JP4601555B2 - Sealed rolling bearing - Google Patents

Description

  The present invention relates to a sealed type rolling bearing incorporated in a rotating shaft support portion of various mechanical devices such as an electromagnetic clutch and a pulley.

  2. Description of the Related Art Conventionally, sealed rolling bearings have been employed in rotating shaft support portions of various mechanical devices in order to prevent grease inside the bearing from leaking to the outside and to prevent foreign substances from entering and entering from the outside.

  As shown in FIG. 3, this sealed type rolling bearing includes an inner ring 30, an outer ring 31, a ball 32 provided so as to freely roll between the inner ring 30 and the outer ring 31, and the inner ring 30 and the outer ring 31. It is comprised from the cyclic | annular sealing member 33 fitted to an axial direction both end surface.

  An inner ring raceway 34 on which the ball 32 rolls is provided on the outer diameter surface of the inner ring 30, and an outer ring raceway 35 facing the inner ring raceway 34 is provided on the inner diameter surface of the outer ring 31. Circumferential seal grooves 36 and 36 are formed on both sides of the inner ring raceway 34, and seal member locking grooves 37 and 37 are formed on the inner diameter surface of the outer ring 31 facing the seal grooves 36. The outer peripheral portion of the seal member 33 is locked in the seal member locking groove 37.

  The seal member 33 is formed by reinforcing an elastic material with a cored bar, and a seal lip 38 is provided on an inner peripheral portion thereof, and an end edge 39 of the seal lip 38 is brought into contact with the side wall surface 40 of the seal groove 36. I am letting.

In the sealed rolling bearing configured as described above, the structure of the seal member 33 is devised in order to prevent the grease inside the bearing from leaking to the outside and to prevent the entry of foreign matter from the outside. Improvement of sealing performance is performed (Patent Document 1).
JP 2001-140907 A

  The seal member 33 incorporated in the sealed rolling bearing defines an angle formed by an end edge portion 39 of the seal lip 38 provided on the inner peripheral portion thereof and the side wall surface 40 and the bottom surface 41 of the seal groove 36. .

  Specifically, as shown in FIG. 4, an inclined wall 42 facing the side wall surface 40 of the seal groove 36 constituting the end edge 39 of the seal lip 38, and on the radially inward side of the inclined wall 42. Of the inner peripheral surface 43 that is located and faces the bottom surface 41 of the seal groove 36, the angle α formed by the inclined wall surface 42 and the side wall surface 40 of the seal groove 36 is 10 ° to 45 °, and the inner peripheral surface 43. And the bottom surface 41 of the seal groove 36 are defined to have an angle β of 0 degrees to 30 degrees, thereby improving the sealing performance.

In the above-mentioned sealed type rolling bearing, the angle β formed by the inner peripheral surface 43 of the seal lip 38 and the bottom surface 41 of the seal groove 36 is defined as 0 ° to 30 °. ), The contact state between the end edge 39 of the seal lip 38 and the side wall surface 40 of the seal groove 36 is important. Therefore, even if this contact state satisfies the above-mentioned definition of the angle β, the expected seal is not necessarily expected. There was a case where the sex could not be obtained.
Further, the bottom surface 41 of the seal groove 36 is not limited to a flat surface when the seal groove is processed, and may be processed into a curved surface. When the bottom surface 41 of the seal groove 36 is processed into a curved surface, there is a problem that it is difficult to define the angle β formed by the inner peripheral surface 43 of the seal lip 38 and the bottom surface 41 of the seal groove 36.

  Furthermore, an electromagnetic clutch that employs a sealed rolling bearing is used at a high temperature of around 150 ° C., and heat resistance is also required for the sealed rolling bearing and a sealing member that is a constituent member thereof. However, nitrile rubber is usually used for the sealing member of the sealed rolling bearing, and its heat resistance temperature is around 120 ° C., so there is a problem in heat resistance.

  Further, the electromagnetic clutch is disposed in the engine room of an automobile and has many opportunities to come into contact with various oils and chemicals. Therefore, excellent chemical resistance is required for the sealed rolling bearing and the sealing member which is a constituent member thereof. .

