Abstract: A spline connection having a hub with a toothing profile on the inner circumference, an axle journal having a toothing profile on an outer circumferential portion, a shoulder for axial support and/or abutment against the hub, and a tensioning device for axially bracing the axle journal with the hub. The hub has a constant toothing profile and the axle journal has a first portion and a second portion with different toothing profiles. The first portion is arranged on the insertion side to be further away from the shoulder than the second portion and has a constant toothing profile with play with respect to the toothing profile of the hub. The second portion is arranged on the shoulder side and has a toothing profile which has reduced tooth spaces compared with the first portion and which is play-free with respect to the toothing profile of the hub.

Abstract: A shaft and hub connection assembly including a shaft and a hub each extending along and rotatable about an axis. One of the shaft and the hub defines a male connection portion, and the other of the shaft and the hub defines a female connection portion. The female connection portion has a radially inner surface comprised of a plurality of inside faces. The male connection portion has a radially outer surface comprised of a plurality of outside faces that nest within the inside faces. A plurality of outside transition regions are located between the outside faces in a circumferential direction and are blended at an outside radius. A plurality of inside transition regions are located between the inside faces of the female connection portion in the circumferential direction and are blended at an inside radius. A gap is provided between the outside and inside transition regions.

Abstract: A shaft coupling for connecting an upper shaft with a lower shaft within a pumping system is designed to handle a large tensile load between the upper and lower shafts. In some embodiments, the upper shaft includes a shaft ring groove and the coupling has a body and a first receiving chamber within the body that receives an end of the upper shaft. The coupling also includes an upper internal groove extending into the body from the first receiving chamber and an upper split ring that is configured to be compressed into a position occupying both the upper internal groove and the shaft ring groove of the upper shaft. Set screws compress the upper split ring into the shaft ring groove of the upper shaft. In another embodiment, the coupling includes a plurality of locking screws that extend through the body into corresponding lock screw grooves in the upper and lower shafts.

Abstract: A shaft-hub connection includes an alignment gearing with a plurality of dogs. The dogs comprise a contouring cross-section, which runs, at least partially, along a prolonged trochoid.

Abstract: A planetary transmission includes at least two planetary stages. A sun shaft of a planetary stage of the at least two planetary stages is connected for transmission of torque via a coupling toothing system to a planetary carrier of a second transmission stage of the at least two planetary stages that follows the first transmission stage. The coupling toothing system is a flat notch toothing system. A drive train of a wind power plant, in which a corresponding planetary transmission is used as transmission, is also provided. A wind power plant that is equipped with a corresponding drive train is provided. An industrial application that has a corresponding planetary transmission as transmission is also provided.

Abstract: A composite bicycle crank with an integral spindle attachment structure provides a unique method for attaching a bicycle crank arm to a bicycle crank spindle, and also for attaching a bicycle crank arm to a crank arm insert. A light-weight crank arm is able to be manufactured separately from the crank spindle or insert, and then securely attached after both pieces have been made. This allows for the pieces of the crank assembly to be manufactured from one or more different materials, and securely connected after manufacturing, to create a lower weight assembly than would be possible otherwise.

Abstract: Embodiments, systems, and methods for error detection in crankshaft tooth encoding for a crank pulse wheel of a vehicle are provided. In some embodiments, a system for crankshaft tooth encoding includes a read module, a buffer module, an error module, and a position module. The read module identifies a tooth type for N number of teeth in a sliding buffer based on at least one tooth characteristic. The buffer module calculates a buffer value for the sliding buffer corresponding to a tooth represented in the sliding buffer. The error module detects an error associated with a tooth of the crank pulse wheel and calculates a revised buffer value based on the error. The position module determines an angular position of the crank pulse wheel based on the revised buffer value. The position module broadcasts the angular position to one or more vehicle systems of the vehicle.

Abstract: The shaft coupling structure includes: a male joint, and a female shaft that is coupled to male joint. The outer peripheral surface of the male joint has an outer peripheral side concave-convex portion having a concave-convex shape in the circumferential direction and an annular concave groove, and the inner peripheral surface of the female shaft has an inner peripheral side concave-convex portion having a concave-convex shape in the circumferential direction. The outer peripheral side concave-convex portion and the inner peripheral side concave-convex portion engage with a concave-convex engagement. The outer peripheral surface of the male joint and an end portion on one side of the female shaft in the axial direction are welded and fixed together, and an embossed portion provided on the inner peripheral surface of the female shaft is arranged on the inner side of the annular concave groove.

