JPH08210368A - Seal plate for bearing - Google Patents

Abstract

PURPOSE: To provide high oil repellency and low coefficient of friction by integrating a seal plate using the mixed resin where the fluoride resin of the prescribed amount is directly and uniformly mixed in the base material consisting of the engineering plastics. CONSTITUTION: A seal plate 1 is integrated using the synthetic resin where 5-20wt.% fluoride resin is uniformly mixed with the engineering plastic as the base resin. When the rate of mixture of the fluororesin falls 5wt.% or less, the oil repellency of the seal plate 1 is reduced, and the grease base oil (low viscosity oil) can not be effectively prevented from being eluded outside through the clearance between an outer circumferential end part 1a of the seal plate 1 and an outer ring 2. When the rate of mixture of the fluororesin exceeds 20wt.%, the manufacturing cost is increased. Even when the rate of mixture is not greater than 20%, the oil repellency enough to effectively prevent the grease base oil from being eluded can be obtained, and the frictional resistance is also reduced to about 50% of the value in the case of the base material only.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a synthetic resin sealing plate used for a seal type bearing, which can easily make the quality of the sealing plate uniform, and can improve the grease base oil (low-viscosity oil) externally. Can be completely prevented from seeping into
Moreover, the present invention relates to a bearing sealing plate capable of significantly reducing the friction coefficient.

[0002]

2. Description of the Related Art Generally, in a seal type bearing,
As shown in FIG. 2, the outer peripheral ends 1a of the synthetic resin sealing plate 1 are fitted into the seal grooves 2a formed at both ends of the inner peripheral surface of the outer ring 2, and the elastic force of the outer peripheral end 1a causes the sealing plate 1 to move to the inner ring 3 and the outer ring. The structure is such that the two are held and fixed substantially vertically. The space 6 between the two sealing plates 1 and 1 is filled with a lubricant (grease) for the balls 5, and the contact portion 7 between the outer peripheral end 1 a of the sealing plate 1 and the outer ring 2 and the sealing plate. The labyrinth sealing portion 8 between the inner peripheral end portion 1b of 1 and the inner ring 3 prevents the grease from leaking to the outside and the dust from entering the space portion 6.

Since the grease receives a centrifugal force due to the rotation of the inner ring 3 during the operation of the bearing, the contact portion 7
It easily exudes to the outside through. On the other hand, if grease or the like leaks to the outside of the sealing plate 1, the peripheral equipment of the bearing will be contaminated and the like, which will have a great adverse effect on precision equipment and the like. Therefore, in the conventional synthetic resin sealing plate 1 of this type, an oil-repellent resin layer 9 such as a fluororesin is formed on the outer peripheral end 1a of the sealing plate 1 by coating, so that the contact portion 7 is passed through. The grease base oil that is about to seep outside is splashed inward to prevent the oil from seeping outside (actual flat 6-
66321, Jitsukaihei 5-34319, etc.).

The fluororesin coating resin layer 9 is formed by inserting a large number of sealing plates 1 on a holding shaft 10 in a stacked manner and spraying a fluororesin liquid from the outside as shown in FIG. A coating resin layer 9 is formed on the outer peripheral end 1a of the plate 1 (Actual No. 5-34319),
Alternatively, the coating resin layer 9 is formed by immersing the outer peripheral end 1a of the sealing plate 1 in a fluororesin tank (Actual Kaihei No. 6-66321).

[0005]

However, the sealing plate 1 is
In the method of spraying the fluororesin liquid on the outer peripheral end 1a of the above or by immersing the outer peripheral end 1a in the fluororesin liquid,
There is a problem that the thickness of the coating resin layer 9 of each sealing plate 1 tends to be non-uniform, and the coating resin layer 9 having a predetermined uniform thickness cannot be formed. Also,
Even with regard to each sealing plate 1, the thickness of the coating resin layer 9 is partially non-uniform, or the coating resin layer 9 may cause some cause during transfer to the drying process or during the drying process. There is a case where the sealing plate 1 is partially peeled off or dust is attached to the coating resin layer 9.
There is a problem that it takes a lot of trouble to control the quality of the product. Further, in the conventional sealing plate 1, the inner peripheral end portion 1b of the sealing plate 1 is brought into contact with the outer surface of the inner ring 3 so that the inner ring 3 and the sealing plate 1 are sealed. As a result, inner ring 3
Therefore, an unnecessary load is applied to the sealing plate 1 due to the contact sliding of the sealing plate 1. Especially, in a miniature bearing or the like, the frictional resistance of the sealing plate 1 becomes a non-negligible problem.

The present invention solves the above-mentioned problems in the sealing plate of the conventional seal type bearing all at once, has a high oil repellency and a low coefficient of friction, and enables easy quality control of the sealing plate. It is intended to provide the bearing sealing plate as described above.

