JP2002147475A - Seal structure of ceramics bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure of a ceramics bearing capable of preventing an invasion of a moisture content and foreign matters from the external side. SOLUTION: In the ceramics bearings 51, 61, 71, rolling elements 14, 24, 34 such as a ball and a roller are clamped between outer rings 12, 22, 32 and inner rings 13, 23, 33. Seal covers 52, 62, 72 for sealing a gap between the outer ring and the inner ring are engaged and fixed on an outer periphery of the outer rings 12, 22, 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ceramic bearing sealing structure.

[0002]

2. Description of the Related Art Ceramic bearings are widely used in various machines under special environments.
Since it has the property of being more easily cracked during processing than general bearing steel, it is not possible to adopt a sealing structure like a general steel bearing.

That is, in a conventional general steel bearing, a groove is formed in one of an outer ring and an inner ring, and an annular sealing member (seal or shield) is fitted into the groove, so that a gap between the outer ring and the inner ring is formed. The gap is sealed to prevent moisture and foreign matter from entering from outside.However, in the case of ceramic bearings, it is difficult to form grooves in the inner and outer rings because the material is easily broken. Therefore, a sealing structure like a conventional steel bearing cannot be adopted. Therefore, when a ceramic bearing is used, at present, an open type having no hermetic structure is used.

FIG. 3 shows an open type ceramic bearing. (A) is a deep groove ball bearing 11, (b) is a roller bearing 2
1, (c) shows a thrust bearing 31. Each bearing 11, 2
1, 31 are outer rings 12, 22, 32 and inner rings 13, 23,
The rolling elements 14, 24, 34 such as balls and rollers are sandwiched between 33. 15 and 25 are retainers.

[0005]

However, conventional ceramic bearings do not have a sealing structure, so that water or foreign substances enter the bearings, and the bearings reach a shorter service life than the rated fatigue life and break. There was a problem that it would.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a sealing structure for a ceramic bearing which can prevent moisture and foreign matter from entering the inside of the bearing and can extend the life of the bearing. And

[0007]

According to a first aspect of the present invention, in a ceramic bearing in which a rolling element is sandwiched between two races, a gap between the two races is sealed on the outer periphery of one race. It is characterized in that the sealing cover is fitted and fixed.

Here, the sealing cover fitted and fixed to one of the races is kept in a non-contact state with the other race so as not to affect the rotation of the other race. Is desirable. However, if a portion reaching the other race is made of a soft material (for example, rubber or the like), the gap between the two races is completely formed by bringing the soft portion into contact with the other race. You may make it hermetically sealed. Also, the tip of the wall of the sealing cover extending from one race to the other race is fastened to the other race in front of the mating member mounting surface, and the tip of the sealing cover interferes with the mating member. It is desirable not to do so. If the tip of the sealing cover is bent along the larger chamfer provided on the other race, the sealing effect is enhanced and the sealing cover is prevented from falling off.

In this ceramic bearing sealing structure, the sealing cover is fitted and fixed to the outer periphery of one of the races.
The bearing can be sealed without forming a groove for mounting the sealing means on the race. Therefore, the present invention can be easily and easily applied to a ceramic bearing in which groove processing is difficult. Further, since the sealing cover is merely fitted on the outer periphery of one of the races, it can be easily attached and detached.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the overall structure of a ceramic bearing of each type (a), (b), and (c) to which the sealing structure of the embodiment is applied, and FIGS. 2 (a), (b), and (c) are diagrams. It is a principal part enlarged view of each type 1 ceramic bearing.

1 and 2, (a) shows a deep groove ball bearing 51 with a sealed structure, and (b) shows a roller bearing 6 with a sealed structure.
1, (c) shows a thrust bearing 71 with a sealing structure. These bearings 51, 61, 71 are respectively provided with sealing covers 52, 62, 72 made of a thin metal plate (thickness of about 0.5 to 0.8 mm) on ceramic bearing bodies 11A, 21A, 31A, respectively. It has a covered structure.

The ceramic bearing bodies 11A, 21A,
31A is the outer ring (track ring) 12, 22, shown in FIG.
32, inner rings (track rings) 13, 23, 33 and rolling elements 1
Chamfering portions 13a, 23a, 33a having a size of about C2.0 are provided at the corners of the inner diameter surfaces of the inner rings 13, 23, 33 of the open type bearing composed of 4, 24, 34, Other configurations are exactly the same as those of the open type, and 15 and 25 are retainers.

In the deep groove ball bearing 51 with the sealing structure shown in FIG. 1A and the roller bearing 61 with the sealing structure shown in FIG.
2, 62 are outer peripheral walls 52a, 62a and both side walls 52b, 6
2b, the outer peripheral walls 52a, 62a are brought into close contact with the outer peripheral surfaces of the outer rings 12, 22, and the outer peripheral side portions (base end portions) of both side walls 52b, 62b are formed as outer rings. In a state of being in close contact with the end faces of the outer races 12 and 22, they are fitted and fixed to the outer races 12 and 22 with interference.

