JP2005069404A - Sealed rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long-life sealed rolling bearing that reliably prevents foreign matter from entering from the outside, does not cause a lip adsorption phenomenon, and has a stable rotational torque.
An outer ring 11 having an outer ring raceway surface 11c formed on an inner peripheral surface, an inner ring 12 having an outer ring raceway surface 12c formed on an outer peripheral surface, and rolling between the outer ring raceway surface 11c and the inner ring raceway surface 12c. A plurality of rolling elements 13 arranged freely, and provided on the side of the rolling element 13, a lip 22 c is slidably contacted with a seal groove 12 a formed in one of the outer ring 11 and the inner ring 12, and the outer ring. 11 and a sealing device 20 mounted on the other of the inner rings 12, wherein the seal groove 12a is subjected to shot peening on at least a sliding contact surface 12d in sliding contact with the lip 22c. It has been subjected.
[Selection] Figure 1

Description

  The present invention relates to a sealed rolling bearing, and more specifically, includes a sealing device, and can prevent entry of foreign matter into the interior even when used under conditions in contact with foreign matter such as water, muddy water, and sand. The present invention relates to a sealed rolling bearing suitable for use in a vehicle machine such as an automobile.

  In an automobile engine room, auxiliary members such as an alternator and an air conditioner compressor, and rotating members such as pulleys for driving the auxiliary devices are rotatably supported by rolling bearings. Auxiliary machinery and pulleys placed around the engine are used under adverse conditions where foreign matter such as water, muddy water, sand, etc. are in direct or indirect contact. Used below. For this reason, if foreign matter enters the inside of the rolling bearing, the grease enclosed inside is altered, or the foreign matter is caught between the rolling elements and the raceway surface, and the lubrication state deteriorates, reducing the bearing performance. Or reduce the bearing life.

As a rolling bearing used in the above-mentioned environment, a sealing type rolling device is provided with sealing devices on both sides, and a lubricant such as grease is sealed inside to prevent the entry of foreign matter from the outside. A bearing is used.
In recent years, the space in the engine room has been restricted with the reduction in weight and compactness of automobiles, and there has been a strong demand for weight reduction and compactness of installed devices. Therefore, it becomes difficult to install a mechanical seal, a labyrinth seal, a cover, and the like for dust-proofing and waterproofing of the rolling bearing, and the sealing device is required to have dust-proofing and waterproofing properties higher than those of conventional ones.

  In order to improve dustproofness and waterproofness, it is common practice to increase the contact area between the lip and the seal groove of the sealing device or increase the contact pressure (stressing force) of the lip. However, if the contact area between the lip and the seal groove is increased, the frictional heat between the lip and the seal groove increases as the rolling bearing rotates, or the temperature of the rolling bearing increases due to heat conduction from the outside. Thereafter, when the rolling bearing is cooled, the pressure in the rolling bearing becomes negative. For this reason, there is a possibility that a so-called adsorption phenomenon occurs in which the lip of the sealing device is firmly attached to the seal groove and the bearing torque is remarkably increased.

  As shown in FIG. 3, the conventional sealed type rolling bearing that prevents the adsorption phenomenon is provided with one or more air holes on the inner diameter side or outer diameter side of the contact seal, and inside and outside the sealed type rolling bearing. A sealed-type rolling bearing 1 is disclosed in which the pressure balance is kept uniform (see, for example, Patent Document 1).

  A conventional sealed type rolling bearing 1 includes a contact seal 2, a seal outer diameter side (head) 2 a is mounted in a seal groove 3 a of an outer ring 3, and a seal lip 2 b is connected to a seal groove 4 a of an inner ring 4. The bearing is slid in contact from the direction, and the sealability of the bearing is achieved.

The contact seal 2 includes an air having an outer diameter surface air hole 5a recessed in the axial direction on the outer diameter surface of the head 2a and an inner surface air hole 5b recessed in the radial direction on the inner surface of the head 2a. A hole 5 is formed. When the pressure balance inside and outside the sealed rolling bearing 1 is lost, the pressure inside and outside the bearing is adjusted through the air holes 5 provided in the contact seal 2 to keep the pressure balance uniform and prevent the adsorption phenomenon of the contact seal 2 It is supposed to be.
JP 2000-65074 A (FIG. 1)

  However, in the sealed rolling bearing 1 of Patent Document 1, in the case of a sealed rolling bearing for a vehicle that is used under severe conditions in which foreign matters such as water, muddy water, and sand are in direct or indirect contact with each other, There is a problem that foreign matters, particularly liquid foreign matters such as water and muddy water, may enter the sealed rolling bearing 1 and reduce the bearing life.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to reliably prevent the entry of foreign matter from the outside, without the occurrence of a lip adsorption phenomenon, and to obtain a stable rotational torque, The object is to provide a long-life sealed rolling bearing.

