WO2015093591A1

WO2015093591A1 - Roller bearing and method for manufacturing same

Info

Publication number: WO2015093591A1
Application number: PCT/JP2014/083675
Authority: WO
Inventors: 竜一橋本; 上野　弘
Original assignee: ダイベア株式会社
Priority date: 2013-12-20
Filing date: 2014-12-19
Publication date: 2015-06-25
Also published as: JPWO2015093591A1

Abstract

A roller bearing is equipped with an inner ring (10), an outer ring (20), multiple balls (30) provided between the inner ring (10) and the outer ring (20), retainers (35) retaining these balls (30), and an annular metal shield (40) that is attached by means of welding to both sides of the outer ring (20) in the axial direction, and prevents the infiltration of foreign objects into the bearing interior (5) where the balls (30) reside. A coating layer (2) that peels away or wears away when in sliding contact with the inner ring (10) is provided on the region of the shield (40) facing the inner ring (10) in the radial direction.

Description

Rolling bearing and manufacturing method thereof

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

Rolling bearings are widely used in various technical fields. As shown in FIG. 6, the general rolling bearing includes an inner ring 91, an outer ring 92, a plurality of rolling elements (balls) 93, and a cage 94 that holds these rolling elements 93. The rolling bearing further includes a shield 96 for preventing foreign matter from entering the bearing interior 95 where the rolling elements 93 are present.

A circumferential groove 97 for mounting the shield 96 is formed on the outer ring 92. Then, the shield 96 is elastically deformed by pressing, and the shield 96 is fitted into the circumferential groove 97 by fitting (forced fitting). Further, in order to ensure the mounting of the shield 96, the circumferential groove 97 is a groove that expands in the axial direction.

In order to mount the shield 96 on both sides in the axial direction of the outer ring 92 as described above, it is necessary to provide the circumferential grooves 97 that extend in the axial direction on both sides in the axial direction of the outer ring 92. The direction dimension B is also increased. For this reason, in the case of a rolling bearing that is reduced in size by reducing the axial dimension B, the space for forming the circumferential groove 97 is scarce and it is difficult to attach the shield 96 to the outer ring 92.

Therefore, a rolling bearing has been proposed in which a groove narrower in the axial direction than the circumferential groove 97 shown in FIG. 6 is provided in the outer ring, and an annular metal shield is attached by welding in this narrow groove (Patent Document 1 (FIG. 1)). reference).

JP-A-11-351263

As disclosed in Patent Document 1, a narrow groove is provided in the outer ring, and a metal shield is attached to the groove of the outer ring by welding, so that the shield can be provided even in a rolling bearing that has a reduced axial dimension and is slimmed. It can be provided.

In order to prevent foreign matter from entering the inside of the bearing by this shield, it is preferable that a gap formed between the shield and the outer peripheral surface of the inner ring is small. However, due to mounting dimension errors when welding and fixing the shield to the outer ring and shield manufacturing errors, the gap dimensions should be set as set values (design values) over the entire circumference. It is difficult.
That is, in order to reduce the axial dimension of the rolling bearing and make it slim, it is difficult to improve the sealing performance by reducing the gap between the shield and the inner ring, while the shield is welded to the outer ring.

Therefore, the present invention is a structure in which a shield is attached to one of the inner ring and the outer ring by welding, and the gap between the inner ring and the outer ring of the inner ring and the outer ring is reduced to achieve a sealing performance. It is an object of the present invention to provide a rolling bearing capable of increasing the height and a manufacturing method thereof.

The rolling bearing according to the present invention includes an inner ring, an outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, a cage that holds the plurality of rolling elements, and the inner ring and the outer ring. An annular metal shield that is attached by welding to at least one side in the axial direction of one of the bearing rings to prevent foreign matter from entering the bearing in which the rolling elements exist, and the inner ring and the A coating layer that peels or wears when it comes into sliding contact with the other raceway is provided in a region facing the other raceway in the radial direction of the outer race.

