Abstract: In some aspects, the techniques described herein relate to a refrigerant compressor, including: a stator; a rotor configured to rotate with respect to the stator; and at least one step seal between the rotor and the stator, wherein the step seal includes a first tooth and a second tooth extending from the rotor toward the stator, wherein a downstream surface of the first tooth and an upstream surface of the second tooth are arranged at an angle relative to one another, wherein the angle is less than 90°.

Abstract: A turbocharger having a centrifugal compressor includes a vaned diffuser. The vaned diffuser is formed by a diffuser ring formed separately from the compressor housing and center housing. The diffuser ring is installed between the compressor and center housings such that a diffuser passage is defined between a surface of the compressor housing and a surface of the diffuser ring. Integral vanes on the diffuser ring extend only partially across the axial width of the diffuser passage. A rectangular-section seal ring is axially compressed between the compressor housing and the diffuser ring for sealing and axial locating of the diffuser ring. Radial locating of the diffuser ring is accomplished by an integral locating pin on the ring, which fits into a receptacle in the center housing.

Abstract: An internal combustion engine, ICE, system, includes a turbocharger having a turbine and a compressor for compressing intake air and feeding the intake air to the ICE. A turbo turbine unit is disposed in an exhaust gas path downstream the turbocharger to receive exhaust gas from the turbocharger. The turbo turbine unit having a turbine wheel, a bearing housing defining an inside volume for containing lubrication oil, and a sealing arrangement positioned in the vicinity of the turbine wheel for preventing lubrication oil from escaping from the inside volume of the bearing housing to an exhaust duct of the turbo turbine unit. A buffer air conduit extends between a selected position at the compressor and a buffer air inlet of the turbo turbine unit.

Abstract: A sealing device includes: a sealing device main body to be attached to an outer periphery side member; and a slinger to be attached to an inner periphery side member. The sealing device main body includes: an annular reinforcement ring centered on an axis; and an annular elastic body part that is made of an elastic body attached to the reinforcement ring and is centered on the axis. A through hole that passes through a portion between an internal space side surface and an atmosphere side surface of the reinforcement ring is formed in the reinforcement ring, and a positioning part for fixing the position of the reinforcement ring at the time of vulcanization is formed on an internal space side surface of the elastic body part. In the sealing device, the through hole and the positioning part are formed at positions separated in the radial direction.

Abstract: A seal system for a bearing chamber of a turbomachine includes a baffle element encircling the axis of the machine. The baffle element is formed with front surface including a plurality of gutter surfaces which are angularly spaced about the rotational axis. The seal system can thus be mounted in any one of a plurality of orientations with respect to the direction of gravity, such that in any of the orientations one of the gutter surfaces is directed downwardly.

Abstract: An electric stator surrounds an electric rotor. A magnetic coupling is attached to an end of the electric rotor. The magnetic coupling is configured to transmit rotational force to or from a separate rotational device. A housing surrounds and isolates the electrical rotor, the electric stator, and a portion of the magnetic coupling, from a wellbore fluid. The housing is flooded with an incompressible fluid. A pressure within the housing is substantially the same or lower than a pressure within a wellbore environment.

Abstract: Provided is a feed screw assembly for a fluid dispense pump, comprising a feed screw; a feed screw shaft extending from the feed screw; a spanner nut about the feed screw shaft; a bearing assembly about the feed screw shaft between the spanner nut and the feed screw The bearing assembly includes an outer ring that directly abuts the spanner nut; and an inner ring that rotates inside and relative to the outer ring, wherein the inner ring is coupled to the feed screw shaft for rotating the feed screw, and wherein the inner ring is separated from the spanner nut by a gap.

Abstract: A rotating machine includes a rotating body rotatably supported in a casing; a rotor blade fixed to an outer peripheral portion of the rotating body; a stator blade arranged on a downstream side in a fluid flow direction with respect to the rotor blade and fixed to an inner peripheral portion of the casing; a sealing device arranged between the inner peripheral portion and a front end of the rotor blade; a swirling flow generation chamber provided in the casing on the downstream side from the sealing device along a circumferential direction of the rotating body; and guiding members provided in the swirling flow generation chamber along a radial direction of the rotating body and in the circumferential direction at predetermined intervals. The swirling flow generation chamber has a wall surface located on the downstream side from an edge of the stator blade on an upstream side.

