Bearing sealing device and method of mounting bearing sealing plate

Abstract: A sealing device for a bearing, which includes a bearing outer race (1) or inner race (3) having a sealing groove (2) including a vertical face and a horizontal support face, and a bearing sealing plate (4) constituted by an adhesive material (6) applied to one or both faces of a sealing material (5) having a ring-hole or not. The bearing sealing plate (4) is bonded and fixed to the horizontal support face of the sealing groove (2). There is also disclosed a method of mounting a sealing plate for a bearing, which includes the steps of causing an adhesive material (6) to adhere either to a surface of a bearing sealing plate (4) contacting an outer race (1) or inner race (3) of the bearing, or to the surface of the outer race or inner race of the bearing contacting the bearing sealing plate (4), bringing the bearing sealing plate (4) into contact with the outer race (1) or inner race (3) of the bearing, and bonding and fixing the bearing sealing plate (4) to the outer race or inner race of the bearing for sealing the bearing.

Description: The present invention generally relates to sealing of a bearing, and more particularly, to a sealing device for the bearing and a mounting method of a sealing plate for a bearing. In a conventional sealing plate for a bearing, it is so arranged that a core metal formed by punching a metallic plate is placed in a recess or concave portion of a metal mold for molding by pouring an elastic material therein, and the bearing sealing plate formed thereby is so adapted that its forward edge diameter is slightly larger than an opening diameter of a bearing sealing groove, and a wall face of the sealing groove of an outer race or inner race of the bearing is sunken so as to force the bearing sealing plate into the sealing groove, thus causing the forward edge portion of the sealing plate to depress the wall face of the sealing groove to achieve the sealing. In the known bearing sealing plate as described above, however, there have been disadvantages that, since it is molded by pouring the elastic material into the metal mold and the constructions and shapes of the sealing plate and the bearing sealing groove are complicated, many steps are needed in the manufacture, for example, in the preparation of the metal mold or removal of burr after the molding, etc., thus requiring much time and expenses, with a consequent rise in cost. Meanwhile, miniaturization of various products is now under way, and following such a trend, reduction of the bearing size has been still more strongly demanded, and thus, the bearing sealing plate which can be accommodated in a much smaller space is required. However, in the small sized bearings, the sealing groove must be reduced in its diameter, thus making it difficult to be efficiently processed, and especially, in the case of a deep sealing groove, there is another problem that strength of the outer race or inner race is undesirably lowered. Moreover, in the case where the bearing sealing plate is made of a metallic material, proper performance of the sealing plate tends to be obstructed through deformation of the bearing outer race or inner race, with a possibility of leakage of grease from the outer circumferential portion of the bearing sealing plate. GB-A-599 095 relates to sealed bearings comprising inner and outer bearing members or race rings having a space between them which is closed at one or each end by an annular closure member or plate bonded to an end face of or into a recess in one of the bearing members or race rings. DE-OS-41 35 035 relates to the lateral sealing of a bearing which comprises at least one layer of a heat-resistant plastics material, is inserted between an inner and outer race in correspondingly shaped flanges (Fig. 2) and is permanently fixed to the outer race by means of an adhesive, which also flows into a concavity in the wall of the groove defined by the flange of the outer race. It is an object of the present invention to provide a bearing with a sealing device and a method of mounting a bearing sealing plate in which constructions of a bearing sealing plate and a sealing groove of a bearing outer race or inner race are simplified, and thus, manufacturing steps are reduced for facilitation of manufacture, with a consequent reduction of time and cost, while being suitable for size reduction of the bearing, and the bearing sealing plate positively maintains the desired sealed state with a lasting mounting strength with respect to the bearing. This object is solved with the features of the claims. It is an essential aspect of the present invention that a concave portion formed on a circumferential wall of the sealing groove allows melted adhesive material adhering to the reserve face of the bearing sealing plate or the wall facing axially outward of the sealing groove to flow in due to heating and pressurization of the bearing sealing plate inserted in the sealing groove, and by the solidification of the adhesive material which has thus been directed into the concave portion, such hardened adhesive material increases the mounting strength of said sealing plate with respect to the sealing groove so as to act as a retainer. These and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which; Fig. 1 is a fragmentary cross section showing essential portions of a bearing sealing device, Fig. 2 is a diagram for explaining a method of applying an adhesive material layer on a sealing material, Fig. 3 is a diagram similar to