Abstract: The invention relates to a machine tool, in particular a hand held machine tool, which has a tool receiving device that is movable, in particular in an oscillating manner, around an output shaft. The tool receiving device is designed to hold a tool device on the machine tool in such a manner that the output shaft and a tool rotation axis substantially coincide. The tool receiving device has at least one torque transmission region and a holding device. In order to transmit a driving force to the tool device, the torque transmission region has at least two output area regions that are arranged at a distance from said output shaft and each have a multiplicity of surface points. Here, the tangent planes to said surface points are inclined in regard to an axial plane which includes said output shaft. Furthermore, the tangent planes are inclined in regard to a radial plane which extends perpendicularly to the output shaft.

Abstract: A planetary gearbox system with a ring gear, a sun gear, a carrier and planetary gears as parts in a geared aircraft turbofan engine, with one static part of the parts being in rest under nominal operation and with a kinematic switch device for decoupling the static part to become a rotatable part or with a kinematic switch device for coupling the rotatable part to become a static part. The invention also relates to a method for operating a planetary gearbox system.

Abstract: A drive shaft (7) as a rotating body includes an engaging portion (7c) engaging with a side gear (14) and a sliding portion (7b) abutted by a differential case (9). The engaging portion (7c) includes a plurality of engaging grooves (15). The engaging grooves (15) engage with the side gear (14). The engaging portion (7c) includes a small diameter portion (15d) at a position corresponding to between the drive shaft (7) and the differential case (9) in a direction of a rotational axis L1. The small diameter portion (15d) has an outer diameter smaller than the outer diameter of the sliding portion (7b).

Abstract: A modular tooling receiver that includes a wall having a port that extends through it, an engaging member that is movably disposed in the port, and a lock actuator that is disposed on a first side of the wall. The lock actuator is moveable between a first position in which the lock actuator urges the engaging member in a first direction defined from the first side of the wall to a second side of the wall and a second position wherein the lock actuator permits the engaging member to move in a second direction defined from the second side of the wall to the first side of the wall. A first biasing element biases the lock actuator toward the first position. A damper controls a rate of motion of the lock actuator from the second position toward the first position.

Abstract: An axle coupler comprises driver teeth to engage teeth of a corresponding driver; a central aperture having a central axis and a circumference; and the central aperture including axle teeth circumferentially surrounding the central axis; each axle tooth having a first dimensional direction parallel to the central axis; each axle tooth having a second dimensional direction orthogonal to the first dimensional direction; a recess formed in each axle tooth to form a first axle tooth portion and a second axle tooth portion.

Abstract: A gas turbine engine, in particular an aircraft engine with a geared turbofan arrangement, with a planetary gearbox being connected through a shaft system with a propulsive fan. The shaft system includes a helical spline coupling coupling two parts of the shaft system, wherein the helical spline coupling is connecting a fan shaft and the planetary gearbox with a axially flexible but torsional stiff flexible element.

Abstract: A power transmission shaft including a male spline formed in an outer periphery thereof, and a diameter increasing portion formed on a part of a tooth bottom of the male spline, which is located on an opposite side to an axial end of the power transmission shaft. The tooth bottom of the male spline has a substantially constant circumferential width extending up to an axial region of the diameter increasing portion. The diameter increasing portion includes a chamfered portion formed in the axial region of the diameter increasing portion, the chamfered portion connecting the tooth bottom and a tooth flank of the male spline to each other to reduce a tooth groove width.

Abstract: A rotational coupling arrangement, such as for use with a vehicle, is provided. The coupling arrangement includes a first rotational component have at least one straight groove, the groove having a sidewall. A second rotational component is coupled to the first rotational component, the second rotational component having at least one projection. The at least one projection having a linear profile between a first end and a second end, the at least one projection having a first section adjacent the first end and a second section adjacent the second end. The first section is sized to define a first gap between the first section and the sidewall, the second section being sized to define a second gap between the second section and the sidewall. The second gap is smaller than the first gap.

