Abstract: A hinge includes internal on-axis stopping mechanisms that cause the hinge to shear and break at an on-axis weakened region of the hinge when rotation of the hinge reaches a predetermined angle with a specified torsional load. The on-axis configuration is compact, has minimal impact on the outer mold line (OML) of the object to which it is mounted both pre and post detachment and allows for accurate tailoring of the torsional load that will detach the hinge.

Abstract: A ball and socket joint assembly is disclosed that includes a body defining a cavity, a collet disposed in the cavity to receive a ball of a connector, and an actuator shaft coupled to the collet for rotating and translating the collet in the cavity. The cavity has a distal opening to accept the ball and an engagement feature extending into the cavity. The collet has an outer diameter larger than the opening in the body when the ball is disposed in the collet, and the collet has a corresponding engagement feature around at least a portion of the outer surface for receiving the engagement feature and converting rotation of the compression member into translation of the compression member along a proximal-distal axis of the body. The collet is compressed against the opening of the cavity when the collet is advanced distally against the opening.

Abstract: A suspension thrust bearing device providing a lower support cap, an upper bearing cap and at least one bearing arranged between the caps. The upper bearing cap includes an outer skirt radially surrounding the lower support cap. The lower support cap having at least one annular deflector flange extending towards the outer skirt of the upper bearing cap while remaining radially spaced apart from the outer skirt, the deflector flange having a lower inclined surface extending obliquely downwards.

Abstract: In one example, a bearing or transmission has an outer race that extends circumferentially about a central axis. An inner race is disposed within the outer race and extends circumferentially about the central axis so as to be coaxial with the outer race. A plurality of load-bearing rolling elements are disposed between the inner race and the outer race, and are spaced circumferentially from one another so as to not contact one another. A plurality of separator rolling elements are disposed within the outer race. Each separator rolling element is disposed between a respective pair of the load-bearing rolling elements such that the separator rolling element is in rolling contact with the load-bearing rolling elements of the respective pair. The load-bearing and separator rolling elements form a contiguous ring.

Abstract: A rolling bearing 1 includes an outer ring 1A, an inner ring 1B, and a plurality of rolling elements. The outer ring IA includes a first outer ring 10 and a second outer ring 20. The inner ring 1B includes a first inner ring 30 and a second inner ring 40. In a cross section including a central axis R, grain flows 111 in the steel constituting the first outer ring 10 extend along a first rolling surface 511, grain flows 211 in the steel constituting the second outer ring 20 extend along a second rolling surface 512, grain flows 311 in the steel constituting the first inner ring 30 extend along a third rolling surface 513, and grain flows 411 in the steel constituting the second inner ring 40 extend along a fourth rolling surface 514.

Abstract: A gib includes a metallic substrate having a first face and a second face and an attachment disposed on the metallic substrate. The attachment includes a first functional surface disposed on the first face of the metallic substrate. The first functional surface is configured as a bearing surface. The attachment may be formed of a fabric resin composite material.

Abstract: A rolling guide device includes a track member, a moving member, and a plurality of rolling bodies. Rolling-body rolling surfaces that come into contact with an rolling-body outer circumferential surface of a rolling body are respectively formed in wall surfaces of a pair of wall portions included in the track member facing each other, a scraper including a pressing portion that presses the rolling-body rolling surfaces is turnably installed in the moving member, the scraper includes at least an attachment portion and a pressing portion, and is formed such that a frictional force of the pressing portion with respect to the rolling-body rolling surfaces is smaller than a frictional force of the attachment portion with respect to an attachment shaft formed in the moving member.

Abstract: Provided is a hybrid fluid film bearing. The hybrid fluid film bearing comprises: a bearing housing installed on an outer diameter surface of a rotary shaft in the form of being coupled via a ring; a sleeve ring installed between the rotary shaft and the bearing housing, having gaps respectively with the rotary shaft and the bearing housing, and having a side in the circumferential direction opened in the radial direction; and a fixing pin connected between the bearing housing and the sleeve ring, and supported by the bearing housing so as to restrict rotation of the sleeve ring when the rotary shaft rotates. Also, the hybrid fluid film bearing may further comprise a compliant spring damper which is provided in the gap between the bearing housing and the sleeve ring and is provided as one or more bump foils.