According to the present invention, in the annular shield, a coating layer that peels or wears when it comes into sliding contact with the other raceway is provided in a region facing the other raceway of the inner race and the outer race in the radial direction. ing. For this reason, in order to attach this shield to one of the inner ring and the outer ring, the shield and the other ring are brought close to each other along the axial direction, and the shield is moved in the axial direction of the one ring. When it is positioned on one side, the coating layer can be slid in contact with the other race. For this reason, the shield is guided to the other race by the coating layer, and the shield can be positioned with respect to the one race so that the center of the shield coincides with the center of the other race. In this state, the shield can be welded and fixed to one of the race rings.
When the rolling bearing assembled in this manner rotates and the coating layer of the shield and the other bearing ring are in sliding contact with each other, a part of this coating layer is peeled off or worn away, and the shield (coating layer) is removed. A minute gap is formed around the entire circumference between the other race ring. As described above, a minute gap is formed between the shield and the other raceway ring, and a rolling bearing with high sealing performance is obtained.

The coating layer is preferably made of a resin. Thereby, the coating layer can be peeled off or worn when it comes into sliding contact with the other race ring.
In particular, the coating layer is preferably made of a fluororesin, whereby when the rolling bearing rotates and the coating layer and the other race ring are in sliding contact with each other, the resistance generated between them is small. Since the layer is provided with water repellency and oil repellency, it is possible to effectively suppress the intrusion of foreign matter including moisture and oil from a gap formed between the coating layer and another race. In particular, the gap between the shield and the other race ring is formed very narrow, and the surface of the shield is attached with fluororesin having high water and oil repellency. It is difficult for the liquid to cause a capillary phenomenon that attempts to reduce the surface area, and it is possible to effectively suppress entry of foreign matter including the liquid from the outside and outflow of lubricating oil from the inside.

Further, the shield is provided with an annular part whose one side in the radial direction is attached to the one race ring by welding, and extending from an end on the other side in the radial direction of the annular part to the bearing inner side. It is preferable that the other raceway ring has a short cylindrical portion opposed in the radial direction, and the coating layer is provided on the short cylindrical portion.
In this case, even if the shield (ring portion) is thin, the short cylindrical portion can function as a reinforcing material to increase rigidity. Furthermore, the region where the coating layer is provided from the outside in the axial direction of the rolling bearing toward the inside of the bearing can be enlarged, and it is possible to more effectively prevent the entry of foreign matter.
Further, as described above, in order to attach the shield to one of the inner ring and the outer ring, the shield and the other ring are brought close to each other along the axial direction, and the coating layer is made to the other ring. When the shield is positioned on one side in the axial direction of one track ring while being in sliding contact, the short cylindrical portion serves as a guide, and the center line of the shield is difficult to tilt with respect to the center line of the other track ring. , Make it easier to install the shield.

Moreover, it is preferable that the said coating layer has the smooth surface formed when the said coating layer peeled or worn partly by sliding-contacting with said other track ring.
By forming such a smooth surface, a minute gap is obtained between the coating layer and the other raceway ring.

The present invention also includes an inner ring, an outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, a cage for holding the plurality of rolling elements, and the inner ring and the outer ring. A rolling bearing manufacturing method comprising an annular metal shield that is attached to at least one side in the axial direction of one of the bearing rings and prevents foreign matter from entering the inside of the bearing in which the rolling element is present, the inner ring and the The step of incorporating a plurality of the rolling elements and the cage between the outer ring and the other raceway in a region of the shield that is radially opposed to the other raceway of the inner ring and the outer ring. Including a step of providing a coating layer that can be slidably contacted with a ring and peeled or worn when slidably contacted, and a step of attaching the shield to at least one side in the axial direction of the one raceway by welding, In the attaching step, the shield and the other raceway are brought close to each other along the axial direction, and the shield is brought into sliding contact with the other raceway while the shield is placed in the axial direction of the one raceway. At least one side is positioned, and the shield is welded and fixed to the one raceway.

According to the present invention, in the attaching step, the shield and the other race are brought close to each other along the axial direction, and the shield is placed on one side while the coating layer provided on the shield is in sliding contact with the other race. It is located on one side in the axial direction of the raceway. For this reason, the annular shield is guided to the other race by the coating layer, and the shield can be positioned with respect to the one race so that the center of the shield coincides with the center of the other race. In this state, the shield is welded to one of the races.
Further, when the completed rolling bearing rotates and the shield and the other raceway are in sliding contact, a part of the coating layer of the shield is peeled off or worn away, and the shield (coating layer) and the other raceway are removed. A gap is formed between the ring and the entire circumference. As described above, a minute gap is formed between the other bearing ring and the shield, and a rolling bearing with high sealing performance is obtained.