Fig. 2, which particularly shows another method therefor, Fig. 4 is a fragmentary cross section showing essential portions of a bearing sealing device, Fig. 5 is a fragmentary cross section showing essential portions of a bearing sealing device, Fig. 6 is a fragmentary cross section showing essential portions of a bearing sealing device, Fig. 7 is a fragmentary cross section showing essential portions of a bearing sealing device, Fig. 8 is a fragmentary cross section showing essential portions of a bearing sealing device, and Figs. 9(A) and 9(B) are fragmentary cross sections showing essential portions of a bearing with a sealing device according to the present invention and for explaining a method of mounting the bearing sealing plate according to the present invention. Before the description of the present invention proceeds, it is to be noted that like parts are designated by like references numerals throughout the accompanying drawings. Further it has to be noted that Figures 1 to 8 serve illustrative purposes, but the embodiments depicted therein do not fall within the scope of the invention defined in the claims. Referring now to the drawings, there is shown in Fig. 1, a bearing with a sealing device for a bearing, which generally includes a bearing outer race 1 having a sealing groove 2 including a vertical face 2a and a horizontal support face 2b, a bearing inner race 3 and a bearing sealing plate 4 constituted by an adhesive material 6 applied to one or both faces of a sealing material 5 having a ring-hole or not, and the bearing sealing plate 4 is bonded and fixed to the horizontal support face of said sealing groove 2. The bearing sealing plate 4 is of a flat plate, and constituted by covering the surface of the sealing material 5 with the adhesive material 6. The sealing material 5 is made of, for example, metal, natural or synthetic rubber, plastics and the like, and is not limited in the raw material therefor so far as it is provided with air tightness. For the adhesive material layer 6, a material which may be bonded by heating, pressurization or known methods can be used, and although the material itself is not limited, an elastic material with adhering nature including an adhesive material of thermo-plastic property of hot-melt group is preferable. Fig. 2 shows one embodiment of the adhering method of the adhesive material layer 6 onto the sealing material 5 for the bearing sealing plate 4, in which the sealing material 5 drawn out of its roll 5a, and that adhesive material 6 drawn out of its roll 6a respectively are passed between a set of rollers 7 for adhesion to each other under pressure. From the belt-like sheet thus prepared by adhering the adhesive material layer 6 to the sealing material 5, the bearing sealing plates 4 of a desired size are punched out by metal dies (not shown in Fig. 2). Fig. 3 shows another method of producing the bearing sealing plate 4. In this method, the adhesive material 6b contained in a vessel 8 is melted through heating by heating means 10, e.g., an electric heater or the like, and the molten adhesive material 6b is discharged through a nozzle 9 of the vessel 8 onto the upper surface of the sealing material 5 drawn out from a roll 5b, thereby to cause the adhesive material 6b to adhere onto the surface of the sealing material 5. The belt-like sheet thus prepared is blanked by metal dies 11 to prepare the bearing sealing plate 4. In still another method of providing the adhesive material layer 6 on the sealing material 5, it may be so arranged to pass the sealing material 5 through the molten adhesive material 6b so as to apply the adhesive material 6b onto both surfaces of the sealing material 5. For mounting such bearing sealing plate 4 as described so far into the sealing groove 2 in the bearing outer race 1, the sealing plate 4 is fitted into the sealing groove 2, with the adhesive material layer 6 directed downwards (in Figure 1), and by contacting the adhesive material layer 6 with the support face 2b of the sealing groove 2, the sealing plate 4 is heated from above (in Figure 1) so as to melt part or all of the adhesive material layer 6, thereby to cause the sealing plate 4 to adhere to said support face 2b for subsequent cooling and fixing. (Fig. 1). It should be noted here that the heating of the bearing sealing plate 4 may be effected before contact with the support face 2b of the sealing groove 2, and that the heating means for the heating of the sealing plate 4 is not limited to any specific means. It should also be noted that the manufacturing method of the bearing sealing plate 4 is not limited to the above, but may, for example, be so modified as to apply the molten adhesive material onto the surface of the sealing material 5 by a sprayer or by a brush. It is further to be noted that, in the formation of the adhesive material layer on the sealing plate 4, it may be so arranged to cause the adhesive material to adhere thereto by painting, spraying or other methods after punching the sealing material 5 in a desired shape. Moreover, in the embodiment as shown in Fig. 1, it may be so modified that the sealing groove 2 is provided on the inner race 3 instead of being formed on the outer race 1, and the adhesive material layer 6 of the bearing sealing plate 4 is brought into contact with the support face of the sealing groove of the inner race 3 for adhesion by heating. In this case, a lip may be provided on the outer peripheral edge of the sealing plate 4 so as to contact the bearing outer race 1. In a modification as shown