction facing the spring 32 around the shaft 7, and the other end of the collar is slidably engaged with the opening 37. Therefore, similar to the side pressure member shown in FIG. 4, the side force is applied to the shaft 7 of the motor by the contracting force of the spring 32.

FIG. 6 is a view of another mechanism for applying a biasing force to the shaft, and is a sectional view when it is applied to a small DC motor. In the figure, the motor 1 is provided with a stator case 3 in a bowl-shaped shield case 2 forming an outer shell, a bearing 21 made of a sintered oil-impregnated alloy in the center of the stator case 3 on the upper side in the figure, and a commutator 10 side. The bearing 5 is provided in the bearing holding portion 9 and the shaft 7 is supported by the bearing 21 and the bearing 5 in the radial direction. A thrust washer 12 is in contact with the lower end of the shaft 7, and the thrust washer 12 receives the load of the rotor. The magnet 4 is arranged on the inner peripheral surface of the stator case 3 formed in an annular shape to form a stator. The magnet 4 is composed of strongly magnetized portions 4-1 and 4-2, one of which is strongly magnetized at one of the upper and lower sides thereof, and the strongly magnetized portions 4-1 and 4-2 have an upper and lower relationship on the opposing surface with the shaft 7 as a boundary. They are arranged so that they are interchanged and face each other. A core 6 around which a coil 8 is wound is arranged with a slight gap in the magnet 4, and the core 6 is fixed to a shaft 7. Further, a commutator 10 is provided on the shaft 7, and a rotor is formed by a structure in which power is supplied to the coil 8 via the commutator 10.

When a predetermined current is applied from the circuit 11 to this motor, the coil 8 is fed through the commutator 10 to magnetize the core 6, and the shaft 7 rotates due to the interaction with the magnet 4. Is. At that time, as described above, the magnet 4 is constituted by the strongly magnetized portions 4-1 and 4-2, one of which is strongly magnetized at the upper and lower sides thereof, and the strongly magnetized portions 4-1 and 4-1 are provided on the opposing surfaces with the shaft 7 as a boundary. Since 4-2 is arranged so as to face each other by exchanging the vertical relationship,
Since the direction of the magnetic force received by one of the salient poles of the plurality of cores is different from the direction of the magnetic force received by one of the salient poles of the other cores, the core 6 is attracted in the direction of arrow q, and a force that tilts in the direction of arrow r receive. As a result, the shaft 7 is biased and exhibits the same effect as the lateral pressure shown in FIGS. 4 and 5. At this time, since the effective magnetic flux of the magnet 4 is smaller than the size of the magnet, the outer shape of the motor having the same output is large.

[0010]

There is a gap between the inner peripheral surface of the central hole of the sintered oil-impregnated bearing and the outer peripheral surface of the shaft, and even if the shaft is subjected to the motion of randomly hitting the bearing by the load, the radial It is an object of the present invention to provide a thrust bearing that can apply lateral pressure with a simple structure in order to realize a motor that does not cause play.

[0011]

According to a first aspect of the present invention, there is provided a bearing device for a motor according to a first aspect of the present invention, in which a rotary shaft is inserted through a central hole and supported in a radial direction. In a motor bearing device having a thrust bearing in contact therewith and receiving a load in the thrust direction of the rotor, the shaft contact surface of the thrust bearing is not orthogonal to the extension direction of the central hole of the slide bearing. It is characterized by being inclined to.

[0012]

A thrust bearing having a predetermined amount of inclined contact surface is provided on one end side of the shaft which is a rotating shaft, and when the curved shaft end abuts on the thrust bearing, the shaft is biased in a certain direction by the thrust bearing. Receive the force you did. This force acts as a force to tilt the shaft in a certain direction, and therefore exerts the same effect as applying a lateral pressure. As a result, it is possible to eliminate the movement of the shaft that randomly hits the bearing, and suppress the vibration and mechanical noise generated by this movement.

[0013]

1 is a sectional view showing an embodiment of a motor according to the present invention. (A) is a sectional view of the entire motor, (b) is a detailed view of its essential parts, and (c) is a main structure. FIG. In the figure, components having the same functions and actions as those in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 1 (b), one end 7a of the shaft 7, which is axially supported by the slide bearing 5, has an end face formed in a curved shape, for example, a hemispherical shape. One end 7a of this shaft 7
The thrust bearing 18 for receiving the shaft is constructed with an inclination having a contact surface with the shaft, and one end 7a of the shaft 7 is in contact with the inclined shaft contact surface 18-1.

As shown in FIG. 1C, the thrust bearing 1
The shaft contact surface 18-1 of No. 8 is inclined by a predetermined angle θ so as not to be orthogonal to the extending direction H of the central hole 5-1 of the slide bearing 5. The predetermined angle θ here is set so as to be non-parallel to the virtual plane L orthogonal to the extension direction H.
It is preferable to incline at an angle of 45 °. This is because if the inclination angle is less than 5 °, the shaft 7 cannot be sufficiently biased, and conversely if the inclination angle is greater than 45 °, the load of the rotor cannot be sufficiently supported.

