JP2018071605A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of suppressing increase of slide resistance to stabilize the slide resistance even in a case where a lead seam is formed at a contact part of a lip.SOLUTION: A sealing device 1 includes an annular reinforcement ring 10 around an axial line x, and an annular elastic body part 20 around the axial line x, which is formed of an elastic body attached to the reinforcement ring 10. The elastic body part 20 has a side lip 21, an intermediate lip 22, and a grease lip 23. On each inner peripheral side surface of the side lip 21, intermediate lip 22 and grease lip 23, a satin-finished part 21b, 22b, 23b is formed. Under a use state of the sealing device 1, a cross sectional area A of a space S between the lips, which is surrounded by the side lip 21, the intermediate lip 22, and a hub ring 55, is not less than 3.5 mm. The shape of the grease lip is designed so that a length L in an extension direction and a thickness t on a cross section along the axial line x satisfy the following relationship: t/L≥0.27, at a grease lip base end 23c.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sealing device, and more particularly, to a sealing device that seals between an annular outer peripheral member and an annular inner peripheral member that can rotate relative to each other about an axis.

  In vehicles such as automobiles, hub bearings that rotatably support wheels are in an environment where they are directly exposed to foreign substances such as rainwater, muddy water, and dust. For this reason, conventionally, a sealing device is attached to the hub bearing in order to seal an internal space formed between the outer ring and the hub that can rotate relative to each other about the axis. This sealing device is intended to seal the lubricant inside the hub bearing and prevent foreign matter from entering the inside. In addition, this sealing device is required to reduce sliding resistance (torque resistance) applied to the hub bearing due to demands for reducing fuel consumption.

  FIG. 6 is a partial cross-sectional view illustrating a schematic configuration of a sealing device (hereinafter also referred to as a hub seal) attached to a conventional hub bearing. As shown in FIG. 6, a sealing device 100 as a conventional hub seal includes an outer ring 201 for sealing an annular space 203 between an outer ring 201 and a hub 202 that are coaxially rotated relative to each other in a hub bearing 200. And the hub 202. The sealing device 100 prevents leakage of the lubricant in the bearing ball 204 existing in the space 203 and prevents foreign matter from entering the space 203.

  As shown in FIG. 6, the sealing device 100 is made of a metal reinforcing ring 111 fitted to the inner peripheral surface of the outer ring 201 of the hub bearing 200 and a rubber material integrally formed so as to cover the reinforcing ring 111. The elastic body portion 112 is provided. In the sealing device 100, the elastic body portion 112 has a side lip 113, an intermediate lip 114 disposed on the inner peripheral side of the side lip 113, and a grease lip 115 extending inwardly inside the intermediate lip 114. The lips 113, 114, and 115 are in sliding contact with the outer peripheral surface 202 a of the hub 202. The side lip 113 and the intermediate lip 114 mainly prevent foreign matters from entering the space 203 of the hub bearing 200, and the grease lip 115 mainly prevents the leakage of the lubricant of the bearing balls 204 existing in the space 203. I am trying.

Utility Model Registration No. 3201207

  The outer peripheral surface 202a of the hub 202 is formed by machining. For this reason, a finishing trace may be left on the outer peripheral surface 202a. Depending on the hub bearing, this finishing trace has a certain direction, that is, the finishing trace (lead eye) formed by a plurality of groove-shaped traces extending along the same axis line as a spiral or a straight line It may be formed on the surface 202a. When leads are formed on the outer peripheral surface 202a of the hub 202, the side lip 113 and / or the intermediate lip 114 contact the outer peripheral surface 202a with a larger width exceeding a predetermined contact width (tightening margin). In other words, a so-called solid state may occur. In this case, the sliding resistance given to the hub 202 by the side lip 113 and / or the intermediate lip 114 when the hub 202 rotates increases, and the driving torque of the hub 202 increases.

  As described above, in the conventional sealing device 100, when used in the hub bearing 200 including the hub 202 having the lead eyes, the contact width of the side lip 113 and / or the intermediate lip 114 with respect to the hub 202 when the hub 202 rotates. , The sliding resistance (friction torque) to the hub 202 increases, and the driving torque of the hub 202 may increase. For this reason, there is a need for a conventional sealing device that can be stabilized without increasing the driving torque of the hub, even when used in a hub bearing having a hub having lead eyes. It was.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress an increase in sliding resistance and stabilize sliding resistance even when lead eyes are formed at the contact portion of the lip. An object of the present invention is to provide a sealing device that can perform the above.

In order to achieve the above object, a sealing device according to the present invention seals between an outer peripheral member that can rotate relative to each other about an axis and an inner peripheral member that is at least partially surrounded by the outer peripheral member. A sealing device, comprising: an annular reinforcing ring around the axis; and an annular elastic body portion formed around an elastic body attached to the reinforcing ring, wherein the elastic body portion is A side lip extending toward one side of the axis that is formed so as to come into contact with the inner peripheral side member from the other side in the axis in the use state; and An intermediate lip extending toward the one side on the inner peripheral side with respect to the side lip formed so as to contact from the side, and the inner peripheral member in contact with the inner peripheral member in the use state A grease lip extending toward the other side of the intermediate lip formed in the above manner, and in use, the side lip, the intermediate lip, and the inner peripheral member are The area of the enclosed space in the cross section along the axis is 3.5 mm ² or more, and the grease lip has a length L in the extending direction and a thickness t in the cross section along the axis of t / L ≧ 0 at the base of the grease lip. .. 27, and the side lip, the intermediate lip, and the grease lip are formed with a matte portion on the inner peripheral surface thereof.