Abstract: Herein disclosed is a centrifugally cast pole having a substantially uniform wall thickness along the long axis of the pole. During centrifugal casting, molten metal is poured inside a rotating, tapered mold. As chilled liquid is poured over the outside of the rotating mold, the metal forms, or paints, to the contour of the mold interior creating a metal pole. By precisely controlling casting gyrations such as the spin, travel, pitch, and yaw of the rotating mold and the calibration and physical mechanisms of the casting machine, hollow, tapered, tubular metal poles are produced with previously unknown uniformity of wall thickness. The controlling principles, designs, and mechanisms of this centrifugal casting method enable wall uniformity to extremely high tolerances. By extension, the ability to precisely control the metal volume painted inside the mold allows, as a design choice, wall thickness variation in any embodiment if so desired.

Abstract: A power transmission apparatus includes a first/second/third rotary shaft, and a positioning member. The first rotary shaft is connected to an output shaft of a drive source. The second rotary shaft is spline-fitted to a rotary shaft of an electric motor. The third rotary shaft is connected to the first rotary shaft and the second rotary shaft. The positioning member is configured to apply an elastic force in a rotational direction to the rotary shaft and the second rotary shaft in a portion where the rotary shaft and the second rotary shaft overlap each other; set each of a position in the rotational direction of a spline of the rotary shaft of the electric motor and a spline of the second rotary shaft to a specified position, and applies the elastic force in the rotational direction to the rotary shaft and the second rotary shaft.

Abstract: A propeller assembly includes a central hub including a first forward-facing end, a second aft-facing end, a hub body extending therebetween, and a plurality of channels spaced circumferentially around the central hub. The propeller assembly further includes blade wedges configured to be inserted into and to retain blades within the channels of the central hub. Each blade includes a blade dovetail including a dovetail face configured to engage a respective channel sidewall and/or a respective wedge sidewall. The dovetail face includes a bearing portion that engages the respective channel sidewall and/or the respective wedge sidewall and a clearance portion that is spaced from the respective channel sidewall and/or the respective wedge sidewall by a clearance gap during a first loading of the propeller assembly and that engages the respective channel sidewall or wedge sidewall during a second loading, the second loading greater than the first loading.

Abstract: A connection for a rotating machine according to an exemplary aspect of the present disclosure includes an interface axially between and adjacent to a first interference fit and a second interference fit.

Abstract: A gas turbine rotor for a gas turbine is provided. The gas turbine rotor includes a compressor rotor shaft, a turbine rotor shaft and a coupling device frictionally connecting the two rotor shafts, wherein the coupling device is designed in such a way that the friction connection also exists when the two rotor shafts are displaced relative to one another. In this case, the turbine rotor shaft is lengthened at the end facing the compressor rotor shaft in such a way that the turbine rotor shaft overlaps with the compressor rotor shaft in the axial direction and the coupling device connects this lengthened end of the turbine shaft to the compressor rotor shaft in the radial direction.

Abstract: A chip or debris trap or collector retains chips, fragments and other debris generated when a serrated or splined, press fit connection is assembled between a shaft and another component such as a housing, gear, pulley or bearing. The chip collector includes a circumferential channel or groove disposed about the shaft adjacent the ring of serrations or male splines and an adjacent circumferential flange. An optional second channel or groove resides in the other component. As the shaft and the component are assembled, chips, fragments or other debris generated by the interference fit and axial sliding assembly of the components are collected in the channel or channels and retained there as the shaft fully seats within the other component.

Abstract: A device for coupling two shafts by a gear mechanism includes a coupling part ending one of the two shafts. The coupling part is fitted concentrically into a complementary coupling part ending the other shaft. Splines of the coupling part have a constant profile along a median zone of the coupling part and which, in a first zone in continuation of the median zone, has a smaller thickness, between flanks of a spline, than a maximum thickness of the same spline in the median zone. Splines of the coupling part continue, beyond the first zone, as far as a centering zone on the same side as the first zone. The splines and the spline bottoms have, in the coupling zone between the centering zone and the first zone, a profile that continuously couples the splines and the spline bottoms to the surface of the centering zone.

Abstract: A rotation transmitting apparatus includes a first shaft on which multiple external teeth are formed so as to be arranged in a circumferential direction, and a second shaft in which multiple internal teeth are formed so as to be arranged in the circumferential direction, the second shaft being fitted to the first shaft so as to be slidable relative to the first shaft in the axial direction and so as to be engageable with the first shaft in a rotational direction through the use of the external teeth and the internal teeth. A protrusion is formed on the tooth flank of one of the external tooth and the internal tooth, the protrusion being projected toward the corresponding tooth flank of the other of the external tooth and the internal tooth. The protrusion is made of a resin that is more elastically deformable than the tooth flank.