in Fig. 4, it is so arranged that the sealing groove 2 is not provided on the bearing outer race 1, but the sealing plate 4A prepared by causing the adhesive material layer 6 to adhere to the sealing material 5 is adapted to contact the upper surface (in Fig. 4) of the bearing outer race 1 at its side of the adhesive material layer 6, and the sealing plate 4A is heated for subsequent forced or spontaneous cooling, thereby to cause the sealing plate 4A to closely contact and to be fixed to the outer race 1. In this case, a clearance is provided between the upper surface (in Fig. 4) of the inner race 3 and the adhesive material layer 6 or the sealing material 5 as shown. The bearing sealing plate 4A in a flat disk-like shape may be modified to be a ring-like shape, and further, to be provided with a known lip in a peripheral edge of its inner hole (not shown). The sealing device in Fig. 4 may be further modified in such a manner that, instead of causing the sealing plate 4A to adhere to the surface of the bearing outer race 1, it may be adapted to adhere to the inner race 3. In that case, it may be so arranged to provide a lip at the outer peripheral edge portion of the bearing sealing plate, so that said lip contacts the bearing outer race. The configurations of the bearing sealing plate are not limited to those as shown in Fig. 1 and Fig. 4. In the bearing sealing plate 4B as shown in Fig. 5, the outer peripheral edge portion 13 is made of a metallic material, and its inner peripheral portion 14 is formed by an elastic material, with the adhesive material layer 6 being provided on the outer peripheral edge portion 13. Moreover, the arrangement may be so modified that the inner peripheral portion 14 is made of a metallic material and the outer peripheral portion 13 is formed by an elastic material in the reverse order as above. In the bearing sealing plates 4 and 4A in Figs. 1 and 4 also, the sealing material made of two kinds of materials may be employed as in the bearing sealing plate 4B in Fig. 5. In the sealing plate 4A in Fig. 4, the outer peripheral edge portion and the inner portion may be formed either by a metallic material or elastic material. The bearing sealing plate 4C as shown in Fig. 6 is of a ring-like shape, with a ring-shaped protrusion 5C being formed along an inner hole edge of the ring, and the adhesive material layer 6 is provided on the face of the sealing material 5 at its side of the protrusion 5C (excluding the under surface of the protrusion 5C) or on the outer side face of the protrusion 5C continuous on said face. The lip in the inner hole of the sealing plate 4C is abbreviated for brevity in the drawing. In the sealing plate 4C, since the adhesive material layer 6 is not provided on the under surface of the protrusion 5C in the ring-like shape, an unused sealing plate 4C may be overlapped therewith for storing. Furthermore, in the sealing plate 4C, it may be so modified to place the outer peripheral portion of the sealing plate 4C on the upper surface (in Fig. 6) of the bearing outer race 1 for use by adhering, without providing the sealing groove 2 on the outer race 1. Moreover, in the bearing sealing plate 4C, the protrusion 5C may be provided on the outer peripheral edge of the sealing plate, instead of being provided on the ring inner hole edge. The bearing sealing plate 4D as shown in Fig. 7 is of a ring-shape, and includes an outer peripheral portion 17 in a horizontal plane, an intermediate portion 18 inclined upwardly from the portion 17, and an inner hole edge portion 19 extending horizontally laterally from said intermediate portion 18 as shown, with an adhesive material layer 6 is provided on the under surface of said outer peripheral portion 17. A lip may further be provided along the inner hole edge. In the case where the bearing sealing plate 4D is fitted into a sealing groove 20 of a conventional bearing outer race 1 for use, after contacting the adhesive material layer 6 on the under surface of the outer peripheral portion 17 of the fitted sealing plate 4D, with the support face 20a of the sealing groove 20, the sealing plate 4D is heated, and thereafter, cooled so as to be bonded and fixed to said support face 20a. Moreover, it may be so modified that the bearing sealing plate 4D is bonded and fixed onto the upper surface (in Fig. 7) of the bearing outer race 1 not provided with the sealing groove 20. In such a case, thickness (i.e., height in Fig. 7) of the bearing outer race 1 is made thinner than that of the inner race 3. As shown in Fig. 8, it is possible to improve the sealing performance of the conventional bearing by using a conventional outer race 1 provided with the sealing groove 20 and a conventional bearing sealing plate 4E, and providing the adhesive material layer 6 on the surface contacting the support face 20a of the sealing groove 20 at the bottom face of the sealing plate 4E so as to melt the adhesive material 6 through heating for subsequent bonding and fixing. Similar effect may be obtained also with respect to the conventional construction in which the sealing groove is provided on the inner race for fitting of the bearing sealing plate. Conventionally, in the bearing sealing plates made of metallic materials, there are available the sealing plates of curl type, root type and washer type, each of which, however, has a problem in the sealing performance. Even in the bearing sealing plates of metallic materials, the sealing performance may be improved by providing the adhesive material layer 6 on the surfaces contacting