According to the rolling bearing of the present invention, the shield is attached to one of the inner ring and the outer ring by welding, and the gap between the other ring of the inner ring and the outer ring and the shield is reduced. It is possible to improve the sealing performance.
According to the method for manufacturing a rolling bearing of the present invention, the rolling bearing can be manufactured.

It is a longitudinal cross-sectional view which shows an example of the rolling bearing of this invention. It is sectional drawing explaining the shield of the axial direction one side (right side of FIG. 1), and its circumference | surroundings. It is a flowchart explaining the manufacturing method of a rolling bearing. It is sectional drawing explaining the process of attaching a shield. It is sectional drawing which further demonstrates the process of attaching a shield. It is a longitudinal cross-sectional view of the conventional rolling bearing. It is sectional drawing explaining the process of attaching the shield of another form.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an example of a rolling bearing 7 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 cage 35, and an annular shield 40. .

The inner ring 10 is a cylindrical member that is fitted on a shaft (not shown), and a raceway groove 11 on which the ball 30 rolls is formed on the outer peripheral surface 15 of the inner ring 10. The outer ring 20 is a member that is fitted into the inner surface of a housing (not shown), and a raceway groove 21 on which the ball 30 rolls is formed on the inner peripheral surface 25 of the outer ring 20. The retainer 35 holds the plurality of balls 30 at predetermined intervals (equal intervals) along the circumferential direction so that the balls 30 can roll. The rolling bearing of this embodiment is a deep groove ball bearing, and the inner ring 10 and the outer ring 20 are arranged concentrically.

In the present embodiment, the inner ring 10, the outer ring 20, and the ball 30 are made of bearing steel (SUJ2), and the cage 35 is made of metal (made of metal press). The cage 35 may be made of resin. The shield 40 is made of stainless steel (SUS304). By making the shield 40 from stainless steel, the shield 40 does not require anti-corrosion measures such as corrosion-resistant coating. As described above, the inner ring 10 and the outer ring 20 and the shield 40 are all made of metal, but are made of different materials.

Also, grease (ester oil grease, urea grease, etc.) is sealed 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 shield 40 can prevent foreign matters existing outside the bearing from entering the inside 5 of the bearing and also prevent the grease provided inside the bearing 5 from flowing out to the outside of the bearing.

In the present embodiment, the shields 40 are provided on both sides of the rolling bearing 7 in the axial direction. Each shield 40 is attached to the outer ring (one raceway ring) 20 by welding, and has a radial clearance from a part of the outer circumference surface 15 (shoulder outer circumference surface 16) of the inner ring (other raceway ring) 10. Then face each other. Since the inner ring 10 and the outer ring 20 can rotate relative to each other, the shield 40 and the inner ring 10 can rotate relative to each other. The shield 40 on one side in the axial direction and the shield 40 on the other side in the axial direction are opposite in mounting direction, but have the same configuration.

The shield 40 is obtained by molding a metal flat plate member by pressing, and has a flat annular portion 41 and a short cylindrical portion 42. The annular portion 41 is an annular flat plate portion having no irregularities, and is provided along a plane orthogonal to the center line of the rolling bearing (the inner ring 10 and the outer ring 20). A part on the outer side in the radial direction of the annular part 41 (an intermediate part of the annular part 41) is attached to the outer ring 20 by welding. For this reason, a welded part (bead) 50 is formed in a part on the outer side in the radial direction of the annular part 41 (an intermediate part of the annular part 41).

FIG. 2 is a cross-sectional view for explaining the shield 40 on one side in the axial direction (the right side in FIG. 1) and its surroundings. A groove 22 having a small axial dimension m is formed on the axial side surface 26 of the outer ring 20. The groove 22 is formed over the entire circumference and is an annular groove. The annular portion 41 is fixed to the outer ring 20 by welding in the groove 22 with the side surface 41a of the annular portion 41 in contact with the side surface 23 in the groove 22. The inner diameter of the peripheral surface (inner peripheral surface) 24 of the groove 22 is set larger than the outer diameter of the shield 40.

The axial dimension m of the groove 22 is set larger than the thickness dimension t of the annular part 41. This is to prevent the extra portion of the weld 50 from protruding in the axial direction from the axial side surface 26 of the outer ring 20. The thickness t of the shield 40 is the same in the annular portion 41 and the short cylindrical portion 42, for example, 0.2 mm.