  In the sealing device according to one aspect of the present invention, the thickness of the grease lip decreases toward the tip of the grease lip.

  In the sealing device according to one aspect of the present invention, the surface roughness of the satin portion is 7 μm Rz JIS or more.

  According to the sealing device of the present invention, even if lead eyes are formed at the contact portion of the lip, an increase in the sliding resistance can be suppressed and the sliding resistance can be stabilized.

It is sectional drawing in the cross section in alignment with an axis for showing schematic structure of the sealing device which concerns on embodiment of this invention. It is a partial expanded sectional view which expands and shows the vicinity of the sub lip, intermediate | middle lip, and grease lip of the sealing device shown in FIG. It is sectional drawing of the hub bearing in the cross section in alignment with an axis for showing the use condition of the sealing device attached to the hub bearing. It is a partial expanded sectional view of the sealing device vicinity in FIG. It is a figure for showing the result of the evaluation test of the sealing device concerning an embodiment of the invention. It is a fragmentary sectional view for showing a schematic structure of a sealing device attached to a conventional hub bearing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view in a cross section along an axis for showing a schematic configuration of a sealing device 1 according to an embodiment of the present invention. A sealing device 1 according to the present invention is a sealing device for sealing between an outer peripheral member that can rotate relative to each other about an axis and an inner peripheral member that is at least partially surrounded by the outer peripheral member. The device 1 is used to seal a space between the outer ring 51 and the hub 52 in the hub bearing 50 as described later.

  Hereinafter, for convenience of explanation, an arrow a (see FIG. 1) direction (one side in the axial direction) is the outside in the axis x direction, and an arrow b (see FIG. 1) direction (the other side in the axial direction) in the axis x direction. Is inside. More specifically, the outer side is a direction away from the space between the outer ring and the hub, which is a space to be sealed, and the inner side is a direction closer to the space to be sealed. Further, in a direction perpendicular to the axis x (hereinafter also referred to as “radial direction”), the direction away from the axis x (the direction of arrow c in FIG. 1) is the outer peripheral side, and the direction approaching the axis x (the arrow d in FIG. 1). Direction) is the inner circumference.

  As shown in FIG. 1, the sealing device 1 includes an annular reinforcing ring 10 around an axis x and an annular elastic body portion 20 that is attached to the reinforcing ring 10 and is formed from an elastic body. I have. The elastic body portion 20 includes a side lip 21, an intermediate lip 22, and a grease lip (radial lip) 23. The side lip 21 is formed so as to come into contact with the hub 52 as an inner peripheral side member from the other side (inner side) in the direction of the axis x in the use state to be described later, and toward the one side (outer side) in the direction of the axis x. It is an annular lip-shaped portion extending in the direction. The intermediate lip 22 is formed so as to come into contact with the hub 52 from one side (inner side) in use, and has an annular lip shape extending toward one side (outer side) on the inner peripheral side of the side lip 21. Part. The grease lip 23 is formed so as to come into contact with the hub 52 from the outer peripheral side in the use state, and extends toward the other side (inside) on the other side (inner side) in the axis x direction than the intermediate lip 22. It is a lip-shaped part.

  Specifically, the reinforcing ring 10 is an annular metal member having the axis x as the center or substantially the center, and is press-fitted into a through hole 57 of the outer ring 51 of the hub bearing 50 described later so as to be fitted. The sealing device 1 is fixed to the outer ring 51 by press-fitting the reinforcing ring 10 into the outer ring 51. For example, as shown in FIG. 1, the reinforcing ring 10 includes a cylindrical fitting part 11 located on the outer peripheral side, a position adjusting part 12 extending from the inner end of the fitting part 11 to the inner peripheral side, And a disc-shaped flange portion 13 extending from the outer end of the joint portion 11 to the outer peripheral side.

  The fitting portion 11 is a cylindrical or substantially cylindrical portion having the axis line x as the center or substantially the center, and in the outer peripheral surface 11a that is a peripheral surface on the outer peripheral side, the outer ring 51 in which the through hole 57 is opened outside. It is formed so as to be in close contact with the inner peripheral surface 58a of the outer opening 58 which is a part. The position adjusting unit 12 has a shape such that the side lip 21, the intermediate lip 22, and the grease lip 23 are arranged at desired positions in the sealing device 1, and extends outward from the inner end of the fitting unit 11. A return portion 12a that is a substantially conical cylindrical shape or a substantially cylindrical portion that returns, a connection flange portion 12b that is a disk-like portion extending from the outer end of the return portion 12a to the inner peripheral side, and an inner portion of the connection flange portion 12b A substantially conical cylindrical return portion 12c extending obliquely from the peripheral end to the inner side and the inner peripheral side, and a seal that is a disk-shaped portion extending from the inner peripheral end of the return portion 12c to the inner peripheral side And a flange portion 12d. The flange portion 13 is a hollow disc shape or a substantially hollow disc shape portion that extends in the radial direction with the axis line x as the center or substantially the center. The reinforcing ring 10 is formed as an integral member from a metal plate by pressing or forging, and the fitting portion 11 and the position adjusting portion 12, and the fitting portion 11 and the flange portion 13 are integrally continuous with each other. Combined with cage. Examples of the metal material of the reinforcing ring 10 include stainless steel and SPCC (cold rolled steel).