the concave portion of the sealing groove of the outer race or the support face of the sealing groove, and by bonding the metallic sealing plate with the bearing outer race with the adhesive material. In any of the foregoing embodiments, the layers or films may be formed through employment of the known adhesive material or elastic material with adhesive nature as the adhesive material of the adhesive material layer 6, and the adhesive material is not limited to the thermo-plastic adhesive material. Moreover, in any of the foregoing embodiments, it may be so arranged to cause the adhesive material to adhere to the surface of the bearing outer race or inner race contacting the sealing plate instead of subjecting the adhesive material to adhere to the sealing plate. Furthermore, in any of the foregoing embodiments, the adhesion between the bearing sealing plate and the bearing outer race or inner race is not limited to that by the heating method, but heating, pressurization or known methods therefor may be employed according to the nature of the adhesive material. Figs. 9(A) and 9(B) show a bearing sealing device and a method for mounting the bearing sealing plate according to the present invention. Specifically, a sealing groove 24 including a circumferential wall 24a, a concave portion 25 and a wall 2b facing axially outward of the groove 24 is provided on the bearing outer race 1. The concave portion 25 is continuously or intermittently formed on the entire surface of the vertical face 24a. The bearing sealing plate 4F is provided with a rather thick adhesive material layer 6F of a thermo-plastic resin formed on at least one surface of a sealing material 5F. This adhesive material layer 6F is adapted to be slightly thicker over the entire surface or at least on the outer peripheral portion thereof. The sealing plate 4F is inserted into the sealing groove 24, with the adhesive material layer 6F directed downward, and thus, the adhesive material layer 6F is caused to adhere to the wall 2b of the sealing groove 24. Then, the sealing plate 4F is heated and pressurized, and part of the molten adhesive material is depressed so as to flow into the concave portion 25 provided in the vertical face 24a and to be filled therein. Subsequently, the bearing sealing plate 6F is subjected to natural or forcible cooling or drying, thereby to solidify the adhesive material. In the bearing sealing plate 4F mounted in the above described method, the protruding portion 6Fa of the adhesive material layer 6F hardened in the concave portion 25 prevents the sealing plate 4F from coming off the sealing groove 24, thus positively maintaining the mounting strength to the bearing outer race. It should be noted here that the arrangement may, for example, be so modified that the sealing groove 24 is provided on the inner race 3 instead of the outer race 1, with a concave portion equivalent to the concave portion 25 being provided in said sealing groove. In such a case, the bearing sealing plate is provided with a rather thick adhesive material layer of a thermo-plastic resin formed on at least one surface of the sealing material. This adhesive material layer is adapted to be slightly thicker over the entire surface or at least on the inner peripheral portion. In this case, the mounting method of the bearing sealing plate and formation of the protrusion of the adhesive layer and its effect, etc. are similar to those in the above arrangement. As is clear from the foregoing description, according to the present invention, favorable effects as follows may be obtained. Since the constructions of the bearing sealing plate, and the sealing grooves in the bearing outer race or inner race are simple for facilitation of manufacture, less time and cost are required in the manufacture as compared with conventional arrangements. In the manufacture of the bearing sealing plate of the present invention, removal of burr as in the conventional arrangements is not required. According to the present invention, the sealing groove of the bearing outer race or inner race may be simply constituted by the circumferential wall, the concave portion and the wall facing axially outward of the groove, and the wall face of the sealing groove is not required to be curved as in the conventional constructions. Moreover, since the bearing outer race or inner race formed with the sealing groove itself may be employed, higher strength can be achieved as compared with conventional outer race or inner race. In the conventional bearings, since the sealing plate is fitted into the sealing groove provided in the bearing outer race or inner race, a space is required therefor, with a consequent increase of diameter and thickness of the bearing, thus presenting a bottleneck for the size reduction of bearings. According to the present invention, however, owing to the fact that the constructions of the sealing groove of the outer race or inner face, and of the sealing plate are simplified, diameter and thickness of the bearing can be reduced for compact size of the bearing. In the present invention, where in the adhesive material of the adhesive material layer is continuously directed into said concave portion to be filled therein for solidification, the hardened adhesive material in said concave portion acts as a retainer or anchor for the bearing sealing plate, thereby providing higher mounting strength of the sealing plate. Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention as defined in the claims, they should be construed as included therein.