[0007]

According to the present invention, in order to improve the oil repellency of a sealing plate and reduce the friction coefficient, a fluororesin liquid is used instead of a fluororesin liquid coating, and a fluororesin is introduced into a base material made of engineering plastic. The sealing plate is integrally molded by directly and uniformly mixing and using the mixed resin. That is, the invention according to claim 1 of the present invention has a basic constitution of uniformly mixing 5 to 20 wt% of a fluororesin with an engineering plastic and integrally molding a bearing sealing plate from the mixed resin. It is a thing. In the invention according to claim 2 of the present invention, the sealing plate except for the outer peripheral end is formed thinner than the outer peripheral end to form a seal thin part that is easily elastically deformed, and The light contact of the peripheral edge with the inner ring is the basic configuration of the invention.

[0008]

By uniformly mixing 5 to 20 wt% of fluororesin into the engineering plastic as the base material resin, the oil repellency of the molded sealing plate is greatly improved.
That is, when the grease base oil (low-viscosity oil content) comes into contact with the sealing plate, the contacting base oil becomes spherical (the solid-liquid contact angle is 90 ° or more) due to the surface tension, and as a result, it passes through the gap between the sealing plate and the seal groove to the outside. It becomes difficult to seep out. Further, due to the non-adhesiveness of the fluororesin mixed into the engineering plastic as the base material resin, the friction coefficient of the sealing plate is reduced by about 50% as compared with the case where only the base material is used. As a result, the contact resistance with the inner ring is reduced, and the energy loss due to heat generation is significantly reduced. In addition, since the sealing plate is thinly formed except the outer peripheral end to form a thin seal part that is easily elastically deformed, and the inner peripheral edge of the thin seal part is lightly contacted with the inner ring. The peripheral end contacts the inner ring with extremely low load. As a result, the friction coefficient of the sealing plate is reduced by the addition of non-adhesive fluororesin, and the contact resistance between the sealing plate and the inner ring is further reduced, and the sliding contact of the sealing plate with the inner ring is reduced. There is no unnecessary load due to. Therefore, even if the inner ring contact type sealing plate is attached to the miniature bearing, no problem occurs.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of a sealed bearing equipped with a sealing plate according to the present invention. In FIG. 1, 1 is a sealing plate, 2 is an outer ring, 3 is an inner ring,
Reference numeral 4 is a retainer, 5 is a ball, 6 is a space filled with grease, 7 is a contact portion between the sealing plate 1 and the inner and outer rings 2 and 3, and 8 is a labyrinth sealing portion.

The sealing plate 1 is integrally molded using a synthetic resin obtained by uniformly mixing 5 to 20 wt% of a fluororesin with an engineering plastic as a base material resin.
Further, except the outer peripheral end 1a of the sealing plate 1, it is formed thinner than the outer peripheral end 1a, and this portion is a thin seal portion 1c which is easily elastically deformed. The wall thickness of the thin seal portion 1c is set to a fraction of the wall thickness of the outer peripheral end portion 1a so that the thin seal portion 1c can be easily elastically deformed with the continuous portion 1d with the outer peripheral end portion 1a as a fulcrum. It has been selected. The outer peripheral end 1a of the sealing plate 1 is fitted into the annular seal grooves 2a formed at both ends of the inner peripheral surface of the outer ring 2 and abuts both side surfaces of the seal groove 2a. The inner peripheral edge of the thin seal portion 1c is in light contact with the side surfaces of the annular groove 3a formed at both ends of the outer peripheral surface of the inner ring 3. That is, the thin seal portion 1c of the sealing plate 1 forms an elastic body with the continuous portion 1d with the outer peripheral end 1a as a fulcrum.
The inner ring 3 comes into contact with an extremely low load. As a result, the contact resistance between the sealing plate 1 and the inner ring 3 is significantly reduced, and the inner ring 3
There is no unnecessary load due to the sliding contact of the sealing plate 1.

Polyamide, polyester, hard nylon and the like are used as the engineering plastic as the base material resin of the sealing plate 1. The fluororesin added to the base resin includes polytetrafluoroethylene (PTFE), tetrafluoroethylene-ethylene copolymer (ETFE), polyvinyl fluoride (PVF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. A polymer (PFA) or the like is used.

As for the mixing ratio of the fluororesin, when the mixing ratio becomes 5 wt% or less, the oil repellency of the sealing plate 1 is lowered, and the grease base oil (low viscosity oil content) is the outer peripheral end 1a of the sealing plate 1 and the outer ring 2. It becomes impossible to effectively prevent the exudation to the outside through the gap. Further, if the mixing ratio of the fluororesin exceeds 20 wt%, the manufacturing cost will increase, and even if it is 20% or less, sufficient oil repellency can be obtained to effectively prevent the grease base oil from seeping out, and the friction resistance can be further improved. Approximately 50 when using only base metal
It is because it decreases to about%.

