Spindle condition detection device for machine tool
AssigneeJtekt Corporation
InventorsKoji Hasegawa, Koji Kito, Takashi Matsui, Nobumitsu Hori, Osamu Higashimoto
Life of this patent
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Abstract
A spindle condition detection device for a machine tool includes: bearing load detecting means for detecting a load on a bearing that rotatably supports a spindle of a machine tool; and present usage ratio calculating means for calculating, based on the load detected by the bearing load detecting means, a present usage ratio that is a ratio of usage of the bearing with respect to a prescribed operating life of the bearing, which is achieved over a period until a present moment.
Claims12
A machine tool including a spindle condition detection device, comprising:
- a spindle;
- a bearing that rotatably supports the spindle;
- a bearing load detector that detects a load on the bearing;
- a rotational speed sensor that detects a rotational speed of the spindle;
- and
- a present usage ratio calculation portion that calculates a present usage ratio based on at least one load that is detected by the bearing load detector,
- wherein the present usage ratio calculation portion:
- divides a range for the rotational speed of the spindle into multiple rotational speed ranges, divides a range for the load on the bearing into a set of load ranges for each rotational speed range,
- presets, for each load range of each rotational speed range, a prescribed operating life of the bearing,
- calculates an operating time in each load range for each rotational speed range from a beginning of use to a present moment, based on loads detected by the bearing load detector and rotational speeds detected by the rotational speed sensor,
- calculates, for each load range of each rotational speed range, a divisional usage ratio of the bearing by dividing a respective operating time by a respective prescribed operating life, and
- calculates the present usage ratio by summing up all the divisional usage ratios.
A machine tool including a spindle condition detection device, comprising:
- a spindle;
- a bearing that rotatably supports the spindle;
- a bearing load detector that detects a load on the bearing;
- a rotational speed sensor that detects a rotational speed of the spindle;
- and
- a present usage ratio calculation portion that calculates a present usage ratio based on at least one load that is detected by the bearing load detector,
- wherein the present usage ratio calculation portion:
- presets a permissible load of the bearing with respect to a rotational speed of the spindle, divides a range for a ratio of present load with respect to the permissible load into multiple load ratio ranges, and presets a prescribed operating life of the bearing for each load ratio range,
- calculates a ratio of present load with respect to the permissible load and an operating time for each load ratio range from a beginning of use to a present moment, based on loads detected by the bearing load detector and rotational speeds detected by the rotational speed sensor,
- calculates, for each load ratio range, a divisional usage ratio of the bearing by dividing a respective operating time by a respective prescribed operating life, and
- calculates the present usage ratio by summing up all the divisional usage ratios.
Dependencies are inferred from the claim text.