JP7219706B2 - Rolling bearing and rolling bearing manufacturing method - Google Patents

Description

The present invention relates to a rolling bearing and a method of manufacturing the rolling bearing.

Rolling bearings are widely used in various fields. A typical rolling bearing includes an inner ring, an outer ring, and multiple rolling elements. Furthermore, a rolling bearing equipped with a sealing member is used to prevent water, foreign matter, etc. from entering the bearing from outside the bearing where the rolling elements are present, and to prevent the grease inside the bearing from flowing out of the bearing. It has been known. Patent Document 1 discloses a rolling bearing provided with an annular shield plate as a sealing member. As a sealing member other than the shield plate, a seal having an annular core and a rubber lip attached to the core is known. In such seals, electrogalvanized steel sheets (SECC), which are relatively inexpensive, are used as the material of the core bar.

Conventionally, in order to attach the above-described sealing member to the outer ring, a circumferential groove is formed on the inner peripheral side of the outer ring, and a portion of the sealing member is fitted into this circumferential groove. In order to secure the fixing of the sealing member, it is preferable to widen the circumferential groove to some extent in the axial direction. However, in the case of a rolling bearing designed to be slim by reducing its axial dimension, the space for the circumferential groove is limited, making it difficult to reliably fix the sealing member to the outer ring.

JP 2008-51304 A

A rolling bearing according to an aspect of the present invention includes an outer ring and an inner ring as bearing rings, a plurality of rolling elements interposed between the outer ring and the inner ring, and one bearing ring of the outer ring and the inner ring. An annular seal attached to the side surface of the, wherein the seal is a stainless steel annular core metal that is superimposed on the side surface and attached by welding as a joint surface between the side surface and the core metal and a rubber lip fixed to a portion of the core bar on the other bearing ring side via an adhesive provided throughout.

A method for manufacturing a rolling bearing according to an aspect of the present invention includes welding an annular seal to a bearing portion having an outer ring and an inner ring as bearing rings and a plurality of rolling elements interposed between the outer ring and the inner ring. In the mounting method, the seal comprises a stainless steel ring-shaped metal core welded to the side surface of one of the outer ring and the inner ring, and an adhesive applied to the entire core metal. and a rubber lip fixed to a part of the core metal on the other race side of the core metal via a lip, the core metal being superimposed on the side surface, and the side surface and the core metal A welding step of performing laser welding from the front surface of the core metal so that the space between the core metal is a joint surface, and in the welding step, the core metal and the The heat of welding decomposes the adhesive existing on the joint surface before the metal around the joint surface between one bearing ring melts.

It is a sectional view showing an example of a rolling bearing of the present invention. FIG. 4 is an enlarged cross-sectional view showing a radially outer portion of the seal and a portion of the outer ring; FIG. 4 is a cross-sectional view for explaining part of the cored bar before being welded to the outer ring; It is a perspective view which shows a welding process. It is an image figure which shows the state in the middle of welding. It is a figure which shows the specification of the rolling bearing of this embodiment, and an example of the welding conditions in a welding process.

<Problems to be solved by the present disclosure>
A means of fixing the sealing member to the outer ring by welding is conceivable. For example, a metal core is placed on the side surface of the outer ring, and the surface of the metal core is irradiated with a laser beam for welding.

In the case of a seal, the core bar is provided with a rubber lip. The lip is provided through an adhesive applied to the core bar so as not to interfere with welding. Even if the lip is provided only on a portion of the core bar, the adhesive is applied to the entire core bar from the viewpoint of ease of application of the adhesive to the core bar.

If the material of the mandrel is electrogalvanized steel plate or ordinary steel, it has high thermal conductivity. Melting of the cored bar immediately progresses up to . Moreover, at the same time that the metal around the joint surface is melted, the adhesive applied to the entire core metal, which is present on the joint surface, is decomposed to generate gas. As a result, the generated gas blows off the molten metal at the joint surface, or the generated gas forms bubbles in the molten metal and remains in a large amount. Conventionally, defects such as pits and porosity are likely to occur in the welded portion (penetration portion), and such defects cause loss of the sealing performance for which the seal is provided.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to suppress the occurrence of poor welding due to an adhesive in a rolling bearing to which a seal is attached by welding.

