Speed-increasing spindle device

A speed-increasing spindle device comprising:

• a device main body incorporating a planet speed increasing mechanism;
• a shank detachably mounted on a main shaft of a machine tool;
• and
• a coupling bolt means for assembling and coupling the device main body and the shank separably in the axial direction;
• wherein
• the coupling bolt means comprises a coupling bolt, a bolt head engaging part provided at one side of the device main body, with the head of the coupling bolt engaged in the axial direction, and a screw hole provided at the other side of the device main body, in which the coupling bolt is screwed and engaged, and the bolt head engaging part possesses a bolt head accommodating space larger than the maximum hole diameter permitted in the shank in terms of strength, and the coupling bolt has an engaging part for a rotary operation tool at its outer end in the axial direction, whereby access to said engaging part is provided through an insertion hole in the shank;
• and wherein
• the coupling bolt has its head rotatably engaged with the bolt head engaging part provided in the front end portion of the shank, and its threaded portion is screwed into the screw hole provided along the axial center of the device main body;
• the engaging part for the rotary operation tool is provided in the head end surface of the coupling bolt;
• the bolt head engaging part comprises a bolt head accommodating space opening to the front end side of the shank having a diameter larger than the insertion hole of the shank;
• and
• a coupling support part for engaging and supporting the head of the coupling bolt in the axial direction, said coupling support part being provided in the accommodating space;
• wherein
• the bolt head accommodating space of the shank is a cylindrical space larger in diameter than the insertion hole of the shank;
• the coupling support part has an annular detent member fitted in the cylindrical space, and the shape and dimensions of the detent member are defined so as to bear the tightening force by the coupling bolt, as being engaged with the head of the coupling bolt in the axial direction, and work as a locking piece of the coupling bolt, and the detent member of the coupling support part is in the form of a stopper ring deforming elastically in the radial direction, and the stopper ring is elastically fitted in an annular fitting groove provided in the cylindrical space.

A speed-increasing spindle device comprising:

• a device main body incorporating a planet speed increasing mechanism;
• a shank detachably mounted on a main shaft of a machine tool;
• and
• a coupling bolt means for assembling and coupling the device main body and the shank separably in the axial direction;
• wherein
• the coupling bolt means comprises a coupling bolt, a bolt head engaging part provided at one side of the device main body, with the head of the coupling bolt engaged in the axial direction, and a screw hole provided at the other side of the device main body, in which the coupling bolt is screwed and engaged, and the bolt head engaging part possesses a bolt head accommodating space larger than the maximum hole diameter permitted in the shank in terms of strength, and the coupling bolt has an engaging part for a rotary operation tool at its outer end in the axial direction, whereby access to said engaging part is provided through an insertion hole in the shank;
• and wherein
• the coupling bolt has its head rotatably engaged with the bolt head engaging part provided in the front end portion of the shank, and its threaded portion is screwed into the screw hole provided along the axial center of the device main body;
• the engaging part for the rotary operation tool is provided in the head end surface of the coupling bolt;
• the bolt head engaging part comprises a bolt head accommodating space opening to the front end side of the shank having a diameter larger than the insertion hole of the shank;
• and
• a coupling support part for engaging and supporting the head of the coupling bolt in the axial direction, said coupling support part being provided in the accommodating space;
• wherein
• the bolt head accommodating space of the shank is a cylindrical space larger in diameter than the insertion hole of the shank;
• the coupling support part has an annular detent member fitted in the cylindrical space, and the shape and dimensions of the detent member are defined so as to bear the tightening force by the coupling bolt, as being engaged with the head of the coupling bolt in the axial direction, and work as a locking piece of the coupling bolt, and the detent member of the coupling support part is in the form of a ring member of split structure divided uniformly in a peripheral direction, and this ring member is fitted and fixed in an annular fitting groove provided in the cylindrical space.