JP2008025685A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing having small bearing torque and excellent sealing property. <P>SOLUTION: The rolling bearing consists of a pair of raceways (an inner ring 2, an outer ring 4) provided facing each other in a relatively rotatable manner, a plurality of rolling elements 6 rollably assembled between raceway grooves (between an inner ring raceway groove 2g and an outer ring raceway groove 4g) that are respectively formed in opposing faces (an inner ring outside face 2s, an outer ring inside surface 4s) of the respective raceways and an annular sealing plate 8 attached between the opposing surfaces of both sides of the respective raceway rings. Coated by rubber J, the base end 8e of the sealing plate is fixed to an annular recessed part by fitting the rubber in the annular recessed part M formed in an opposing face of one of the raceway rings. Its tip end 8t is positioned for the opposing face of the other raceway ring in a non-contact state and partially inserted in an annular sealing groove P formed in the opposing face. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing that supports a rotary drive system such as a motor for a vacuum cleaner or a power tool, a motor for an electric fan for cooling an automobile radiator, or an alternator (generator).

  The installation environment of rotary drive systems such as various motors and generators may be filled with, for example, wear powder generated by brush wear of brush motors or dust entering from the outside, and rolling used in such an environment. The bearing is required to have high sealing performance. By the way, if foreign matter such as abrasion powder or dust enters the inside of the bearing and rotates, for example, between the raceway surface of the inner and outer rings and the rolling element, the grinding action by the foreign matter works and the raceway surface or The surface of the rolling element may be worn or worn. In addition, when the foreign matter that has entered enters the lubricant, the deterioration of the lubricant may be accelerated. In this case, if the bearing surface continues to rotate with the raceway surface or the rolling element surface worn or worn, or the lubricant has deteriorated, for example, abnormal noise may be generated or seizure may occur. It becomes difficult to extend the life.

  Therefore, in order to solve such a problem, a rolling bearing has been proposed in which a sealing plate is disposed between the inner and outer rings to prevent foreign matter from entering the bearing. For example, the rolling bearing shown in Patent Document 1 uses a contact rubber seal whose base end is fixed to the outer ring and whose tip is in contact with the inner ring. For example, the rolling bearing shown in Patent Document 2 has a base end. A non-contact shield is used in which is fixed to the outer ring and the tip is not in contact with the inner ring.

However, in a rolling bearing using a contact rubber seal, the bearing torque (for example, start-up torque, rotation torque) increases because the tip of the contact rubber seal and the inner ring rotate relative to each other during rotation. In this case, since the rotational efficiency of the rolling bearing is lowered, the operating efficiency of the apparatus incorporating the bearing is also lowered. On the other hand, in a rolling bearing using a non-contact shield, the tip of the non-contact shield and the inner ring rotate relative to each other without sliding contact with each other. In this case, although the bearing torque can be reduced, since a predetermined gap is formed between the tip of the non-contact shield and the inner ring, foreign matter is easily mixed from the gap. As a method of preventing the intrusion of foreign matter, it is conceivable to reduce the gap, but it is necessary to increase the processing accuracy of the shield plate and the base end mounting portion (for example, plate groove, annular recess, etc.), which increases the cost. Cost.
Japanese Utility Model Publication No. 7-10556 JP 2002-115724 A

  The present invention has been made to solve such problems, and an object of the present invention is to provide a rolling bearing having a small bearing torque and excellent sealing performance.

  In order to achieve such an object, the present invention is incorporated in a freely rollable manner between a pair of raceways opposed to each other so as to be rotatable relative to each other and raceway grooves formed on opposite surfaces of each raceway. A rolling bearing having a plurality of rolling elements and an annular sealing plate attached between opposing surfaces of each raceway ring, and the base end of the sealing plate is covered with rubber, The base end of the sealing plate is fixed to the annular recess by fitting the rubber into the annular recess formed on the facing surface of one of the races, and the tip of the sealing plate is on the facing surface of the other race ring. On the other hand, it is positioned in a non-contact state, and partially enters an annular seal groove formed on the facing surface.