The present invention is achieved by the following configurations.
(1) An outer ring having an outer ring raceway surface formed on the inner peripheral surface, an inner ring having an inner ring raceway surface formed on the outer peripheral surface, and a plurality of rolls disposed between the outer ring raceway surface and the inner ring raceway surface in a freely rotatable manner. A rolling device, and a sealing device that is provided on a side of the rolling member and is attached to the other of the outer ring and the inner ring by sliding a lip in a seal groove formed on one of the outer ring and the inner ring, A hermetic rolling bearing with
The seal-type rolling bearing according to claim 1, wherein the seal groove is subjected to shot peening on at least a sliding contact surface with which the lip slides.
(2) The hermetic rolling bearing according to (1), wherein the shot peening process is a precision shot peening process.

  According to the sealed rolling bearing of the present invention, since the shot contact peening is performed on the sliding contact surface where at least the lip of the sealing device of the sealing groove is in sliding contact, the sliding contact surface has a surface texture (texture) in which unevenness is uniformly dispersed. It is formed. Moreover, the lubricant is held in the recesses of an appropriate size, and a fluid film can be formed. As a result, the sliding surface and the lip are fluid-sealed to ensure sealing performance and to prevent the entry of foreign matter from the outside, and to improve the lubrication of the sealed rolling bearing over a long period of time. It can be maintained and the life of the bearing can be extended. In addition, even if the pressure inside the sealed rolling bearing becomes negative due to temperature change and the lip is strongly pressed against the sliding surface of the seal groove, the frictional force between the seal groove and the lip can be reduced. Occurrence of the adsorption phenomenon can be prevented. Thereby, increase of the rotational torque of a sealed rolling bearing can be prevented.

  In addition, since the sliding contact surface of the seal groove is precision shot peened, unevenness can be formed uniformly on the entire surface of a small sealed rolling bearing, that is, a seal groove that is difficult to process due to its small size. The adsorption phenomenon can be effectively prevented. Further, burrs and turning marks in the turning process, scales and welded materials in the heat treatment process can be removed, and the contact state with the seal lip can be improved.

Hereinafter, a sealed rolling bearing according to an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an essential part of a sealed rolling bearing according to an embodiment of the present invention. As shown in FIG. 1, the sealed rolling bearing 10 is a deep groove ball bearing including an outer ring 11, an inner ring 12, a plurality of balls 13 that are rolling elements, a cage 14, and a sealing device 20.

  The outer ring 11 has an outer ring raceway surface 11c formed on the inner peripheral surface 11b and a seal fixing groove 11a provided on the side end. The inner ring 12 has an inner ring raceway surface 12c formed on the outer peripheral surface 12b and a seal groove 12a provided on the side end. The plurality of balls 13 are held at a predetermined interval in the circumferential direction by a cage 14 and are disposed between the outer ring raceway surface 11c and the inner ring raceway surface 12c so as to roll freely.

  In the sealing device 20, an elastic body 22 having elasticity such as rubber and synthetic resin is integrally formed in an annular shape on a ring-shaped cored bar 21 in which a plate material having high rigidity such as metal and synthetic resin is formed in a ring shape. The mechanical strength of the elastic body 22 is reinforced by the ring-shaped cored bar 21. A fixing portion 22 a is formed on the outer peripheral edge of the sealing device 20 by enclosing the outer diameter portion 21 a of the ring-shaped cored bar 21 with an elastic body 22. The fixing portion 22 a is press-fitted and fixed in a seal fixing groove 11 a provided in the outer ring 11. Is done.

  Further, on the inner peripheral side of the ring-shaped cored bar 21, an elastic body 22 is extended in the inner peripheral direction to form an annular neck portion 22b. The inner peripheral end of the neck portion 22b is formed with a first lip 22c that is the lip of the present invention that branches off inward in the axial direction of the sealed rolling bearing 10 and a second lip 22d that branches off in the axial direction. The first lip 22c and the second lip 22d are displaced in conjunction with each other by bending from the root portion.