Abstract: An assembly is provided for a turbine engine. This assembly includes a static structure and an impeller rotor housed within the static structure. The impeller rotor includes a vane structure and a shroud. The vane structure includes a first sidewall, a second sidewall and a plurality of vanes arranged circumferentially about a rotational axis. The vanes include a first vane. The first vane includes a first portion, a second portion and a third portion. The first portion is axially between the first sidewall and the second sidewall. The second portion is radially between the first sidewall and the shroud. The third portion is radially between the second sidewall and the shroud. The shroud circumscribes the vane structure. A gap is formed by and extends between the shroud and the static structure. A dimension of the gap changes as the gap extends along the shroud.

Abstract: A lubricant supply device includes a porous body including a first porous portion and a second porous portion in contact with the first porous portion, the porous body being impregnated with a lubricant. A penetration depth of the lubricant in the second porous portion is larger than a penetration depth of the lubricant in the first porous portion.

Abstract: A substrate cleaning device that facilitates control of the amount of liquid supplied to a substrate and reduces adverse influences of the liquid supplied to a bearing part on the substrate is provided. The substrate cleaning device includes: a holding part that has a bearing part configured to rotatably hold a cleaning member for cleaning a substrate; a first supply part that has at least a part provided inside the holding part and supplies a first liquid into the cleaning member through the inside of the holding part; and a second supply part that supplies a second liquid to the bearing part.

Abstract: Method for delivering a gas/liquid mixture fluid via a screw spindle pump that has a housing in which a drive spindle and a running spindle are accommodated. The spindles delimit together with the housing multiple pump chambers. A respective one of the pump chambers that is initially open toward the respective fluid inlet is closed off. The resulting closed-off pump chamber is moved axially toward the fluid outlet and, there, upon attainment of an opening rotation angle, is opened toward the fluid outlet. The drive spindle is driven so that the pressure in the respective pump chamber prior to and/or upon attainment of the opening rotation angle is increased in relation to the suction pressure of the screw spindle pump by at most 20% or by at most 10% of a difference in pressure between the suction pressure and the pressure in the region of the fluid outlet.

Abstract: A rotary actuator includes: an electric motor; a case that receives the electric motor; a rotatable body that is configured to transmit an output of the electric motor to an outside of the case; a seal member that seals between the rotatable body and the case; and a labyrinth forming portion that forms a labyrinth space in a path that extends from an outside space of the case to a sealing point of the rotatable body, at which the rotatable body is sealed by the seal member.

Abstract: To provide an axial flow turbine that can eliminate a circumferential velocity component of a leakage flow effectively, and attempt to collect motive power. A shroud of the axial flow turbine includes: an annular first protruding portion protruding toward the upstream side in a rotor's axis direction; an annular second protruding portion that is positioned on the outer side in the rotor's radius direction relative to the first protruding portion, protrudes toward the upstream side in the rotor's axis direction, and is longer than the first protruding portion; a circulating-flow generating chamber formed between the first protruding portion and the second protruding portion; and guide plates positioned in the circulating-flow generating chamber.

Abstract: An annular cap for collecting lubricating oil for turbomachine equipment is configured to extend around the equipment and to rotate about an axis. The cap includes through-orifices through which the oil can pass radially under the effect of spinning. The cap further includes means of deflecting the oil leaving the orifices in a direction substantially transverse to the axis and substantially tangential to the cap.

Abstract: A device for lubricating an antifriction bearing of an electric motor includes a lubrication chamber located around a shaft of the electric motor and adjacent to the antifriction bearing when the shaft rotates. The lubrication chamber has a radial outer wall which is provided with at least one opening. An oil reservoir configured for arrangement on an exterior or an interior of the electric motor includes an oil pan and a ring-shaped or disk-shaped oil delivery member which directly or indirectly moves along on the shaft and is configured to run through the oil pan and to enable oil to be transported from the oil pan into the lubrication chamber, with oil being able to flow out of the lubrication chamber via the at least one opening back into the oil pan.