As shown in FIG. 1, the short cylindrical portion 42 of the shield 40 is a portion that extends from the radially inner end (the other radial side) of the annular portion 41 toward the bearing inner 5 side, and is short. The center line of the cylindrical portion 42 coincides with the center line of the rolling bearing (the inner ring 10 and the outer ring 20). As shown in FIG. 2, the short cylindrical portion 42 faces a part of the outer peripheral surface 15 (shoulder outer peripheral surface 16) of the inner ring (the other race ring) 10 with a gap. In the present embodiment, the coating layer 2 is provided on the inner peripheral surface 43 of the short cylindrical portion 42. The inner peripheral surface (3) of the coating layer 2 faces a part of the outer peripheral surface 15 (shoulder outer peripheral surface 16) of the inner ring (the other race ring) 10 with a gap δ in the radial direction. With this gap δ, the shield 40 ensures hermeticity while not in contact with the inner ring 10.

The coating layer 2 is made of a resin, and in this embodiment, in particular, a fluororesin. Among the fluororesins, polytetrafluoroethylene (PTFE) is preferable. Specific examples include Fluorosurf FG-3020 manufactured by Fluorosurf Technology Co., Ltd., which is used as a binder for dry lubricants. The value of the gap δ is a dimension value in the radial direction from the inner peripheral surface (3) of the coating layer 2 to the shoulder outer peripheral surface 16 of the inner ring 10, and this value is about 0.03 mm. The material of the coating layer 2 is such a hardness that it can be easily scraped off by the shoulder outer peripheral surface 16 of the inner ring 10 when the shield 40 is fitted on the inner ring 10 and enters the inside of the rolling bearing 7. Even if it is a substance that does not affect the abnormal wear, paraffin or the like may be used.

In order to improve the sealing performance, that is, in order to prevent foreign matter from entering the inside 5 of the bearing by the shield 40, the gap δ is preferably small (for example, less than 0.1 mm). The dimension (diameter direction dimension) of the gap δ is set smaller than the thickness dimension (t = 0.2 mm) of the shield 40. For example, the gap δ is set to 0.15 mm in addition to 0.03 mm.

However, it is difficult to weld and fix the shield 40 to the outer ring 20 in such a manner that the gap δ is reduced and the gap δ is uniform in the circumferential direction.
Therefore, in the present embodiment, the rolling bearing 7 is manufactured by attaching the shield 40 to the outer ring 20 as follows.

A method for manufacturing the rolling bearing 7 will be described. FIG. 3 is a flowchart for explaining this manufacturing method. In this manufacturing method, in addition to the assembly process of incorporating a plurality of balls 30 and a cage 35 between the inner ring 10 and the outer ring 20, the coating for forming the coating layer 2 on the shield 40 before being attached to the inner and

outer rings

10 and 20. A layer forming step and an attaching step of attaching the shield 40 on which the coating layer 2 is formed to the raceway ring (in this embodiment, the outer ring 20) are included.

First, the assembly process is performed. A plurality of balls 30 and a cage 35 are incorporated between the inner ring 10 and the outer ring 20. This step can be performed by employing a conventionally performed method. At this time, the shield 40 is not yet attached to the outer ring 20.

Then, a coating layer forming process is performed. This coating layer forming step is a step of providing the coating layer 2 in a region of the shield 40 facing the inner ring 10 in the radial direction. The coating layer 2 can be slidably contacted with the outer peripheral surface 16 of the shoulder portion of the inner ring 10 and can be peeled off or worn when slidable. In the present embodiment (see FIG. 5A), the resin (PTFE) coating layer 2 is formed on the entire inner peripheral surface 43 of the short cylindrical portion 42 of the shield 40.

Specific examples regarding the coating layer forming step will be described. The main body portion (the annular portion 41 and the short cylindrical portion 42) of the shield 40 is made of steel (SUS304). Therefore, a coating material containing a resin material (PTFE) is applied to the surface (inner peripheral surface 43) of the short cylindrical portion 42 by dipping and drying to form a film, which is used as the coating layer 2. In this step, it is preferable that the thickness of the coating layer 2 is controlled (measured) so that the thickness of the coating layer 2 is substantially uniform over the entire circumference of the inner peripheral surface 43 of the short cylindrical portion 42. The coating layer 2 is formed over the entire circumference of the inner peripheral surface 43 of the short cylindrical portion 42, and the film thickness is such that the inner diameter of the formed coating layer 2 is smaller than the outer diameter of the shoulder outer peripheral surface 16 of the inner ring 10. Is managed. The inner diameter of the short cylindrical portion 42 is set larger than the outer diameter of the shoulder outer peripheral surface 16. The film thickness of the coating layer 2 is 105% to 150% of the radial dimension of the gap between the inner peripheral surface 43 of the short cylindrical portion 42 of the shield 40 and the shoulder outer peripheral surface 16 of the inner ring 10, more preferably 105% to 110%.