The thrust bearing 18 is, for example, a bearing formed of a sintered alloy, or a hard resin or metal body coated with a sliding material such as Teflon. The back surface 18-2 of the shaft contact surface 18-1 is formed substantially parallel to the virtual surface L, and is fitted to the bearing holding portion 9 provided on the stator side together with the outer peripheral surface 18-3.

When one end 7a of the shaft abuts the thrust bearing 18 with a certain load, it receives the divided loads in the x and y directions corresponding to the inclination angle and is biased in the resultant force direction z. Reference numeral 16 denotes a spring that applies a load to the thrust bearing 18 and biases the thrust bearing 18 in the direction of the thrust bearing 18. The spring 16 is composed of a leaf spring or the like and always applies a predetermined load to the thrust bearing 18. When there is a load above the plane of the drawing, the thrust bearing 18 is loaded by the weight of the load itself or the rotor itself, but when there is no load above the plane of the paper, the thrust bearing 18 receives a predetermined load only by the weight of the rotor. There is a risk that it will not be installed and it will be installed. Therefore, the spring 16 is not required when the weight of the rotor is within a predetermined range, and can be freely removed depending on the usage state of the motor.

Depending on the structure of the motor, in addition to the structure in which pressure is applied to the thrust bearing 18 by the weight of the rotor, the center of the magnetic pole of the armature and the center of the magnetic field of the magnetic field are offset in the thrust direction. Although there is a motor having a structure in which the rotor is sucked and pressure is applied to the thrust bearing 18 side, the bearing device of the present invention can be applied to any structure of the motor.

FIG. 2 is a view showing another structure of the thrust bearing used for the purpose of the present invention in place of the thrust bearing 18 shown in FIG. 1. The thrust washer 19 as the thrust bearing is made of a metal plate and has a bowl shape. The thrust bearing 15 is provided on the both sides of the bearing case 9 in a slanted manner, and the thrust bearing is constructed. Therefore, the one end 7a formed on the curved surface of the shaft 7 axially supported by the slide bearing 5 is
In this state, the thrust washer 19 leans against the extension direction of the central hole of the slide bearing 5 and receives the load. Although the thrust washer 19 is made of a metal plate in the above description, a member made of resin or a member made by coating a metal plate with resin such as Teflon may be used.

FIG. 3 is a diagram showing a case where the thrust bearing having the inclination angle of this structure is applied to another motor. The motor shown in the figure is used in an FDD device or the like. In the figure, an opening 31 for mounting and fixing a thrust receiving plate 17 as a thrust bearing on a substrate 14 that supports a motor.
Is provided, and the upright portion 13 is formed in a part of the peripheral portion of the opening. The erected portion 13 is erected at the same time when the substrate 14 is plastically processed. At this time, the height of the standing portion 13 can be freely set in association with the diameter of the thrust receiving plate 17. This means that the angle θ formed by the axis of the shaft 7-1 and the angle θ formed by the vertical line of the bottom surface of the thrust receiving plate 17 when the shaft is flatly inserted into the central hole of the slide bearing 5 is It means that it can be set freely by changing the height of. In addition,
Also in this embodiment, with respect to the extension direction of the central hole of the slide bearing 5 which supports the shaft 7-1 in the radial direction,
The shaft contact surface 17-1 of the thrust receiving plate 17 is inclined so as not to intersect at right angles.

One end 7-1a of the shaft is the thrust receiving plate 1
When abutting against the shaft 7, a horizontal component force of the weight of the rotor loaded on the shaft is applied, and one end 7-1a of the shaft has a bottom surface of the thrust receiving plate and a sliding bearing 5 is biased downward. Is.

As described above, the present invention is applicable to a motor that receives a thrust load in a motor that receives a load of a rotor and a motor that can apply a predetermined load to a thrust receiving plate even if the load of the rotor is outside the predetermined range. Can be adapted.

[0023]

As described above, according to the present invention, since the thrust bearing having the inclined shaft contacting surface capable of biasing the motor shaft is inclined, one end of the shaft is displaced in the thrust direction and the lateral pressure is applied to the shaft. It can give the same effect as, and suppress the radial play of the shaft. As a result, vibration and mechanical noise are suppressed, and the noise can be reduced without affecting the others.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a configuration of a thrust bearing of the present invention.

FIG. 3 is a diagram showing a case where the thrust bearing having an inclination angle of the present invention is applied to another type of motor.

FIG. 4 is a diagram showing a conventional example in which a lateral pressure is applied.

FIG. 5 is a diagram showing another conventional example in which lateral pressure is applied.

FIG. 6 is a diagram showing yet another conventional example in which lateral pressure is applied.

[Explanation of symbols]

 5 Sliding bearing 7 Shaft (rotating shaft) 7a One end of shaft 18 Trust bearing 18-1 Shaft abutment surface H Extension direction of central hole of sliding bearing

Claims (1)

[Claims] 1. A slide bearing for supporting a rotary shaft in a radial direction by inserting the rotary shaft into the central hole, and a thrust bearing for abutting against a curved end of the rotary shaft to receive a load in the thrust direction of the rotor. In the motor bearing device, the shaft contact surface of the thrust bearing is inclined so as not to be orthogonal to the extending direction of the central hole of the slide bearing.