Abstract: The turbo machine includes a rotor 1 with a rotating shaft 3, a stator 2 enclosing the rotor 1 and a sealing device 20 installed in a clearance passage defined between the rotor 1 and the stator 2, the sealing device 20 controlling a leakage flow from the clearance passage B. The sealing device 20 includes a plurality of sealing fins 24 disposed on at least one of the rotor 1 and the stator 2, and arranged in an axial direction of the rotor 1. The sealing device 20 further includes at least one deceleration controlling member 25 provided on the rotational side. The deceleration controlling member 25 projects toward a chamber 30 defined between the sealing fins 24 and is configured to control a reduction in the velocity of the leakage flow B in the chamber 30 in the rotational direction of the rotor 1.

Abstract: A bearing assembly for a vehicle includes an inner race having an interior surface and an exterior surface, an outer race having an interior surface and an exterior surface, a first sealing member disposed between the inner race and the outer race, the first sealing member having a sealing surface adjacent to the interior surface of the outer race, and a second sealing member disposed radially inward of the first sealing member and adjacent to a shoulder surface of the outer race, wherein the first sealing member permits grease bleed-off from the bearing prior to the first sealing member setting against the second sealing member.

Abstract: A CV joint for a downhole drilling motor includes a center shaft including a top shaft section and a bottom shaft section. The top shaft section is at least partially housed within a cavity of a first insert, which is housed within a cavity of a rotor adapter. The bottom shaft section is at least partially housed within a cavity of a second insert, which is housed within a cavity of a drive shaft adapter. An outer surface of the top and bottom shaft sections may include multiple top shaft pockets and multiple bottom shaft pockets, respectively. The first and second inserts may each include a series of recesses. Top shear members may be partially housed within the top shaft pockets and the recesses of the first insert. Bottom shear members may be partially housed within the bottom shaft pockets and the recesses of the second insert.

Abstract: A contra-flow strip for inhibiting leakage of a fluid between a rotating member and a stationary member includes, for example, a base supportable by the stationary member coaxially around the rotating member, and means, extending from the base coaxially towards the rotating member between a low pressure region and a high pressure region, for generating a contra flow of a portion of a tangential flow of fluid in the low pressure region to the high pressure region between the stationary member and the rotating member.

Abstract: A sealing system for sealing shafts against liquid media, for example propeller shafts, impeller shafts, rudder stocks of ships and the like. Opposing corner regions of the sealing system that are located radially inside of a clamping space, for clamping at least one sealing ring, are formed by inclined run-on surfaces that diverge when viewed radially from the inside towards the outside. For accommodation in the clamping space, a clamping section of the sealing ring comprises two opposite edge regions that are formed by inclined surfaces that correspond to the run-on surfaces.

Abstract: A rolling bearing assembly including at least one hydraulic fluid gallery for adjusting at least one seal is provided. The rolling bearing assembly includes a radially inner ring and outer ring. The radially outer ring includes a first circumferentially extending seal groove. The radially outer ring includes a second circumferentially extending seal groove having a pressure groove therein, and at least one hydraulic fluid gallery including an inlet and an outlet connected to the pressure groove. The at least one seal includes a radially outer end engaged within the second circumferentially extending seal groove, and a radially inner end located in the first circumferentially extending seal groove, and the pressure groove is located inside of an axial end face of the at least one seal.

Abstract: Various aspects of the present disclosure are directed towards an apparatus/method including rolling elements, an outer ring surrounding an inner ring and the inner and outer rings guiding rotation of the rolling elements in a rotation region therebetween, and a cap secured to the inner ring. The apparatus further includes a bearing shield arrangement secured to one of the outer and inner rings and configured with the other of the outer and inner rings to define a gap for the flow of vapor or lubricant from the rotation region through a vapor restricting pathway.

Abstract: A cartridge bearing assembly for rotatably coupling a shaft with a housing includes a bearing having a central axis and opposing axial ends. The bearing includes first and second, axially spaced inner rings disposeable upon the shaft, at least one outer ring disposed circumferentially about the two inner rings, and first and second sets of rolling elements disposed between the inner and outer rings. A carrier includes a first tubular portion disposed generally about the bearing first axial end and a second tubular portion disposed generally about the bearing second axial end. The first and second tubular portions are coupled together to enclose the bearing, the carrier being at least partially disposeable within the housing bore so as to couple the bearing with the housing. Preferably, a coupler is provided to connect the first and second inner rings so as to establish preload within the bearing.

