JP2002139048A - Electric corrosion preventive rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric corrosion preventive rolling bearing at a low cost, assuring an enhanced lubricating peformance to lead to enhancement of the durability. SOLUTION: The electric corrosion preventive rolling is formed by installing ceramic balls 3 manufactured by a normal pressure sintering method using a material chiefly containing silicon nitride, zirconia, alumina, silicon carbide, and grease is attached to pores generated at the surface of each ball 3 so that a grease sump is formed, and thereby the lubricated condition is enhanced and the durability is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-corrosion rolling bearing for use in a fan motor for an air conditioner, a water heater, a ventilation fan, a cooling fan or the like by inverter control, or a motor used in a device for inverter control. About.

[0002]

2. Description of the Related Art In a motor of this type or the like, electric current may flow through a bearing to cause electrolytic corrosion. Conventionally, as a countermeasure against electric corrosion, a review of the motor (such as providing an insulating layer inside the motor) and the use of an anti-corrosion bearing have been performed. However, in the countermeasure in the motor structure, there is a demand for a countermeasure in an anti-corrosion bearing because the mechanism of current generation is not clear or the countermeasure differs for each motor due to the motor structure.

[0003]

A conventional anti-corrosion bearing is:
Prevents electric corrosion by coating an insulating layer on the inner ring or outer ring end surface (ceramic coating), winding resin such as polyphenylene sulfide (PPS), or incorporating a ceramic ball mainly made of silicon nitride by a pressure sintering method Is being planned. However, in the case of using a conventional anti-corrosion bearing by coating an insulating layer on the inner or outer ring end surface or by winding a resin, creep due to aging or the like, or a film (ceramic coating film, resin If the film is missing, complete measures cannot be taken.

Further, when a conventional anti-corrosion bearing incorporating a ceramic ball formed by a pressure sintering method is used, it has excellent insulation properties and is effective in preventing corrosion. Ceramic balls are usually classified into a pressure sintering method typified by a HIP method and a normal pressure sintering method without pressing. In the case of a fan motor, a pressure sintering method (HIP method, etc.) having excellent sound is used. It is common to use ceramic balls. But,
In the case of pressure sintering, the ball surface formed by the pressure sintering method (HIP method), which is expensive, has a pore size of 2μ because it is densely formed.
m or less, for example, in an environment where the oil film formation conditions are severe (when stationary and subject to vibration), there is a possibility that physical adhesion may occur. That is, for example, when used under a light load such as a fan motor, the durability is extended under conditions where the oil film between the balls / grooves is reduced due to the dense surface. Then, there is a possibility that the improvement in acoustic performance may be affected.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a low-cost anti-corrosion rolling bearing having improved lubrication and improved durability. It is to provide.

[0006]

The technical means achieved by the present invention to achieve the above object comprises an outer ring, an inner ring, and a rolling element incorporated between the outer ring and the inner ring. The rolling element is made of a ceramic material mainly made of silicon nitride, zirconia, alumina and silicon carbide and manufactured by a normal pressure sintering method.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an anti-corrosion rolling bearing according to an embodiment of the present invention. Although the present embodiment shows a ball bearing as an embodiment of the rolling bearing of the present invention, it merely shows one embodiment, and is not limited to this embodiment. It is possible within the scope of the invention.

FIG. 1 shows a first embodiment of the present invention. An outer ring 1 having a deep groove outer raceway 1a having an arc-shaped cross section on the inner peripheral surface, an inner ring 2 having an inner raceway 2a having an arc-shaped cross section on the outer peripheral surface, and the outer raceway 1a and the inner race It has the same structure as the conventional structure including a plurality of rolling elements (balls) 3... That are rotatably incorporated via a retainer 4 between the track 2a. The inner peripheral surface 1 at both ends of the outer race 1
b, an outer peripheral edge 5a of an annular sealing plate (including both a sealing plate and a shielding plate) 5 is locked, and the inner peripheral edge 5b of the sealing plate 5 is brought into close proximity to the outer peripheral surface 2b at both ends of the inner ring 2. ing. In the present embodiment, the outer ring 1, the inner ring 2, the retainer 4, and the sealing plate 5 are not particularly limited, and a well-known configuration such as a material and a shape thereof can be appropriately applied within the scope of the present invention. In this embodiment, the radial thickness of the outer race 1 and the radial thickness of the inner race 2 are substantially the same, and the position of the rolling element (ball) 3 (PCD: Pitch Circ)
le Diameter or pitch circle diameter) is disposed substantially at the center of the bearing.

The rolling elements 3 are balls made of a ceramic material mainly composed of silicon nitride, zirconia, alumina and silicon carbide and manufactured by a normal pressure sintering method. The diameter and the number of balls are not particularly limited, and can be set within the scope of the present invention.