  The elastic body portion 20 is attached to the reinforcing ring 10 and is integrally formed with the reinforcing ring 10 so as to cover the reinforcing ring 10 from the outside as shown in FIG. The elastic body portion 20 has a base portion 25, and the intermediate lip 22 and the grease lip 23 extend from end portions on the inner peripheral side of the base portion 25. Further, the side lip 21 extends from the base portion 25 so as to be radially separated from the intermediate lip 22 on the outer peripheral side of the intermediate lip 22. The base portion 25 is a portion of the elastic body portion 20 that spreads on the outer surface of the reinforcing ring 10 across the flange portion 13, the fitting portion 11, and the position adjusting portion 12 of the reinforcing ring 10. 20 is integrally attached to the reinforcing ring 10 in the base portion 25.

  The side lip 21 extends outward from the base portion 25 in an annular shape with the axis x as the center or substantially the center, and the use of the sealing device 1 described later in which the sealing device 1 is attached to a desired position in the hub bearing 50. In the state, the tip portion is formed so as to contact the hub 52 (hub wheel 55) with a predetermined tightening allowance. The side lip 21 has, for example, a conical cylindrical shape whose diameter increases toward the outside in the axis x direction.

  The intermediate lip 22 extends outward from the base portion 25 in an annular shape with the axis x as the center or substantially the center, and the distal end portion of the intermediate lip 22 has a predetermined allowance when the sealing device 1 is used. It is formed so as to contact the ring 55). The intermediate lip 22 has, for example, a conical cylindrical shape that increases in diameter toward the outside in the direction of the axis x. The intermediate lip 22 may extend outward in parallel with the side lip 21, and may have a gentler inclination with respect to the axis x than the side lip 21, as shown in FIG. 1. The reverse is also possible.

  The grease lip 23 extends from the base portion 25 toward the inner side and the inner peripheral side in an annular shape with the axis x as the center or substantially the center. The grease lip 23 is formed so that the tip end portion contacts the hub 52 (hub wheel 55) with a predetermined tightening margin when the sealing device 1 is in use.

  The shape of the grease lip 23 is designed so that the length L in the extending direction and the thickness t in the cross section along the axis x satisfy the relationship of t / L ≧ 0.27. As shown in FIG. 2, the length L in the extending direction, which is the length in the extending direction of the grease lip 23, is the grease lip base end 23c that is the base of the grease lip 23 (the connecting portion with the base portion 25), and the grease lip. This is the distance in the extending direction between the grease lip tip 23d, which is the tip of 23. The cross-sectional thickness t, which is the thickness of the grease lip 23, is a thickness in a direction perpendicular to the extending direction of the grease lip 23 in the cross section along the axis x. In the present embodiment, the thickness (cross-sectional thickness t1) of the grease lip 23 at the grease lip base end 23c of the grease lip 23 shown in FIG. 2 satisfies the relationship t / L ≧ 0.27. Its shape is designed. That is, the grease lip 23 has a shape that satisfies t1 / L ≧ 0.27. The cross-sectional thickness t of the grease lip 23 is the maximum value at the cross-sectional thickness t1 at the grease lip base end 23c, and the grease lip 23 becomes thinner toward the grease lip end 23d. The thickness (cross-sectional thickness t2) of the grease lip 23 at the slip tip 23d is the minimum value. The grease lip 23 may have a uniform thickness (cross-sectional thickness t = constant) in the extending direction, or the thickness may increase toward the grease lip tip 23d. The cross-sectional shape of the grease lip 23 may be other shapes. For example, in the cross section, the contour of the outer peripheral surface of the grease lip 23 may be a curved line instead of a straight line or a substantially straight line. Similarly, in the cross section, the contour of the inner peripheral side surface 23a of the grease lip 23 is not a straight line or a substantially straight line. It may be a curve.

  In addition, an outer peripheral ring protrusion 24 is formed on the elastic body portion 20. The outer peripheral ring protrusion 24 is an annular protrusion around the axis line x that is provided on the outer peripheral side of the side lip 21 and protrudes outward. The outer end 24 a that is the outer end is connected to the hub 52 (hub wheel 55). It is formed so as to form a gap therebetween. Specifically, the outer peripheral ring protrusion 24 protrudes outward from the outer peripheral end of the base portion 25, and extends around the axis line x as a center or substantially the center. As shown in FIG. 1, the outer peripheral ring protrusion 24 protrudes obliquely from the base portion 25 toward the outer side and the outer peripheral side.

  Further, the elastic body portion 20 has a weir portion 26 that is an annular portion protruding toward the outer peripheral side on the outer peripheral side of the outer peripheral ring protrusion 24. As will be described later, the weir portion 26 protrudes to the outer peripheral side from the outer end surface 58b that is a portion that contacts the sealing device 1 in the axis x direction of the outer ring 51 in a state where the sealing device 1 is attached to the outer ring 51. Is formed. For example, as shown in FIG. 1, the weir portion 26 is formed so as to cover the outer peripheral end of the flange portion 13 of the reinforcing ring 10 on the outer peripheral side.

  As shown in FIG. 1, the elastic body portion 20 also has a gasket portion 27 that at least partially covers the inner surface of the flange portion 13 of the reinforcing ring 10. The gasket portion 27 extends in an annular shape around the axis line x and continues to the end portion on the inner peripheral side of the weir portion 26.

  The elastic body portion 20 is integrally attached to the reinforcing ring 10, and the side lip 21, the intermediate lip 22, the grease lip 23, the outer peripheral ring protrusion 24, the base portion 25, the dam portion 26, and the gasket portion 27 described above are included. The elastic body portion 20 is formed as an integral member, and is integrally continuous. Examples of the elastic body of the elastic body portion 20 include various rubber materials. Examples of the various rubber materials include synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluorine rubber (FKM).

