JPH0730786B2 - Bearing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bearing device using a porous plain bearing.

[Conventional technology]

For small motors used in home appliances and automobile parts,
A bearing device in which a motor shaft is supported by a porous plain bearing is often used.

FIGS. 4 and 5 show a bearing structure in which a motor shaft is vertically supported by using this type of bearing device. In this structure, a porous plain bearing 1 held in upper and lower housings 3 and 3 is used. 2, the motor shaft 4 having the rotor 5 fixed therein is inserted, the washer 6 for thrust bearing and the retaining ring 7 are attached to the motor shaft 4, and the washer 6 on the lower side is attached to the porous slide bearing 1 The motor shaft 4 is supported by the end face of the motor shaft.

Further, an oil impregnated felt 8 for supplying lubricating oil to the bearings is arranged on the outer periphery of the porous plain bearings 1 and 2, and the motor oil 4 on the lower side of each of the bearings 1 and 2 is provided for splashing the lubricating oil. Oil drain washers 12, 12 are installed.

In the above bearing structure, the porous plain bearings 1, 2 are previously prepared.
When the pores of the motor are impregnated with lubricating oil and the motor shaft 4 is rotated, the lubricating oil exudes from the bearings 1 and 2 due to the heat generated by the motor operation and the pumping action between the bearings 1 and 2 and the motor shaft 4, Lubricate the bearing surface.

[Problems to be Solved by the Invention]

By the way, in the above structure, when the lubricating oil flowing out from the porous plain bearings 1 and 2 along the motor shaft 4 is shaken off by the oil washer 12, it scatters and adheres to the housing 3 and propagates through the housing 3. And drip out. Further, also in the sliding portion between the porous plain bearing 1 and the thrust bearing washer 6, the lubricating oil that has exuded to the end surface of the bearing 1 is blown out by the centrifugal force and flows out.

However, since the lubricating oil once leaked in this way does not return to the bearings 1 and 2 again, the oil film is cut off on the bearing surface due to long-term operation, and seizure easily occurs.
Lubricating oil that has flowed out from the upper bearing 2 may enter the motor and cause damage to the motor. In order to deal with the above problem, it is conceivable to enlarge the oil impregnated felt 8 or to provide a mechanism for collecting the scattered lubricating oil, but this causes a problem that the bearing space is expanded and the cost is increased.

Further, in the contact portion between the thrust bearing washer 6 and the bearing 1, when the lubricating oil that has exuded to the bearing end surface flows out and becomes almost unlubricated, the rotational torque increases and wear occurs at each rotation, causing the rotational torque to increase. Becomes unstable, resulting in poor durability. On the other hand, in order to deal with this,
As shown in the figure, use thrust bearings with two washers 6 and 6
In the case where the washers 6 and 6 are slidably contacted with each other, since there is no lubricating oil between the washers 6 and 6, the rotation torque is increased between the washers 6 and 6 in the same manner as in the above case, and durability is improved. It has the drawback of getting worse.

The present invention has been made in view of the above problems, and an object thereof is to provide a bearing device that prevents scattering of lubricating oil by a simple and inexpensive means and realizes high durability.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, a bearing device of the present invention comprises a porous sliding bearing containing lubricating oil and two washers arranged so as to rotate relative to the upper and lower end surfaces of the bearing. On one of the upper and lower end faces of each washer or the facing face of each washer, a dynamic pressure generating groove whose inner pressure is higher than the outer circumference by the relative rotation of both is provided, the upper washer is brought into contact with the upper end face of the bearing, and each washer is made of synthetic resin. It was made of a thin plate.

In the above structure, the thrust load is received by the contact between the upper end face of the porous bearing and the upper washer, and the lubricating oil that has exuded to the upper end face of the bearing is pushed back to the inner peripheral side by the pumping action of the dynamic pressure generating groove. Lubrication is maintained. Further, the lubricating oil flowing out to the lower end face of the bearing is pushed back to the inner peripheral side of the bearing by the action of the power generation groove between the bearing end face and the lower washer, and is prevented from scattering to the outside.