And an attachment process is performed. FIG. 4 is an explanatory diagram of this process. This attachment process is a process of attaching the shield 40 provided with the coating layer 2 to a predetermined position of the outer ring 20 by welding.
In the attaching process, as shown in FIG. 4A, the shield 40 and the inner ring 10 are brought closer along the axial direction. At this time, as shown in FIGS. 5A to 5B, the coating layer 2 formed on the short cylindrical portion 42 is applied to the axial end 15 a (shoulder outer peripheral surface 16) of the outer peripheral surface 15 of the inner ring 10. The shield 40 is fitted onto the shoulder outer peripheral surface 16 while being in sliding contact, and the shield 40 is positioned on the axial side surface 26 (one side in the axial direction) of the outer ring 20.

Although the short cylindrical portion 42 is short but has a length in the axial direction, the short cylindrical portion 42 makes it difficult for the center line of the shield 40 to be inclined with respect to the center line of the inner ring 10, so that the shield 40 is accurately positioned. Easy to install. As described above, since the inner diameter of the coating layer 2 formed over the entire inner circumferential surface of the short cylindrical portion 42 is smaller than the outer diameter of the shoulder outer circumferential surface 16 of the inner ring 10, the shield 40 is slightly It will be fitted on the inner ring 10 with a tight margin. At this time, a part of the coating layer 2 is peeled off by sliding contact with the outer peripheral surface 15 (shoulder outer peripheral surface 16) of the inner ring 10 (see FIG. 5B). A convex rounded portion (circular cross-section arc portion) 17 is formed on the outer peripheral edge of the axial end portion of the inner ring 10. The coating layer 2 is on the inner side in the axial direction (on the raceway groove side) than the rounded portion 17. ). Thereby, the parallel part which opposes between the coating layer 2 and the inner ring | wheel 10 can be ensured about predetermined length, and a sealing performance can be improved.

Further, as described above, the inner diameter of the peripheral surface (inner peripheral surface) 24 of the groove 22 for attaching the shield 40 formed on the outer ring 20 is set larger than the outer diameter of the shield 40 (FIG. 5A). (See (B)). Therefore, when the shield 40 is fitted on the shoulder outer peripheral surface 16 of the inner ring 10 and provided at a predetermined position on the axial side surface 26 of the outer ring 20, a degree of freedom is given to the radial movement of the shield 40. It is possible to prevent 40 from interfering with the peripheral surface 24 of the groove 22.

As shown in FIGS. 4B and 5B, the shield 40 is brought to a position where the annular portion 41 of the shield 40 contacts the side surface 23 of the groove 22 of the outer ring 20. Then, the shield 40 is welded and fixed to the outer ring 20. At this time, a part (intermediate portion) on the radially outer side of the shield 40 is welded to the side surface 23 of the groove 22 of the outer ring 20. This welding is performed by precision laser welding, and welding is performed on the entire circumference of the annular shield 40. Further, this welding method uses a fiber laser having a small spot diameter, and the thin shield 40 can be welded without greatly affecting the other part of the outer ring 20. Thereby, the space between the outer peripheral edge of the shield 40 and the outer ring 20 is completely sealed. The laser spot diameter is suitably about 0.05 mm to 0.08 mm.

The shield 40 is welded and fixed to the outer ring 20 on the other side in the axial direction in the same manner as this. That is, the inner ring 10 and the outer ring 20 with the shield 40 fixed on one side in the axial direction are reversed (upside down), and the grease G is filled into the bearing interior 5 for a specified amount as shown in FIG. Then, on the other side in the axial direction, the shield 40 and the inner ring 10 are approached along the axial direction (see FIG. 4D), and the coating layer 2 of the shield 40 is applied to the inner ring 10 (shoulder outer peripheral surface). The shield 40 is positioned on the other side surface in the axial direction of the outer ring 20 while being in sliding contact with the outer ring 20, and the shield 40 is welded to the outer ring 20 and fixed (see FIG. 4E).
With the above manufacturing method, the rolling bearing 7 shown in FIG. 1 can be manufactured (see FIG. 4F).