Abstract: A seal assembly is for sealing a clearance space about a shaft, the shaft being rotatable about a central axis, and includes a generally annular sealing member disposed about the shaft. The sealing member is radially deflectable between an inner position and an outer position, the sealing member sealing the clearance space when located at the inner position. A generally annular rotor is disposed about and rotatably coupled with the shaft, the rotor having a generally annular cavity sized to receive the sealing member and at least one and preferably a plurality of lift passages extending at least partially radially through the rotor. Each lift passage has an inner port fluidly coupled with the cavity and an outer port fluidly coupled with an exterior atmosphere such that suction generated within the lift passages when the rotor angularly displaces about the axis generally retains the sealing member at the outer position.

Abstract: Gas turbine engine systems involving rotor bayonet coverplates and tools for installing such coverplates are provided. In this regard, a representative turbine assembly for a gas turbine engine includes: a turbine disk operative to mount a set of turbine blades; and a coverplate having an annular main body portion and a spaced annular arrangement of tabs extending radially inwardly from the main body portion with open-ended gaps being located between the tabs, the tabs being operative to secure an inner diameter of the coverplate to the turbine disk.

Abstract: The present disclosure relates to a vehicle driveline differential with improved efficiency during vehicle cold starts, the differential includes: a pinion; and a pinion bearing journaled onto a shaft of the pinion. The pinion bearing includes a thermal-insulation sleeve.

Abstract: A rotary seal having first and second parts mobile relative to each other about a rotation axis. The first and second mobile parts each include an interface area having a plurality of protruding and recessed members with complementary shapes, the protruding and recessed members of one part engaging the protruding and recessed members of the other part in order to define decompression chambers with an increasing volume. The interface areas are located at a distance from each other without any friction between them.

Abstract: A sealing device in which oil (O) is supplied by ejection to a sealing device body (3). In the sealing device, an increase in friction of a seal lip (33) caused by the pressure of the oil (O) is prevented, and effective lubrication by the oil (O) is promoted. The sealing device has the sealing device body (3) having the seal lip (33) slidably in intimate contact with the outer peripheral surface of a rotating shaft (2), an oil ejection opening (12) for ejecting the oil (O) toward a position on the outer peripheral side of the seal lip (33) of the sealing device body (3), and oil splashing means (4) for splashing the oil (O), ejected from the ejection opening (12), back to a portion near a sliding portion (S) of the seal lip (33).

Abstract: To improve durability of a seal lip (4) of an oil seal (1) in slidably contact with the peripheral surface of a shaft (23), a lubricating oil supply section (11) for collecting adhered oil and dropping it on the shaft (23) is provided at a forward end portion of an installation section (2), the lubricating oil supply section (11) has projections (12) formed on the inner peripheral surface of the installation section (2) to collect oil on the surface thereof, the surface of each projection (12) has a recess (13) for temporarily accumulating oil, guidance projections, or a slope for collecting the oil, and dams are formed on a forward end face (2a) of the installation section (2) to block the oil flowing down along the circumferential direction on the forward end face (2a) and guides the oil toward each projection (12).

Abstract: In a gear chamber 10, a sealing member 21 is attached to a rotary shaft 12 of an electric motor 11, and a grease return part 21a is provided on this sealing member 21. Thus, grease raked by a helical gear 12a is blown off diagonally forward with respect to a radial direction as a result of a centrifugal force, and it is possible to prevent the grease from leaking out of a ball bearing 20.

Abstract: A seal assembly is for a compressor including a casing having first and second chambers and a shaft extending through the casing between the two chambers. The seal assembly includes a main body disposed about the shaft and between the two chambers and having a central axis, an inner surface spaced radially outwardly from the shaft to form a seal chamber. Annular sealing members are connected with the main body and extend radially from the body inner surface toward the shaft, the sealing members preventing flow between the first and second chambers through the seal chamber. A separator is coupled with the shaft adjacent to the main body and has separation passages fluidly connecting one of the two chambers with the seal chamber, each passage extending radially with respect to the shaft axis so as to direct liquids and solids contacting the passage inner surface away from the seal chamber.

Abstract: A method of assembling a sealing assembly for a turbomachine is provided. The method includes positioning at least one sealing element that includes a substantially tortuous flow path defined therein within at least one channel defined in a rotatable element of the turbomachine. The sealing element is extended circumferentially about the rotatable element such that the sealing element extends into a cavity defined between the rotatable element and a stationary element. This facilitates substantially reducing flow leakage from an upstream region of the cavity to a downstream region of the cavity.