  Further, the side lip 21, the intermediate lip 22, and the grease lip 23 are formed with matte portions 21b, 22b, and 23b on inner peripheral surfaces (inner peripheral side surfaces 21a, 22a, and 23a).

  Specifically, as shown in FIG. 2, the inner peripheral side surface 21a (the surface facing the dotted line in FIG. 2), which is the inner peripheral surface of the side lip 21, is subjected to a satin finish treatment. On the surface of 21a, minute irregularities are formed to form a satin portion 21b. Thus, the inner peripheral side surface 21a of the side lip 21 is a matte portion 21b. For example, the surface roughness of the satin portion 21b is 7 μm Rz JIS or more. The value of the surface roughness is a value obtained according to JIS B 0601-1994 (the same applies hereinafter).

  Similarly, as shown in FIG. 2, the inner peripheral side surface 22a (the surface facing the dotted line in FIG. 2) which is the inner peripheral surface of the intermediate lip 22 is subjected to a satin finish, and the inner peripheral side surface 22a On the surface, fine irregularities are formed to form a satin portion 22b. Thus, the inner peripheral side surface 22a of the intermediate lip 22 is a satin portion 22b. For example, the surface roughness of the satin portion 22b is 7 μm Rz JIS or more.

  Similarly, as shown in FIG. 2, the inner peripheral side surface 23a (the surface facing the dotted line in FIG. 2) which is the inner peripheral side surface of the grease lip 23 is subjected to a satin finish treatment. The surface is formed with fine irregularities to form a satin portion 23b. Thus, the inner peripheral side surface 23a of the grease lip 23 is a matte portion 23b. For example, the surface roughness of the satin portion 23b is 7 μm Rz JIS or more.

  Further, grease G as a lubricant may be applied to the inner peripheral side surfaces 21 a, 22 a, and 23 a of the side lip 21, the intermediate lip 22, and the grease lip 23. That is, as shown in FIG. 2, the grease G may be applied along the dotted lines on the inner peripheral side surfaces 21a, 22a, and 23a. In the use state described later, the sealing device 1 is used with the grease G applied as described above.

  Grease G does not contain a urea-based thickener containing a urea group in the thickener. Alternatively, the grease G contains a small amount of a urea-based thickener in the thickener. When the grease G contains a small amount of a urea-based thickener in the thickener, the ratio of the urea-based thickener in the thickener of the grease G is the effect of the grease G described later. It is only necessary that the grease G can be prevented from being scraped off along the lead eyes.

  As the grease G, a conventionally known grease that satisfies the above-described conditions can be applied. Examples of the grease G include the following grease.

  As the type of base oil, all oils (mineral oil-based, synthetic oil-based or natural oil-based lubricants) that are usually used as base oils for lubricating oils can be used. Specifically, as mineral oil-based lubricating oil, mineral oil is refined by appropriately combining vacuum distillation, oil removal, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, hydrorefining, etc. Can be used. Examples of synthetic oils include hydrocarbon oils, aromatic oils, ester oils, ether oils, and the like. Examples of the natural oil-based lubricating oil include beef tallow, lard, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, and other oils and hydrides thereof. These base oils can be used alone or as a mixture, and are adjusted to a desired base oil kinematic viscosity. However, considering compatibility with a general nitrile rubber as an elastic material of the seal member, mineral oil or hydrocarbon oil is preferable.

  Thickeners are, for example, metal soaps such as metal soaps such as Li and Na, metal soaps such as composite metal soaps whose metal components are Li, Na, Ba, Ca, etc. Non-soaps such as benton, silica gel, urethane compounds, etc. Amino acid-based gelling agents (N-2-ethylhexanoyl-L-glutamic acid dibutylamide, N-lauroyl-L-glutamic acid-α, γ-n-dibutylamide, etc.), benzylidene sorbitol derivatives (dibenzylidene sorbitol, ditrilidene) Sorbitol, asymmetric dialkylbenzylidene sorbitol, etc.) can be appropriately selected and used. These thickeners can be used alone or as a mixture. Urea-based thickeners include urea compounds and urea / urethane compounds.

  An additive may be added to the grease G depending on the purpose. For example, amine-based, phenol-based, sulfur-based, antioxidants such as zinc dithiophosphate and zinc dithiocarbamate, sulfonic acid metal salts, ester-based, amine-based, naphthenic acid metal salts, rust preventives such as succinic acid derivatives, phosphorus Additives conventionally used for lubrication alone or mixed, such as system, extreme pressure agents such as zinc dithiophosphate, organic molybdenum, oil improvers such as fatty acids and animal and vegetable oils, metal deactivators such as benzotriazole Can be added.