<Overview of Embodiments of the Present Invention>
Hereinafter, the outline of the embodiments of the present invention will be listed and described.

The rolling bearing of this embodiment includes an outer ring and an inner ring as bearing rings, a plurality of rolling elements interposed between the outer ring and the inner ring, and a side surface of one of the outer ring and the inner ring. An annular seal is attached, and the seal is provided on the entirety of a stainless steel annular core bar that is superimposed on the side surface and attached by welding with the joint surface between the side surface and the side surface. and a rubber lip fixed to a portion of the core bar on the side of the other bearing ring via an adhesive.

In this rolling bearing, the core metal of the seal is fixed to one of the outer ring and the inner ring by welding. Since the core metal is made of stainless steel, its thermal conductivity is lower than that of electrogalvanized steel sheets and ordinary steel. For this reason, when welding is performed, the progress of melting of the core metal to the joint surface between one bearing ring and the core metal is delayed. Also, the decomposition temperature of the adhesive is sufficiently lower than the melting temperature of the core metal. Therefore, the adhesive existing on the joint surface is decomposed before the metal surrounding the joint surface melts, and gas is generated and diffused. Therefore, it is possible to prevent the molten metal from being blown away by the gas. In addition, since the temperature of the metal core made of stainless steel does not easily drop, the liquid phase remains for a long time when melted. Therefore, even if part of the molten metal core is blown away by the gas generated by the decomposition of the adhesive and the thickness is insufficient, a sufficient amount of time can be secured to fill in the insufficient thickness. As a result, it is possible to suppress the occurrence of welding defects.

The core metal has an annular portion attached to the side surface by welding, and the annular portion has a contact surface that contacts the side surface and a contact surface that faces the side surface and extends radially from the contact surface. and a sloping surface away from the side surface. In this case, the core bar contacts the side surface of one bearing ring at the contact surface, but a gap is formed between the contact surface and the side surface in a region extending radially from the contact surface. Therefore, during welding, the gas generated by the decomposition of the adhesive on the joint surface between one bearing ring and the core metal can escape to the outside through the gap. Therefore, it is possible to more effectively prevent the molten metal from being blown away by the gas.

Moreover, it is preferable that the core bar has a bent portion that is bent in the axial direction from the annular portion. In this case, the gas generated by the decomposition of the adhesive on the joint surface between one bearing ring and the core bar can escape from the bent portion side. Therefore, it is possible to more effectively prevent the molten metal from being blown away by the gas.

The manufacturing method of the rolling bearing of the present embodiment is a method of attaching an annular seal to a bearing portion provided with an outer ring and an inner ring as bearing rings and a plurality of rolling elements interposed between the outer ring and the inner ring by welding. The seal is composed of a stainless steel annular core metal attached by welding to the side surface of one of the outer ring and the inner ring, and an adhesive provided on the entire core metal. and a rubber lip fixed to a part of the core metal on the side of the other raceway ring, the core metal being in a state of being superimposed on the side surface, and the gap between the side surface and the core metal. A welding step of performing laser welding from the front surface of the core metal so as to be a joint surface, and in the welding step, the core metal and the one raceway are separated by the metal core being made of stainless steel. The heat of welding decomposes the adhesive present on the joint surface before the metal surrounding the joint surface between the rings melts.

According to this manufacturing method, it is possible to prevent the molten metal from being blown away by the gas generated by the decomposition of the adhesive. In addition, since the temperature of the metal core made of stainless steel does not easily drop, the liquid phase remains for a long time when melted. Therefore, even if part of the molten metal core is blown away by the gas generated by the decomposition of the adhesive and the thickness is insufficient, a sufficient amount of time can be secured to fill in the insufficient thickness. As a result, it is possible to suppress the occurrence of welding defects.

