JP2006242246A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent intrusion of dust and leakage of a lubricant; and to reduce torque. <P>SOLUTION: This rolling bearing is provided with: an inner ring 21; an outer ring 22; a plurality of rolling bodies (balls) 24 arranged between the outer ring 22 and the inner ring 21; retainers 23 for guiding and retaining the rolling bodies 24 at equal intervals; and contact type seal members 30 mounted between the outer ring 22 and the inner ring 21. The seal member 30 is composed of a cored bar 31 and seals 32 and 33 made of rubber. A seal lip 35 is formed on the inner ring side of each of the seals 32 and 33. Dimple-like recessed parts 36 are formed on a contact surface of the seal lip 35 to the inner ring 21, and a solid lubrication material coating 37 is formed on the recessed parts 36. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing provided with a sealing device, and in particular, automotive electrical parts, alternators and intermediate pulleys that are engine auxiliary machines, electromagnetic clutches for car air conditioners, water pumps, hub units, electromagnetic clutches for gas heat pumps, and compressors. The present invention relates to a rolling bearing which is used under high temperature, high speed, high load conditions such as, and is suitable for a portion where water or muddy water is easily mixed.

  Examples of the rolling bearing include an outer ring, an inner ring, a plurality of rolling elements (balls) disposed between the outer ring and the inner ring, a cage that guides and holds the rolling elements at equal intervals, and a seal lip portion. Inner ring rotation type with a contact seal that is slidably contacted with the seal groove of the inner ring and mounted between the outer ring and the inner ring, or an outer ring rotation in which the seal lip of the contact seal slides on the seal groove of the outer ring A type is known (see Patent Document 1). According to this type of rolling bearing, the seal lip portion is in sliding contact with the side wall of the inner ring to form a contact-type sealing device, and the outer ring and the inner ring are sealed by the seal lip portion. It is possible to block the intrusion of the grease and the like and to prevent the grease from leaking from the inside.

On the other hand, the sealing device is required to reduce the torque generated by the sliding contact between the seal and the inner ring. For example, a seal ring is used to reduce torque as well as to prevent dust leakage and grease leakage. The outer-diameter side seal lip, the inner-diameter side seal lip, and the radial seal lip are provided from the outer ring to the inner ring. Both side seal lips prevent rainwater from entering, and the radial seal lip prevents grease from entering. Proposals have been made to prevent the leakage and further reduce the rotational torque by thinning the inner diameter side side seal lip (see Patent Document 2).
JP 2002-155960 A (pages 2 to 3, FIG. 1) JP-A-9-287619 (pages 3 to 5, FIGS. 1 and 2)

  In the prior art, the inner side seal lip is thinned to reduce the rotational torque, but the properties of the contact surface of the seal lip with the inner ring are not sufficiently considered, and the torque is reduced. Is not enough.

  The present invention provides a rolling bearing capable of improving the properties of the contact surface of the seal lip with the raceway ring, preventing dust intrusion and lubricant leakage, and reducing the torque. It is the purpose.

  In order to solve the above-mentioned problems, the present invention provides a sealing device in which a plurality of rolling elements are disposed between an outer ring and an inner ring, and the outer ring or the inner ring is used as a race ring and a seal lip is brought into contact with the race ring. In the rolling bearing provided with the device, the rolling bearing is characterized in that a dimple-like recess is provided on a contact surface of the seal lip with the raceway.

When configuring the rolling bearing, the dimple-like recesses form a sphere or ellipse of 1.0 to 40 μm, and the dimple-like recesses inject shot powder having a diameter of 2 to 130 μm. It is also possible to adopt a configuration in which a pressure of 2.0 to 9.0 kg / cm ² is directly injected onto the seal lip or transferred to a mold. Furthermore, it is possible to employ a configuration in which the surface of the dimple-like recess is covered with a solid lubricant by 75% or more by area ratio, or a solid lubricant is covered by 75% or more and 95% or less. In this case, tin, MoS ₂ , Sn, PTFE, WS ₂ , or BN can be used as the solid lubricant.

In the present invention, as an example, tin, MoS ₂ , Sn, PTFE, WS ₂ , and BN were used as solid lubricants, but there is no particular limitation as long as similar effects are obtained, and other solid lubricants are used. Examples thereof include polyethylene, fluororesin, nylon, polyacetal, polyolefin, polyester, PTFE, metal soap, graphite, calcium fluoride, barium fluoride, tin alloy, and copper alloy.