  Next, the usage state of the sealing device 1 will be described. FIG. 3 is a cross-sectional view of the hub bearing 50 in a cross-section along the axis x to show a use state of the sealing device 1 attached to the hub bearing 50, and FIG. 4 is a portion in the vicinity of the sealing device 1 in FIG. It is an expanded sectional view. As shown in FIG. 3, the hub bearing 50 is a conventionally known hub bearing and is provided in a vehicle or the like, and rotatably supports a wheel in an axle or a suspension device. Specifically, as shown in FIG. 3, the hub bearing 50 is capable of rotating relative to the outer ring 51 and an annular outer ring 51 that is centered or substantially centered on the axis x as the outer peripheral side member. A hub 52 is provided as an inner peripheral member centered on or approximately at the partially surrounded axis x, and a plurality of bearing balls 53 disposed between the outer ring 51 and the hub 52. When the hub bearing 50 attached to the vehicle or the like is in use, the outer ring 51 is fixed, and the hub 52 can be rotated relative to the outer ring 51. Specifically, the hub 52 includes an inner ring 54 and a hub ring 55. The hub ring 55 includes a cylindrical or substantially cylindrical shaft portion 55a extending along the axis x, and a wheel mounting flange 55b. have. The wheel mounting flange 55b is a portion that spreads in a disk shape from one end of the shaft portion 55a (the outer end portion of the hub bearing 50) toward the outer periphery, and is a portion to which a wheel (not shown) is attached by a plurality of hub bolts. The shaft portion 55a and the wheel mounting flange 55b are smoothly connected on the inner side, and the transition portion 55c, which is the portion where the shaft portion 55a and the wheel mounting flange 55b are connected on the inner side, has an arc shape in a cross section along the axis line x. Or an arc-shaped smooth contour. The inner ring 54 is fitted to an end portion on the inner side (arrow b direction side) of the shaft portion 55 a of the hub ring 55 in order to hold the bearing ball 53 in the space between the outer ring 51 and the inner ring 54. In the space between the outer ring 51 and the hub 52, the bearing ball 53 is held by a cage 56.

  The outer ring 51 has a through hole 57 extending in the direction of the axis x. The shaft part 55 a of the hub wheel 55 of the hub 52 is inserted into the through hole 57, and the shaft part 55 a and the through hole 57 are connected to each other. An annular space extending along the axis x is formed therebetween. In this space, the bearing balls 53 are accommodated and held by the cage 56 as described above, and a lubricant is applied or injected. The sealing device 1 is attached to the outer opening 58 of the outer ring 51 that forms an opening in which the space between the shaft portion 55a and the through hole 57 is opened outside (arrow a direction side). Another sealing device 59 is attached to the inner opening 58 ′ of the outer ring 51, which forms an opening in which the space between the hole 57 is opened inside (arrow b direction side). The sealing devices 1 and 59 seal the space between the shaft portion 55a and the inner ring 54 and the through hole 57, and prevent the internal lubricant from leaking to the outside. It is intended to prevent foreign matter from entering the inside. The sealing device 59 is a conventionally known sealing device and will not be described in detail. Further, the sealing device 1 can be applied as the sealing device 59. In this case, in the hub bearing 50, the outer side is in the direction of arrow b, and the inner side is in the direction of arrow a. The configuration of the hub bearing to which the sealing device 1 is applied is not limited to the configuration of the hub bearing 50 described above.

  As shown in FIG. 4, the sealing device 1 is attached to the outer opening 58 of the outer ring 51. Specifically, the sealing device 1 is fixed to the outer ring 51 by fitting and fitting the fitting portion 11 of the reinforcing ring 10 into the outer opening 58 of the outer ring 51. The outer peripheral surface 11 a of the fitting portion 11 of the reinforcing ring 10 is in close contact with the inner peripheral surface 58 a facing the inner peripheral direction of the outer opening 58 of the outer ring 51, and sealing between the reinforcing ring 10 and the outer ring 51 is performed. It is illustrated. In the state of use, as shown in FIG. 4, the reinforcing ring 10 has an annular surface in which the flange portion 13 faces the gasket portion 27 of the elastic body portion 20 extending inward to the outside of the outer opening portion 58. The outer ring 51 is attached so as to be pressed against the outer end surface 58b. Thereby, between the outer side end surface 58b and the flange part 13, the gasket part 27 is compressed, and the sealing performance between the outer ring | wheel 51 and the sealing device 1 is improved in the outer side end surface 58b. As shown in FIGS. 1 and 4, the gasket portion 27 is preferably formed with a bead 27 a that is an annular protrusion protruding inward. When the bead 27a is pressed against the outer end surface 58b of the outer opening 58 in the use state, the sealing performance between the outer ring 51 and the sealing device 1 can be further improved on the outer end surface 58b. The gasket portion 27 may not have the bead 27a.

  In use, the weir portion 26 of the elastic body portion 20 extends beyond the outer end surface 58b of the outer opening 58 to the outer peripheral side and exceeds the outer peripheral surface 58c facing the outer peripheral direction of the outer opening 58 to the outer peripheral side. It protrudes. For this reason, even when foreign matter such as rainwater, muddy water, and dust moves outward through the outer peripheral surface 58c of the outer opening 58 of the outer ring 51 in the use state, the foreign matter is directed toward the inside of the dam portion 26. It hits the inner side surface 26a, which is a surface, and the movement of the foreign matter further outward is blocked. In this way, foreign matter is prevented from entering the side lip 21 along the outer peripheral surface 58c of the outer opening 58 of the outer ring 51.

  In the state of use, the side lip 21 has a distal end portion corresponding to the above-described predetermined tightening allowance (contact width) at the surface of the hub wheel 55, for example, a surface facing the inner side of the wheel mounting flange 55b (inner surface 55d). ) Is slidably in contact with the hub wheel 55. Further, the intermediate lip 22 has a distal end portion corresponding to the above-described predetermined tightening allowance (contact width), and the hub wheel 55 is slidably in contact with the surface of the hub wheel 55, for example, the transition portion 55c. . Further, the grease lip 23 has a hub ring on the surface of the hub wheel 55, for example, the outer peripheral surface 55e which is the outer peripheral side surface of the shaft portion 55a, at a portion (contact width) corresponding to the predetermined tightening allowance. 55 is in slidable contact. The side lip 21 and the intermediate lip 22 prevent foreign matter from entering the through hole 57, and the grease lip 23 prevents the lubricant from flowing out of the through hole 57.