Further, during the welding, the core metal is axially pressed against the side surface and restrained, and the core metal and the side surface are partially in contact with each other. It is preferable to adjust the force to push the cored bar in the axial direction so that the other portion of the core bar is not in contact with the other portion. According to this method, a portion of the core bar contacts the side surface of one bearing ring, but a gap is formed between the side surface and the other portion adjacent to the radial direction of the portion. Therefore, the gas generated by the decomposition of the adhesive on the joint surface between one bearing ring and the core bar can escape to the outside through the gap. Therefore, it is possible to more effectively prevent the molten metal from being blown away by the gas.

<Effects of the present disclosure>
According to the present disclosure, it is possible to suppress the occurrence of poor welding in a rolling bearing to which a seal is attached by welding.

<Details of the embodiment of the present invention>
[Regarding rolling bearings]
FIG. 1 is a sectional view showing an example of the rolling bearing of the present invention. The rolling bearing 7 includes an inner ring 10 , an outer ring 20 , a plurality of balls (rolling elements) 30 provided between the inner ring 10 and the outer ring 20 , an annular retainer 35 and an annular seal 40 . The rolling bearing 7 shown in FIG. 1 is a deep groove ball bearing.

The inner ring 10 is a cylindrical member that is externally fitted and fixed to a shaft (not shown), and a raceway (raceway groove) 11 in which the balls 30 roll is formed on the outer periphery. The outer ring 20 is a member that is fitted and fixed to the inner surface of a housing (not shown), and has a raceway (raceway groove) 21 along which the balls 30 roll. A plurality of balls 30 are interposed between the inner ring 10 and the outer ring 20, and the inner ring 10 and the outer ring 20 are arranged concentrically. The retainer 35 retains the plurality of balls 30 at predetermined intervals (equal intervals) along the circumferential direction. In this embodiment, the inner ring 10 is a rotating ring that rotates with the shaft, and the outer ring 20 is a stationary ring that remains stationary with the housing.

Grease is filled as a lubricant in the bearing interior 5 between the inner ring 10 and the outer ring 20 where the balls 30 are present. The seal 40 prevents water and foreign matter present outside the bearing from entering the bearing interior 5 and prevents grease in the bearing interior 5 from flowing out of the bearing.

The seals 40 are provided on both axial sides of the rolling bearing 7 . Each seal 40 is attached to the side 23 of the outer ring 20 by welding. Laser welding is employed in this embodiment. A portion of the lip 42 of this seal 40 contacts a portion of the inner ring 10 (the circumferential groove 12 in this embodiment). The seal 40 on one side in the axial direction and the seal 40 on the other side in the axial direction have the same configuration although their mounting directions are opposite.

The inner ring 10, outer ring 20 and balls 30 are made of bearing steel. The retainer 35 is made of resin or metal such as stainless steel (metal press). The seal 40 has an annular core metal (metal ring) 41 and a lip 42 . The core bar 41 is made of stainless steel (SUS304 or SUS430). The lip 42 is made of rubber and has elasticity. SUJ2 can be used as the bearing steel for the inner ring 10, the outer ring 20, and the balls 30, but other steel materials may also be used. The material of the inner ring 10, the outer ring 20 and the balls 30 may be stainless steel.

[Regarding the seal 40]
The seal 40 has an annular core 41 and a lip 42 as described above. The lip 42 is provided only on a portion of the radially inner side (inner ring 10 side) of the cored bar 41 . A portion of the radially outer side (on the outer ring 20 side) of the cored bar 41 is fixed to the outer ring 20 by welding.

The metal core 41 is obtained by pressing a flat plate member made of stainless steel, and has a small thickness. The thickness t of the cored bar 41 is, for example, 0.1 mm or more and 0.5 mm or less, and is a thin annular member. The inner diameter of the seal 40 is, for example, 10-150 millimeters. The core bar 41 has a first bent portion 43, an annular portion 44, a second bent portion 45, and a body portion 46 from the radially outer side. The core metal 41 is provided over the side surface 25 of the outer ring 20 and is attached by welding with the space between the side surface 25 as a joint surface.

