A main spindle device for a machine tool that checks the seating of a tool holder using compressed air, wherein the main spindle device for a machine tool comprises: a main spindle that has a distal end face in close contact with a flange end of the tool holder; an annular recess that is formed on the distal end face of the main spindle so as to be covered by the flange end of the tool holder; an air supply flow channel that is linked to the annular recess and that supplies compressed air to the annular recess; a compressed air source that supplies air to the air supply flow channel; and a pressure detector that detects the pressure of the compressed air in the air supply flow channel. The annular recess has a first section and a second section that is deeper than the first section, and the air supply flow channel is opened to the second section.

A main spindle device for a machine tool that checks the seating of a tool holder using compressed air, wherein the main spindle device for a machine tool comprises: a main spindle that has a distal end face in close contact with a flange end of the tool holder; an annular recess that is formed on the distal end face of the main spindle so as to be covered by the flange end of the tool holder; an air supply flow channel that is linked to the annular recess and that supplies compressed air to the annular recess; a compressed air source that supplies air to the air supply flow channel; and a pressure detector that detects the pressure of the compressed air in the air supply flow channel. The annular recess has a first section and a second section that is deeper than the first section, and the air supply flow channel is opened to the second section.

A main shaft device is attached to a work machine. The main shaft device is provided with a main shaft that supports a tool or a workpiece, and a main shaft motor that causes the main shaft to rotate. The main shaft device is provided with bearings that are rolling bearings which support the main shaft in an inner race, and a housing and a rear housing that secure an outer race of the bearings. The housing and the rear housing are formed of a material having a coefficient of thermal expansion greater than that of the main shaft.

A main shaft device is attached to a work machine. The main shaft device is provided with a main shaft that supports a tool or a workpiece, and a main shaft motor that causes the main shaft to rotate. The main shaft device is provided with bearings that are rolling bearings which support the main shaft in an inner race, and a housing and a rear housing that secure an outer race of the bearings. The housing and the rear housing are formed of a material having a coefficient of thermal expansion greater than that of the main shaft.

The inventive working spindle comprises a spindle housing and a spindle shaft with axial positioning surface and axial contact surface by which the correct axial position of each fitting provided spindle shaft in the spindle housing is obtained. For torque-proof holding of the spindle shaft in the spindle housing, preferably with stationary motor, a braking unit is provided that comprises a radial outer part that is coupled with the spindle housing in a torque-proof manner and a radial inner part that is coupled with the spindle shaft in a torque-proof manner. The largest outer diameter of the peripheral surface of the inner part is smaller than the narrowest location of the through-opening of the spindle housing between the braking unit and the tool side end of the spindle housing. For this reason the spindle shaft can be readily removed from the spindle housing without disassembly measures of the braking unit, if required, and can be reinserted in reverse route. The inventive working spindle is simply constructed and can be versatilely used. Concurrently it is remarkably easy to maintain.

The inventive working spindle comprises a spindle housing and a spindle shaft with axial positioning surface and axial contact surface by which the correct axial position of each fitting provided spindle shaft in the spindle housing is obtained. For torque-proof holding of the spindle shaft in the spindle housing, preferably with stationary motor, a braking unit is provided that comprises a radial outer part that is coupled with the spindle housing in a torque-proof manner and a radial inner part that is coupled with the spindle shaft in a torque-proof manner. The largest outer diameter of the peripheral surface of the inner part is smaller than the narrowest location of the through-opening of the spindle housing between the braking unit and the tool side end of the spindle housing. For this reason the spindle shaft can be readily removed from the spindle housing without disassembly measures of the braking unit, if required, and can be reinserted in reverse route. The inventive working spindle is simply constructed and can be versatilely used. Concurrently it is remarkably easy to maintain.

An integrated online dynamic balance terminal by 3D rapid prototyping includes a central tapered hole formed at a lower portion thereof, a plurality of identical balance cavities peripherally and spacedly formed on the integrated online dynamic balance terminal. Each two the adjacent balance cavities are separated by a cavity partition. The integrated online dynamic balance terminal further has a plurality of guiding channels indently formed on an inner peripheral surface thereof, wherein each of the four guiding channels communicates with a corresponding balance cavity through a corresponding trapezoidal hole. The integrated online dynamic balance terminal has a plurality of bored holes spacedly formed on an engagement surface. The integrated online dynamic balance terminal is configured from 3D rapid prototyping so as to form an integral one-piece structure, wherein some portions requiring high precision are arranged to undergo additional machining processes.

An integrated online dynamic balance terminal by 3D rapid prototyping includes a central tapered hole formed at a lower portion thereof, a plurality of identical balance cavities peripherally and spacedly formed on the integrated online dynamic balance terminal. Each two the adjacent balance cavities are separated by a cavity partition. The integrated online dynamic balance terminal further has a plurality of guiding channels indently formed on an inner peripheral surface thereof, wherein each of the four guiding channels communicates with a corresponding balance cavity through a corresponding trapezoidal hole. The integrated online dynamic balance terminal has a plurality of bored holes spacedly formed on an engagement surface. The integrated online dynamic balance terminal is configured from 3D rapid prototyping so as to form an integral one-piece structure, wherein some portions requiring high precision are arranged to undergo additional machining processes.

A spindle device includes a cover member. The cover member has, formed therein, a gas flow path configured to flow a compressed gas for providing sealing between a chuck portion as a rotating member and the cover member and sealing between the chuck portion and the spindle housing. The gas flow path includes a first conduit configured to communicate the outside of the cover member and a second conduit configured to allow the first conduit to communicate with a gap between the chuck portion and the spindle housing, the second conduit being larger than the outlet of the first conduit. The outlet of the second conduit faces a surface of the spindle housing.

A spindle device includes a cover member. The cover member has, formed therein, a gas flow path configured to flow a compressed gas for providing sealing between a chuck portion as a rotating member and the cover member and sealing between the chuck portion and the spindle housing. The gas flow path includes a first conduit configured to communicate the outside of the cover member and a second conduit configured to allow the first conduit to communicate with a gap between the chuck portion and the spindle housing, the second conduit being larger than the outlet of the first conduit. The outlet of the second conduit faces a surface of the spindle housing.