Abstract: A rotating seal for a gas turbine engine includes: (a) an annular seal body; (b) a sealing component carried by the seal body which is adapted to form one-half of a rotating seal interface; and (c) an impeller carried by the seal body which comprises a plurality of radially-inwardly-extending impeller blades.

Abstract: A hydraulic seal is defined between a rotating member such as a turbocharger shaft and a stationary member such as part of a bearing housing of a turbocharger. The members define a projecting annular disc that is received in an annular channel that is filled with hydraulic sealing fluid such as oil. Rotation of the rotary member applies a centrifugal force to the fluid thereby ensuring that it is retained in the channel between walls thereof and the disc. This annulus of fluid provides a hydraulic seal around the shaft between the bearing housing and the compressor or turbine housing. The oil is delivered into the channel from a supply in the rotary member. One of the walls of the channel serves as a weir whereby when the channel has an excess supply of oil is overflows the wall and passes the drain.

Abstract: A floating seal is provided between the fixed housing and the drive wheel, and an outside seal is provided so as to cover the outer circumference of the floating seal. The outside seal is composed of a gap between the fixed seal member secured to the fixed housing serving as a vehicle body and the rotating seal member rotatably secured integrally with the drive wheel. Blades that rotate on the outer circumference of the outside seal are provided on the outer circumference of the rotating seal member so as to protrude therefrom. By means of the blades, dirt accumulated in the fixed housing is scraped off. Therefore, dirt is prevented from being accumulated on the outer circumference of the outside seal, wherein it is possible to prevent dirt from entering the position of the floating seal and to appropriately discharge the dirt that has entered to the outside.

Abstract: A sealing device for performing sealing by a throw off effect of a slinger (2) is provided with a stationary sealing element (1), which has a thrust lip (12) and a radial lip (13) on the radially inner side thereof and is installed on a stationary member (101), and the slinger (2), which has a sleeve (21) fitted on a rotary member (102) and a flange (22) extending from one end of the sleeve (21). The thrust lip (12) slidably contacts with the flange (22), and the radial lip (13) slidably contacts with the outer peripheral surface of the sleeve (21). A circumferentially continuous dam (23) is provided on the outer peripheral surface of the sleeve (21) to be positioned on the flange (22) side of an intimate contact slide section (S2) of the radial lip (13). The dam (23) is a ridge (231) or a groove.

Abstract: A circumferential seal system for sealing a high pressure region from a low pressure region separated by a runner with an outer circumferential surface and a seal ring disposed about the outer circumferential surface is described. The seal system includes a plurality of groove sets separately disposed along the outer circumferential surface. Each groove set further includes at least two grooves. At least one groove within each groove set exerts a lifting force via a fluid from the high pressure region onto the seal ring as the runner translates with respect to the seal ring along an axis substantially perpendicular to the rotation of the runner. The continuous feed of fluid onto the seal ring ensures a thin film between the seal ring and the runner regardless of their relative arrangement during axial excursions of the runner resulting from conditions within a turbine engine.

Abstract: A compressor of a gas turbine engine comprises blades 2, 4 provided on blade platforms 8, 12 of a rotor. Stator vanes 20 lie between the blades 2, 4 and are connected to a vane support structure 22. Sealing rings 38 are secured to the vane support structure 22 to restrict air flow into stator wells 36 on each side of the vane support structure 22. The sealing rings 38 are made from a flexible material so that they deflect on installation of the vane support structure 22 in a direction radially inwards between the adjacent blade platforms 8, 12.

Abstract: A circumferential seal system for sealing a high pressure region from a low pressure region separated by a runner with an outer circumferential surface and a seal ring disposed about the outer circumferential surface is described. The seal system includes a plurality of groove sets separately disposed along the outer circumferential surface. Each groove set further includes at least two grooves. At least one groove within each groove set exerts a lifting force via a fluid from the high pressure region onto the seal ring as the runner translates with respect to the seal ring along an axis substantially perpendicular to the rotation of the runner. The continuous feed of fluid onto the seal ring ensures a thin film between the seal ring and the runner regardless of their relative arrangement during axial excursions of the runner resulting from conditions within a turbine engine.

