Aoyama Seisakusho Co., Ltd.

Masataka Mizuno

Keigo Kato

Keigo Katou

Yoshio Hirooka

The invention provides a fastening method and a fastening tool which can stably fasten a nut to a bolt securely and with a small dispersion at a desired axial force. A fastened member is fastened by inserting a bolt to the fastened member, thereafter temporarily fastening a nut and the bolt, pulling a leading end of a shaft portion of the bolt in an axial direction of the bolt, rotating the nut so as to screw into the bolt while elastically deforming the bolt so as to generate an axial force, and thereafter canceling the pulling of the bolt.

Fastening tool

The invention includes a fastening method and a fastening tool which can stably fasten a nut to a bolt securely and with a small dispersion at a desired axial force. A fastened member is fastened by inserting a bolt through the fastened member, thereafter temporarily positioning a nut and the bolt together, pulling a leading end of a shaft portion of the bolt in an axial direction of the bolt, rotating the nut so as to screw the nut into the bolt while elastically deforming the bolt so as to generate an axial force, and thereafter canceling the pulling of the bolt.

Fastening method and fastening tool

A spool valve is provided which has a plurality of small-diameter portions formed at predetermined spacings on a peripheral surface of a shaft, and pairs of annular ridges on peripheral surfaces of the small-diameter portions to have a larger diameter than an inner diameter of collars. The collars are closely fitted between the annular ridges to make valve bodies, and the collars include an inner wall, an outer wall and at least one connection therebetween, and an annular gap is provided between the inner wall and the outer wall.

Method for manufacturing spool valve

Spool valve

A method of manufacturing a shaft having modified surfaces. The method comprises forming thread grooves on surfaces of a cylindrical-shaped base material for a shaft, continuously winding a length of wire in and along the thread grooves, and compressing a peripheral surface of the base material for the shaft with the length of wire wound and received in the thread grooves, in a direction of diameter reduction to perform plastic deformation of crests of thread ridges between the adjacent thread grooves or the crests and the wire to have the length of wire being fixed to and united with the base material for the shaft. The method improves the hardness of surfaces of a base material for a shaft in a relatively simple manner, and transforms properties of surfaces of the base material for a shaft to make the base material for the shaft applicable to other uses.

Method of manufacturing a shaft with surfaces thereof modified

Method of manufacturing a shaft having a fluid flow passage

A process for manufacturing a spool valve whereby a plurality of quenching processed collars are fitted to a shaft material so that the collars are arranged at predetermined positions on the shaft material. The collars have respective substantially central holes through which the shaft material extends. The diameter of portions of the shaft material is contracted in a vicinity of both opposite ends of each of the collars by rolling dies so as to cause plastic flow of a metal constituting the shaft material. Pairs of circular convex portions are then formed on outer circumferential faces of the diameter contracted portions of the shaft material. The circular convex portions each have an outer diameter larger than an inner diameter of the substantially central holes of the collars, and the circular convex portions are formed such that side faces thereof are in close contact with respective associated circular concave portions formed at both ends of the collars in a vicinity of the substantially central holes of the collars, whereby the collars are fixed to the shaft material.

Process for manufacturing a spool valve

A spool valve includes a shaft having plural small diameter portions formed at intervals along the shaft on a circumferential surface of the shaft. The small diameter portions have linear outer surfaces extending substantially parallel to an axis of the shaft. A collar to be mounted to the shaft has a substantially central hole defining an inner diameter of the collar and through which the shaft is passable for mounting the collar to the shaft. The collar has a length shorter than a length of the small diameter portions of the shaft, and a linear inner surface extending substantially parallel to the axis of the shaft and the linear outer surfaces of the small diameter portions. A pair of circular convex portions are integrally formed on outer circumferential faces of a corresponding one of the small diameter portions. The pair of circular convex portions each have an outer diameter larger than the inner diameter of the collar which is to be mounted to the shaft, and are spaced apart from each other by a distance substantially corresponding to the length of the collar. The collar is arranged between the circular convex portions so that side faces of the circular convex portions are in close contact with opposite side surface portions of the collar in a vicinity of the substantially central hole of the collar.

Growing community of inventors

Kasugai, Japan

Masataka Mizuno