In the case of the structure in which the dynamic pressure generating groove is provided on the end surface of the bearing and the facing surface of the washer in this way, the parallelism between the bearing end surface and the washer becomes a problem. It is necessary to bring the end face and the washer into close contact with each other. In this case, by using a thin plate made of a washer synthetic resin, the washer easily elastically deforms along the bearing end face, so that the bearing end face and the washer can be brought into intimate contact with each other as a whole by the pump action of the dynamic pressure generating groove. A high-pressure oil film can be generated between the bearing end surface and the washer.

In addition, when the washer is made of synthetic resin, the rotating torque at the time of contact can be made smaller than in the case of being made of metal, and the complicated dynamic pressure generating groove can also be formed by integral molding, so the manufacturing cost can be reduced. There are advantages.

When grease containing a thickener is used as the lubricating oil contained in the porous plain bearing, the grease does not flow easily as compared with general lubricating oil and tends to stay on the bearing surface for a long time. It has the effect of further preventing the outflow.

Further, the present invention provides a porous sliding bearing, which is applied to the above-mentioned bearing device, in which a through hole through which a rotary shaft is inserted is provided between end surfaces arranged in parallel, and a lubricating oil is contained inside. A structure having a dynamic pressure generating groove on the end face is adopted.

The lubricating oil contained in the bearing may be grease containing a thickener as described above.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings FIG. 1 to FIG.

This embodiment is applied to the structure for vertically supporting the motor shaft shown in FIG. 4, and FIG. 1 shows only the lower bearing portion thereof.

As shown in the figure, in the bearing device of the embodiment, one washer 6 for the thrust bearing is brought into contact with the upper end surface 1a of the porous plain bearing 1, and the washer 9 for holding the oil is
It is attached to the lower end surface 1b of the bearing 1 with a slight gap. Both washers 6, which are opposed members to the bearing 1,
9 is integrally formed of ultra-high molecular weight polyethylene.

Further, on the upper and lower end surfaces 1a and 1b of the porous plain bearing 1, as shown in FIGS. 2 and 3, dynamic pressure generating grooves 10 and 11 composed of a large number of spiral grooves are formed. The dynamic pressure generating grooves 10 and 11 are formed such that the spiral grooves have a width that narrows from the outer side toward the inner side in the rotation direction of the motor shaft 4, and the bearing 1 and the washers 6 and 9 rotate relative to each other. At this time, the pressure is set to be higher on the inner peripheral side than on the outer peripheral side.

In addition, the porous plain bearing 1 is filled with grease having a thickener concentration of 0.1% by weight or more in the pores therein. This grease is contained by subjecting a semi-solid grease to a homogenizing treatment in which the contained crystal is made into fine particles and uniformly dispersed, and the product is vacuum impregnated into the pores of the bearing 1.

In the embodiment having the above structure, the grease is retained in the pores of the bearing 1 in the stopped state and in the operated state,
The bearing temperature rises with the rotation of the motor shaft 4 and the action of the pump causes leaching on the surface of the bearing 1 for lubrication.

In this case, the grease that has exuded to the surface other than the bearing surface has a higher viscosity than the base oil and is much less likely to flow spontaneously than general lubricating oil, so the amount of the grease that remains on the bearing surface is extremely large, and the outflow is extremely small. To be prevented.

Also, the grease that has exuded on the upper and lower end surfaces 1a, 1b of the bearing 1
Upper and lower end faces 1 with the difficulty of natural flow of grease
The dynamic pressure generating grooves 10 and 11 provided in a and 1b are retained on the end surface of the bearing 1 against the centrifugal force in order to perform a pumping action to constantly push the grease back to the inner peripheral side. Therefore, the grease is prevented from flowing out from the bearing 1 during the operation of the motor, and sufficient grease is present on the bearing surface to maintain a good lubrication state.