Claims: A bearing with a sealing device, which comprises a bearing outer race (1) and inner race (3), one of them having a sealing groove (24) including a circumferential wall (24a), a concave portion (25) protruding into the circumferential wall, and a wall (2b) facing axially outward of the groove (24), and a bearing sealing plate (4F) constituted by an adhesive material (6F) applied to at least one face of a sealing material (5F) having a ring-hole or not, wherein the adhesive material (6F) fills the concave portion (25) and the gap between the periphery of the sealing plate (4F) and the circumferential wall (24a) of the groove (24). A bearing as claimed in Claim 1, wherein said bearing sealing plate (4F) is constituted by two kinds of sealing materials including a metallic material and an elastic material. A bearing as claimed in any one of claims 1 or 2, wherein the concave portion (25) of the sealing groove (24) is formed continuously or intermittently all over an entire periphery of said circumferential wall (24a). A bearing as claimed in any one of Claims 1 to 3, wherein said adhesive material (6) is made of an elastic material having adhesion. A bearing as claimed in any one of claims 1 to 4, wherein the adhesive material layer (6F) is being made thicker entirely or in the vicinity of an outer periphery of said sealing material (5F). A method of mounting a sealing plate for a bearing as claimed in any one of Claims 1 to 5, which comprises the steps of: a) providing on either a bearing outer race (1) or inner race (3), a sealing groove (24) including a circumferential wall (24a), a concave portion (25) and a wall (2b) facing axially outward of the groove (24), b) forming a bearing sealing plate (4F) by applying an adhesive material layer (6F) made of a thermo-plastic resin adhesive material at least onto one face of a sealing material (5F), having a ring hole or not, c) bringing said bearing sealing plate (4F) into contact with said wall (2b) facing axially outward of said sealing groove (24), d) heating said bearing sealing plate (4F) to fuse the adhesive material (6F), and e) filling said molten adhesive material (6F) by causing said adhesive material to flow into said concave portion (25) and the gap between the periphery of the sealing plate (4F) and the circumferential wall (24a) of the groove (24), thereby to solidify said adhesive material (6F) through natural or forced cooling. A method as claimed in claim 6, wherein the bearing sealing plate (4F) is inserted into the sealing groove (24) with said adhesive material layer (6F) directed downward. A method of mounting a sealing plate in a bearing as claimed in any one of claims 1 to 5, which comprises the steps of: a) providing on either a bearing outer race (1) or inner race (3), a sealing groove (24) including a circumferential wall (24a), a concave portion (25) and a wall (2b) facing axially outward of the groove (24), b') applying an adhesive material layer (6F) made of a thermo-plastic resin adhesive material onto an entire face of said wall (2b) facing axially outward of the groove (24), with said adhesive material layer (6F) being made thicker entirely or in the vicinity of the concave portion of said circumferential wall (24a), c') inserting a bearing sealing plate (4F) constituted by a sealing material (5F) into said sealing groove (24) so as to contact the adhesive material layer on said wall (2b) facing axially outward of the groove (24), d) heating said bearing sealing plate (4F) to fuse the adhesive material (6F), and e) filling said molten adhesive material (6F) by causing said adhesive material to flow into the concave portion (25) and the gap between the periphery of the sealing plate (4F) and the circumferential wall (24a) of the groove (24), thereby to solidify said adhesive material through natural or forced cooling.

Inventors: SAIGUSA SHIGEHARU, SAIGUSA, SHIGEHARU
Applicants: TOYO SEAL IND CO LTD, TOYO SEAL INDUSTRIES,CO.,LTD.
Application year: 1993
Main classification: F16C33
IPC codes: F16C33, F16J15