Dmg Mori Seiki Co., Ltd.

Dmg Mori Company Limited

The University of Tokyo

Sanyo Electric Co., Ltd.

Koji Yamamoto

Hiroshi Fujimoto

Shinji Ishii

Yuki Terada

Teruaki Ishibashi

Akira Kimura

Katsuhiko Ono

Keiichi Nakamachi

Kimiyuki Nishimura

Kenichiro Ueno

Hongzhong Zhu

A machine tool includes a spindle including a tool insertion portion having a shape of an opening into which a shank of a tool is inserted and configured to attach the tool thereto, a tool change unit configured to change the tool attached to the spindle while gripping the tool, an air supply unit configured to supply air to a gap between the tool insertion portion and the shank of the tool when the tool change unit changes the tool, and a controller configured to control driving of at least any one of the spindle and the tool change unit to allow the tool and the tool insertion portion to reciprocate relative to each other in a predetermined direction with the shank of the tool inserted into the tool insertion portion and with a gap provided between the tool insertion portion and the shank of the tool.

Machine tool

A tool changer includes a holding member having a tool change arm disposed thereon, a rotation mechanism rotating the holding member at a first rotation speed in normal and reverse directions, a forward/backward movement mechanism moving the holding member forward and backward at a first forward/backward movement speed, and a controller comparing a first difference as a difference between a command value for the rotation and an output value of an encoder with a first threshold. When the first difference is equal to or greater than the first threshold, a rotational speed of the holding member is chained to a second rotation speed slower than the first rotation speed. Alternatively, when the first difference is less than the first threshold, the rotational speed of the holding member is maintained at the first rotation speed.

Tool changer

A tool changer includes a holding member having a tool change arm, a rotating mechanism for rotating the holding member, a forward/backward moving mechanism for moving the holding member forward and backward, and a controller controlling the mechanisms. A zero return controller determines whether the tool change arm is holding tools. When it is not holding tools, the tool change arm is rotated to a predetermined non-interference angle, the tool change arm is translated to a forward/backward movement zero point, and the tool change arm is rotated to a rotation zero point. When it is holding tools, the tool change arm is translated to a forward end, the tool change arm is rotated to position it on an expected path, and the tool change arm is moved along the expected path, thereby moving the tool change arm to the rotation zero point and the forward/backward movement zero point.

A controller has a varying speed signal generation unit generating a varying speed command signal varying at predetermined amplitude and period, a current control unit generating a current command signal based on the varying speed command signal, a feedback control unit generating a correction signal based on a deviation between the varying speed command signal and a present rotational speed of the spindle motor and adding the correction signal to the current command signal, and a learning control unit calculating a disturbance component caused by cutting resistance based on the deviation every predetermined rotation angle of the spindle motor and, in synchronism with a rotation angle of the spindle motor corresponding to the varying speed command signal input into the current control unit, generating a compensation signal based on the disturbance component corresponding to the rotation angle and adding the compensation signal to the varying speed command signal.

Controller for spindle motor

Using a machine tool, a workpiece is machined while periodically varying the rotational speed of a spindle thereof. Correlation data on correlation between a speed variation rate RVA of the spindle rotational speed, a speed variation period ratio RVF thereof, and vibration of a tool when machining the workpiece while periodically varying the spindle rotational speed is previously obtained. Based on the correlation data, the speed variation rate RVA and the speed variation period ratio RVF are set so that the vibration of the tool and machining accuracy are within their respective allowable ranges, and based on the set speed variation rate RVA and speed variation period ratio RVF, a variation amplitude and a variation period of the spindle rotational speed are determined. The spindle is rotated at the rotational speed varying at the determined amplitude and period with respect to a target rotational speed, thereby machining the workpiece.

Machining method

A controller has a control unit generating a control signal to control a drive motor and a friction compensation unit adding a friction compensation signal to the control signal for compensating for a positioning error caused by friction in a guide unit. When reversing the direction of movement of the movable body, the friction compensation unit generates a friction compensation signal in accordance with a function f(&#x3b1;) representing a friction compensation value uf by a relationship with a variable &#x3b1; and asymptotically approaching the maximum value and the minimum value of the friction compensation value uf and having an inflection point therebetween, and adds the generated friction compensation signal to the control signal generated by the control unit during movement of the movable body a predetermined movement distance from before to after the reversing.

Controller and control method

A positioning control apparatus has a moving body, a feed device having a guide mechanism for guiding the moving body in the direction of its feed axis and a drive mechanism for moving the moving body, a structural body supporting the feed device and a controller for controlling a moving position of the moving body with respect to a reference position on a machine tool by controlling the operation of the drive mechanism, and further has a calculating section calculating displacement of the feed device in the feed-axis direction with respect to the reference position caused by displacement of the structural body and a compensating section receiving the displacement data measured by the calculating section and adding modification data for eliminating the displacement to a control signal in the controller.

Positioning control apparatus and machine tool provided therewith

The monitor camera () comprises a pedestal () to be attached to a mounting surface, an imaging device () rotatably attached so as to be rotatable around the central axis L of the pedestal (), and a dome-type cover () having a window () and being rotatably attached to the pedestal () so as to cover the imaging device (). The dome-type cover () includes an inner cover () having an open window () in the position corresponding to the window () and an outer cover () placed over the inner cover (). The outer cover () and the inner cover () have an engagement part () at which both the covers () and () are engaged by a specific manual operation of the outer cover ().

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Nara, Japan

Koji Yamamoto