Polyamide resin is used as the base material resin, and polytetrafluoroethylene (PT) is used as a fluororesin.
A sealing plate 1 having a shape as shown in FIG. 1 (outer diameter of about 3.6 mmφ, maximum thickness of about 0.2) is formed by using a resin in which 10% by weight of FE) is mixed.
mm) was molded, and the oil repellency test and the friction coefficient were measured. According to the test results, it was confirmed that the grease base oil (low-viscosity oil content) can be prevented from seeping out to the outside under normal operating conditions of the bearing and normal processing accuracy of each member. It was also found that the friction coefficient was reduced to about 50 to 55% of that of the base resin (polyamide resin). The grease used in the test is a multi-purpose grease (thickness based), which is generally used for bearings.

Since the sealing plate 1 according to the present invention contains the fluororesin component, the properties such as heat resistance, oil resistance and abrasion resistance are improved as compared with the sealing plate made of only the base material. Also,
By mixing the fluororesin, the mechanical strength of the sealing plate is lower than that of the sealing plate made only of the base material, cracks and the like are more likely to occur, the sealing plate 1 is easily separated from the sealing groove 2a, or the sealing plate 1 It never happened that the molding process would become difficult.

In the above example, the sealing plate 1 is attached to the inner ring 3
Although the contact type is used, in another example, the sealing plate 1 may be a non-contact type in which the inner peripheral end of the sealing plate 1 is brought close to the inner ring 3. Further, the sectional shape and size of the sealing plate 1 are not limited to those in the above example.

[0016]

INDUSTRIAL APPLICABILITY As described above, the present invention provides a synthetic resin bearing sealing plate having an improved oil repellency, which is not limited to the fluoroplastic coating to enhance the oil repellency. 5-20wt
% Fluorine resin is uniformly mixed, and the sealing plate is integrally molded using the mixed resin. As a result, unlike the conventional coating method, the thickness of the coating resin layer becomes non-uniform, and the quality control of the sealing plate such as detection of the peeled portion of the coating resin layer does not take any trouble, which is high. A sealing plate of uniform quality having excellent properties such as oil repellency and low friction coefficient can be obtained very easily.

Further, in the sealing plate of the present invention, since the mixing ratio of the fluororesin is 5 to 20% by weight, the raw material cost of the fluororesin is almost offset by the cost required for coating. Even when compared with a sealing plate having improved oil repellency by the coating method, the manufacturing cost is not inferior.

Further, in the sealing plate of the present invention, since the fluorine resin having non-adhesiveness is added, the friction coefficient is reduced by about 50% as compared with the case where only the base material is used, and the sealing is performed. The oil resistance, abrasion resistance, heat resistance, etc. of the plate as a whole are significantly increased, which is extremely advantageous in practical use.

In addition, in the sealing plate according to the second aspect of the present invention, except the outer peripheral end portion, a thin seal portion that is elastically deformable is formed by forming a thin wall portion, and the inner peripheral end of the thin seal portion. Since the edge is lightly contacted with the inner ring, the sealing plate comes into contact with the inner ring with extremely low load. As a result, the friction coefficient of the sealing plate is reduced by the addition of fluororesin, and the contact resistance between the sealing plate and the inner ring is further reduced, and the inner ring does not need to move due to contact sliding of the sealing plate. There is no load. The present invention has excellent practical utility as described above.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a bearing using a sealing plate according to the present invention.

FIG. 2 is a cross-sectional view showing a main part of a bearing using a sealing plate having an oil repellency enhanced by a conventional coating.

FIG. 3 is an explanatory view of a conventional coating method for the outer peripheral edge of the sealing plate.

[Brief description of reference numerals]

1 is a sealing plate, 1a is an outer peripheral end, 1b is an inner peripheral end, 1c is a thin seal portion, 2 is an outer ring, 2a is a seal groove, 3 is an inner ring,
3a is a groove, 4 is a retainer, 5 is a ball, 6 is a space portion, 7
Is a contact portion, 8 is a labyrinth sealing portion, and 9 is a coating resin layer.

Claims (3)

[Claims] 1. A bearing sealing plate having enhanced oil repellency, the outer peripheral end of which is fitted into an annular seal groove formed at both ends of the inner peripheral surface of the outer ring to seal between the inner and outer rings. , The sealing plate is 5-20w on engineering plastic
A bearing sealing plate, characterized in that t% fluororesin is uniformly mixed and integrally molded from the mixed synthetic resin. 2. The sealing plate except for the outer peripheral end is formed thinner than the outer peripheral end to form a thin seal portion that is easily elastically deformed, and the inner peripheral edge of the thin seal portion is lightly contacted with the inner ring. The bearing sealing plate according to claim 1, characterized in that. 3. The fluororesin is polytetrafluoroethylene (PTFE) or tetrafluoroethylene-ethylene copolymer (ETFE), and the engineering plastic is polyamide or polyester.
Alternatively, the bearing sealing plate according to claim 2.