ROLLING ELEMENT BEARING WITH SEALS

Abstract: It is well-known that in case a bearing seal is subjected to severe circumstances e.g. splashing mud and water, to execute the sealing lip in such a way that it rests with high contact forces on its counterface. Higher friction will be generated and consequently higher temperature and wear. These disadvantages are obviated by the claimed seal arrangement which is characterized in that at the outside of the seal (14) a stiff shield (8′) is applied which in sectional view is mainly L-shaped. The shield (8′) with its short leg (9′) is fixed on the bearing inner-ring (1′). The seal lip (16) rests on a supporting ring (10′) of shield (8′). The improvement consists therein that between a bearing ring part (11′) and end-part of shield (8′) a split (12′) as well as between shield (8′) and seal (14) a space (13′) are both present. Due to this arrangement and under influence of centrifugal forces contaminated liquid are circulated in said space (13′) to the outside of the bearing via said split (12′) forming a sealing by itself as tests have shown.

Description: The invention is related to a rolling element bearing, comprising an inner race, an outer race and in between these at least one row of rolling elements with a lubricant, and sealing means between and at the outside of the races, said sealing means each being formed by a generally annular element which at its outer circumference is attached to the outer race and which at its inner circumference includes a sealing lip of a flexible material which is adjacent to the inner race; whereby beside and at some distance from the side facing outward of each annular element a shield of a basically rigid material is placed, which is attached to the outer circumference of the inner race; whereby between the shield and the outer race there is a generally slot-shaped opening; whereby between each annular element and shield a space is formed which is connected via the slot-shaped opening to the environment of the bearing; whereby each shield includes a - with regard to the bearing - axially inwardly projecting ring-part which surrounds the inner race; and whereby said sealing lip of each annular element is basically adjacent to the outer circumference of this ring-part. Such a rolling element bearing is known from FR-A-2 504 231. It comprises shields which consist of metal. Such shields are manufactured by stamping them out of a metal plate, which has the disadvantage of leaving waste material. Furthermore, in the stamping process only a limited number of particular shapes may be obtained. The aim of the invention is therefore to provide a rolling bearing element of the type described above which does not have these disadvantages. This aim is achieved in that each shield is made of a synthetic material and comprises around the outer circumference of the ring-part an element for attachment of said shield, against which element the sealing lip of the annular element rests. The shield, consisting of a synthetic material, can easily be manufactured with any specific shape at very low cost, e.g. by injection moulding. The metal element is only applied for connecting the shield to the inner bearing race, and for providing a seal together with the sealing lip of the sealing means. Moreover, it has been shown that during operation of the bearing the centrifugal forces generate a current in the space between the shield and the corresponding annular element. In this connection, the shield can be given the most effective shape in order to generate said current for effectively removing moisture, water and/or dirt from said space. The invention is further described with reference to the drawing in which: Figure 1 shows in axial section part of a ball bearing according to the invention and Figure 2 shows part of another form of execution of a bearing according to the invention, in axial section. As represented in Figure 1, the bearing includes an inner race 1 and an outer race 2, and in between these a row of ball elements 3 in a lubricant (not further indicated). An annular sealing element 4 is contained at the outer circumference in a groove 5 formed in the outer race 2. This sealing ring consists of a flexible material 4A with, along part of it, an element 6 for support and rigidity, and a sealing lip 7 along the inner circumference of the sealing ring 4. Around the inner race 1 there is an annular shield 8 manufactured of a basically rigid synthetic material. Part of the shield 8 forms a ring 9 projecting inwardly in an axial direction, while an element for attachment 10 is applied around this ring 9. The outer circumference of the shield 8 is located at some distance from a bow-shaped recess 11 in the outer race 2, so that a slot-shaped opening 12 is formed. When the hearing shown in Figure 1 is used in a moist, watery or muddy environment, the moisture or water can penetrate through the slot-shaped opening 12 into the space 13 formed between the sealing ring 4 and the shield 8. When the roller hearing is placed under load whereby, for example, the inner race 1 rotates, a current is generated in the moisture or water in space 13 under the influence of, among others, centrifugal forces, as indicated by the arrows in Figure 1, which current prevents moisture or water from penetrating between the sealing lip 7 and the ring 10 into the bearing, because it has been shown that, under the circumstances, the current is directed away from the sealing lip 7. The roller hearing shown in Figure 2 corresponds largely to the bearing shown in Figure 1, so that corresponding parts are indicated by the same reference numbers, but with the addition of a prime symbol. However, in the bearing shown in Figure 2, the sealing ring 14 and the support element 15 ate almost straight, so that a somewhat different space 13' is formed between this ring-shaped sealing ring 14 and the shield 8'. The sealing lip 16 of the sealing ring 14 also rests against the attachment ring 10'. The extra sealing action which follows from the construction measure according to the invention again the same as in the bearing model shown in Figure 1. The advantage in this respect, however, is that the space B for the lubricant with regard to the space 13' for the current, can be adapted to specific circumstances according to the application of the bearing, for example, through the application of a larger amount of lubricant.

Claims: Rolling element bearing, comprising an inner race (1; 1'), an outer race (2; 2') and in between these at least one row of rolling elements (3; 3') with a lubricant, and sealing means (4; 14) between and at the outside of the races, said sealing means each being formed by a generally annular element which at its outer circumference is attached to the outer race (2; 2') and which at its inner circumference includes a sealing lip (7; 16) of a flexible material which is adjacent to the inner race (1; 1'); whereby beside and at some distance from the side facing outward of each annular element (4; 14) a shield (8; 8') of a basically rigid material is placed, which is attached to the outer circumference of the inner race (1; 1'); whereby between the shield (8; 8') and the outer race (2; 2') there is a generally slot-shaped opening (12; 12'); whereby between each annular element (4; 14) and shield (8; 8') a space (13; 13') is formed which is connected via the slot-shaped opening (12; 12') to the environment of the bearing; whereby each shield (8; 8') includes a - with regard to the bearing - axially inwardly projecting ring-part (9; 9') which surrounds the inner race (1; 1'); and whereby said sealing lip (7; 16) of each annular element (4; 14) is basically adjacent to the outer circumference of this ring-part (9; 9'), characterized in that each shield (8; 8') is made of a synthetic material and comprises around the outer circumference of the ring-part (9; 9') an element (10; 10') for the attachment of said shield (8; 8'), against which element (10; 10') the sealing lip (7, 16) of the annular element (4, 14) rests. Rolling bearing according to claim 1, characterized in that the slot-shaped opening (12: 12') is formed just between the bearing race (2; 2') and the end-part of the shield (8; 8').

Inventors: BRAS, JOHAN CHRISTIAAN MARINUS, LANKAMP, HERMAN, DR.
Applicants: SKF INDUSTRIAL TRADING & DEVELOPMENT COMPANY B.V.
Application year: 1985
Main classification: F16C33
IPC codes: F16C33