  In the state of use, the outer end 24a of the outer peripheral ring protrusion 24 faces the inner side surface 55d of the wheel mounting flange 55b of the hub wheel 55 with a minute gap in the axis x direction. It is not in contact with the wheel mounting flange 55b. The outer peripheral ring protrusion 24 may form a labyrinth seal by forming a minute space between the outer end 24a and the wheel mounting flange 55b.

  As shown in FIG. 4, a step 55 f may be formed on the outer peripheral side of the inner surface 55 d of the wheel mounting flange 55 b of the hub wheel 55. In the step 55f, the outer peripheral portion of the inner side surface 55d is recessed outward from the inner peripheral portion. The outer peripheral ring protrusion 24 extends on the outer peripheral side from the step 55f.

As described above, when the sealing device 1 is mounted on the hub bearing 50, the side lip 21 is in contact with the hub wheel 55 (the wheel mounting flange 55b) at a predetermined tightening margin on the inner peripheral side surface 21a. The intermediate lip 22 is in contact with the hub wheel 55 (wheel mounting flange 55b) at a predetermined tightening allowance on the inner peripheral side surface 22a, and the side lip 21, the intermediate lip 22, and the wheel mounting flange 55b of the hub wheel 55 are An inter-lip space S that is an annular space is defined. In this state of use, the inter-lip space cross-sectional area A, which is the area (cross-sectional area) in the cross-section along the axis x of the inter-lip space S surrounded by the side lip 21, the intermediate lip 22 and the hub wheel 55, is 3.5 mm ² or more. ing. That is, the shapes of the side lip 21 and the intermediate lip 22 are designed such that the inter-lip space cross-sectional area A, which is the cross-sectional area of the inter-lip space S in use, is A ≧ 3.5 mm ² . .

  As described above, when the sealing device 1 is in use, the side lip 21 contacts the inner surface 55d of the wheel mounting flange 55b of the hub wheel 55 with a predetermined tightening margin, and the intermediate lip 22 is wheel mounted with a predetermined tightening margin. The flange 55 b contacts the transition portion 55 c, and the grease lip 23 contacts the outer peripheral surface 55 e of the shaft portion 55 a of the hub wheel 55 with a predetermined tightening allowance, so that the sealing device 1 is disposed between the outer ring 51 and the hub 52. The space is sealed.

According to the sealing device 1, the side lip 21, the intermediate lip 22, and the like are formed even when the outer peripheral surface 55e, the transition portion 55c, and the inner surface 55d of the hub wheel 55 are formed with lead marks that are finishing marks of processing. It is possible to suppress the occurrence of solid contact of the grease lip 23. This is because the inter-lip space cross-sectional area A, which is the cross-sectional area of the inter-lip space S surrounded by the side lip 21, the intermediate lip 22, and the hub wheel 55, is 3.5 mm ² or more. In the conventional sealing device, when the lead ring is formed on the hub ring, the reason why the sub lip, the intermediate lip and the grease lip stick to each other is that the lead ring is in the space surrounded by the side lip, the intermediate lip and the hub ring. It is thought that this is because negative pressure is generated by the pumping effect. On the other hand, in the sealing device 1, the shape of the side lip 21 and the intermediate lip 22 is designed so that the inter-lip space sectional area A in use is 3.5 mm ² or more. For this reason, even if the hub 52 rotates in the use state, the influence of the pump effect by the lead stitch on the inter-lip space S is low. That is, by setting the inter-lip space cross-sectional area A to A ≧ 3.5 mm ² , the influence of the lead pumping effect on the inter-lip space S can be reduced. It is possible to prevent a negative pressure that increases the contact width of the lips 21 to 23 from being generated. For this reason, in the sealing device 1, even when lead eyes are formed on the hub wheel 55, an increase in sliding resistance of the side lip 21, the intermediate lip 22, and the grease lip 23 with respect to the hub wheel 55 is suppressed. be able to.

  The larger the inter-lip space sectional area A of the inter-lip space S, the better. This is because the larger the space cross-sectional area A between the lips, the more the influence of the pump effect of the lead can be reduced. However, the upper limit value of the size of the inter-lip space cross-sectional area A can be determined according to a specific form of the sealing device 1 corresponding to a specific application target (hub bearing). Or the upper limit of the magnitude | size of the space cross-sectional area A between lips is decided according to the specific form of the sealing device 1 corresponding to a specific application object (hub bearing). The optimum size of the inter-lip space cross-sectional area A of the sealing device 1 is, for example, the size in the radial direction in a specific mode of the sealing device 1, for example, the size of the diameter of the side lip 21 or the intermediate lip 22. Can be set based on.

  In the sealing device 1, as described above, the relationship between the cross-sectional thickness t of the grease lip 23 and the length L in the extending direction is t / L ≧ 0.27. For this reason, the rigidity of the grease lip 23 can be appropriately adjusted, the solid contact of the grease lip 23 can be suppressed, and the increase in sliding resistance of the grease lip 23 with respect to the hub wheel 55 can be suppressed. When the relationship between the cross-sectional thickness t of the grease lip 23 and the length L in the extending direction is t / L ≧ 0.27, the use environment of the sealing device 1 is changed from 20 ° C. to 120 ° C. Even in other words, even when the pressure in the through hole 57 of the hub bearing 50 is changed, the solid contact of the grease lip 23 can be suppressed.