Abstract: A wheel supporting device includes: a hub unit that has a rotary ring having a first spline on its axially inner end face; and a joint that has an outer ring having a second spline, meshing with the first spline, on its axially outer end face. At least one projection included in a plurality of projections of the first spline projects in the axial direction by a larger amount than the remaining projections of the first spline. When a crest of the at least one projection contacts a crest of one of projections of the second spline, a play is caused between the rotary ring and the outer ring due to the at least one projection that works as a fulcrum.

Abstract: A power transmission device is used to distribute torque from a power source to an external device and an auxiliary device. The power transmission device is comprised of a first bearing and a second bearing both secured to a stationary member, a first sprocket rotatably supported by the first bearing, a second sprocket capable of being drivingly coupled with the auxiliary device, a chain coupling the first sprocket with the second sprocket, a rotary shaft rotatably supported by the second bearing, which is drivingly coupled with the power source and drivingly engageable with the external device to transmit a first part of the torque to the external device, and a joint drivingly linking the rotary shaft with the first sprocket to transmit a second part of the torque to the first sprocket.

Abstract: A rotational assembly comprises a first shaft having a plurality of circumferentially arranged axially extending outer splines on an outer surface thereof and a second shaft having a plurality of circumferentially arranged axially extending inner splines on an inner surface of an axially extending shaft recess. The first shaft is located with the shaft recess such that the outer splines are engaged with the inner splines. At least one biasing element is also provided which is arranged to rotationally bias the first and second shafts towards one another such that the driving faces of the inner and outer splines are forced together.

Abstract: An interface element between a first tool element and a second tool element includes a projection on one of the first and second tool elements and a cavity that receives the projection on the other of the first and second tool element. The cavity includes inner contours which are designed to receive polygonal and/or stellate projections.

Abstract: A part engaging structure having sufficient intensity while reducing the use amount of material, and having high positioning accuracy is provided. An engaging structure allows a protruding portion formed at a first part to be received by a receiving portion formed at a second part and engages the first part with the second part. The protruding portion is formed of a structure body having a plurality of ribs combined in a polygonal shape lacking part of sides, and at least two of corner portions of the polygon of the structure body contact an inner surface of the receiving portion.

Abstract: A shaft assembly comprising a first shaft and a second shaft. The first shaft has a plurality of first splines that each have an end portion and a chamfer disposed on the end portion. The second shaft is coaxial with the first shaft and has a plurality of second splines. The plurality of second splines each have a base portion and an end portion. The end portion defines an inverted chamfer having a base and a tip. The tip projects from the base radially away from the second shaft and axially away from the base portion of the plurality of second splines. The base of the inverted chamfer undercuts the tip of the inverted chamfer. The plurality of first splines engage with the plurality of second splines to couple the first shaft and the second shaft for common rotation.

Abstract: A connector system facilitates the connection of a first tree trunk to a second tree trunk of an artificial tree system, and further protects one or more ends of a trunk when, for example, the artificial tree system is being shipped or stored. The connector system comprises a sleeve. The sleeve comprises a cylindrical shaped body. The outer of the body has a uniform cylindrical shape. The interior of the sleeve has different diameters at its top and bottom. The interior includes a notch or shoulder. The shoulder is in proximity to the top end of the sleeve. The sleeve further comprises a cutout for assisting with connecting and securing the trunks together.

Abstract: Apparatus is provided comprising first and second coaxial shafts, the first and second shafts extending along, and being rotatable about, a central axis. The first and second shafts are coupled together by a splined major coupling at a coupling region of the apparatus, which major coupling enables the shafts to co-rotate about the central axis. A torque element is connected to the first and second shafts, the torque element being operable to force the first and second shafts to relatively rotate about the central axis in order to apply a preload to the major coupling. The apparatus may be comprised in a gas turbine engine, whereupon the first shaft may be a fan shaft and the second shaft may be a LP turbine shaft.

Abstract: A coupling shaft assembly includes a coupling shaft with a first radial shoulder and a second radial shoulder, the first radial shoulder and the second radial shoulder each include at least one slot to provide a lubricant flow path.

Abstract: The invention relates to a toothing, in particular of a drive spindle for driving a roll in rolling mills or continuous casting plants, which comprises several teeth and meshes with a second toothing in the manner of a spline, wherein a flank line of the teeth has a curvature and a deflection angle is formed between the rotational axis of the second toothing and the rotational axis of the toothing, wherein the toothing (1) is designed as having at least one of the following modifications: a tooth root relief of the teeth (2), and/or a tooth tip relief of the teeth (2), and/or a twist of the teeth (2).

