Hitachi, Ltd.

Chikakazu Ninomiya

Kuninori Imai

Takeji Shiokawa

Mitsuo Miyamoto

Mitsuya Mikawa

Hideaki Sasaki

A fastener structure for fastening a first member and a second member using a taper implant having a threaded hole therein. The taper implant has a frusto-conical outer surface, a projecting portion connected to a larger diameter end and a threaded hole passing therethrough. The first member has a wall portion with a tapered hole extending therethrough and a counterbored portion adjacent a larger diameter end to receive the projection portion of the taper implant. The taper implant is inserted into the hole of the first member and held therein by frictional contact. The second member has a wall portion with a hole therethrough. The second member is positioned in contact with the first member and the two members are fastened together by inserting a male screw through the hole of the second member and threading the male screw into engagement with the threaded hole of the taper implant.

Fastening structure using a taper implant

A method of fastening a first member and a second member using a taper implant having a threaded hole therein includes providing a taper implant having a frusto-conical outer surface, a projecting portion connected to a larger diameter end and a threaded hole passing therethrough and providing a first member having a wall portion with a tapered hole extending therethrough and having a counterbored portion adjacent a larger diameter end to receive the projection portion of the taper implant. The taper implant is inserted into the hole of the first member and held therein by frictional contact. A second member is provided having a wall portion with a hole therethrough. The second member is positioned in contact with the first member and the two members are fastened together by inserting a male screw through the hole of the second member and threading the male screw into engagement with the threaded hole of the taper implant.

Taper implant and a screw-fastening structure using a taper implant with female threads

A method of fixing a taper implant to a receiving member includes providing a taper implant having a frusto-conical outer surface, a projecting portion connected to a larger diameter end and a smaller diameter end. A receiving member is provided which has a wall portion with a passing-through hole therein with at least a portion of the passing-through hole being tapered to form a frusto-conical shape whereby the taper portion has a larger diameter end and a smaller diameter end and the passing through hole has a cylindrical counterbored portion adjacent to the larger diameter end in which the projecting portion of the taper implant is received. A taper rate of the taper portion of the passing through hole is the same as a taper rate of the taper portion of the taper implant. The larger diameter end of the taper portion of the passing through hole has a diameter which is smaller than a diameter of the larger end of the taper portion of the taper implant whereby there is a tight-fit allowance when the taper implant is inserted into the passing through hole. The taper implant is fixed in the passing through hole of the receiving member by the outer surface of the taper portion of the taper implant being in contact with a surface of the taper portion of the passing through hole by applying a force to the taper implant whereby a friction force is generated between the taper portion of the taper implant and the wall portion.

Method for fixing a taper implant to a receiving member

A taper implant includes a taper portion having an outer surface frust-conical in shape. A flange portion is formed at an outermost end of the taper portion on the larger-diameter side to project outwardly with respect to the taper portion and having a flat surface situated perpendicularly to the axial direction of the taper portion, and female threads serving as a fit portion extending in the axial direction of the taper portion. A hole taper portion and a hole step portion are drilled at the same time to bore a hole in one of the members to be fastened, and the taper implant is driven into the hole, thereby providing a screw fastening structure for the fastened members.

A balance adjustment method of an end mill for increasing the accuracy of the machined surface and also for lengthening the tool lifetime, in which mass unbalance between an end gash part of a primary cutting edge and an end gash part of a secondary cutting edge of the end mill having asymmetric cutting parts is balanced by decreasing an end gash angle, an end gash part, a clearance angle or a corner of tooth face of the secondary cutting edge.

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Hadano, Japan

Chikakazu Ninomiya