  According to the above-described means, the contact area of the contact surface (bearing sliding contact surface) between the seal lip and the raceway is reduced by providing the dimple-like concave portion on the contact surface of the seal lip with the raceway. Can be realized. Moreover, since the convex part is formed in the periphery of the concave part, the sealing performance can be sufficiently secured. Furthermore, the torque can be further reduced by forming the solid lubricant film in the dimple-like recess.

  According to the present invention, it is possible to prevent the intrusion of dust and the leakage of the lubricant, and to reduce the torque.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a rolling bearing showing an embodiment of the present invention, and FIG. 2 is a sectional view of a sealing device used for the rolling bearing.

  1 and 2, the rolling bearing 20 is, for example, an automobile electrical component, an alternator or intermediate pulley as an engine auxiliary machine, an electromagnetic clutch for a car air conditioner, a water pump, a hub unit, an electromagnetic clutch for a gas heat pump, a compressor, or the like. An inner ring 21, an outer ring 22, a plurality of rolling elements (balls) 24 disposed between the outer ring 22 and the inner ring 21, and rolling elements that are used under high temperature, high speed, and high load conditions. A cage 23 that guides and holds 24 at equal intervals, and a contact-type seal member (sealing device) 30 that is mounted between the outer ring 22 and the inner ring 21 are configured. The seal member 30 includes a metal core 31 and rubber seals 32 and 33, the outer ring side of the seals 32 and 33 is mounted in the seal groove 25 of the outer ring 22, and a seal lip 35 is disposed on the inner ring side of the seals 32 and 33. Is formed. The seal lip 35 is in sliding contact with the seal groove 26 formed in the inner ring 21. In other words, the rolling bearing 20 has a sealing structure in which the seal member 30 seals between the outer ring 22 and the inner ring 21, and as the inner ring rotating type, the seal lip 35 is moved along the rotation of the inner ring 21. The inner ring 21 is in sliding contact with the seal groove 26. For this reason, the rolling bearing 20 in the present embodiment can prevent intrusion of dust and leakage of lubricant (grease). The present invention can also be applied to an outer ring rotating type in which the seal lip is in sliding contact with the seal groove of the outer ring. Further, the shapes of the inner ring 21, the outer ring 22, the seal member 30 and the like are not limited to those shown in the drawings, and other shapes can be used.

Further, in the rolling bearing 20 in the present embodiment, a dimple-like concave portion is formed on the contact surface of the seal lip 35 with the raceway ring, that is, the contact surface (sliding contact surface) with the inner ring 21 to reduce the torque. When forming a dimple-like recess in the contact surface of the seal lip 35 with the inner ring 21, a seal for a deep groove ball bearing having an inner diameter of 17 mm, an outer diameter of 52 mm, and a width of 16 mm is used as the rolling bearing seal member 30. A member was prepared, and this seal member was subjected to shot peening treatment under the conditions shown in Table 1 below to produce a seal lip 35 having the surface properties shown in Table 1. For example, a shot powder having a substantially spherical shape and having a diameter of ² to 130 μm is sprayed onto the seal lip 35 at an injection pressure of 2.0 to 9.0 kg / cm ² , and the diameter of the shot lip 35 on the contact surface with the inner ring 21 is 0.1 A spherical or elliptical concave portion of 10 μm was formed, and this concave portion was made to have a hardness higher than that of a portion removed from the concave portion.

ここで、ショット後の表面性状の測定には、非接触型の光干渉式形状測定試験機を用い、ディンプル状の凹部の深さに関しては、測定した形状曲線の中心線からの最大深さとし、凹部径に関しては、光干渉型形状測定機から得られた二次元画像を二値化して現われる凹部の直径を測定して求めた。

Here, for the measurement of the surface properties after the shot, a non-contact type optical interference type shape measuring tester is used, and the depth of the dimple-like concave portion is set to the maximum depth from the center line of the measured shape curve, The recess diameter was determined by measuring the diameter of a recess that appears by binarizing a two-dimensional image obtained from an optical interference type shape measuring machine.

  FIG. 3A shows an example of an optical microscopic structure representing the surface shape when a dimple-like recess is formed on the contact surface of the seal lip 35 with the inner ring 21. FIG. 3B shows an example of a light microscopic structure representing the surface shape of a conventional seal lip. From the surface shape of FIG. 3A, it can be seen that the surface of the seal lip 35 according to the present invention is formed with dimple-like irregularities having a spherical shape or an elliptical shape that are not found in the conventional one.

  Further, from the component analysis results after the shot, a small amount of solid lubricant used as the shot material was detected as a coating on the seal lip surfaces shown in Examples 2 to 7 and Examples 10 and 11.