  In the present invention, the diameter dimension of the front end of the sealing plate is set to a predetermined difference from the diameter dimension of the annular seal groove. In this case, the sealing plate is formed with a convex portion curved in a convex shape toward the outer side at a central portion between the proximal end and the distal end, and the convex shape while fitting the proximal end into the annular recess. By pressing the part from the outer side and elastically deforming the sealing plate, the sealing plate is attached between the facing surfaces of the races in a state where the tip end partly enters the annular seal groove. A plurality of slits may be formed at a predetermined interval along the circumferential direction at the tip of the sealing plate.

  According to the present invention, a rolling bearing having a small bearing torque and excellent sealing performance is realized by partially inserting the front end of the sealing plate into an annular seal groove formed on the facing surface of the raceway in a non-contact state. can do.

Hereinafter, a rolling bearing according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1 (a), the rolling bearing of the present embodiment includes a pair of race rings (inner ring 2 and outer ring 4) arranged so as to be relatively rotatable with each other, and opposed surfaces of inner and outer rings 2 and 4 ( A plurality of rolling elements 6 which are rotatably incorporated between raceway grooves (between the inner ring raceway groove 2g and the outer ring raceway groove 4g) respectively formed on the inner ring outer diameter surface 2s and the outer ring inner diameter surface 4s); 2 and 4 and an annular sealing plate 8 attached between the opposing surfaces 2s and 4s on both sides.

  In addition, in the said bearing, although the several rolling element 6 is rotatably hold | maintained one by one with the holder | retainer 10, the kind of this holder | retainer 10 is not specifically limited. In addition, a lubricant (for example, grease or oil) is enclosed in a region surrounded by the opposing surfaces 2s and 4s of the inner and outer rings 2 and 4 and the sealing plate 8, but the lubricant is illustrated in the drawing. Omitted. Furthermore, as the rolling element 6, a ball is illustrated in the drawing, but a roller may be used.

  In this case, the base end 8e of the sealing plate 8 is fitted and fixed to an annular recess M formed on the facing surface of one of the race rings, and the tip 8t thereof is opposed to the facing surface of the other race ring. While being positioned in a non-contact state, it partially enters an annular seal groove P formed on the facing surface. In the present embodiment, in the drawing, the base end 8e is fitted and fixed in the annular recess M of the outer ring 4 (outer ring inner diameter surface 4s), and the tip 8t is partially in the annular seal groove P of the inner ring 2 (inner ring outer diameter surface 2s). Although the enclosing sealing plate 8 is illustrated, the present invention is not limited to this. For example, the sealing plate 8 as shown in FIGS. 1B and 1C may be used.

  In this case, for example, as shown in FIGS. 1 (g) and 1 (h), the sealing plate 8 is formed of a metal shield plate, and the rubber J is fixed (covered) to the base end 8e. By fitting into the recess M, the base end 8e of the sealing plate 8 may be elastically fixed to the annular recess M of the inner surface 4s of the outer ring. As described above, the rubber J is interposed between the base end 8e of the sealing plate 8 and the annular recess M of the inner surface 4s of the outer ring, whereby the annular recess (also referred to as an outer ring seal groove) M is caused by the elastic force of the rubber J. Since the substantially uniform stress acts, the collapse of the roundness of the rolling bearing after the sealing plate 8 is fixed can be reduced. As a material of the rubber J, for example, nitrile rubber, acrylic rubber, silicon rubber or the like may be applied.

  In the configuration example of FIG. 1B, the sealing plate 8 has a base end 8e fitted and fixed in an annular recess M of the inner ring 2 (inner ring outer diameter surface 2s) and a tip 8t formed in an annular shape of the outer ring 4 (outer ring inner diameter surface 4s). The seal groove P is partially inserted into the non-contact state. In the configuration example of FIG. 1C, the sealing plate 8 on one side of the bearing has a base end 8e fitted and fixed in an annular recess M of the inner ring 2 (inner ring outer diameter surface 2s), and a distal end 8t having an outer ring 4 (outer ring). The seal plate 8 on the other side of the bearing is positioned in a non-contact state by partially entering the annular seal groove P of the inner diameter surface 4s), and the base end 8e of the seal plate 8 on the other side of the bearing is in the annular recess M of the outer ring 4 (outer ring inner diameter surface 4s). It is fitted and fixed, and the tip 8t partially enters the annular seal groove P of the inner ring 2 (inner ring outer diameter surface 2s) and is positioned in a non-contact state.

