Provided is a misalignment determining device having a size thereof in an axial direction being made short. The misalignment determining device includes a case, a dial gauge, a holder portion, a support portion, a pivotal portion, a lever member, and a slide member. The slide member is placed in contact with a stylus of the dial gauge. While the pivotal portion and the lever member are rotated in synchronism with rotation of the holder portion, a pivot amount of the pivotal portion is transmitted to the slide member via the lever member, and based on an amount of movement of the slide member along an axis direction, the dial gauge determines the pivot amount.

There is provided a machine tool for suppressing the adverse effect of run-out of the rear end of a spindle on the rotation detection accuracy when processing a workpiece within a processing area. The machine tool includes a rotation driver, the spindle that is rotated by the rotation driver, a rotational angle detector that is provided to face a part forming the spindle in order to detect a rotational angle of the spindle, and at least two bearings that support the spindle and are arranged on a side of the processing area with respect to the rotation driver. The rotational angle detector is arranged at a position on the side of the processing area with respect to the rotation driver, the position being on the side of the processing area with respect to the bearings, on a side of the rotation driver with respect to the bearings, or between the bearings.

A method of grinding or turning a workpiece, such as a bearing workpiece, involves several steps. One step includes locating the bearing workpiece on a chuck with an axis of rotation of the chuck positioned off-center relative to an axis of the bearing workpiece. Another step includes determining an offset between the chuck's axis of rotation and the bearing workpiece's axis based on the off-center position between the chuck's axis of rotation and the bearing workpiece's axis. Yet another step includes determining a path of engagement of a grinding wheel relative to the bearing workpiece based on the offset previously determined between the chuck's axis of rotation and the bearing workpiece's axis.

The invention relates to a machine tool system (1) comprising a machine tool (2) comprising a spindle (3) that can be rotatably driven for machining workpieces, with a plurality of tools each clamped in chucks (5), in the form of so-called tool heads (4), that can be coupled to the spindle (3), and a balancing device (8) for balancing the tool heads (4), the machine tool system (1) comprising a data memory (11) in which the balancing protocol associated with each system-associated tool head (4) is stored, and a controller (12) that reads balancing data from the balancing protocol, for a tool head (4) coupled to the spindle (3), and compares it with at least one parameter of the machining for which said tool head (4) is provided, or with at least one general balancing parameter, the machine tool system (1) preferably being designed such that it rejects a tool head (4) when there is no available balancing data for said tool head (4).

A balance and runout amount adjustment system for a rotary tool includes a rotary tool constituted of a tool holder mounted on a spindle, a balance determining device configured to obtain outer circumference position data of the rotary tool and to determine a mass balance of the rotary tool based on the outer circumference position data obtained, in the course of rotation of the rotary tool and a runout determining device configured to obtain shape data of the rotary tool and to determine a runout amount of the rotary tool based on the shape data obtained, in the course of rotation of the rotary tool. The rotary tool is configured to be capable of adjustment of the mass balance based on the result of the determination made by the balance determining device and capable also of adjustment of the runout amount based on the result of the determination made by the runout determining device.

A machine tool for machining a workpiece includes a spindle configured to rotate a holder mounted with a tool used for machining, one or more moving shafts configured to move the holder and/or a work base on which the workpiece is placed, a torque measurement unit configured to measure driving torque of the spindle and/or the one or more moving shafts, a reference value calculation unit configured to use, as a reference value, the driving torque measured by performing a no-load operation by rotating the spindle in a normal state, a torque comparison unit configured to compare, to the reference value, the driving torque measured by performing a no-load operation by rotating the spindle before actual machining, and an alarm unit configured to determine whether to issue an alarm on the basis of results of the comparison.

A machine assessment system of the present disclosure is for a machining tool including a spindle. The machine assessment system includes a calibrated spindle tool configured to couple to a distal end of the spindle, a displacement sensor configured to measure a performance characteristic of the machining tool based on a controlled excitation of the calibrated spindle tool, and a controller communicably coupled to the displacement sensor to acquire the performance characteristic. In measuring the performance characteristic, the displacement sensor is detached from the calibrated spindle tool. The controller is configured perform a machine health assessment based on the performance characteristic.

A spindle abnormity detection device includes a first sensor configured to measure oscillation of a spindle of a machine tool, a second sensor configured to measure radial runout of an axis of a tool unit attached to the spindle, and a computer configured to perform abnormity determination of the spindle based on an oscillation comparison result and a runout comparison result, the oscillation comparison result being obtained by comparing a detection result obtained by the first sensor with an oscillation standard of the spindle, the runout comparison result being obtained by comparing a detection result obtained by the second sensor with a runout standard of the tool unit.

A machine tool for machining a workpiece includes a spindle configured to rotate a holder mounted with a tool used for machining, one or more moving shafts configured to move the holder and/or a work base on which the workpiece is placed, a torque measurement unit configured to measure driving torque of the spindle and/or the one or more moving shafts, a reference value calculation unit configured to use, as a reference value, the driving torque measured by performing a no-load operation by rotating the spindle in a normal state, a torque comparison unit configured to compare, to the reference value, the driving torque measured by performing a no-load operation by rotating the spindle before actual machining, and an alarm unit configured to determine whether to issue an alarm on the basis of results of the comparison.

The present invention provides a lathe that is provided with an eccentricity adjustment mechanism that makes it possible for electrical components that are readily affected by the environment to be eliminated from the turntable; for slip rings in particular, which exhibit problems in terms of the durability of signal transmission during high-speed rotation, to be eliminated as well, and for safe and stable adjustment of workpiece eccentricity to be easily achieved. A lathe provided with an eccentricity adjustment mechanism, in which a linear motion guide unit (6) is provided in an inclined state in an engaging part of the center part of a turntable (1) and an axial-direction-movement part (5A) of a center shaft (5); and, due to the center shaft (5) being moved, the turntable (1) moves in the radial direction by the radial pressing force generated by the linear motion guide unit (6) being inclined, and the eccentricity of the workpiece (3) is adjusted.