A spindle unit for machine tools that includes a working spindle rotationally bearing-mounted in axially spaced spindle bearings in a spindle case, and an electric driving motor. The working spindle includes at its head side a clamping device for a tool and at its rear side a non-rotating ring cylinder for activating said clamping device via a rotating tie rod, and rotational bushing for supplying said tool with cooling and/or lubricating agents through a hydraulic conduit extending longitudinally through said working spindle. At least a segment of the non-rotating ring cylinder may be received in the rear end portion of said working spindle.

A spindle apparatus according to the present disclosure includes a housing, a spindle rotatably installed in the housing, a tool releasably engaged with one end of the spindle and having an insert tip movable in a radial direction of the tool, a first draw-bar movably mounted in the spindle, and a second draw-bar movably mounted in the first draw-bar. The tool and one end of the first draw-bar are releasably engaged with the one end of the spindle by a movement of the first draw-bar, and the insert tip is configured to move in the radial direction by a movement of the second draw-bar.

This invention concerns a clamping device for firmly holding a part to be clamped at a clamping recess in which the clamping device is arranged. The clamping device comprises a collet with a first external protrusion for engagement with an internal recess in an inner peripheral area of the part that is to be clamped and with a second external protrusion for engagement with an internal recess in an inner peripheral area of the clamping recess. At least one of the first external protrusion or the second external protrusion comprises a first external taper or a second external taper for pulling the part to be clamped axially into the clamping recess by a radial outward movement of the collet or a section of the collet and an operation stud including an external tapered section for effecting the radial outward movement of the collet. The connection between the operation stud and the collet is self-locked and pre-loaded after a clamping movement of the operation stud in axial direction that locks and pre-loads the external taper of the operation stud and the collet or a part between the collet and the operation stud with each other. The invention includes a method for a part to be clamped in a clamping recess.

Provided is a lathe capable of shortening the spindle. The lathe comprises a spindle, a spindle support which supports the spindle through a bearing on an outer side of the spindle, a collet disposed on a front end of the spindle, an inner ring holder provided on the spindle to hold a front of an inner ring of the bearing, an outer ring holder provided on the spindle support to hold a front of an outer ring of the bearing, a cap screwed into the spindle in front of the inner ring holder, and a cover detachably provided on the spindle support side. The cover has an inner circumferential surface facing an outer circumferential surface of the cap. A first air purging unit is provided between the inner circumferential surface of the cover and the outer circumferential surface of the cap.

A cutting tool rest (31) includes a clamping mechanism part (131) and a first piston (61). First piston (61) includes a first facing section (63) and a second facing section (64), and clamping mechanism part (131) includes a lever (135). First piston (61) reciprocates between a first position at which lever (135) and first facing section (63) are in contact with each other to operate clamping mechanism part (131) in a clamped state and a second position at which lever (135) and second facing section (64) are in contact with each other to operate clamping mechanism part (131) in an unclamped state. Cutting tool rest (31) includes a second piston (71) that moves first piston (61) to a third position between the first position and the second position. When first piston (61) is located at the third position, lever (135) is separated from first facing section (63) and second facing section (64).

A workholding apparatus (10) wherein a draw bar (22) effects chucking and de-chucking of a workpiece (W) and wherein un-seating of the workholding apparatus is effected by piston-like mechanisms (30) located in a machine spindle (2).

A tool changing mechanism includes a tool base housing, a mandrel disposed therein and having a chamber and a keyway provided axially, and first and second linked units. A first shoulder portion is provided at an end of the keyway, and pulling jaws are disposed at the other end. The first linked unit has a first pulling rod, an end of which has an external thread, and the other end has a connecting portion driven by a pneumatic cylinder. The second linked unit has a second pulling rod, an end of which has an internal thread, and a pressing head is disposed at the other end. The second pulling rod has a sliding key located in the keyway. The first pulling rod is screwed into the second pulling rod, and the relative screwing rotation therebetween attains tool pulling for fixing or tool loosening for removing the cutting tool.

A tool rest has a base, a tool holder rotatably supported on the base, and rotatably holding a tool, a rotational mechanism rotating the tool holder, a plurality of flexible linear members in which one ends of the plurality of linear members are connected with the tool holder and a winding device connected with the other ends of the plurality of linear members, and winding up the plurality of linear members by rotating when the tool holder is rotated by the rotational mechanism.

To provide a clamp device which is designed to shorten a spindle than before, thus enabling the downsizing of a spindle device. In a clamp device for removably mounting a tool holder to a spindle of a rotary spindle device, a clamp mechanism is placed in a clamp state by a reciprocation drive mechanism producing a rearward movement in which a draw-in sleeve (9) engaged therewith via steel balls (13) is moved rearward to bring through-holes (12) thereof to rearward large diameter portion (4d) in a bore region of a spindle body (4) and further rearward to a position where the steel balls (13) are retained between the rearward large diameter portion (4d) and a jig large diameter portion (14a), while the retreated draw-in sleeve (9) moves rearward a draw-in bolt (8) and a clamp sleeve (5) by means of a biasing force of an elastic member (10).

A holder for clamping a tool includes a clamping mechanism for clamping the tool, and an exposed portion. The clamping mechanism is switchable between a clamping state and an unclamping state. The clamping state is a state in which removal of the tool from the holder is hindered. The unclamping state is a state in which removal of the tool from the holder is allowed. The exposed portion is exposed outside the holder and directly or indirectly and mechanically linked to the clamping mechanism. The exposed portion is pushed in one direction for movement to thereby switch the clamping mechanism to the unclamping state.