Specifically, the surface shape of the seal lip 35 according to the present invention is schematically shown in FIGS. 4 (a) and 4 (b). That is, as shown in FIG. 4A, a dimple-like recess 36 is formed on the contact surface of the seal lip 35 with the inner ring (orbital ring) 21. As shown in FIG. A dimple-like recess 36 is formed on the contact surface of the seal lip 35 shown in FIGS. 7 to 7 and Examples 10 and 11 with the inner ring (orbital ring) 21, and MoS ₂ , Sn, PTFE, A solid lubricant film 37 of either BN or WS ₂ is formed. As shown in FIG. 4C, the conventional contact surface of the seal lip 50 with the inner ring 51 is formed in a flat plate shape.

  Next, the seal member 30 manufactured under the conditions shown in Table 1 is incorporated into a deep groove ball bearing having an inner diameter of φ17 mm, an outer diameter of φ52 mm, and a width of 16 mm, and the following tests are performed based on the respective test conditions using a rotational tester manufactured by NSK Ltd. I went.

Test 1: Seal torque test The torque during the bearing rotation test is measured. The test conditions were as follows, and the torque 12 hours after the start of bearing rotation was measured as a stable torque.

  The test results are also shown in Table 1. Each torque amount was expressed as a relative value when the torque of Comparative Example 20 having the seal lip property of the conventional product was set to 100.

Number of tests: 2 (test results adopt average value)
Atmospheric temperature: Room temperature Rotation speed: 2,000 rpm
Test time: 200hrs
Test 5: Grease leakage test The bearing was the same as that used in Test 1, except that only the amount of grease filled was 35% of the bearing internal space volume. This was continuously rotated for 20 hours at a bearing outer ring temperature of 120 ° C., radial load = axial load = 98 N, 10000 rpm, and the grease leakage rate was measured. The test results are also shown in Table 1.

  As a method of calculating the area ratio of the obtained solid lubricant film, the surface of the rolling element after the treatment was observed with EPMA (magnification × 2000, 30 fields of view), and the 200 μm square of the coated surface was magnified 1000 times. When the film is formed in a region having an intensity of 10 times or more of the element characteristic X-ray intensity before coating, the result is subjected to image analysis to calculate the coating area ratio after coating, and the average value As sought.

  From the results shown in Table 1, it can be seen that in the examples of the present invention, low torque is achieved while maintaining the leakage performance compared to the conventional product.

  In Comparative Examples 12, 14, 16, and 18, the shot particle size, the shot injection pressure, the concave diameter after the shot, and the concave depth after the shot are smaller than those of the present invention, so the torque cannot be reduced. It was. In Comparative Examples 13, 15, 17, and 19, the shot particle size, the shot injection pressure, the concave diameter after the shot, and the concave depth after the shot are larger than those of the present invention. However, the leak performance is inferior to the conventional product. In addition, about the item excluded from this invention among comparative examples, the background is shown by hatching.

The longitudinal cross-sectional view of the rolling bearing which shows one Example of this invention. Sectional drawing of the sealing member used for a rolling bearing. A photomicrograph of an example of an optical microscopic structure representing the surface shape of a seal lip. The principal part sectional drawing which showed the surface shape of the seal lip typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Rolling bearing 21 Inner ring 22 Outer ring 23 Cage 24 Rolling body 30 Seal member 35 Seal lip 36 Dimple-shaped recessed part 37 Solid lubricant coating

Claims (5)

  A rolling bearing having a sealing device in which a plurality of rolling elements are disposed between an outer ring and an inner ring, and the outer ring or the inner ring is used as a race ring and a seal lip is brought into contact with the race ring. A rolling bearing comprising a dimple-like recess provided on a contact surface with the raceway.   The rolling bearing according to claim 1, wherein the dimple-shaped recess has a spherical shape or an elliptical shape of 1.0 to 40 μm. The dimple-like recess is formed by transferring a shot powder having a substantially spherical shape having a diameter of ² to 130 μm directly injected onto the seal lip at an injection pressure of 2.0 to 9.0 kg / cm ² or transferred to a mold. The rolling bearing according to claim 1 or 2, wherein   4. The rolling bearing according to claim 1, wherein the surface of the dimple-like recess is covered with a solid lubricant of 75% or more by area ratio.   4. The rolling bearing according to claim 1, wherein the surface of the dimple-shaped recess is covered with a solid lubricant of 75% or more and 95% or less in terms of area ratio. 5.

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