Abstract: System and method for the identification of a mechanical component, in particular a bearing or a hub bearing unit of a vehicle or a ring thereof, consisting of a marking applied directly onto an exposed surface of the mechanical component, performed using a photopolymerizable ceramic ink which is printed on the exposed surface by an inkjet printer having a resolution equal to, or greater than, 700 dpi and which is at least partly vitrified using a heat treatment at a temperature equal to or higher than 700° C., preferably after fixing of the ceramic ink on the exposed surface by UV irradiation.

Abstract: There are disclosed methods for withdrawal of a bearing from a gate mechanism including a mechanism housing, a carrier assembly, and discrete fasteners. The carrier assembly includes a carrier housing and a carrier bearing. The carrier bearing is supported for rotation within the carrier housing. The carrier housing has a carrier support mating with a receiving bore of the mechanism housing. The carrier housing has multiple flange fasteners aligning with housing fasteners and housing surfaces of the mechanism housing when the carrier housing mates with the receiving bore. Multiple discrete fasteners are removed from a first group of the flange fasteners aligned with the housing fasteners. The carrier assembly is displaced from the mechanism housing in response to inserting the plurality of discrete fasteners to a second group of the plurality of flange fasteners aligned with the plurality of housing surfaces.

Abstract: A tripod type constant velocity universal joint includes an outer joint member that includes track grooves, a tripod member that includes three leg shafts protruding in a radial direction, a roller that is inserted into the track groove, and an inner ring that is fitted onto the leg shaft, and rotatably supports the roller. A hardened layer is formed on a surface of each leg shaft by carburizing, hardening, and tempering. The tripod member is formed a steel material having a carbon content of 0.23% to 0.44%. An effective hardened layer depth of the hardened layer by using, as a Ts torque, 0.3 times a minimum static torsional torque at which a shaft coupled to the tripod member causes torsional fracture and 600HV as limit hardness is equal to or greater than a maximum shear stress depth Z when the Ts torque is applied.

Abstract: A coupling assembly includes a multiple-position actuation mechanism and a detent assembly holding the actuation mechanism in a discrete position. The detent assembly may include a mechanical detent. In one example, the mechanical detent engages the actuation mechanism and holds the actuation member in a neutral or middle position.

Abstract: A system comprises a powertrain including an engine configured to output torque to a driveline, and an electronic control system operatively coupled with the powertrain. The electronic control system is configured to determine an engine torque value, and control a component of the driveline in response to the engine torque value. The engine torque value may account for an effect of air-fuel ratio (AFR) on engine torque. The engine torque value may account for an effect of charge transport delay on engine torque.

Abstract: An electric driveline system is provided. The electric driveline system includes a first electric machine and a second electric machine mechanically coupled to a transmission and a power take-off (PTO) assembly coupled to the first electric machine. The PTO assembly includes a first clutch coupled to a PTO gearset and designed to selectively disconnect a PTO from the first electric machine and the PTO gearset is mechanically coupled to the first electric machine.

Abstract: Disclosed herein a caliper brake includes a carrier in which a pair of pad plates are installed to move forward and backward toward a disk; a caliper housing slidably installed on the carrier and provided with a cylinder; a piston installed in the cylinder and configured to move forward and backward toward the pair of pad plates by a braking hydraulic pressure; a seal member in close contact with an outer surface of the piston and an inner surface of the cylinder, the seal member having a ring-shaped; and a seal groove formed to be recessed in the inner surface of the cylinder to accommodate the seal member, the seal groove including a front braking surface facing a front surface of the seal member; wherein the front braking surface includes a protrusion protruding toward the seal member.

Abstract: A disk brake apparatus may include a caliper body installed on the outer circumference of a disk; a piston member installed in the caliper body, and moved by hydraulic pressure; a brake pad pressed toward the disk by the piston member; and a shim plate installed between the piston member and the brake pad, formed in a plate shape, and abutting on a piston contact part installed on a surface of the piston member, facing the brake pad, the shim plate may include a cover shim brought into contact with the piston contact part; and a pad shim stacked on a surface of the cover shim, facing the brake pad, and including an opening formed through a region which overlaps at least a part of the piston contact part.

Abstract: A method adjusts the slack of a brake assembly having a brake disc, a brake pad, an actuator with an output shaft driven in a forward direction to bring the brake pad and brake disc into frictional engagement defining a braking position and a reverse direction to disengage the brake pad and brake disc and to move the brake pad into a rest position, and a slack adjuster for adjusting a predetermined axial slack distance between the brake pad and the brake disc. The brake pad is moved from the rest position in the reverse direction into a predetermined reference position, and an adjustment of the axial slack distance between the brake pad and brake disc is initiated.