As described above, in the case of the normal pressure sintering method, pores (not shown) of about 2 to 40 μm are formed on the surface of the ball 3. In the case of grease lubrication, grease adheres to these pores and grease is accumulated. . Therefore, when used in a state such as a fan motor that rotates for a long time or receives vibration while stopped during transportation, the oil film is retained and wear is reduced.

In the case of a ball bearing, the inner ring groove r ratio 51
It is preferable to set the outer ring groove r ratio to 52 to 65%.

In the case of the normal pressure sintering method, since the surface roughness of the ball 3 is generally large, the sound may be large. However, the sound can be reduced by combining the ball 3 with a high-viscosity grease. Table 1 shows the test results. In this test, outer ring 1
Was performed using a deep groove ball bearing having an outer diameter of 22 mm and an inner diameter of the inner ring 2 of 8 mm.

[0013]

[Table 1]

In the above embodiment, at least the rolling elements 3
Is a ball made of a ceramic material mainly manufactured by silicon nitride, zirconia, alumina and silicon carbide by a normal pressure sintering method. Alternatively, it is within the scope of the present invention that all parts are made of a ceramic material mainly manufactured by silicon nitride, zirconia, alumina, and silicon carbide by a normal pressure sintering method.

FIG. 2 shows a second embodiment of the present invention. In the present embodiment, the P, C, and C in the bearing of the first embodiment are used.
4 shows a low-torque anti-corrosion rolling bearing in which D, the ball diameter, the number of balls, and the like are changed. Note that the other configuration, operation, effects, and the like are the same as those in the first embodiment. That is, in the present embodiment, while maintaining the same outer diameter as the outer ring 1 of the first embodiment, the radial thickness of the outer ring 1 is made larger than the radial thickness of the inner ring 2, and the rolling element (ball) 3 is formed. P. C. D is arranged on the inner diameter side of the bearing. The bearing of the present embodiment is intended for a low-speed and high-speed rotation for supporting a rotating shaft of a home vacuum cleaner or a blower of a home air conditioner in a housing. For example, when supporting the rotating shaft of a fan motor for a vacuum cleaner, the outer ring 1 is fixedly fitted inside a fixed housing, and the inner ring 2 is fixedly fitted outside the rotating shaft. With the configuration described above, the moment required for rolling the rolling element 3 is reduced to reduce the torque. Even when the torque is to be reduced in this manner, the outer diameter of the outer ring 1 does not need to be smaller than that of the conventional structure, so that it is not necessary to change the inner diameter of the housing in which the outer ring 1 is to be fixed. There is also an advantage that the housing that has been used can be used as it is.

Further, with the above-described configuration, the diameter of the ball can be reduced accordingly, and the cost can be further reduced.

Further, as in the present embodiment, the P.P. C. Since D is reduced and the ball diameter of each rolling element 3 is reduced accordingly, the anderon value is improved. this is,
It is considered that the kinetic energy of each rolling element 3 is reduced and the exciting force of each rolling element is reduced. Further, as described above, the P.P. C. Since D is reduced, noise when incorporated in the motor can be reduced. This is because the P.P. C.
When D is reduced, the number of rolling elements 3 increases, while
It can be considered that the number of resonance peaks falling within the resonance frequency band with the motor among the vibration components of the rolling elements 3 is reduced, which works acoustically favorably. This function and effect can sufficiently cope with noise countermeasures in combination with the above-described acoustic reduction effect of the combination of the ceramic ball 3 and the high-viscosity grease by the normal pressure sintering method.

[0018]

Since the present invention has the above-described structure, it is possible to provide a low-cost anti-corrosion rolling bearing with improved lubrication and improved durability.

That is, the grease adheres to the pores formed on the surface of the ceramic ball by the normal pressure sintering method, and the grease accumulates, so that the lubrication state is improved and the durability is increased. Further, since the cost of the normal pressure sintering method is lower than that of the pressure sintering method, a low-cost insulated bearing can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 1: Outer ring 2: Inner ring 3: Rolling element

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3J101 AA02 AA32 AA42 AA52 AA62 BA10 EA43 EA44 EA63 FA11 FA31 GA29 4G001 BB22 BB32 BC56 BD12 BE31 4G030 AA36 BA19 CA07 GA23 4G031 AA12 BA19 CA07 GA07

Claims (1)

[Claims] 1. An atmospheric pressure sintering method comprising an outer ring, an inner ring, and a rolling element incorporated between the outer ring and the inner ring, wherein at least the rolling elements are mainly composed of silicon nitride, zirconia, alumina, and silicon carbide. An anti-corrosion rolling bearing comprising a ceramic material produced by the method described above.