Abstract: In a gear chamber 10, a sealing member 21 is attached to a rotary shaft 12 of an electric motor 11, and a grease return part 21a is provided on this sealing member 21. Thus, grease raked by a helical gear 12a is blown off diagonally forward with respect to a radial direction as a result of a centrifugal force, and it is possible to prevent the grease from leaking out of a ball bearing 20.

Abstract: A sealing member can include a radially-working lip which contacts a drive shaft in a radial direction to seal a gap between the drive shaft and the housing in the radial direction, an axially-working lip extending in an axial direction, and a contact member which contacts the axially-working lip to seal the gap between the drive shaft and the housing in the axial direction. The contact member can be fitted to the drive shaft to rotate with the drive shaft.

Abstract: A shaft sealing assembly for static and dynamic axial sealing of a centrally located rotating and movable shaft is provided. The assembly includes at least one first sealing member for sealing said shaft, at least one rotor member-attached to said shaft, and a stator member attached to a housing. A first sealing member is arranged in a recess in said rotor member effectively sealing one side of the assembly from its other side when a pressure difference exists between the media on the two sides of the assembly. Upon rotation of the shaft, the static sealing member is centrifugally moved axially and radially away from its static sealing position and friction between the sealing member and the stator is eliminated. Dynamic sealing is affected by a pressure difference caused by a turbine effect of the rotor member.

Abstract: A dustproof device for a ball screw disposed on an end surface of a nut comprises: an absorber, an oil scraping piece and a wiping member. The absorber is made of liquid-absorbing material. The oil scraping piece has an oil scraping portion contacting the surface of the screw. The wiping member is formed with a threaded portion for meshing with the surface of the screw. And a plurality of protrusions is formed between the wiping member and the oil scraping piece for defining at least one radial through hole between the wiping member and the oil scraping piece. Therefore, the dustproof device can block and remove powder and liquid, and prevent lubricant leakage out of the nut and can absorb a tiny amount of cutting fluid passing through the oil scraping piece.

Abstract: A sealing arrangement for turbomachines with a shaft bearing, a throw-off ring and a shaft seal which is assigned to a sealing gap and has a seal housing wherein opposing faces of the throw-off ring and the seal housing form an annular gap for centrifuging out dirt and oil particles.

Abstract: A seal assembly including a rotatable seal head subassembly also includes a fan that rotates with the seal head assembly, with the fan drawing air through a pump housing for purposes of cooling.

Abstract: The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

Abstract: A sealing device for a water pump bearing employs a seal member without an axial lip, and having only a radial lip. The sealing device includes an annular seal member which is fixed to a shoulder portion of one end in an axial direction of an outer race of a water pump bearing and an annular slinger which is positioned on a side of the one end in the axial direction with respect to the seal member and externally fixed to the outer peripheral face of a pump shaft serving as an inner race. The seal member has a section shape which is bent along a disk portion and an outer cylindrical portion of the slinger. A labyrinth seal portion is formed between the seal member, and the disk portion and the outer cylindrical portion of the slinger. Radial lips are formed on an inner periphery of the seal member.

Abstract: A wafer scrubbing unit includes a mounting assembly for a scrubber brush. The mounting assembly has a rotary flow through tube through which cleaning liquid is delivered to the brush. A stationary tube may be mounted in the bore of the rotary tube. Spinning shields mounted on the rotary tube form labyrinth seals to protect a bearing housing from the cleaning liquid. Bearings for rotatably mounting the rotary tube are mounted within the housing.

Abstract: A structure of a water pump is provided without increasing the cost thereof, or without enlarging the size to improve the durability of the water pump. A seal apparatus having a seal ring 13 and a slinger 14 in combination to prevent foreign matter from progressing into the rolling bearing 6a. The amount of compression &dgr; of the second seal lip 23, which occurs when the tip edge of the second seal lip 23 of the seal ring 13 comes in contact with the outer peripheral surface of the outer-diameter-side cylindrical section 26 that is formed at the outer peripheral edge of the slinger 14, is at least {fraction (1/10)} and up to {fraction (7/10)} the height of the second seal lip 23 in the free state. In addition, the roughness of a portion of the outer peripheral surface of the outer-diameter-side cylindrical section 26 which the tip edge of the second seal lip 23 comes in sliding contact with is from 0.2 &mgr;m to 2.0 &mgr;m in the arithmetic mean Ra, or is from 0.8 &mgr;m to 8.