Abstract: A method of making a wet friction material layer includes adding a media in liquid form to a material base including filler particles embedded in a matrix of fibers; drying the media to solidify the media on the filler particles such that the media plugs holes in the filler particles; adding a binder to the material base; and unplugging at least some of the holes in the filler particles by removing at least some of the media from the material base.

Abstract: A bushing having a bearing wall that extends partially around an axis. The bearing wall may include a first end surface, a second end surface, and an inner side that may extend from the first end surface to the second end surface. The inner side may define the bushing opening having an elliptical configuration.

Abstract: A power transmission device includes a flywheel, a torque limiter unit, and a damper unit. The torque limiter unit includes first and second side plates and a friction plate. The first side plate is attached to the flywheel. The first side plate is disposed on a first axial side to the flywheel. The friction plate is disposed axially between the first side plate and the second side plate. The damper unit includes input rotational bodies, an output plate, and an elastic member. The output plate is disposed axially between the first side plate and the flywheel.

Abstract: The present invention provides a flexible member having excellent load resistance and flexibility while achieving a reduction in size. This flexible member is provided with: a main body part which includes multiple wave washers that are stacked in an axial direction and are joined to one another by multiple joint parts, and which is capable of bending relative to the axial direction by elastic deformation of the wave washers; and easily deformable parts formed between the joint parts that are adjacent to one another in the circumferential direction in each wave washer.

Abstract: A tuned mass absorber assembly comprises a mass structure, and a flexure system comprising first and second flexure sections (e.g., cross bar flexures) supported by, and extending in opposing directions from, the mass structure. The flexure system can comprise flexure section mounts situated at distal ends of the first and second flexure sections, respectively, and that are operable to mount the tuned mass absorber assembly to a structure subject to induced vibrations therein. A mass of the mass structure and a stiffness of the flexure system can be tuned to attenuate vibrations at a specific input frequency generated in response to induced vibrations of the structure. A system can comprise a vibration isolator attached to a chassis (e.g., of an airplane), and supporting a payload (sensors(s)) and isolating the payload from vibrations. A tuned mass absorber assembly can be mounted to the vibration isolator for attenuating vibrations at a specific input frequency that may affect the payload.

Abstract: A vehicle suspension damper including: a cylinder; a piston assembly; and an adjuster, wherein the piston assembly compresses fluid as it moves within the cylinder and the adjuster obstructs fluid flow from a first side of a damping piston of the piston assembly to a second side of the damping piston.

Abstract: A valve seat member is provided in a cap member. A first sub valve is provided in another side chamber. A second sub valve is provided in a cap chamber formed between a bottom portion of the cap member and the valve seat member. In a second passage, an orifice is disposed on an upstream side or a downstream side from the first sub valve in flow by which the first sub valve is opened. In a region in which a piston speed is low, a valve of a second damping force generating mechanism is opened in a state in which a valve of a first damping force generating mechanism is closed. In a speed region in which the piston speed is higher than in another region, the valve of the first damping force generating mechanism and the valve of the second damping force generating mechanism are both opened.

Abstract: A head unit system for controlling motion of an object includes a secondary object sensor and a head unit device that include shear thickening fluid (STF) and a chamber configured to contain the STF. The chamber further includes a front channel and a back channel. The head unit device further includes a piston housed at least partially radially within the piston compartment and separating the back channel and the front channel. The piston includes a first piston bypass and a second piston bypasses to control flow of the STF between opposite sides of the piston. The chamber further includes a set of fluid flow sensors and a set of fluid manipulation emitters to control the flow of the STF to cause selection of one of a variety of shear rates for the STF within the chamber to control motion of the object with regards to a secondary object.

Abstract: Systems and a method for resisting a fluctuation in a value of a parameter relating to well equipment using a magnetorheological dampener system are described herein. The method includes continuously determining the value of the parameter relating to the well equipment, determining a fluctuation in the value of the parameter, and comparing the fluctuation in the value of the parameter to a preset limit. The method also includes energizing an electromagnet to increase a viscosity of a magnetorheological fluid (MRF) if the fluctuation exceeds the preset limit.