Further, since the grease is always retained on the contact surface between the bearing 1 and the thrust bearing washer 6 to maintain the lubrication state, only one washer 6 can sufficiently function as a thrust bearing. Therefore, it is possible to reduce one washer as compared with the conventional structure shown in FIG.

Here, the grease has a higher viscosity than the base oil as described above, but in a portion having a high shear rate such as a load portion of the plain bearing, the grease is lubricated almost in the base oil state. Therefore, even if grease is used as the lubricating oil, the rotational torque does not change and smooth bearing performance is not impaired.

Further, the grease remaining on the surface of the bearing 1 returns to the inside of the bearing 1 again and is reused because the bearing temperature decreases when the operation of the motor is stopped.

In the above example, the dynamic pressure generating groove is formed on the upper and lower end surfaces 1a of the bearing 1,
Although it is provided in 1b, the same effect can be obtained even if it is provided in the thrust bearing washer 6 or the oil holding washer 9.

The shape of the dynamic pressure generating groove is not limited to the spiral groove shown in the figure, and may be a herringbone groove or the like. That is,
Any shape can be used as long as there is a portion where the pressure is higher than the outer circumference and a force that resists the centrifugal force is generated.

Further, the material used for the washers 6 and 9 is not limited to ultra-high molecular weight polyethylene, but a synthetic resin that has a small rotational torque during sliding, can be thinly formed into a sheet, and has excellent mass productivity is used. be able to. This includes
For example, polyetheretherketone (PEEK), which has higher heat resistance than ultra-high molecular weight polyethylene, can be mentioned.
Further, when importance is attached to sliding characteristics and durability, polyimide or the like is preferable.

〔The invention's effect〕

As described above, according to the present invention, the dynamic pressure generating groove is provided between the end surface of the porous plain bearing and the opposing member arranged so as to rotate relative to the end surface, and the action of this groove causes the lubricating oil to remain on the end surface of the bearing. Since the outflow is prevented, the lubrication state of the bearing surface can always be kept good, and the durability of the bearing can be dramatically improved.

In addition, washers are provided facing the upper and lower end surfaces of the bearing, and the outflow of lubricating oil from the upper and lower sides of the bearing is stopped by the dynamic pressure generation groove, so that oil scattering from the bearing can be reliably prevented, and there is a sufficient amount of oil inside the bearing. The amount of lubricating oil can be stably retained for a long period of time.

Furthermore, by using a thin plate made of synthetic resin as the washer to facilitate elastic deformation, the washer and the bearing end surface can be brought into close contact with each other as a whole, so that the pumping action of the dynamic pressure generation groove causes a gap between the washer and the bearing end surface. A high-pressure oil film can be formed, and the thrust load capacity can be greatly improved.

In addition, by using the grease containing the thickener as the lubricating oil, the lubricating oil easily stays on the bearing end surface for a long time, and the outflow of the lubricating oil from the bearing surface can be effectively reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention, FIG. 2 is a view showing an upper end surface of the porous plain bearing, FIG. 3 is a view showing a lower end surface of the same, and FIG. FIG. 5 is a vertical sectional front view showing the bearing structure of the motor, and FIG. 5 is a vertical sectional front view showing the main part of the same. 1, 2 ... Porous plain bearing, 3 ... Housing, 4 ... Motor shaft, 5 ... Rotor, 6 ... Thrust bearing washer, 7 ... Retaining ring, 8 ... Oil impregnated felt, 9 ... Oil Holding washer, 10, 11 ... Dynamic pressure generating groove.

Claims (2)

[Claims] 1. A porous sliding bearing containing a lubricating oil, and a pair of bearings arranged so as to rotate relative to the upper and lower end surfaces of the bearing.
One washer, and one of the upper and lower end surfaces of the bearing or the facing surface of each washer is provided with a dynamic pressure generating groove whose inner side is higher than the outer circumference by relative rotation of the both, and the upper washer is attached to the upper end surface of the bearing. A bearing device in which each washer is formed of a thin plate made of synthetic resin while being brought into contact with each other. 2. The bearing device according to claim 1, wherein grease containing a thickener is used as the lubricating oil.