  Therefore, an object of the present invention is to easily define the contact state between the seal lip and the seal groove, to improve the sealability, and to provide a seal member excellent in heat resistance and chemical resistance.

  In order to solve the above-described problems, the present invention provides a sealing member having a contact angle α between the inclined wall surface of the edge of the seal lip and the side wall surface of the seal groove of 13 to 44 degrees and the seal lip. The contact angle β between the inner peripheral surface of the end edge and the side wall surface of the seal groove is defined as 91 degrees to 100 degrees.

  In this way, the contact state between the inclined wall surface of the end edge of the seal lip of the seal member and the side wall surface of the seal groove can be easily defined regardless of the shape of the bottom surface of the seal groove. Further, the sealing performance can be improved by the sealing lip of the sealing member that satisfies the regulation of the contact state.

  Specifically, a seal groove is formed on the outer diameter surface of the inner ring, and an outer peripheral edge portion of a seal member reinforced with an elastic material is fixed to the inner diameter surface of the outer ring facing the seal groove. In a sealed rolling bearing in which a seal lip is provided at a peripheral portion and the seal lip is in contact with a side wall surface of the seal groove, the seal lip includes an inclined wall surface facing the side wall surface of the seal groove, and the inclined wall surface An inner peripheral surface located on the inner side in the diametrical direction and opposed to the bottom surface of the seal groove, and a curved portion that continues the inclined wall surface and the inner peripheral surface, and this curved portion is contacted with the side wall surface of the seal groove. The contact angle α between the side wall surface of the seal groove and the inclined wall surface is set to 13 ° to 44 °, and the contact angle β between the side wall surface of the seal groove and the inner peripheral surface is 91. A configuration with a degree of 100 degrees was adopted.

  In the above configuration, the contact angle α between the side wall surface of the seal groove and the inclined wall surface of the seal lip is defined as 13 ° to 44 ° when the contact angle α is less than 13 °. This is because, due to the tolerance, the entire inclined wall surface of the seal lip contacts the side wall surface of the seal groove, and a minute gap is generated due to a wedge action that occurs when grease is pushed out to the seal groove side, which adversely affects the sealing performance. In addition, when the contact angle α exceeds 44 degrees, the edge portion of the seal lip becomes sharp, and the rigidity of the edge portion may be lowered.

  The contact angle β between the side wall surface of the seal groove and the inner peripheral surface of the seal lip is defined as 91 ° to 100 ° when the contact angle β is 90 ° or less. The contact angle β between the lip and the inner peripheral surface of the seal lip becomes an acute angle, and not only foreign matter that enters between these two planes is not discharged, but also this foreign matter creates a minute gap, which adversely affects the sealing performance. is there. Also, if the contact angle β exceeds 100 degrees, the end edge of the seal lip becomes sharp as in the case of the contact angle α described above, and the rigidity of the end edge may be lowered.

  Since the present invention is configured as described above, the contact state between the inclined wall surface of the edge of the seal lip of the seal member and the side wall surface of the seal groove can be easily defined, and the sealing performance can be improved. it can.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
A sealed rolling bearing according to an embodiment of the present invention is shown in FIGS. As shown in FIG. 1, the sealed type rolling bearing of this embodiment includes an inner ring 1, an outer ring 2, a ball 3 provided so as to freely roll between the inner ring 1 and the outer ring 2, the inner ring 1, It is comprised from the cyclic | annular sealing member 4 fitted to the axial direction both end surfaces of the outer ring | wheel 2.

  An inner ring raceway 5 on which the balls 3 roll is provided on the outer diameter surface of the inner ring 1, and an outer ring raceway 6 facing the inner ring raceway 5 is provided on the inner diameter surface of the outer ring 2. Circumferential seal grooves 7 and 7 are formed on both sides of the inner ring raceway 5, and seal member locking grooves 8 and 8 are formed on the inner diameter surface of the outer ring 2 facing the seal grooves 7. The outer peripheral edge 9 of the seal member 4 is locked in the seal member locking groove 8.