Abstract: A clamp for open ended flat belts. The clamp has a tapered housing with an aperture at a first end providing access to the housing interior and a second open end also providing access to the interior. A tapered wedge is removable and replaceable from the interior of the housing, the wedge having a first end and a radiused second end and having a surface comprising alternating ribs and lands. The clamp includes a lock having a concave surface similar to the radiused second end of the tapered wedge. The housing may have a removeable and replaceable side wall providing access to the interior.

Abstract: A rope coupling apparatus configured for connecting or terminating a rope without the use of rope knots or terminations is disclosed. The rope coupling apparatus may include a retainer member with a first portion, a second portion and opposing side portions, an opening through the first portion of the retainer member, a rope receiver on the second portion of the retainer member; and a plurality of notches disposed on one or both of the opposing side portions of the retainer member.

Abstract: An object of the present invention is to provide a silent chain drive device that can minimize loss of strength and wear of link plates, as well as prevent the chain from lifting up to achieve better power transmission efficiency. The silent chain drive device includes a silent chain designed for inside flank meshing/inside flank seating, and a sprocket with sprocket teeth. The plurality of link plates in the silent chain, which each have a pair of teeth, are configured to make contact with the sprocket teeth only at the inside flanks of each pair of teeth when the silent chain wraps around the sprocket and meshes with all of the sprocket teeth.

Abstract: The present invention relates to a linear actuator comprised of a tube and method of deploying 3 spools of strips into a tube by consolidating the strips in an overlapping condition with each other each in a helical form of a constant diameter.

Abstract: A drive transmission device according to one embodiment of the disclosure includes: an arm having a motor that generates a rotational force; a speed reducer that is provided in the arm and has a carrier for decelerating rotation of the motor and outputting the decelerated rotation; a bucket fixed to the carrier by a reamer bolt, the reamer bolt being inserted in a bracket through hole formed in the bucket; and a resin bush provided between an internal surface of the bracket through hole and an external lateral surface of the reamer bolt. The mechanical strength of the resin bush is lower than the mechanical strength of the bucket and the mechanical strength of the reamer bolt.

Abstract: An electric actuator having a hand-screw release device, including: housing, drive motor, transmission assembly, rotary screw rod and driving nut, and further including: clutch device configured to engage or disengage power transmission between the transmission assembly and the rotary screw rod; a self-locking device configured to produce a friction resistance against the rotary screw rod when the rotary screw rod rotates reversely; and a hand-screw release device including a release rotary knob, the first driving member being connected to the clutch device, the second driving member being configured to connect the self-locking device, and the release rotary knob being turned to present an initial state and a completely released state, wherein in the course of switching from the initial state to the completely released state, the first driving member activates the clutch device to disengage the power connection, and the second driving member activates the release torsion spring to release.

Abstract: In one example, a line of transmissions is provided comprising, a first transmission and a second transmission. Each transmission includes an input shaft with a first pair of gears arranged thereon and a first clutch positioned therebetween designed to selectively rotationally couple at least one of a first gear and a second gear of the first pair of gears to the input shaft. Each transmission includes a layshaft with a second pair of gears fixedly coupled thereto. Each transmission includes an output shaft with a third pair of gears arranged thereon and a second clutch positioned therebetween designed to selectively rotationally couple at least one of a third gear and a fourth gear in the third pair of gears to the output shaft. The first transmission has the second gear fixed to the input shaft. The second transmission has the fourth gear fixed to the output shaft.

Abstract: A transmission for a vehicle includes a first input shaft, a second input shaft, an output shaft, a planetary gear set arranged on the output shaft, including a sun gear, planet carrier and ring gear, an output shaft first gearwheel, an output shaft second gearwheel, wherein the first input shaft gearwheel is drivingly connected with the output shaft first gearwheel and the second input shaft gearwheel is drivingly connected with the output shaft second gearwheel, wherein the output shaft second gearwheel is permanently connected to the sun gear and rotatable with respect to the output shaft, the output shaft first gearwheel is rotatable with respect to the output shaft, and the output shaft first gearwheel is further engageable with the output shaft in a first gear mode and engageable with the output shaft second gearwheel in a second gear mode.