The side walls 52b, 6 of the sealing covers 52, 62
The inner peripheral ends 52c and 62c of the inner ring 2b seal the gaps between the outer rings 12 and 22 and the inner rings 13 and 23 while the inner rings 13 and 23 are closed.
The inner chamfers 13a, 2a at both ends of the inner surfaces of the inner rings 13, 23
It is bent inward along 3a. That is, the inner diameters of the sealing covers 52 and 62 are formed slightly larger than the inner diameters of the inner rings 53 and 63, and the sealing covers 52 and 62 are formed.
A gap B is secured between the inner peripheral ends 52c, 62c of the shafts and the outer peripheral surface of the shaft (partner member) fitted to the inner rings 53, 63,
The sealing covers 52 and 62 do not protrude toward the inner diameter side of the bearing.

In this case, the side walls 5 of the sealing covers 52, 62
2b, 62b, the width of the inner rings 13, 23 in the axial direction is set to be in a state of non-contact with the inner rings 13, 23,
The gap H is formed between the end faces of the inner rings 13 and 23 and the inner faces of the side walls 52b and 62b of the sealing covers 52 and 62.

In the thrust bearing 71 with a sealing structure shown in FIG. 1C, the sealing cover 72 is formed as an annular body having an L-shaped cross section having an end wall 72a having a central hole 72d and a peripheral wall 72b. The peripheral wall 72b is in close contact with the outer peripheral surface of the outer race 32, and the end wall 72a is in close contact with the outer end surface of the outer race 32, and is fitted and fixed to the outer race 32 with an interference.

The tip 72c of the peripheral wall 72b of the sealing cover 72
Extends to a position short of the outer end surface (the mating member mounting surface) of the inner ring 33 while sealing the gap between the outer ring 32 and the inner ring 33. It is bent inward along. That is, the sealing cover 7
The height of the second peripheral wall 72b is smaller than the height of the bearing main body 31A, so that a gap B is secured between the distal end 72c of the peripheral wall 72b of the sealing cover 72 and the mating member attached to the inner ring 33. It has become.

The outer wall of the inner ring 33 is formed smaller than the outer diameter of the outer ring 32 so that the peripheral wall 72b of the sealing cover 72 is not in contact with the inner ring 33.
A gap H is secured between the outer peripheral surface of the seal cover 72 and the inner surface of the peripheral wall 72b of the sealing cover 72.

As described above, the sealing cover 5 is provided for each type.
2, 62, 72, and the bearing bodies 11A, 21A, 3
Since the gap between the outer races 12, 22, 32 and the inner races 13, 23, 33 of 1A is sealed, it is possible to reliably prevent moisture or foreign matter from entering the inside of the bearing from the outside, and to extend the life of the bearing. Can be. Also, the sealing covers 52, 62, 7
No. 2 is simply fitted and fixed to the outer races 12, 22, 32 and does not require any special groove processing, so that it can be applied to a conventional ceramic bearing as it is.

The sealing covers 52, 62, 72 fitted and fixed to the outer rings 12, 22, 32 are
3 is kept in a non-contact state, and therefore does not affect the rotational performance of the bearing. In addition, the sealing cover 5
Since 2, 62 and 72 do not protrude on the mating member mounting surfaces of the inner rings 13, 23 and 33, the rotation performance is not affected. Also, the sealing covers 52, 62, 7
2 of the side walls 52b, 62b and the end of the peripheral wall 72b (the inner peripheral end 1).
3a, 23a and the tip 33a) with the inner rings 13, 23, 3
3 is bent along the chamfered portions 13a, 23a, 33a, so that more reliable sealing performance can be maintained.

The production and attachment of the sealing covers 52, 62, 72 can be easily carried out by press working while using the bearing bodies 11A, 21A, 31A as molds.

In addition, the materials, shapes, dimensions, forms, numbers, locations, and the like of the outer ring, inner ring, rolling members, cage, base, pocket, eccentric mass, etc. exemplified in the above-described embodiment are the present invention. Is arbitrary as long as it can achieve
Not limited.

[0023]

As described above, according to the first aspect of the present invention, the gap between the two bearing rings is sealed by the sealing cover fitted and fixed to one of the bearing rings. Intrusion of moisture or foreign matter into the inside can be reliably prevented, and the life of the ceramic bearing can be extended. In addition, since the sealing cover is fitted and fixed to the outer circumference of one raceway, there is no need to apply grooves to the outer ring or inner ring to attach the sealing cover. It can be applied without difficulty.

[Brief description of the drawings]

FIG. 1 is a view showing each example of a ceramic bearing according to an embodiment of the present invention, wherein (a) is a deep groove ball bearing, (b) is a roller bearing,
(C) is a sectional view showing the entire configuration of the thrust bearing.

2 (a) to 2 (c) are enlarged views of main parts of the ceramic bearing of FIGS. 1 (a) to 1 (c).

FIG. 3 is a view showing each example of a conventional ceramic bearing.
(A) is a sectional view showing the whole structure of a deep groove ball bearing, (b) is a roller bearing, and (c) is a thrust bearing.

[Explanation of symbols]

 12, 22, 32 Outer ring (track ring) 13, 23, 33 Inner ring (track ring) 14, 24, 34 Rolling element 51, 61, 71 Bearing with sealing structure 52, 62, 72 Sealing cover

Claims (1)

[Claims] 1. A rolling bearing having a rolling element sandwiched between two races, wherein a sealing cover for sealing a gap between the two races is fitted and fixed to an outer periphery of one race. Ceramic bearing sealing structure.