  In the sealing device 1, the side lip 21, the intermediate lip 22, and the grease lip 23 are subjected to the matte treatment on the inner peripheral side surfaces 21 a to 23 a, respectively, and the matte portions 21 b to 23 b are respectively disposed on the inner peripheral side surfaces 21 a to 23 a. Is formed. The surface roughness of the satin portions 21b to 23b is 7 μm Rz JIS or more. For this reason, the pump effect of the lead eye can be reduced, the solid contact of the side lip 21, the intermediate lip 22, and the grease lip 23 can be suppressed, and the side lip 21, the intermediate lip 22, and the grease lip 23 with respect to the hub wheel 55 An increase in sliding resistance can be suppressed.

  Further, as the surface roughness of the matte portions 21b to 23b is increased, the sliding resistance of the side lip 21, the intermediate lip 22, and the grease lip 23 with respect to the hub wheel 55 can be reduced. However, the sealing performance of the side lip 21, the intermediate lip 22, and the grease lip 23 decreases as the surface roughness of the matte portions 21b to 23b increases. When only the sealing property is considered, the surface roughness of the satin portions 21b to 23b is preferably a value of 5 μmRzJIS or more and 20 μmRzJIS or less.

  When a grease containing a urea-based thickener is used as the grease G applied to each of the lips 21 to 23, the grease G is easily scraped along the lead eyes when the hub 52 rotates. This is presumably because grease containing a urea-based thickener tends to adhere to metal. When the grease G is scraped along the lead eyes during the rotation of the hub 52, a negative pressure is generated in the inter-lip space S. For this reason, when a grease containing a urea-based thickener is used, the side lip 21, the intermediate lip 22, and the grease lip 23 are solid, and the side lip 21, the intermediate lip 22, and the hub lip 55 of the grease lip 23 are generated. The sliding resistance with respect to will increase. In the sealing device 1, as the grease G applied to each lip 21 to 23, grease containing no urea-based thickener or grease containing only a small amount of urea-based thickener is used as the thickener. ing. For this reason, when the hub 52 rotates, the grease G is prevented from being scraped along the lead eyes, and it is possible to prevent the generation of negative pressure that increases the contact width of the lips 21 to 23. Thus, an increase in sliding resistance of the side lip 21, the intermediate lip 22, and the grease lip 23 with respect to the hub wheel 55 can be suppressed.

  Next, an evaluation test result of the sealing device 1 according to the embodiment of the present invention will be described. The inventor manufactured the sealing device 1 according to the embodiment of the present invention (Test Example 1), and performed an evaluation test of the torque performance (sliding resistance) of the sealing device 1. FIG. 5 is a graph showing the results of this evaluation test.

In Test Example 1, the inter-lip space cross-sectional area A is set to A = 4.0 mm ^2, and the diameter between the side lip tip 21 c that is the tip of the side lip 21 and the intermediate lip tip 22 d that is the tip of the intermediate lip 22. An inter-lip distance W (see FIG. 2) which is an interval in the direction is set to W = 3.2 mm, and an intermediate lip group which is an inner end portion of the intermediate lip 22 which is a joint portion of the intermediate lip 22 to the base portion 25 The intermediate lip height H (see FIG. 2), which is the distance in the axis x direction between the end 22c and the intermediate lip tip 22d, was set to H = 2.9 mm. Specifically, the inter-lip distance W is a radial distance between the inner peripheral edge of the side lip tip 21c and the outer peripheral edge of the intermediate lip tip 22d. The intermediate lip height H is the length of the intermediate lip 22 in the axis x direction. Further, the length L of the grease lip 23 in the extending direction is L = 1.24 mm, the thickness of the grease lip 23 at the grease lip base end 23c (cross-sectional thickness t1) is t1 = 0.38 mm, and The thickness (cross-sectional thickness t2) of the grease lip 23 was set to t2 = 0.17 mm. The surface roughness of the satin portions 21b to 23b was 10.7 μm Rz JIS, and a metal soap containing Li was used as a thickener for the grease G.

  The evaluation test was performed under the conditions where Test Example 1 was attached to a test hub bearing (see FIG. 3), the ambient temperature was 30 ° C., and the bearing internal pressure, which is the pressure in the through hole 57, was 22 kPa. In the evaluation test, the evaluation was performed by measuring the driving torque of the hub wheel (hub) when each of the following predetermined steps was performed for 10 cycles and the cycle was performed for each cycle. In the above-described one cycle, first, the hub is rotated for 10 minutes at a rotational speed of 10 rpm, and then the hub is rotated for 60 minutes at a rotational speed of 1000 rpm. Further, lead eyes were formed on the inner peripheral side surface of the hub wheel of the test hub bearing (see FIG. 3, transition portion 55c, inner side surface 55d, outer peripheral surface 55e).