  The sealing member 4 is obtained by reinforcing an elastic body 11 made of synthetic rubber or the like with a cored bar 10. A constricted portion 12 is formed in the elastic body 11, and the thickness of the elastic body 11 is reduced in the constricted portion 12. A seal lip 13 extending inward in the radial direction from the constricted portion 12 is formed.

  As the synthetic rubber or the like used for the elastic body 11, hydrogenated nitrile rubber or ester acrylic rubber can be employed. Hydrogenated nitrile rubber is superior to nitrile rubber generally used as a sealing member and has no problem in chemical resistance, so it maintains stable properties and can be used at higher temperatures. it can. Ester-resistant acrylic rubber, like hydrogenated nitrile rubber, is superior in heat resistance compared to nitrile rubber and has improved chemical resistance against chemicals such as acrylic rubber ester oil and air conditioner compressor oil. Therefore, stable properties can be maintained and use at higher temperatures is possible.

  As shown in FIG. 2, the seal lip 13 includes an end edge portion 16 extending toward the side wall surface 14 on the inner side in the axial direction of the pair of side wall surfaces 14 and 15 constituting the seal groove 7, and an outer side in the axial direction. The projecting portion 17 projects in the direction.

  The end edge portion 16 is opposed to the side wall surface 14 of the seal groove 7 and is inclined in a direction away from the side wall surface 14 toward the outer side in the radial direction. The cylindrical inner peripheral surface 20 and a curved portion 21 that makes the inclined wall surface 18 and the inner peripheral surface 20 continuous are provided in a free state facing the bottom surface 19 of the seal groove 7.

  When the outer peripheral edge portion 9 of the seal member 4 configured as described above is locked in the seal member locking groove 8 of the outer ring 2, the seal lip 13 is elastically deformed outward in the axial direction, and the curved portion 21. Is in contact with the side wall surface 14 of the seal groove 7.

  In this state, a contact angle α between the side wall surface 14 and the inclined wall surface 18 is defined as 13 to 44 degrees. When the contact angle α is less than 13 degrees, the entire inclined wall surface 18 of the seal lip 13 is in contact with the side wall surface 14 of the seal groove 7 and the grease is pushed out to the seal groove 7 side due to processing tolerance of each part. The resulting wedge action creates a minute gap, which adversely affects the sealing performance. When the contact angle α exceeds 44 degrees, the end edge 16 of the seal lip 13 becomes sharp, and the rigidity of the end edge 16 may be reduced.

  Further, a contact angle β between the side wall surface 14 and the inner peripheral surface 20 is defined as 91 degrees to 100 degrees. When the contact angle β is 90 degrees or less, the contact angle formed between the side wall surface 14 of the seal groove 7 and the inner peripheral surface 20 of the seal lip 13 becomes an acute angle, and foreign matter that has entered between these two planes is not discharged. However, a minute gap is generated by this foreign matter, which adversely affects the sealing performance. If the contact angle β exceeds 100 degrees, the edge 16 of the seal lip 13 becomes sharp as in the case of the contact angle α described above, and the rigidity of the edge 16 may be reduced.

  In order to confirm the effect of the present invention, a test conducted by the present inventor will be described. In order to clarify the relationship between the seal lip contact state and the sealing performance, this test verified the seal lip contact state and muddy water resistance, and operated under the following operating conditions. Checked the condition.

(Operating conditions)
Muddy water: Kanto loam powder JIS 8 types 10wt%
Rotational speed: 2000r / min
Test time: 3 hours (specimen)
Material: Synthetic rubber (NBR (acrylonitrile butadiene rubber))

Table 1 shows the test results of the comparative examples and the examples.

  As described above, in the embodiment in which the contact angle α is 13 ° to 44 ° and the contact angle β is 91 ° to 93 °, a good sealing property is ensured. Further, when the contact angle β is applied to the contact angle β described in Patent Document 1 and expressed as β ′, it is as shown in Table 1 above, and satisfies the condition of 0 degree <β ′ <30 degrees. However, the sealing performance may be inferior (Comparative Examples 2 and 3). Furthermore, in the case of the comparative example 4, although the contact angles α and β described in Patent Document 1 were satisfied, the sealing performance was inferior.