  When the fixing portion 22a is press-fitted and fixed in the seal fixing groove 11a, the first lip 22c has a predetermined contact pressure (tightening force) applied to the side wall 12d of the seal groove 12a while bending the neck portion 22b axially outward from the root portion. ) To make a sliding contact. Also, the second lip 22d is disposed opposite to the neck portion 22b by bending the neck portion 22b outward in the axial direction so as to form a slight clearance C1 with the mouth portion outer diameter surface 12e of the seal groove 12a. The labyrinth packing is constituted by the two lips 22d and the mouth portion outer diameter surface 12e of the seal groove 12a to perform a sealing action. In addition, you may make it the 2nd lip 22d contact lightly with the mouth part outer diameter surface 12e.

  Further, a third lip 22e is branched from the base portion of the neck portion 22b toward the inner side in the axial direction of the sealed rolling bearing 10. The third lip 22e branches off from the base of the neck portion 22b and is formed independently of the first lip 22c and the second lip 22d. Therefore, the third lip 22e is less affected by the bending of the neck portion 22b, and the first lip 22c. And even if the second lip 22d is displaced, it is hardly displaced. The third lip 22e is disposed opposite to the outer peripheral surface 12b of the inner ring 12 with a slight clearance C2 to constitute a labyrinth packing.

The surface of the seal groove 12a has been subjected to shot peening and has a surface configuration (texture) in which irregularities of an appropriate size are uniformly dispersed in the circumferential direction and the axial direction. Microscopically, the surface of the seal groove 12a has a convex portion that forms a contact surface with the lip, and a concave portion that acts as an oil sump and stores a lubricant to form a fluid film. Uniformly distributed in the axial direction. As a result, it is possible to recirculate the lubricant by forming two forward and reverse flows in the axial direction, and the surface of the seal groove 12a and the sealing device 20 are sealed through an oil film having an appropriate thickness. A fluid seal is constructed to ensure sealing performance.
In particular, since the concave portion acts as a pool of oil, a fluid film is easily generated, friction between the lip and the sliding contact surface of the seal groove 12a is reduced, and an increase in bearing torque can be suppressed.

  The shot peening process may be performed at least on the side wall 12d of the seal groove 12a, which is a sliding contact surface with which the first lip 22c of the sealing device 20 is in sliding contact. However, the shot peening process may be performed on the entire seal groove 12a. Good.

  As the processing conditions for shot peening, appropriate conditions can be adopted depending on the bearing size to be processed, particularly the dimensions and shape of the seal groove 12a. In particular, in rolling bearings for electromagnetic clutches of compressors for car air conditioners, alternators, idler pulleys, and the like, it is preferable to perform precision shot peening because the seal groove 12a is small. For example, WPC (Wonder Process Craft) Processing (shot peening processing provided by Fuji Seisakusho Co., Ltd. and Fuji Machine Sales Co., Ltd.) is preferably used.

  As shown in FIG. 1, the sealed rolling bearing 10 of the present invention is sealed at both ends by a sealing device 20, and grease (not shown) sealed in the bearing space contains balls 13, outer ring raceway surfaces 11 c and inner rings. Lubrication with the raceway surface 12c is performed. In the first lip 22c, the neck portion 22b is bent outward in the axial direction from the root portion and contacts the side wall 12d of the seal groove 12a with an appropriate contact pressure to seal the sealed rolling bearing 10.

  The second lip 22d is disposed to face the outer diameter surface 12e of the mouth portion with a slight clearance C1, and acts as a labyrinth packing to mainly prevent foreign matter from entering from the outside of the sealed rolling bearing 10. The second lip 22d is displaced in conjunction with the first lip 22c when the neck portion 22b is bent. For example, the first lip 22c is worn or a pressing force to the side wall 12d of the seal groove 12a. In FIG. 1, the neck portion 22b is pivotally displaced clockwise around the root portion in FIG. This rotational displacement is based on the elastic force of the neck 22b. As a result, the first lip 22c comes into contact with the side wall 12d of the seal groove 12a or strengthens the tightening force, and the second lip 22d is displaced in a direction approaching the mouth outer diameter surface 12e to narrow the clearance C1, The sealing function is maintained.