表１は、１番目のサイクル（第１サイクル）で測定された駆動トルクの平均値に対する各サイクル（第２〜第１０サイクル）で測定された駆動トルクの平均値の比であるトルク相対値（第ｎサイクルの駆動トルク／第１サイクルの駆動トルク）を表している。なお、上述の第１〜第１０サイクルの各サイクルにおいて測定された駆動トルクとは、ハブの回転速度が１０００ｒｐｍである時の駆動トルクである。図５には、第１〜第１０サイクルの間のトルク相対値の変化を示すグラフが記載されている。表１及び図５に示すように、各サイクルのトルク相対値は１．０８〜１．３４の間で推移しており、各サイクルにおいてトルク相対値の変化は小さく、また、サイクル数が増えていってもトルク相対値が大きく上昇していかないことが分かる。このように、各サイクルにおいてハブ輪の駆動トルクは安定していた。つまり、各サイクルにおいて、リップ間空間Ｓに負圧が発生することが抑制され、サイドリップ２１、中間リップ２２、及びグリースリップ２３のベタ当たりの発生が抑制されていることが分かった。このように、本評価試験から、本密封装置１によれば、サイドリップ２１や中間リップ２２、グリースリップ２３のハブ輪５５に対する摺動抵抗の増大を抑制できることが分かった。 The results shown in Table 1 and FIG. 5 were obtained from the evaluation test.

Table 1 shows a torque relative value (ratio of the average value of the driving torque measured in each cycle (second to tenth cycles) to the average value of the driving torque measured in the first cycle (first cycle). The driving torque of the nth cycle / the driving torque of the first cycle). The driving torque measured in each of the first to tenth cycles described above is the driving torque when the hub rotation speed is 1000 rpm. FIG. 5 shows a graph showing changes in the relative torque value during the first to tenth cycles. As shown in Table 1 and FIG. 5, the torque relative value of each cycle changes between 1.08 and 1.34, the change of the torque relative value is small in each cycle, and the number of cycles is increased. However, it can be seen that the relative torque value does not increase greatly. Thus, the driving torque of the hub wheel was stable in each cycle. That is, it was found that in each cycle, the generation of negative pressure in the inter-lip space S was suppressed, and the occurrence of sticking of the side lip 21, the intermediate lip 22, and the grease lip 23 was suppressed. Thus, from this evaluation test, it was found that according to the sealing device 1, an increase in sliding resistance of the side lip 21, the intermediate lip 22, and the grease lip 23 with respect to the hub wheel 55 can be suppressed.

  As described above, according to the sealing device 1 according to the embodiment of the present invention, even if lead eyes are formed in the contact portions (hub wheels 55) of the lips 21 to 23, the hubs of the lips 21 to 23 are formed. It is possible to stabilize the sliding resistance by suppressing an increase in the sliding resistance with respect to the wheel 55.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to the sealing device 1 which concerns on said embodiment, All the aspects included in the concept of this invention, and a claim including. In addition, the configurations may be appropriately combined as appropriate so as to achieve at least part of the problems and effects described above. For example, the shape, material, arrangement, size, and the like of each component in the above embodiment can be changed as appropriate according to the specific usage mode of the present invention.

  Further, the sealing device 1 according to the present embodiment is applied to the hub bearing, but the application target of the sealing device according to the present invention is not limited to this, and other vehicles, general-purpose machines, and industries The present invention is applicable to all configurations that can utilize the effects of the present invention, such as machines.

1,59,100 Sealing device 10,111 Reinforcement ring 11 Fitting portion 11a Outer peripheral surface 12 Position adjustment portion 12a Return portion 12b Connection flange portion 12c Return portion 12d Seal flange portion 13 Flange portion 20, 112 Elastic body portion 21, 113 Side Lips 21a to 23a Inner peripheral side surfaces 21b to 23b Rinse portion 21c Side lip tip 22, 114 Intermediate lip 22c Intermediate lip base 22d Intermediate lip tip 23, 115 Grease lip 23c Grease lip base 23d Grease lip tip 24 Outer ring protrusion 24a Outside End 25 Base portion 26 Weir portion 26a Inner side surface 27 Gasket portion 27a Bead 50, 200 Hub bearing 51, 201 Outer ring 52, 202 Hub 53, 204 Bearing ball 54 Inner ring 55 Hub wheel 55a Shaft portion 55b Wheel mounting flange 55c Transition portion 55d Side surface 55e, 202a Outer peripheral surface 55f Step 56 Cage 57 Through hole 58 Outer opening 58a Inner peripheral surface 58b Outer end surface 58c Outer peripheral surface 58 'Inner opening 203 Space A Inter-lip space cross-sectional area G Grease H Intermediate lip height L Extension Direction length S Space between lips t, t1, t2 Cross section thickness W Distance between lips x Axis

Claims (3)

A sealing device that seals between an outer peripheral member that can rotate relative to each other about an axis and an inner peripheral member that is at least partially surrounded by the outer peripheral member,
An annular reinforcing ring around the axis;
An annular elastic body portion around the axis that is attached to the reinforcing ring and formed from an elastic body;
The elastic body portion includes a side lip extending toward one side of the axis that is formed so as to contact the inner peripheral member from the other side of the axis in the use state, and the inner periphery in the use state. An intermediate lip extending toward the one side on the inner peripheral side than the side lip formed so as to contact the side member from the other side, and contacting the inner peripheral member from the outer peripheral side in the use state A grease lip extending toward the other side of the intermediate lip formed on the other side,
In the use state, the area in the cross section along the axis of the space surrounded by the side lip, the intermediate lip, and the inner peripheral side member is 3.5 mm ² or more,
The grease lip has a shape such that the length L in the extending direction and the thickness t in the cross section along the axis satisfy the relationship of t / L ≧ 0.27 at the base of the grease lip,
The side lip, the intermediate lip, and the grease lip are each provided with a matte portion on the inner peripheral surface thereof.   The sealing device according to claim 1, wherein the grease lip has a thickness that decreases toward a tip of the grease lip.   The sealing device according to claim 1 or 2, wherein a surface roughness of the satin portion is 7 µm Rz JIS or more.

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