According to this manufacturing method, in the step of attaching the shield 40 to the outer ring 20, as described above, the shield 40 and the inner ring 10 are brought close to each other along the axial direction (see FIG. 4A), and the shield 40 is provided on the shield 40. While the coating layer 2 is in sliding contact with a part of the outer peripheral surface 15 of the inner ring 10, the shield 40 is fitted on the inner ring 10, and the shield 40 is positioned on one side (side part) of the outer ring 20 in the axial direction. (See FIG. 5). The film thickness of the coating layer 2 of the shield 40 is formed to be substantially uniform over the entire circumference of the inner peripheral surface 43 of the short cylindrical portion 42. For this reason, the shield 40 is guided to the shoulder outer peripheral surface 16 of the inner ring 10 by the coating layer 2, and the shield 40 is positioned with respect to the outer ring 20 so that the center of the shield 40 coincides with the center of the inner ring 10. it can. In particular, since the outer peripheral surface 15 (shoulder outer peripheral surface 16) of the inner ring 10 is subjected to high-precision finishing (polishing), the outer peripheral surface 15 (shoulder outer peripheral surface 16) is used as a reference surface. By attaching the shield 40, the shield 40 is attached to the inner ring 10 in a concentric manner with high accuracy. Then, the shield 40 is welded to the outer ring 20 in a state where the center of the shield 40 and the center of the inner ring 10 are aligned (a state where they are arranged concentrically) (see FIG. 4B). As described above, when the shield 40 is attached to the outer ring 20, the reference for positioning the shield 40 is the outer peripheral surface 15 (shoulder outer peripheral surface 16) of the inner ring 10. 40 centering is performed.

When the completed rolling bearing rotates and the coating layer 2 of the shield 40 and the shoulder outer peripheral surface 16 of the inner ring 10 are in sliding contact with each other, a part of the coating layer 2 is peeled off or worn away, and FIG. As shown, a gap δ is formed between the coating layer 2 and the shoulder outer peripheral surface 16 over the entire circumference.

That is, the coating layer 2 that can be slidably contacted with the inner ring 10 and peels or wears when slid on the region of the shield 40 facing the inner ring 10 is provided. It is made of resin (PTFE). For this reason, when the bearing 7 rotates and the coating layer 2 comes into sliding contact with the outer peripheral surface 16 of the shoulder portion, the coating layer 2 is gradually peeled off or worn and partially removed, and the thickness in the radial direction is thin. Become. Then, the gap δ is formed. The dimension value in the radial direction of the gap δ is the same as the dimension value in the radial direction in which the relatively rotating inner ring 10 and outer ring 20 can move relative to each other in the radial direction.

When the rolling bearing 7 is used in this way, the coating layer 2 is formed by the coating layer 2 being partially peeled off or worn by being in sliding contact with the inner ring 10 (shoulder outer peripheral surface 16). A smooth surface 3 can be provided. By forming the smooth surface 3, a minute gap δ is obtained between the coating layer 2 and the inner ring 10 (shoulder outer peripheral surface 16).

And this gap δ is extremely small, and it has a structure with high sealing performance while being non-contact. In particular, in the present embodiment, since the coating layer 2 is made of fluororesin (PTFE), even when the coating layer 2 and the inner ring 10 are further in sliding contact with each other due to the axial runout of the inner and

outer rings

10 and 20, there is no gap between them. The resulting resistance is small. For this reason, it becomes possible to suppress the heat_generation | fever resulting from this, and it becomes possible to suppress the fall of a bearing life.

Furthermore, since the coating layer 2 has water repellency and oil repellency, it is possible to more effectively suppress the entry of foreign matter including moisture and oil from the gap formed between the coating layer 2 and the inner ring 10. It becomes possible. In addition, the grease inside the bearing 5 can be effectively prevented from flowing out.
In particular, the gap between the shield 40 and the inner ring 10 is formed very narrow, and a fluororesin (coating layer 2) having high water and oil repellency adheres to the surface of the shield 40. In such a case, it is difficult for a liquid such as water or oil to cause a capillary phenomenon that attempts to reduce the surface area, and it is possible to effectively suppress the intrusion of foreign matter including the liquid from the outside and the outflow of lubricating oil from the inside. Become.