Abstract: A mechanical connection includes first and second components supported for rotation, the first component formed with first spline teeth, the second component formed with second spline teeth meshing with the first spline teeth, and a damper fitted in a groove formed in one of the first and second components, including an extension secured to the damper, contacting and extending between at least some of the first and second spline teeth.

Abstract: A flanged coupling member is provided with a shaft portion to which a drive force is input, and a flange portion formed in one end of the shaft portion. The flanged coupling member is coupled to a front housing member with a bolt in which a shaft portion thereof is coaxially arranged in a front housing member and a flange portion contacts an outer surface in an axial direction of a bottom portion of the front housing member. The flange portion is provided with a tubular engagement portion that extends in an axial direction from an outer peripheral edge thereof. The engagement portion is arranged on an outer circumference of the front housing member on the basis of the fastening, and the engagement portion and the front housing member are engaged via a spline. The flanged coupling member is fastened to the front housing member at the shaft portion.

Abstract: A system for efficient torque transmission, consisting of at least one driving member and at least one driven member, which uses a complementing spline profile having almost nil stress concentration which enhances the overall torque transmission capacity of a shaft with a given diameter.

Abstract: A positioning arrangement is disclosed for positioning a rotor 12 relative to a shaft 14, the positioning arrangement comprising a collar 16 provided with a formation 18 cooperable with a corresponding formation 20 provided upon the shaft 14 to resist relative angular movement between the collar 16 and the shaft 14, the collar 16 being provided with an external, generally axially extending rib 22 cooperable with a part 24a of the rotor 12 to deform the said part 24 of the rotor 12 to resist relative rotation between the collar 16 and the rotor 12.

Abstract: A spline structure, in the form of an aeronautical brake drive bar, has wheel attachment points at its ends for engaging a wheel rim. Each wheel carries a regularly spaced series of these drive bars for engaging friction discs carried by the wheel hub. The main body of each brake drive bar is formed from titanium internally reinforced by composite blocks each comprising a bundle of silicon carbide fibers contained in a matrix that is diffusion bonded within the main body. Other spline structures can be formed in a similar manner.

Abstract: A shaft coupling assembly includes a hub bounding an opening. The interior surface of the hub includes an annular coupling surface and a receiving surface, the receiving surface sloping away from opening. An alignment rib projects from the receiving surface into the opening. An elongated shaft includes a driver that is configured to be received within the opening of the hub. The driver has an exterior surface that includes an annular engaging surface, a guide surface, and a guide rib radially, outwardly projecting from the guide surface. The guide rib is configured such that when the driver is being inserted within the opening with the guide rib being aligned with the alignment rib, the guide rib contacts the alignment rib so that the guide rib must be offset from the alignment rib before the driver can be fully received within the opening.

Abstract: A constant velocity universal joint having a recess-projection engagement configuration in which backlash at a shaft connecting region does not easily occur, and an inner joint component and a shaft can he firmly connected. hi the constant velocity universal joint, the inner joint component and the shaft (5) fitted into an axis hole (22) of the inner joint component are connected by die recess-projection engagement configuration. Engagement contacting regions (38) of projections (35) and recesses (36) corresponding thereto are in close contact over the whole region.

Abstract: A hydraulic detachable coupling, which can transmit rated torque in a manner stable to vibrations, and can fully withstand abnormal torque. For this purpose, in a hydraulic detachable coupling (4) mounted detachably on a rotor (1) of a steam or gas turbine or other machine, a coupling sleeve (4b), which is fitted on a shaft end portion of a casing penetrating shaft (2) in the rotor (1), includes a taper hole portion (4b-a) which is interference-fitted on a taper shaft portion (2a) of the shaft end portion by a hydraulic pressure, and a straight hole portion (4b-b) having teeth (13) engaging a plurality of teeth (12) formed in a straight shaft portion (2b) of the shaft end portion, the taper hole portion (4b-a) and the straight hole portion (4b-b) being located adjacent to each other.