  In any configuration example, as shown in FIG. 1 (d), the diameter dimension of the tip 8 t of the sealing plate 8 is set to a predetermined dimension difference W with respect to the diameter dimension of the annular seal groove P. More specifically, when the annular seal groove P is formed in the inner ring 2 (inner ring outer diameter surface 2s), the inner diameter of the tip 8t of the sealing plate 8 is the outer diameter of the outer diameter portion Rp of the annular seal groove P. The dimension difference W is set smaller than the dimension. On the other hand, when the annular seal groove P is formed in the outer ring 4 (outer ring inner diameter surface 4s), the outer diameter dimension of the tip 8t of the sealing plate 8 is larger than the inner diameter dimension of the inner diameter portion Rp of the annular seal groove P. Set a larger size difference W.

  Note that the shape of the tip 8t of the annular sealing plate 8 is not limited to a shape that extends substantially straight toward the annular seal groove P as shown in FIG. Any shape can be applied as long as the shape partially enters the annular seal groove P. For example, as shown in FIG. 1 (e), it is folded back toward the inner side (the rolling element 6 side), for example, as shown in FIG. 1 (f), it is folded toward the outer side (the opposite side to the rolling element 6). A different shape is also acceptable. Further, the thickness and surface treatment (plating treatment) of the sealing plate 8 are not particularly limited.

Here, an example of a method for attaching the sealing plate 8 between the inner and outer rings 2 and 4 will be described with reference to FIGS.
As shown in FIG. 2A, before mounting between the inner and outer rings 2 and 4, the inner diameter dimension of the tip 8t of the sealing plate 8 is smaller than the outer diameter dimension of the outer diameter portion Rp of the annular seal groove P. Only set larger. Further, the sealing plate 8 is formed with a convex portion 8a curved in a convex shape toward the outer side at a central portion between the base end 8e and the distal end 8t.

  After preparing such a sealing plate 8, as shown in FIG. 2 (b), the base 8e is fitted into the annular recess M and the convex portion 8a is axially moved from the outer side with a predetermined pressure F ( Press in the axial direction) to cause plastic deformation. In this case, as a method of pressing the convex portion 8a, an existing pressing jig may be used. Therefore, the pressing jig is not particularly limited here.

  Then, as shown in FIG. 2 (c), when the convex portion 8a of the sealing plate 8 is further pressed, the sealing plate 8 is stretched in the radial direction under the action of the pressing force F. The inner diameter dimension of becomes smaller. Thereafter, by adjusting the pressing force F applied to the convex portion 8a, the base end 8e is fitted and fixed in the annular concave portion M of the outer ring 4 (outer ring inner diameter surface 4s) as shown in FIG. A sealing plate 8 whose tip 8t partially enters the annular seal groove P of the inner ring 2 (inner ring outer diameter surface 2s) can be attached between the inner and outer rings 2 and 4.

  In such an attachment method, for example, as shown in FIG. 3, if a plurality of slits 8m are formed at predetermined intervals along the circumferential direction at the tip 8t of the sealing plate 8, the sealing plate 8 can be easily deformed. , The mounting property can be improved. The number and width of the slits 8m are not particularly limited here because they are arbitrarily set according to the size and type of the sealing plate 8. Instead of forming the slit 8m, for example, the tip 8t of the sealing plate 8 may be thinned along the circumferential direction to facilitate attachment.

  As described above, according to the present embodiment, since the tip 8t of the sealing plate 8 is partially inserted into the annular seal groove P, a labyrinth seal with a narrow gap between the tip 8t and the annular seal groove P is provided. Can be built. For this reason, even when the enclosed lubricant is pushed outward during rotation of the bearing, the pushed lubricant is retained so as to fill the gap between the tip 8t and the annular seal groove P, so-called grease seal. It becomes a state called. As a result, it is possible to reliably prevent the lubricant from leaking outside the bearing. The same effect can be obtained by previously filling the gap between the tip 8t of the sealing plate 8 and the annular seal groove P with a lubricant.