Abstract: An electric drive vehicle includes an electric motor having an output shaft, a gearbox assembly operably coupled to the output shaft, and a differential assembly configured to drive first and second axle shafts, where the first axle shaft includes separated first and second shaft portions. A disconnect system is configured to selectively connect the first shaft portion and the second shaft portion. In a driving mode, the disconnect system connects the first and second shaft portions for common rotation. In a towing mode, the disconnect system disconnects the first and second shaft portions to enable the electric drive vehicle to be towed without backdriving the electric motor.

Abstract: A gear-hydraulic-rhombic pyramid integrated multi-mode hybrid transmission device includes an input assembly, a hydraulic transmission mechanism, a front planetary gear mechanism, a rhombic pyramid-type continuously variable transmission mechanism, a rear planetary gear mechanism, an output assembly, a clutch assembly, and a brake assembly. The clutch assembly connects an output end of the input assembly to an input end of the hydraulic transmission mechanism and an input end of the front planetary gear mechanism. The clutch assembly connects an output end of the hydraulic transmission mechanism to the front planetary gear mechanism and the rear planetary gear mechanism. The clutch assembly connects the front planetary gear mechanism, the rhombic pyramid-type continuously variable transmission mechanism, the rear planetary gear mechanism, and the output assembly in sequence. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input assembly and the output assembly.

Abstract: A multi-function differential (MFD) assembly includes a differential case, a differential gear assembly disposed in the differential case, a mechanical limited slip differential (mLSD) clutch assembly disposed in the differential case, and an electronic limited slip differential (eLSD) clutch assembly disposed in the differential case. The mLSD clutch assembly is configured to provide the MFD assembly with mLSD functionality, and the eLSD clutch assembly is configured to provide the MFD assembly with eLSD functionality.

Abstract: In a strain wave gearing, in order to regulate axial-direction movement of an externally toothed gear thereof, first balls are directly interposed between a first annular end surface and a device housing, whereby the first annular end surface and the device housing are in rolling contact with one another. Similarly, second balls, are directly interposed between a second annular end surface and an output shaft, whereby the second annular end surface and the output shaft are in rolling contact with one another. No contact occurs other than rolling contact of contact portions. Additionally, pressure is applied in the axial direction to the portions that make rolling contact, and axial-direction rattling is eliminated, whereby axial-direction movement of the externally toothed gear is reliably suppressed, and generation of high thrust force is prevented.

Abstract: A pulley device for a tensioner roller or winding roller of a transmission element, having a pulley, a bearing, and an annular protective flange. The flange provides a first radial portion of small diameter, the first radial portion bearing against a fixed inner ring of the bearing, a second radial portion of large diameter, and a substantially axial intermediate portion connecting the first and second radial portions. The intermediate portion forms a circumferential trough, the bottom of which is offset radially towards the inside of the pulley device compared with the outer edge of the fixed inner ring.

Abstract: A worm shaft includes: an insertion portion; a wall surface; a tapered portion; and a main body portion, the gear portion is formed on the main body portion and the tapered portion such that a bottom land of the gear portion is positioned at radially outer side of a line extending in parallel with a rotation center axis of the worm shaft and passing through a boundary between the wall surface and the tapered portion.

Abstract: A supporting device includes first and second supporting flanges coupled with first and second transmissions, respectively, and a support via which a supporting force is transmittable from the first supporting flange to the second supporting flange. The support includes a lever element which is coupled in an articulated manner with an attachment element on the first supporting flange and thus articulated with the first supporting flange, and a supporting element which is coupled in an articulated manner with the lever element and connected to the second supporting flange and which includes two spaced-apart supporting parts. The lever element is arranged partly between two spaced-apart attachment parts of the attachment element and partly between the supporting parts of the supporting element and is coupled in an articulated manner with the attachment element via the attachment parts and in an articulated manner with the supporting element via the supporting parts.

Abstract: A composite transmission housing for a vehicle drive train transmission is configured for sealingly enclosing transmission shafts, gearwheels, and a lubricant fluid within an internal space of the housing and includes: a first carbon-fibre skeleton part having a first attachment region; a second carbon-fibre skeleton part having a first attachment region; a first sealing cover part made of plastic material and having a first sealing surface; and a second sealing cover part made of plastic material and having a second sealing surface. The first attachment regions of the first and second carbon-fibre skeleton parts are mutually connected for providing a rigid structural framework that defines said internal space, and the first and second sealing surfaces of the first and second sealing cover parts are pressed together or against corresponding sealing surfaces associated with the first and second carbon-fibre skeleton parts, for providing a sealing envelope around said internal space.