FIG. 2 is an enlarged cross-sectional view showing a radially outer portion of the seal 40 and a portion of the outer ring 20. As shown in FIG. A concave peripheral groove 24 is formed in the side portion 23 of the outer ring 20 . The concave circumferential groove 24 has a side surface 25 facing one side in the axial direction and an inner circumferential surface 26 facing radially inward. The side surface 25 serves as a mounting surface for fixing the cored bar 41 by welding. A joint surface J is formed by welding between the side surface 25 and an annular side surface 49 of the annular portion 44 which is a part of the cored bar 41 . A portion of the weld penetration 27 is present on the joint surface J. As shown in FIG. The melt-in portion 27 is a portion where a portion of the core metal 41 (annular portion 44) and a portion of the outer ring 20 are melted together, and is also called a nugget or a bead. A gap is provided between the inner peripheral surface 26 and the metal core 41 (first bent portion 43). The side surface 25 is provided along an imaginary plane F orthogonal to the central axis C of the rolling bearing 7 (see FIG. 1). A central axis C of the rolling bearing 7 coincides with the central axes of the inner ring 10 , the outer ring 20 and the seal 40 .

A concave rounded corner portion 24a is formed in the concave circumferential groove 24, and a part of the first bent portion 43 is a convex rounded portion 43a. The curvature radius of the convex rounded portion 43a is larger than the curvature radius of the corner rounded portion 24a. Further, as described above, a gap is provided between the inner peripheral surface 26 and the metal core 41 (first bent portion 43). This prevents the edge portion (first bent portion 43 ) of the cored bar 41 from interfering with the rounded corner portion 24 a so that the entire cored bar 41 is lifted from the side surface 25 .

The annular portion 44 is an annular portion that is provided along the side surface 25 of the outer ring 20, is provided overlapping the side surface 25, and is attached to the side surface 25 by welding as a joint surface J. FIG. 3 is a cross-sectional view illustrating part of the core bar 41 before being welded to the outer ring 20. As shown in FIG. FIG. 3 shows a state in which the metal core 41 is placed on the side surface 25 (state before welding). The annular portion 44 has a contact surface 47 that contacts the side surface 25 and an inclined surface 48 that faces the side surface 25 and axially separates from the side surface 25 as it extends radially inward from the contact surface 47 . In this embodiment, the entire annular side surface 49 of the annular portion 44 on the side of the outer ring 20 is a tapered surface. With the contact surface 47 in contact with the side surface 25, the maximum value of the gap e formed between the inclined surface 48 and the side surface 25 is, for example, about 0.02 mm to 0.05 mm.

As will be described later in the manufacturing method, when welding the core metal 41 to the outer ring 20, the core metal 41 is pressed against the side surface 25 in the axial direction (in the case of FIG. is constrained. The cored bar 41 is axially pushed in the body portion 46 by a jig (not shown). Therefore, the cored bar 41 is elastically deformed in a region including the annular portion 44 . The contact area between the contact surface 47 and the side surface 25 becomes wider than the state before welding (the state shown in FIG. 3). In this contact area welding is performed and a penetration 27 (see FIG. 2) is formed in the contact surface 47 . The metal core 41 is axially pressed against the side surface 25, but the welding is performed with the gap e left.
As described above, in the welded rolling bearing 7 , the annular portion 44 (see FIG. 2 ) has the contact surface 47 including (a part of) the penetration portion 27 and contacting the side surface 25 and the inclined surface 48 . The inclined surface 48 faces the side surface 25 and has a shape that separates from the side surface 25 in the radial direction from the contact surface 47 . Note that the inclined surface 48 may have a shape that separates from the side surface 25 toward at least one of radially inward and outward from the contact surface 47 . In this embodiment, the inclined surface 48 separates from the side surface 25 as it goes radially inward from the contact surface 47 .