In addition, for example, the penetration of foreign matter (for example, water and dust) into the bearing varies depending on the pressure difference between the inside of the bearing and the outside of the bearing. In this case, as a measure for preventing the intrusion of foreign matter, for example, the distance from the outside of the sealing plate 8 to the inner ring raceway groove 2g (outer ring raceway groove 4g) may be increased, or the pressure difference between the inside and the outside may be reduced. In the present embodiment, since the tip 8t of the sealing plate 8 is partially inserted into the annular seal groove P, the distance from the outside of the sealing plate 8 to the inner ring raceway groove 2g (outer ring raceway groove 4g) is increased. At the same time, the pressure fluctuation inside and outside can be reduced. Thereby, invasion of foreign matter can be reliably prevented.
Further, since the tip 8t of the sealing plate 8 is positioned in a non-contact state with respect to the annular seal groove P, the bearing torque (for example, starting torque, rotational torque) does not become larger than the contact rubber seal when the bearing rotates. .

Here, a comparative test of the sealing performance between the rolling bearing of the present embodiment and the conventional bearing will be described.
In this comparative test, for example, two bearings (Comparative Examples 1 and 2) as shown in FIGS. 4A and 4B were prepared as conventional bearings. In Comparative Example 1 in FIG. 2A, a substantially flat annular seal groove P is formed on the inner ring 2 (inner ring outer diameter surface 2s), and the tip 8t of the sealing plate 8 is formed on the annular seal groove P. The dimension difference W is set larger than the outer diameter dimension of the outer diameter portion Rp (FIG. 4C). Further, in Comparative Example 2 in FIG. 5B, the inner ring 2 (inner ring outer diameter surface 2s) is formed with a deepened annular seal groove P, and the tip 8t of the sealing plate 8 is formed in the annular seal groove. It is set larger than the outer diameter dimension of the outer diameter portion Rp of P by a dimension difference W (FIG. 4C). In this case, in both the bearings of Comparative Examples 1 and 2, the tip 8t of the sealing plate 8 is positioned in a non-contact state with respect to the annular seal groove P.

On the other hand, as the rolling bearing of the present embodiment, for example, a bearing (Example 1) shown in FIG. The configuration other than the sealing plate 8 was set the same for the three parties (Comparative Examples 1 and 2 and Example 1). For example, the outer diameter of the bearing is 22 mm, the inner diameter of the bearing is 8 mm, the bearing width is 7 mm, and the cage 10 is made of resin. Further, as the lubricant, a thickener and a base oil were prepared by appropriately using additives so that the kinematic viscosity at 40 ° C. was 48 mm ² / s and the penetration degree was 230. Then, the lubricant was sealed inside the bearing so as to be 30% by volume of the bearing space volume. In this case, as the thickener, for example, urea, lithium soap, sodium soap, bentonite, PTFE, carbon black and the like can be selected, and as the base oil, for example, synthetic hydrocarbon oil, ester oil, ether oil, Fluorine oil, silicone oil, mineral oil, etc. can be selected.

FIG. 6 shows an example of the configuration of a test apparatus used for the sealability comparison test.
In the test apparatus, a hollow housing 14 is interposed in a test main body 12, and a rotating shaft 16 extends and is disposed in the housing 14. Further, a bearing 18 (Comparative Examples 1 and 2 and Example 1) used for a comparative test can be set between the housing 14 and the rotating shaft 16. Specifically, the outer ring 4 is fitted in the housing 14, and the inner ring 2 is fitted on the rotary shaft 16, and then the inner ring 2 is pressed in the axial direction by the sleeve 20, thereby applying a predetermined preload to the bearing 18. In this state, the inner ring 2 can be fixed to the rotating shaft 16. A dust reservoir 22 is formed in the housing 14.

In this test, 0.1 g of silica sand (diameter: 6.6 to 8.6 μm) was sealed in the dust reservoir 22. In addition to 97% or more of SiO ₂ , the chemical composition of silica sand contains 3% or less of Fe ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , and MgO. Moreover, the particle density of silica sand is a value of 2.6 to 2.7 g / cm ³ .

