A heat treatment method is provided in which a first steel component (11) formed with a coating (111) thereon is fitted in first holes (123, 124) of a second steel component (12) subjected to a quenching treatment. The heat treatment method includes a heating step of heating the second steel component to a first temperature (T.sub.1) equal to or higher than a tempering temperature (T.sub.0) of the second steel component and higher than a temperature of the first steel component by a temperature difference (T) for achieving shrink fitting and a shrink-fitting step of shrink-fitting the first steel component in the first holes of the second steel component in a state of maintaining the temperature difference for achieving shrink fitting between the first steel component and the second steel component.

A method for inserting an insert into a hole in a composite material made from a plurality of carbon fiber layers suspended in a resin material includes lowering a temperature of the insert to a reduced temperature at which a coefficient of thermal expansion of a material of the insert causes the insert to contract to a first perimeter, inserting the insert at the reduced temperature into the hole, and permitting the temperature of the insert to increase from the reduced temperature to an operational temperature. At the operational temperature, the insert expands to a second perimeter so that the insert is retained within the composite material due to an interference between the insert and the composite material. The interference transfers a structural load from the insert to the composite material and results in damage to the composite material if the insert is dislodged at the operational temperature.

A transmission comprising a shaft (6) made as a single piece or as at least two shaft sections (6A, 6B) on a common axis, a drive toothed wheel (5) mounted to rotate freely on said shaft (6), and an automatically clutching clutch mechanism (8) arranged between the drive wheel (5) and the shaft (6) or each of the shaft sections (6A, 6B), the or each clutch mechanism (8) comprising: a clutch plate (81) mounted to rotate freely on the associated shaft (6) or shaft section (6A, 6B); a part (82) that is carried by and constrained to rotate with the associated shaft (6) or shaft section (6A, 6B); and a brake of said clutch plate that acts continuously on the angular speed of said plate (81). The brake (83) of the at least one of the clutch plates (81) is threaded on the shaft (6) or the shaft section (6A, 6B) carrying said plate (81).

A high capacity radial-fit coupling bolt (or expanding sleeve bolt) has a pair of tapered sleeves about a shank of a bolt to which can be applied a tensioning load. An extrudable ring, or a compression ring, is interposed between a head nut or head flange at one end of the shank, and one end of an inner sleeve. A tensioning load is applied to the shank, the inner sleeve causing the outer sleeve to expand diametrically. At a preset load limit, the extrudable ring is extruded through at least one bore in a drive piston between the head nut and the extrudable ring, to allow shank to move relative to the inner sleeve until the tensioning load is fully applied. Alternatively, a drive member is provided between the head nut or head flange and the compression ring, and at a preset limit, the compression ring allows the shank to move relative to inner sleeve until the tensioning load is fully applied. The preset limit will typically correspond to the force required to fully expand the outer sleeve.

The invention relates to a method for installing metallic fastener (10; 40) for the interference fit assembly of at least two structural elements (20, 22) comprising a through hole, the fastener comprising an enlarged head (12; 42), a shaft (14; 44) having an external diameter before installation that is greater than an internal diameter of the hole, said shaft comprising a conductive surface (26; 56). Before installation, at least the conductive surface (26; 56) is coated with a lubricating layer (30), which comprises a mixture of at least one polyolefin and one polytetrafluoroethylene, for example, having sufficient adherence to prevent its abrasion by manual manipulation of the fastener and being weak enough to be at least partly stripped from the conductive surface during the interference fit assembly of the fastener.

The invention is applicable to the assembly of aircraft structures.

A crimp portion provided to a damping force adjustable shock absorber includes a crimp groove portion provided on an outer peripheral surface of a solenoid case along a circumferential direction thereof, and one end portion of a thin wall portion of a valve case that is contained while being bent in this crimp groove portion. The crimp groove portion includes an inclined surface inclined into a case 40 from a valve case side toward a solenoid case side. Due to this configuration, the damping force adjustable shock absorber can securely fix the solenoid case and the valve case by crimping while reducing a load on a solenoid block and a valve block due to the crimp fixation to a minimum load.

An assembly comprising first and second structural elements having aligned holes, an fastener that occupies at least respective portions of the holes without a surrounding sleeve, and a mating part that is coupled to the fastener. The fastener comprises: a head; a circular cylindrical shank extending from the head; a mating portion comprising external projections; and a transition portion disposed between the shank and the mating portion. The transition portion comprises a first radiused lead-in section that meets the shank at a shank/lead-in intersection and a second radiused lead-in section that meets the first radiused lead-in section. The first radiused lead-in section curves gradually in a first axial direction toward the mating portion and has a first profile that is a circular arc having a first radius, while the second radiused lead-in section curves abruptly in the first axial direction and has a second profile that is a circular arc having a second radius which is much smaller than the first radius.

According to one embodiment, a crank portion is formed from a crank piece, an element separate from a shaft portion. The crank piece includes a fitting hole in which the shaft portion is fit by predetermined interference and a slit-like slot with one end opened in an inner circumferential surface of the fitting hole, and an other end closed inside the crank piece. The fitting hole is deformed so as to expand its diameter when expanding a width of the slot. The shaft portion is fit in the fitting hole of the crank piece by the predetermined interference when inserted in the deformed fitting hole and the fitting hole restores an original form while the shaft portion is in the fitting hole.

Provided is a joint component manufacturing method for reducing occurrence of burrs upon bonding between a first member having a hole and a second member having a shaft portion and firmly bonding both members. In the method for manufacturing a joint component 100, a hole-side weak press-fit portion 112 is formed at a hole 111 of a flat plate ring-shaped first member 110. Moreover, each of a shaft-side weak press-fit portion 122 and a shaft-side strong press-fit portion 124 is formed at a shaft portion 121 of a cylindrical second member 120. The hole-side weak press-fit portion 112 and the shaft-side weak press-fit portion 122 are defined by a first weak press-fit interference Lw1 formed thinner than a first strong press-fit interference Ls1. The shaft-side strong press-fit portion 124 is defined by a first strong press-fit interference Ls1 as the minimum necessary press-fit interference for electric resistance welding upon electric resistance welding between the hole 111 and the shaft portion 121.

Provided is a joint component manufacturing method for reducing occurrence of burrs upon bonding between a first member having a hole and a second member having a shaft portion and firmly bonding both members. In the method for manufacturing a joint component 100, a hole-side weak press-fit portion 112 is formed at a hole 111 of a flat plate ring-shaped first member 110. Moreover, each of a shaft-side weak press-fit portion 122 and a shaft-side strong press-fit portion 124 is formed at a shaft portion 121 of a cylindrical second member 120. The hole-side weak press-fit portion 112 and the shaft-side weak press-fit portion 122 are defined by a first weak press-fit interference Lw1 formed thinner than a first strong press-fit interference Ls1. The shaft-side strong press-fit portion 124 is defined by a first strong press-fit interference Ls1 as the minimum necessary press-fit interference for electric resistance welding upon electric resistance welding between the hole 111 and the shaft portion 121.