In FIG. 2, the first bent portion 43 is a portion that is axially bent from the annular portion 44 . More specifically, the first bent portion 43 is a portion that extends radially outward from the annular portion 44 and extends axially. A boundary between the annular portion 44 and the first bent portion 43 is indicated by a two-dot chain line. The first bent portion 43 is out of contact with the side surface 25 and the inner peripheral surface 26 of the outer ring 20 .

The second bent portion 45 includes a first portion 51 axially bent from the annular portion 44 and a second portion 52 radially bent from the first portion 51 . The second bent portion 45 is out of contact with the side surface 25 of the outer ring 20 due to the clearance e. A boundary between the annular portion 44 and the second bent portion 45 is indicated by a two-dot chain line.

In FIG. 2, the main body 46 has an annular flat plate portion without irregularities, and this flat plate portion is provided parallel to the imaginary plane F described above. However, as shown in FIG. 1, the end portion of the body portion 46 on the inner ring 10 side has a bent portion. A lip 42 is fixed to this bent portion.

The lip 42 is made of nitrile, silicon, acrylic, or fluorine rubber and has elasticity. An adhesive 50 is applied to the entire surface of the cored bar 41 to fix the lip 42 to a portion of the cored bar 41 . The lip 42 is provided only on a portion of the cored bar 41 , whereas the adhesive 50 is applied to the entire surface (whole surface) of the cored bar 41 . This is because it is easier to apply the coating to the entire surface than the coating, and is advantageous in terms of the total cost. This cored bar 41 is installed in a mold, and a lip 42 is formed by the mold. That is, the seal 40 is manufactured by insert molding with the metal core 41 mounted in a mold. The adhesive 50 used for bonding the core bar 41 and the lip 42 is phenol resin or epoxy. The thickness of the adhesive 50 applied to the entire surface of the cored bar 41 is, for example, 1 micrometer or more and 5 micrometers or less. In the portion of the core metal 41 covered by the lip 42, a layer (cured layer) of the adhesive 50 is interposed between the core metal 41 and the lip 42, and the portion not covered by the lip 42. , the layer of adhesive 50 (cured layer) is exposed.

As described above, the radial outer portion of the metal core 41 of the seal 40 is laser-welded, and the seal 40 is attached to the side surface 25 of the outer ring 20 by welding. More specifically, a midway portion (annular portion 44), which is radially inward by a predetermined dimension from the outer peripheral edge of the cored bar 41, is laser-welded. In this embodiment, the entire circumference is welded along the circumferential direction. The core bar 41 of this embodiment has a first bent portion 43 and a second bent portion 45 . Therefore, the rigidity of the cored bar 41 is high, and distortion of the cored bar 41 due to welding is suppressed.

[Regarding the manufacturing method of the rolling bearing 7]
A method of manufacturing the rolling bearing 7 having the above configuration will be described. Referring to FIG. 1, in this manufacturing method, first, the inner ring 10, the outer ring 20, the balls 30, and the retainer 35 are assembled and integrated to form the bearing portion 8, which is an intermediate product (assembly step). Before welding, the seal 40, which is separate from the bearing portion 8, has the ring-shaped metal core 41 made of stainless steel and the lip 42 made of rubber, as described above. The lip 42 is provided on a portion of the core metal 41 on the inner ring 10 side via an adhesive 50 provided (applied) to the entire core metal 41 .

Next, a preparatory step is performed in which a portion (annular portion 44 ) of the seal 40 is superimposed on the side surface 25 of the outer ring 20 of the bearing portion 8 . After that, a welding process is performed for laser welding (fiber laser welding) the seal 40 to the side surface 25 of the outer ring 20 (see FIG. 4). In the case of the rolling bearing 7 shown in FIG. 1 , the preparatory step and the welding step are performed on one axial side of the bearing portion 8 , and then the preparatory step and the welding step are performed on the other axial side of the bearing portion 8 . By completing the welding process, the rolling bearing 7 is completed.