  The third lip 22e is disposed so as to face the outer peripheral surface 12b of the inner ring 12 with a clearance C2, and acts as a labyrinth packing, and mainly prevents the enclosed grease from leaking to the outside. The third lip 22e branches off from the base of the neck 22b and is formed independently of the first lip 22c and the second lip 22d. For example, the first lip 22c is worn or the side wall of the seal groove 12a Even if the tightening force to 12d is reduced and the neck portion 22b is rotationally displaced about the root portion, it is hardly affected. That is, the clearance C2 between the third lip 22e and the outer peripheral surface 12b of the inner ring 12 does not change. Therefore, the leakage of grease to the outside is stably prevented.

  Since the third lip 22e is non-contacted, an increase in rotational torque can be avoided, and furthermore, the first lip 22c and the seal groove 12a are passed through the clearance C2 with a very small amount of the base oil of the enclosed grease. Is supplied to the sliding contact surface with the side wall 12d and lubricated. The base oil of the grease supplied to the sliding contact surface is stored in a recess formed in the side wall 12d of the seal groove 12a by shot peening to form a fluid film (oil film). That is, the sliding contact surface between the side wall 12d and the first lip 22c is lubricated by the oil film and fluid-sealed, so that the entry of foreign matter from the outside is prevented.

  Further, when the temperature of the sealed rolling bearing 10 rises due to frictional heat between the side wall 12d and the first lip 22c or heat conduction from the outside, and then cooled, the pressure inside the sealed rolling bearing 10 becomes negative. The first lip 22c is strongly pressed against the side wall 12d, but since the sliding contact surface between the side wall 12d and the first lip 22c is lubricated by an oil film, the frictional resistance is extremely small and the rotational torque may be increased. Absent.

  According to the sealed rolling bearing according to the present embodiment, since the shot contact peening is performed on the sliding contact surface where at least the lip of the sealing device of the sealing groove is in sliding contact, the surface structure (texture is uniformly distributed on the sliding contact surface. ). Moreover, the lubricant is held in the recesses of an appropriate size, and a fluid film can be formed. As a result, the sliding surface and the lip are fluid-sealed to ensure sealing performance and to prevent the entry of foreign matter from the outside, and to improve the lubrication of the sealed rolling bearing over a long period of time. It can be maintained and the life of the bearing can be extended. In addition, even if the pressure inside the sealed rolling bearing becomes negative due to temperature change and the lip is strongly pressed against the sliding surface of the seal groove, the frictional force between the seal groove and the lip can be reduced. Occurrence of the adsorption phenomenon can be prevented. Thereby, increase of the rotational torque of a sealed rolling bearing can be prevented.

  Further, according to the sealed rolling bearing according to the present invention, since the slide contact surface of the seal groove is subjected to precision shot peening, a small-sized sealed rolling bearing, that is, a seal groove having a small size and difficult to process. Unevenness can be uniformly formed on the entire surface, and the adsorption phenomenon can be effectively prevented. Further, the surface can be cleaned by precision shot peening to remove burrs, turning marks, or scales, welds, etc. adhering to the seal groove 12a during turning or heat treatment. And the contact state between the side wall 12d can be improved.

  Next, the sealability and the presence / absence of an adsorption phenomenon were confirmed using an example according to the sealed rolling bearing of the present invention that was shot peened and a comparative example that was not shot peened.

  As the sealed rolling bearings used for the tests, double-row angular contact ball bearings for electromagnetic clutches of compressors for car air conditioners, which are engine auxiliary machines with strict requirements for dustproofing and waterproofing, were used in both Examples and Comparative Examples. The size of the angular ball bearing was set to an inner diameter of 35 mm, an outer diameter of 52 mm, and a width of 20 mm. A precision shot peening process (WPC process) was performed on the entire surface of the seal groove of the sealed rolling bearing used in the examples under the following conditions. On the other hand, shot peening was not performed on the seal groove of the sealed type rolling bearing used in the comparative example, and the conventional method was left as it was.

<Precision shot peening processing conditions>
Abrasive
Material: SiO ₂
Hardness: Hv900
Average particle size: 45 μm
Injection pressure: 0.4 MPa
Injection distance: 70mm
Injection time: 20 seconds

  Both the sealed rolling bearings of the example and the comparative example are subjected to a submergence test in which the rolling bearing is submerged in water to check the sealing performance, and the presence or absence of the adsorption phenomenon is determined by the bearing starting torque before and after the submergence test. This was done by confirming the change. The test conditions and judgment method of the submergence test are as follows.