The shield 40 has an annular portion 41 whose end on the radially outer peripheral side is attached to the outer ring 20 by welding, and an end on the radially inner peripheral side of the annular portion 41 toward the bearing interior 5 ( A short cylindrical portion 42 that extends in the axial direction and faces the inner ring 10. For this reason, even if the shield 40 (annular part 41) is thin, the short cylindrical part 42 functions as a reinforcing material and can increase rigidity. And the area | region of the coating layer 2 is expanded toward the bearing inside 5 side from the axial direction outer side of the rolling bearing 7 by providing the coating layer 2 in the whole region of the internal peripheral surface 43 of the short cylindrical part 42. Intrusion of foreign matter can be further effectively prevented. In addition, the grease inside the bearing 5 can be effectively prevented from flowing out.
Further, as described above, in order to attach the shield 40 to the outer ring 20, the shield 40 and the inner ring 10 are brought close to each other in the axial direction, and the shield 40 is slidably contacted with the inner ring 10 while the shield 40 is attached to the outer ring 20. When positioned in the groove 22, the short cylindrical portion 42 serves as a guide, and the center line of the shield 40 is less likely to be inclined with respect to the center line of the inner ring 10, so that the shield 40 can be easily attached.

Further, since the shield 40 having a thin plate shape is attached by welding to the axial side surface 26 of the outer ring 20, the axial dimension m of the groove 22 should be equal to or slightly larger than the thickness t of the shield 40. As a result, the groove 97 (see FIG. 6) that expands in the axial direction as in the prior art becomes unnecessary.
For this reason, in the rolling bearing 7 of the present embodiment, the axial dimension is reduced without changing the size of the ball 30 and the inner diameter and outer diameter of the bearing 7 from the standard product, that is, without reducing the load capacity. The bearing can be made slimmer than the standard product. For example, although the rolling bearings have the same load capacity, it is possible to configure the rolling bearing 7 which is narrow and light in the axial dimension of 85% or less of a standard product (ISO product).
Since the rolling bearing 7 can be narrowed, the volume of the space between the shields 40 installed on both sides in the axial direction (the space inside the bearing 5) is reduced, and the amount of grease filled is reduced. Can do.

In the embodiment shown in FIG. 7A, the coating layer 2 is formed so that the inner diameter of the coating layer 2 is larger than the outer diameter of the shoulder outer peripheral surface 16 of the inner ring 10. The film thickness of the coating layer 2 in the present embodiment is 80% to 95% of the radial dimension of the gap between the inner peripheral surface 43 of the short cylindrical portion 42 of the shield 40 and the shoulder outer peripheral surface 16 of the inner ring 10. .
In this case, as shown in FIG. 7B, a gap is formed between the coating layer 2 and the outer peripheral surface 15 of the inner ring 10, and the shield 40 is slightly eccentric with respect to the outer ring 20 by this gap. However, the coating layer 2 makes it possible to avoid contact between metals.

Further, advantages of the above embodiments of the present invention will be described.
In order to prevent foreign matter from entering the bearing interior 5 by the shield 40, the gap formed between the shield 40 and the outer peripheral surface 15 (shoulder outer peripheral surface 16) of the inner ring 10 is preferably small. However, due to an attachment dimension error when welding and fixing the shield 40 to the outer ring 20, a manufacturing error of the shield 40, and the like, the dimension of the gap is set as a set value (design value) over the entire circumference. Is difficult to set.

Here, in the conventional rolling bearing shown in FIG. 6, the shield 96 attached to the outer ring 92 is eccentric with respect to the inner ring 91 due to the error as described above, and the inner ring 91 and the outer ring 92 are further shaken. When the part of the shield 96 and the outer peripheral surface of the inner ring 91 come into contact with each other, the shield 96 and the inner ring 91 are both made of metal, so that the contact becomes a metal contact, and the rotational resistance of the bearing increases. There is a problem.
Furthermore, due to this, heat is generated and the bearing becomes high temperature. For example, the lubricant (grease) inside the bearing 95 is deteriorated, which causes a decrease in bearing life.
Such a problem occurs even in a configuration in which the shield is attached to the outer ring by welding, as in the rolling bearing disclosed in Patent Document 1, and the gap between the shield and the inner ring is as small as possible. In the case of making it small, it is particularly likely to occur.