In the preparation process and the welding process, laser welding is performed from above with the central axis C of the bearing portion 8 as the vertical direction (see FIG. 4). In this embodiment, the bearing portion 8 with the seal 40 overlaid thereon is placed on the rotating stage 38 . A laser irradiation port (head) 39 that irradiates the laser beam L is in a stationary state, and a rotating stage 38 is rotationally driven to perform welding along the circumferential direction. Also, gas is injected from the assist gas injection port 37 . The focal length of the laser beam L can be changed at the laser irradiation port 39 , and the output of the laser beam L can be changed by the welding device having the laser irradiation port 39 . In this way, in the welding process, as shown in FIGS. 4 and 5, the metal core 41 is superimposed on the side surface 25 of the outer ring 20 so that the joint surface J is formed between the side surface 25 and the metal core 41. Then, laser welding is performed from the front surface 44a of the metal core 41 opposite to the joint surface J. As shown in FIG.

Further, in the welding process, the cored bar 41 is pressed axially downward against the side surface 25 and restrained. The cored bar 41 is pressed against the side surface 25 by a jig (not shown) in the body portion 46 (see FIG. 5). This pressing force is set to a predetermined value. More specifically, the core metal 41 is arranged so that the core metal 41 and the side surface 25 are partially in contact with each other, but are not in contact with each other adjacent to the radially inner side of the core metal 41 . Adjust the pushing force in the axial direction. The portion that contacts the side surface 25 is the contact surface 47 , and the other portion that is not in contact with the side surface 25 is the inclined surface 48 . The gap e is left between the inclined surface 48 and the side surface 25, and welding is performed while maintaining this state.

FIG. 5 is an image diagram showing a state in the middle of welding. 5 shows a state immediately after the front surface (upper surface) 44a of the annular portion 44 of the cored bar 41 is irradiated with the laser beam L. As shown in FIG. In this state, the melting of the cored bar 41 has not progressed to the joint surface J, that is, the annular side surface 49 of the annular portion 44 . In FIG. 5, the area where the metal core 41 is melted by the laser beam L is indicated by cross hatching.

Here, a layer of the adhesive 50 (a layer obtained by curing the adhesive 50) is formed on the entire surface of the core metal 41 as described above. Therefore, a layer of the adhesive 50 is also formed on the annular portion 44 (annular side surface 49 ) of the cored bar 41 .

When the front surface (upper surface) 44a of the annular portion 44 is irradiated with the laser beam L, the core metal 41 melts in the irradiated region. The core metal 41 is made of stainless steel and has low thermal conductivity. For this reason, the melting of the cored bar 41 is delayed as compared with conventionally used electrogalvanized steel sheets (SECC). Although the core metal 41 has a low thermal conductivity, due to the high heat generated by the laser beam L, the back surface 44b (lower surface, annular side surface 49) of the annular portion 44 is immediately heated to the decomposition temperature (approximately 300° C.) of the adhesive 50. reach. Therefore, the bonding surface J reaches the decomposition temperature before the temperature at which the metal core 41 melts, that is, before the bonding surface J side melts, and the decomposition of the adhesive 50 is started. occurs. Gas generated by decomposition of the adhesive 50 on the joint surface J is released to the outside (atmosphere) through the gap e and from the first bent portion 43 side, as indicated by arrow G in FIG. Incidentally, the thermal conductivity of the stainless steel used for the metal core 41 in this embodiment is 0.16 W/m° C.×10̂2. On the other hand, the thermal conductivity of electrogalvanized steel sheet (SECC) is 0.58 W/m° C.×10̂2.

FIG. 6 shows an example of specifications of the rolling bearing 7 of this embodiment and welding conditions in the welding process. The laser output has a pulse waveform for welding. Welding conditions such as the duty ratio may be other than the conditions shown in FIG. 6 and can be changed. Also, the size of the rolling bearing to be applied can be changed.