<Test conditions>
Rotation speed (outer ring rotation): 3000rpm
Belt load (radial load): 200N
Submerged state: Position the bearing center 100mm below the water surface (complete submerged state)
Water temperature: Not controlled Test time: 2 hours

<Judgment method>
1. Sealability: “Bearing weight after test−Bearing weight before test” was determined, and the increase in weight was determined as the amount of water intrusion by the test.
2. Presence or absence of adsorption phenomenon: Judgment was made by measuring the bearing starting torque before and after the test.

  As a result of conducting the submergence test under the above test conditions, the sealing performance was 100 mg or less in water penetration amount in both the Example, the Comparative Example, and any of the sealed rolling bearings, and no difference was observed between the two.

  On the other hand, regarding the presence or absence of the adsorption phenomenon, each bearing starting torque before and after the submergence test is made dimensionless with reference to the starting torque of the sealed rolling bearing of the comparative example (conventional product) before the test as a reference (1.0). Shown in As shown in FIG. 2, the starting torque of the sealed type rolling bearing of the comparative example reaches approximately 2.2 after the submergence test, and it can be seen that the adsorption phenomenon is strongly generated. On the other hand, the starting torque of the sealed type rolling bearing of the example in which the shot groove is subjected to shot peening processing shows a small value of approximately 0.6 before the submergence test, and it can be seen that the friction resistance of the lip is small. Further, even after the submergence test, the occurrence of the lip adsorption phenomenon is about 1.3, which is slight, and the starting torque is about ½ that of the sealed rolling bearing of the comparative example.

  From the above test results, it was proved that the sealed rolling bearing of the present invention is effective for preventing the adsorption phenomenon while maintaining the sealing performance.

The present invention is not limited to the above-described embodiments and examples, and can be appropriately modified and improved.
In the present embodiment, the sealing device has a cored bar. However, the present invention is not limited to this, and may be configured only by an elastic body without using the cored bar. Further, although the sealing device having three lips has been described, the number of lips is not limited to three, and a sealing device having one lip may be used. Is optional.

  In the present embodiment, the rolling bearing in which the sealing device is used has been described as a deep groove ball bearing. However, the present invention is not limited to this, and other types of rolling bearings such as angular ball bearings and various roller bearings used in the examples are used. The present invention can also be applied to a bearing, and the same effect can be obtained. In addition, an inner ring sliding contact type rolling roller bearing in which a lip is slidably contacted with a seal groove formed in the inner ring has been described as an example, but an outer ring slide in which a lip of a sealing device is slidably contacted with a seal groove formed in an outer ring. It may be a contact-type sealed rolling bearing.

Furthermore, the shot peening process applied to the seal groove is not limited to the precision shot peening process, and may be a shot peening process under other conditions. For example, as disclosed in Japanese Patent Application Laid-Open No. 2000-161371, metal particles forming a parent phase such as tin (Sn) on a sliding surface of a seal groove, molybdenum disulfide (MoS ₂ ), tungsten disulfide ( WS ₂ ), boron nitride (BN), particles of solid lubricant such as fluororesin (for example, PTFE) were mixed, and the solid lubricant was dispersed in the matrix. It is also possible to form a film.

It is a principal part longitudinal cross-sectional view of the sealing type rolling bearing which is one Embodiment of this invention. It is a graph which shows the change of the starting torque before and after the submergence test which shows the presence or absence of the adsorption | suction phenomenon, making it dimensionless on the basis of the starting torque of the conventional sealed rolling bearing. It is a longitudinal cross-sectional view of the sealing type rolling bearing currently disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sealing type rolling bearing 11 Outer ring 11b Inner peripheral surface 11c Outer ring raceway surface 12 Inner ring 12a Seal groove 12b Outer peripheral surface 12c Inner ring raceway surface 12d Side wall (sliding contact surface)
13 balls (rolling elements)
20 Sealing device 22c 1st lip (lip)

Claims (2)

An outer ring having an outer ring raceway surface formed on an inner peripheral surface, an inner ring having an outer ring raceway surface formed on an outer peripheral surface, and a plurality of rolling elements arranged to roll between the outer ring raceway surface and the inner ring raceway surface And a sealing device mounted on the other of the outer ring and the inner ring with a lip slidably brought into contact with a seal groove formed on one of the outer ring and the inner ring. Sealed rolling bearings,
The seal-type rolling bearing according to claim 1, wherein the seal groove is subjected to shot peening on at least a sliding contact surface with which the lip slides.   The hermetic rolling bearing according to claim 1, wherein the shot peening process is a precision shot peening process.

Images