  In such a configuration, the inside of the air supply unit 24 is pressurized to 0.15 MPa, and air is ejected from the air intake 26 to the dust storage unit 22. At this time, the air introduced into the dust storage part 22 flows out from the housing opening 14 a via the bearing 18 set between the housing 14 and the rotating shaft 16. At this time, the inside of the dust reservoir 22 was set to 80 ° C. by heating the housing 14 with the heater 28 for heating. Then, by rotating the rotating shaft 16 at 40,000 rpm, the sound increase values every 16 hours were compared, and the sealing properties of Comparative Examples 1 and 2 and Example 1 were evaluated. In addition, the axial load (Fa) of the bearing 18 at the time of sealing performance evaluation was set to 49N. In addition, a grease noise tester (NSK Technical Journal No.667, published in 1999) was used as a bearing acoustic measurement value before and after this test. The measurement conditions in this case were 1800 rpm, Fa = 29N, and a high band (HB) value was adopted as data.

  In this test, if dust enters the bearing 18 and enters between the inner and outer rings 2 and 4 and the rolling elements, damage to the raceway due to the biting of dust occurs, thereby increasing the sound (Anderon). . Therefore, it can be evaluated that the smaller the acoustic increase value, the better the sealing performance. FIG. 5 shows the acoustic rise values of Comparative Examples 1 and 2 and Example 1 in this test. As is apparent from the evaluation results, the bearings of Example 1 are compared with Comparative Examples 1 and 2. Compared with the acoustic increase value. Thereby, it can be evaluated that the rolling bearing according to the present embodiment is excellent in sealing performance.

(a) is sectional drawing which shows the structural example of the rolling bearing which concerns on one embodiment of this invention, (b) is sectional drawing which shows the other structural example of a rolling bearing, (c) is other than rolling bearing. FIG. 4D is a partial cross-sectional view illustrating a configuration example of the tip portion of the sealing plate attached to the rolling bearing, and FIG. 5E illustrates another configuration example of the tip portion of the sealing plate. Partial sectional view, (f) is a partial sectional view showing another configuration example of the distal end portion of the sealing plate, (g) is a sectional view showing a configuration example of a rolling bearing in which the base end of the sealing plate is covered with rubber, (h) is sectional drawing which expands and shows the base end part of the sealing board shown by the same figure (g). (a)-(d) is sectional drawing for demonstrating the attachment method of a sealing board. The top view which shows the structural example which formed the slit in the front-end | tip of a sealing board. (a) is a partial cross-sectional view of a bearing according to Comparative Example 1 used in the sealability comparison test, (b) is a partial cross-sectional view of a bearing according to Comparative Example 2 used in the sealability comparison test, and (c) is a comparison. The expanded sectional view of the front-end | tip part of the sealing board used for the bearing of Example 1, (d) is an expanded sectional view of the front-end | tip part of the sealing board used for the bearing of the comparative example 2. FIG. The figure which shows the result of a sealing property comparison test. The fragmentary sectional view of the testing machine used for a sealing property comparison test.

Explanation of symbols

2 Inner ring 2s Inner ring outer diameter surface 4 Outer ring 4s Outer ring inner diameter surface 6 Rolling element 8 Seal plate 8e Base end of seal plate 8t Tip of seal plate 10 Cage J Rubber M Annular recess P Annular seal groove

Claims (4)

A pair of bearing rings arranged so as to be capable of relative rotation with each other, a plurality of rolling elements incorporated in a freely rolling manner between raceway grooves formed on opposite surfaces of each bearing ring, and opposite sides of each bearing ring A rolling bearing with an annular sealing plate attached between the faces,
The base end of the sealing plate is covered with rubber, and the base end of the sealing plate is fixed to the annular recess by fitting the rubber into the annular recess formed on the facing surface of one of the race rings. The tip is positioned in a non-contact state with respect to the opposing surface of the other race ring, and partially enters an annular seal groove formed in the opposing surface. Rolling bearing.   The rolling bearing according to claim 1, wherein a diameter dimension of a tip of the sealing plate is set to a predetermined dimension difference with respect to a diameter dimension of the annular seal groove.   The sealing plate is formed with a convex portion curved in a convex shape toward the outer side at the central portion between the base end and the tip end, and the convex portion is removed while fitting the base end into the annular recess. 2. The sealing plate is attached between opposing surfaces of each raceway ring in a state in which the tip of the sealing plate partially enters the annular seal groove by being elastically deformed by being pressed from the side. 2. A rolling bearing according to 2. The rolling bearing according to any one of claims 1 to 3, wherein the sealing plate has a plurality of slits formed at the tip thereof at predetermined intervals along the circumferential direction.

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