As described above, the manufacturing method of the rolling bearing 7 in which the annular seal 40 is welded to the assembled bearing portion 8 includes the following steps. In other words, this manufacturing method includes a welding step (see FIG. 4) for welding the metal core 41 and the outer ring 20 together. In this welding process, since the cored bar 41 is made of stainless steel, the metal around the jointed surface J (see FIG. 5) between the cored bar 41 and the outer ring 20 is present on the jointed surface J before it melts. The adhesive 50 is decomposed by the heat of welding.

In the rolling bearing 7 manufactured by the manufacturing method described above, the core metal 41 of the seal 40 is fixed to the outer ring 20 by welding. Since the metal core 41 is made of stainless steel, it has low thermal conductivity. For this reason, as described above, when welding is performed, progress of melting of the core metal 41 to the joint surface J between the outer ring 20 and the core metal 41 is delayed. Also, the decomposition temperature of the adhesive 50 is sufficiently lower than the melting temperature of the cored bar 41 . Therefore, as explained with reference to FIG. 5, the adhesive 50 existing on the joint surface J is decomposed before the metal surrounding the joint surface J is melted. Therefore, it is possible to prevent the melted metal from being blown away by the gas generated by the decomposition of the adhesive 50 . In addition, since the temperature of the metal core 41 made of stainless steel does not easily drop, the liquid phase remains for a long time after being melted. Therefore, even if part of the molten metal core 41 is blown away by the gas generated by the decomposition of the adhesive 50 and the thickness is insufficient, a sufficient amount of time is secured for filling the insufficient thickness. As a result, it is possible to suppress the occurrence of welding defects.

Further, during welding, as described above, the core metal 41 is axially pressed against the side surface 25 and restrained. At this time, the force to push the core metal 41 in the axial direction is adjusted so that the core metal 41 and the side surface 25 are partially in contact with each other, but are not in contact with each other in the radial direction adjacent to the core metal 41 . be done. According to this method, the cored bar 41 is partially in contact with the side surface 25, but a gap e is formed between the side surface 25 and the other portion adjacent to this portion in the radial direction (see FIG. 5). Therefore, the gas generated by the decomposition of the adhesive 50 on the joint surface J between the outer ring 20 and the core bar 41 can escape to the outside through the gap e. Therefore, it is possible to more effectively prevent the molten metal from being blown away by the gas.

Further, as shown in FIG. 5, the cored bar 41 has a first bent portion 43 that is bent axially from the annular portion 44 . Therefore, the gas generated by the decomposition of the adhesive 50 on the joint surface J can escape from the bent portion 43 side. Therefore, it is possible to more effectively prevent the molten metal from being blown away by the gas.

According to the rolling bearing 7 manufactured by the manufacturing method described above, the outer ring 20 and the seal 40 can be firmly joined, and defects such as pits and porosity are prevented from occurring in the welded portion (penetration portion 27). It can be suppressed, and the sealing performance is also high. Since the seal 40 is fixed to the outer ring 20 by welding, a conventional wide mounting groove for fitting is not required, and the axial dimension of the rolling bearing 7 can be reduced (slimmed). Since the seal 40 is provided within the axial range of the concave circumferential groove 24 (see FIG. 2), the seal 40 does not protrude from the bearing portion 8 in the axial direction.

[About others]

The core bar 41 shown in FIGS. 1 and 2 has a first bent portion 43, an annular portion 44, a second bent portion 45, and a body portion 46 in order from the radially outer side. In FIG. 2 , a circumferentially continuous recess 59 is formed in a region surrounded by the first bent portion 43 , the annular portion 44 and the second bent portion 45 . A part of the melt-in portion 27 exists in this concave portion 59 . The recessed portion 59 prevents the welded portion 27 from protruding from the side surface of the outer ring 20 .