  As described above, the sealability can be improved by simultaneously defining the contact angles α and β between the end edge portion 16 of the seal lip 13 and the side wall surface 14 of the seal groove 7.

Sectional drawing which shows the sealing type rolling bearing of embodiment Enlarged view of FIG. Partial sectional view showing a conventional sealed rolling bearing Enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 4 Seal member 5 Inner ring raceway 6 Outer ring raceway 7 Seal groove 8 Seal member engagement groove 9 Outer peripheral edge portion 10 Core metal 11 Elastic body 12 Neck portion 13 Seal lip 14 Side wall surface 15 Side wall surface 16 Edge portion 17 Protruding portion 18 Inclined wall surface 19 Bottom surface 20 Inner circumferential surface 21 Curved portion 30 Inner ring 31 Outer ring 32 Ball 33 Seal member 34 Inner ring raceway 35 Outer ring raceway 36 Seal groove 37 Seal member locking groove 38 Seal lip 39 End edge 40 Side wall surface 41 Bottom surface 42 Inclined wall surface 43 Inner peripheral surface

Claims (1)

A seal groove (7) is formed on the outer diameter surface of the inner ring (1), and the outer peripheral edge (9) of the seal member (4) is fixed to the inner diameter surface of the outer ring (2) facing the seal groove (7). In the sealed rolling bearing in which the seal lip (13) is provided on the inner peripheral portion of the seal member (4), and the seal lip (13) is brought into contact with the side wall surface (14) of the seal groove (7),
The seal groove (7) is formed of an axially inner side wall surface (14), an axially outer side wall surface (15), and a bottom surface (19) that connects both side wall surfaces (14, 15), The axially inner side wall surface (14) is composed of a straight portion having a straight cross section and a round portion having a circular arc shape continuing radially inward of the straight portion, and the seal member (4) is made of an elastic material. (11) is reinforced with a cored bar (10), and the elastic material (11) is an ester oil resistant acrylic rubber, and the constricted portion (12) having a small thickness in the elastic material (11) portion. The seal lip (13) extending inward in the radial direction from the constricted portion (12) is formed at an end edge extending toward the axially inner side wall surface (14) of the seal groove (7). (16) and a protruding portion (17) protruding outward in the axial direction The edge (16) has an inclined wall surface (18) opposed to the side wall surface (14) on the axially inner side of the seal groove (7), and a diameter inner side from the inclined wall surface (18). An inner peripheral surface (20) positioned and opposed to the bottom surface (19) of the seal groove (7), and a curved portion (21) that connects the inclined wall surface (18) and the inner peripheral surface (20), In a state where the curved portion (21) is in contact with the axially inner side wall surface (14) of the seal groove (7), the curved portion (21) is more than the boundary portion between the straight portion and the rounded portion. The contact angle α between the side wall surface (14) in the axial direction of the seal groove (7) and the inclined wall surface (18) is 13 degrees to 44 degrees, and is in contact with the position on the straight portion side. Contact angle β between the axially inner side wall surface (14) of the groove (7) and the inner peripheral surface (20) The inner diameter of the seal lip (13) is substantially the same as the outer diameter of the shoulder on the outer side in the axial direction of the seal groove (7), and the protrusion (17) is on the inner peripheral side. Is provided with an inclined surface formed so as to gradually increase in diameter toward the tip of the projecting portion (17), and the inclination angle of the inclined surface in the outer diameter direction is the inner peripheral surface of the seal lip (13). (20) is set to be larger than the inclination angle and is set to be smaller than the inclination angle of the axially outer side wall surface (15) of the seal groove (7), and the inclined surface is formed on the inner end portion in the axial direction. A stepped portion projecting toward the side wall surface (15) on the axially outer side of the groove (7) is provided, and is provided continuously through the stepped portion on the inner peripheral surface (20) of the edge portion (16). Sealed type rolling bearing characterized by that.

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