However, according to the rolling bearing 7 of each of the embodiments of the present invention, even in such a case, it is possible to suppress an increase in the rotational resistance of the bearing and heat generation resulting therefrom.
That is, in each embodiment, when the shield 40 is externally fitted to the inner ring 10, the shield 40 is guided to the shoulder outer peripheral surface 16 of the inner ring 10 by the coating layer 2 formed on the inner peripheral surface 43 of the short cylindrical portion 42. Then, the shield 40 can be positioned so that the center of the shield 40 and the center of the shoulder outer peripheral surface 16 of the inner ring 10 coincide. For this reason, the gap between the inner peripheral surface 43 of the short cylindrical portion 42 of the shield 40 and the shoulder outer peripheral surface 16 of the inner ring 10 can be set to a predetermined size, and the shield 40 has some manufacturing errors. However, it is not necessary to use a special jig for aligning the centers of the shield 40 and the inner ring 10. Further, when the rolling bearing 7 rotates, the coating layer 2 is removed by peeling or wearing a part of the coating layer 2 in due course. As a result, a minute gap δ is formed between the coating layer 2 and the inner ring 10 over the entire circumference, so that an increase in bearing rotation resistance and heat generation due to this are suppressed while maintaining sealing performance. It becomes possible.

In the above-described embodiment (see FIG. 1), the shield 40 has been described as being attached to the outer ring 20, but may be attached to the inner ring 10. In this case, the radially inner side of the shield 40 is attached to the axial side surface of the inner ring 10 by welding, and the radially outer side of the shield 40 faces the outer ring 20 with a gap.
Moreover, although the said embodiment (refer FIG. 1) demonstrated the case where the shield 40 was attached to the axial direction both sides of the outer ring | wheel 20, you may attach only to the one side of an axial direction.
That is, the shield 40 only needs to be attached to at least one of the inner ring 10 and the outer ring 20 in the axial direction of one of the race rings by welding, and a part of the shield 40 is formed between the inner ring 10 and the outer ring 20. It becomes the structure facing the other track ring of them.

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. Further, the manufacturing method may be another method within the scope of the present invention. In addition to the ball bearing, the rolling bearing of the present invention may be a roller bearing in which the rolling element is a roller.

In the embodiment described above, the shield 40 has the short cylindrical portion 42. However, the short cylindrical portion 42 may be omitted, and in this case, the inner peripheral surface of the annular portion 41 is coated. Layer 2 is provided.

2: Coating layer 3: Smooth surface 5: Inside of bearing 7: Rolling bearing 10: Inner ring 20: Outer ring 30: Ball (rolling element) 35: Cage 40: Shield 41: Ring part 42: Short cylindrical part

Claims

Inner ring, outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, a cage for holding the plurality of rolling elements, and a shaft of one of the inner ring and the outer ring An annular metal shield that is attached by welding to at least one side of the direction and prevents foreign matter from entering the bearing in which the rolling element exists,
Of the shield, a coating layer is provided in a region facing the other raceway in the radial direction of the inner race and the outer race, which peels or wears when slidably contacting the other raceway. Rolling bearing.
The rolling bearing according to claim 1, wherein the coating layer is made of resin.
The rolling bearing according to claim 2, wherein the coating layer is made of a fluororesin.
The shield includes an annular portion whose one radial direction is attached to the one raceway by welding, and extends from the other radial end of the annular portion to the bearing inner side. A short cylindrical portion facing the raceway and the radial direction,
The rolling bearing according to any one of claims 1 to 3, wherein the coating layer is provided on the short cylindrical portion.
The coating layer according to any one of claims 1 to 4, wherein the coating layer has a smooth surface formed by being partly peeled or worn by sliding contact with the other raceway ring. Rolling bearings.
Inner ring, outer ring, a plurality of rolling elements provided between the inner ring and the outer ring, a cage for holding the plurality of rolling elements, and a shaft of one of the inner ring and the outer ring A method of manufacturing a rolling bearing comprising an annular metal shield that is attached to at least one side of a direction and prevents foreign matter from entering the inside of the bearing in which the rolling element exists,
Incorporating a plurality of the rolling elements and the cage between the inner ring and the outer ring;
In the shield, a coating layer that can be slidably contacted with the other raceway in the radial direction with the other raceway of the inner race and the outer race and is peeled or worn when slidable is provided. Process,
Attaching the shield to at least one side in the axial direction of the one raceway by welding, and
In the attaching step, the shield and the other raceway are moved close to each other in the axial direction, and the shield is brought into sliding contact with the other raceway, and the shield is placed in the axial direction of the one raceway. A method of manufacturing a rolling bearing, comprising: positioning the shield on at least one side of the bearing and welding and fixing the shield to the one raceway ring.