The second bent portion 45 has a shape extending axially outward (to the right in FIG. 1) toward the inner ring 10 side. The second bent portion 45 is connected to a flat, ring-shaped body portion 46 . According to the second bent portion 45 , the main body portion 46 is located axially outside the annular portion 44 and widens the distance from the retainer 35 . Grease can be present in this widened area. As a result, the amount of grease enclosed inside the bearing 5 increases.

In the case of the seal 40 of the present embodiment, in the preparatory step, the area between the first bent portion 43 and the second bent portion 45, that is, the range of the annular portion 44, is visually identified as a portion to be welded. is easy. Since the core bar 41 has the second bent portion 45 in this way, it is easy to visually align and weld the seal 40 to the outer ring 20 .

Although the seal 40 is attached to the outer ring 20 in each of the embodiments described above, the seal 40 may be attached to the inner ring 10 . That is, the seal 40 is attached to the side surface of one of the outer ring 20 and the inner ring 10 .

The rolling bearing of the present invention is not limited to the illustrated form, and may be of other forms within the scope of the present invention. Moreover, the manufacturing method may also be in another form within the scope of the present invention.
For example, in each of the above-described embodiments, the case of a ball bearing has been described, but the rolling bearing may be a roller bearing in which the rolling elements are rollers.
Further, in each of the above-described embodiments, the seals 40 are attached to both sides of the outer ring 20 in the axial direction, but the seals 40 may be attached to only one side in the axial direction.

7: Rolling bearing 10: Inner ring 20: Outer ring 25: Side surface 30: Ball (rolling element) 40: Seal 41: Core bar 42: Lip 43: First bent portion 44: Annular portion 44a: Front surface 47: Contact surface 48: Inclined surface 50: Adhesive J: Joint surface

Claims (4)

An outer ring and an inner ring as bearing rings, a plurality of rolling elements interposed between the outer ring and the inner ring, and an annular seal attached to the side surface of one of the outer ring and the inner ring. ,
The seal includes a stainless steel ring-shaped metal core overlaid on the side surface and attached by welding with a joint surface between the side surface and the core via an adhesive provided throughout the core metal. a rubber lip secured to a portion of the metal on the other race side ;
The one bearing ring has a recessed circumferential groove on its side, and the recessed circumferential groove has the side surface facing the axial direction and the circumferential surface facing the other bearing ring side in the radial direction. ,
The core bar is
an annular portion having a contact surface that contacts the side surface and attached to the side surface by welding;
an arcuate surface that is bent in the axial direction from the annular portion and is separated from the side surface as it extends from the contact surface toward the peripheral surface and is not in contact with the side surface; a first bend having an end face that is in contact;
rolling bearing. 2. The rolling bearing according to claim 1, wherein said annular portion faces said side surface and has an inclined surface which moves away from said side surface in the radial direction from said contact surface toward the side opposite to said peripheral surface. 3. The rolling according to claim 2, wherein the core bar has a second bent portion located on the opposite side of the first bent portion with respect to the annular portion and axially bent from the annular portion. bearing. A method for manufacturing a rolling bearing, wherein an annular seal is attached by welding to a bearing portion including an outer ring and an inner ring as bearing rings and a plurality of rolling elements interposed between the outer ring and the inner ring,
The seal includes a stainless steel ring-shaped core metal attached by welding to the side surface of one of the outer ring and the inner ring, and the core metal via an adhesive provided over the entire core metal. a rubber lip fixed to a portion of the other race side of
a welding step of performing laser welding from the front surface of the core metal so that the core metal is superimposed on the side surface and the joint surface is between the side surface and the core metal,
In the welding step, since the core metal is made of stainless steel, the adhesion that exists on the joint surface before the metal around the joint surface between the core metal and the one bearing ring melts. The agent is decomposed by the heat of welding ,
When the welding is performed, the core bar is axially pressed against the side surface and restrained,
Adjusting the force to push the core bar in the axial direction so that the core bar and the side surface are partially in contact with each other, but are not in contact with other portions adjacent to the one in the radial direction;
A method for manufacturing a rolling bearing.

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