Abstract: A control method and apparatus may be applied to an electric drive system. The electric drive system includes an oil pump, a motor, a reducer, and a housing, the motor and the reducer are disposed in the housing, lubricating oil is stored in the housing, and the oil pump is configured to pump the lubricating oil. The method includes: obtaining a first rotational speed of the motor, a second rotational speed of the oil pump, and a temperature of the lubricating oil in the housing; and controlling a rotational speed of the oil pump to be a third rotational speed based on the first rotational speed, the second rotational speed, and the temperature. In this way, the rotational speed of the oil pump can be adjusted to change liquid levels of the lubricating oil in a cavity and oil pump power at different rotational speeds of the oil pump.

Abstract: An axle assembly having a differential carrier, a differential assembly, and a lubricant deflector. The differential assembly is mounted to the differential carrier and is rotatable about a differential axis. The lubricant deflector is mounted to the differential carrier and directs lubricant that is splashed or sprayed by a ring gear of the differential assembly into a lubricant passage of the differential carrier.

Abstract: A planetary transmission system is disclosed. In an example, the system may include a planet gear, an outer bearing, and a planetary gear pin including an inner bore fluidly coupled to an outer bore, wherein the outer bore is narrower in diameter than the inner bore and a difference in diameter therebetween allows oil flow by gravity from the inner bore to the outer bore and reduces oil from flow from the inner bore to the outer bore, wherein oil exits the inner bore via a plurality of holes fluidly coupling the inner bore to the outer bearing without valves.

Abstract: Proposed is a transmission of a working vehicle. The transmission of a working vehicle includes an ultra-low speed gearbox having an ultra-low speed shift rod which moves axially and an ultra-low speed shift fork coupled to the ultra-low speed shift rod, a sub-gearbox which operates by receiving power shifted from the ultra-low speed gearbox and has two sub-shift rods and two sub-shift forks, and a stopper which is disposed between the ultra-low speed gearbox and the sub-gearbox and limits an ultra-low speed shift stage engagement of the ultra-low speed gearbox when the sub-gearbox is engaged in a specific stage (a sub-shift highest stage), thereby preventing damage or breakage to parts of an associated transmission due to the rapid rotation of the sub-gearbox during an ultra-low speed and high load operation.

Abstract: A packing assembly providing a seal point configurable at multiple locations. The packing assembly includes a soft bed having at least one energizing ring and at least one seal ring. The assembly includes a spacer ring sealable with the at least one energizing ring. The assembly further includes at 1=least one adapter ring abutting either end of the soft bed to provide two seal locations relative to the spacer ring.

Abstract: A sliding component includes a pair of sliding members being slidable relative to each other on sliding surfaces of the sliding members. One of the sliding surfaces includes a dimple group in which dimples are arranged in a radial direction and a circumferential direction, each of the dimples having an opening portion whose shape has a long axis and a short axis orthogonal to the long axis. A dimple angle formed by a radial axis passing through an intersection of the long axis and the short axis of the dimple and a rotational center of the sliding surface and the long axis changes in at least one of the radial direction and the circumferential direction of the one of the sliding surfaces.

Abstract: An annular sealing device in a recess in a housing has a movable annular piston; and an annular inner periphery sealing lip adhered to part of a first edge along an inner periphery of the piston and that slides while in contact with the recess. The first edge has a first inner periphery edge with a first thickness; a second inner periphery edge adjoining the first inner periphery edge and with a thinner second thickness; and a third inner periphery edge adjoining the second inner periphery edge and with a thinner yet third thickness. The first, second, and third inner periphery edges are in this order from the outer periphery of the piston. The inner periphery sealing lip is adhered to the third inner periphery edge and part of the second inner periphery edge to cover a step formed by thickness differences between the second and third inner periphery edges.

Abstract: A piston ring includes a plurality of first ring pieces placed inside the ring groove in a stacking manner such that the first ring pieces adhere to each other in the axis direction. The first ring pieces include respective piston ring gap portions each having end surfaces separated from each other in the circumferential direction of the first ring pieces such that the end surfaces face each other via a ring gap having a predetermined dimension. The respective piston ring gap portions of the first ring pieces are displaced from each other in the circumferential direction. A closing member is provided to close the piston ring gap portions of the first ring pieces in the radial direction of the first ring pieces.