Abstract: A wheel support apparatus including a hub wheel which includes a hub shaft and is to mount a wheel thereon, a first side surface spline being formed on an end surface of the hub shaft, and a constant velocity joint which includes an outer ring connected to the hub shaft in a torque-transmitting manner, a second side surface spline meshed with the first side surface spline being formed on an end surface of a side wall portion of the outer ring abutting against the end surface of the hub shaft. Each of the first and second side surface splines includes a number of spline teeth and bottom lands defined between the spline teeth. The tooth tops of the spline teeth of one of the two side splines and the bottom lands of the other side spline are formed into a tapering surface inclined relative to a plane perpendicular to a center axis of the hub shaft. The tapering tooth tops contact the corresponding tapering bottom lands so that the hub shaft and the outer ring can be aligned with each other.

Abstract: A tubular connector system for joining two pipe ends without the necessity of rotating the pipe ends. A coupling has opposing tapered ends. Each of the tapered ends slopes inwardly from an inner extent to an outer extent to form a respective mouth opening of the body. Each tapered end of the coupling has a contoured surface which is made up of a series of alternating helical spline wedges. The wedges are oppositely tapered from an inner extent to an outer extent, whereby the helical spline wedges form an alternating series of lands and grooves on the body as viewed from the respective mouth openings. The two opposing pipe ends have mating engagement surfaces which engage and mate with the contoured surfaces of the coupling as one pipe end is pushed toward the other during assembly.

Abstract: A locking artificial tree trunk including a first generally cylindrical, hollow trunk portion including an upper end, the upper end defining a notch, and a second generally cylindrical trunk portion including a body portion, a lower end having an insertable portion, and an upper end. The locking artificial tree trunk also includes a coupling mechanism having a body portion and an upper portion having a tab, and defining a channel for receiving the insertable portion of the lower end of the second trunk portion. The body portion is inserted substantially into the upper end of the first trunk portion with the tab of the upper portion aligned with the notch, thereby preventing rotation of the coupling mechanism within the upper end of the first trunk portion.

Abstract: A trochoid pump, comprising a driving shaft, wherein a drive gear comprising of a bevel gear is fixed on one end thereof and an inner rotor is penetrated onto the other end thereof, an outer rotor, the center of which is decentered to the inner rotor, wherein both rotors are covered with the cap and the casing, a first regulatory structure, wherein the driving shaft or a means of control fixed on the driving shaft regulates an one-way movement to the casing, a second regulatory structure, wherein an end face on the other side of the driving shaft is engaged with one end of the cap and regulates the other way movement of the cap, wherein the thrust of the driving shaft is axially regulated by the first regulatory structure and by the second regulatory structure.

Abstract: A standoff arrangement for ladders and the like, comprising a ladder attachment portion and a ladder support portion. The attachment portion is releasably securable to ladder, and the support portion extends from the ladder attachment portion, having a pair of individually adjustable bearing arms which can be universally adjusted in relation to the structure against which the ladder standoff arrangement bears.

Abstract: A multi-lobed gear system is provided in which the lobes of an input gear and a corresponding, mating pair of lobes in an output gear are uniformly in contact. The lobed gear tooth profile of the present invention reduces material galling, shuttering and whipping within a drivetrain assembly in comparison to square or helical splines that incorporate single point contacts between meshed pairs. An internal pinion gear or slip yoke internal shaft employs a lobed gear tooth profile that forms a sinusoidal outer perimeter shape. The perimeter surface is in constant contact with the complementary shaft or gear across its entire surface. A small clearance gap may be provided for lubrication, fitment and manufacturing considerations.

Abstract: A motor direct driven compressor system includes a motor, a coupling and a compressor, and the coupling is coupled between the motor and the compressor, and a second assembling portion, a coupling portion and a metal plate of the coupling are used for connecting a driving shaft of the motor and a transmission shaft of the compressor. With this design, the driving force of the motor can be transmitted to the compressor and provided for the operation of the compressor. In addition, errors produced by the rotation and transmission during the transmission process can be minimized, so that the compressor can be operated accurately and normally.

Abstract: A power transmission shaft mitigates the concentration of both tensile stress and shear stress to achieve an improvement in terms of fatigue strength. A male spline section is formed on an outer periphery of the power transmission shaft. On a valley section of the male spline section, at an axially opposite end side portion thereof, there is provided a diameter-expanded section whose outer diameter dimension is gradually increased toward an axially opposite end. Rounded sections having a circular arc cross-section are provided on both circumferential sides of the diameter-expanded section. A radius of curvature of the rounded sections is gradually increased toward the axially opposite end.