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JP6637844B2 - Method for determining warm-up operation time before bearing diagnosis in machine tool, machine tool - Google Patents

Method for determining warm-up operation time before bearing diagnosis in machine tool, machine tool Download PDF

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JP6637844B2
JP6637844B2 JP2016117222A JP2016117222A JP6637844B2 JP 6637844 B2 JP6637844 B2 JP 6637844B2 JP 2016117222 A JP2016117222 A JP 2016117222A JP 2016117222 A JP2016117222 A JP 2016117222A JP 6637844 B2 JP6637844 B2 JP 6637844B2
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JP2017224045A (en
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直樹 川田
直樹 川田
一成 小池
一成 小池
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Okuma Corp
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Description

本発明は、回転軸の軸支に用いられる転がり軸受の異常を検知するための軸受診断手段を備えた工作機械において、軸受診断に伴う暖機運転時間を決定する方法と、軸受診断を実行可能な工作機械とに関する。   The present invention provides a method of determining a warm-up operation time associated with a bearing diagnosis and a bearing diagnosis in a machine tool including a bearing diagnosis unit for detecting an abnormality of a rolling bearing used for a bearing of a rotating shaft. Machine tools.

工作機械に設けられる主軸等の回転軸を備える回転軸装置において、回転軸を軸支するために用いられる転がり軸受(以下単に「軸受」という。)は、内輪と、外輪と、両輪間に設けられる複数の転動体(玉やころ等)と、転動体の間隔を保つための保持器とを含んでなり、内輪が回転軸と一体に回転し、外輪が主軸ハウジング等に組み込まれて固定される。
この軸受に発生する異常としては、潤滑不良、異物の混入、摩耗、過大荷重等が挙げられる。これらの異常が発生すると、回転不良や焼き付きが生じ、工作機械の正常運転に支障をきたすため、軸受の異常を診断するのが望ましい。
そこで、軸受の異常を診断する方法として、特許文献1には、軸受を有する回転装置の温度と停止時間とを監視して、温度に応じて予め設定された基準停止時間と比較して軸受の異常の有無を判定する発明が開示されている。また、特許文献2には、軸の惰性回転時の回転数の変化から摩擦トルクを算出し、この摩擦トルクを基準値と比較して軸受の異常を判定する発明が開示されている。
BACKGROUND ART In a rotating shaft device provided with a rotating shaft such as a main shaft provided in a machine tool, a rolling bearing (hereinafter simply referred to as a “bearing”) used to support the rotating shaft is provided between an inner ring, an outer ring, and both wheels. A plurality of rolling elements (balls, rollers, etc.) and a retainer for keeping the spacing between the rolling elements, the inner ring rotates integrally with the rotating shaft, and the outer ring is incorporated and fixed in the main shaft housing or the like. You.
Abnormalities that occur in the bearing include poor lubrication, inclusion of foreign matter, wear, and excessive load. When these abnormalities occur, rotation failure or seizure occurs, which hinders the normal operation of the machine tool. Therefore, it is desirable to diagnose bearing abnormalities.
Therefore, as a method for diagnosing an abnormality of a bearing, Patent Document 1 discloses monitoring a temperature and a stop time of a rotating device having a bearing and comparing the temperature with a reference stop time set in advance according to the temperature. An invention for determining the presence or absence of an abnormality is disclosed. Patent Document 2 discloses an invention in which a friction torque is calculated from a change in the number of revolutions during coasting rotation of a shaft, and the friction torque is compared with a reference value to determine an abnormality in the bearing.

特許第4091885号公報Japanese Patent No. 4091885 特公平6−65189号公報Japanese Patent Publication No. 6-65189 特開2005−34929号公報JP 2005-34929 A 特開2009−113138号公報JP 2009-113138 A

特許文献1,2に記載されているような軸受の摩擦特性に起因する指標は、様々な要因に左右される繊細な情報であるため、測定時の軸受状態を安定させるのが望ましい。
ここで、軸受の摩擦特性は、軸受予圧、潤滑油粘度、回転速度に依存することが知られているが、このうち軸受予圧と潤滑油粘度とは、温度に左右されるため、安定した軸受診断を行う際には、暖機運転を行って測定時の温度条件を揃える必要がある。特に、軸受予圧に関しては、温度変化による熱変位の影響も考慮する必要がある。
こうした暖機運転による安定化の技術として、特許文献3には、工作機械の起動後、暖機運転を行い、ボールネジの温度が、変位量が飽和する閾値を越えた際に暖機運転を終了して加工を開始する発明が記載されている。また、特許文献4には、必要以上の暖機運転を防止するために、工具の先端位置をカメラ等の撮像データを解析して算出し、先端位置の変化量が設定許容精度以内である状態が設定範囲時間継続したら、工具の先端位置が安定したとみなして暖機運転を終了する発明が開示されている。
Since the index caused by the friction characteristics of the bearing as described in Patent Literatures 1 and 2 is delicate information affected by various factors, it is desirable to stabilize the bearing state at the time of measurement.
Here, it is known that the friction characteristics of a bearing depend on the bearing preload, the lubricating oil viscosity, and the rotation speed. Of these, the bearing preload and the lubricating oil viscosity are dependent on the temperature, so that a stable bearing is obtained. When performing a diagnosis, it is necessary to perform a warm-up operation to make the temperature conditions at the time of measurement uniform. In particular, regarding the bearing preload, it is necessary to consider the influence of thermal displacement due to temperature change.
As a technique for stabilization by such a warm-up operation, Patent Document 3 discloses that a warm-up operation is performed after the machine tool is started, and the warm-up operation is terminated when the temperature of the ball screw exceeds a threshold value at which the displacement amount saturates. The invention is described in which the machining is started. Further, in Patent Document 4, in order to prevent unnecessary warm-up operation, the tip position of a tool is calculated by analyzing imaging data of a camera or the like, and the amount of change in the tip position is within a set allowable accuracy. Discloses that the warm-up operation is terminated when the position of the tool tip is considered to be stable if the setting continues for the set range time.

しかし、このような暖機運転に係る発明を軸受診断に採用した場合、特許文献3の発明では、単純に温度閾値を暖機運転終了の目安とするため、軸受異常時に発熱量が変化して定常状態の温度が変わると、暖機運転の終了のタイミングが不適切となって正確な軸受診断が行えなくなる。特許文献4の発明は、工具の先端位置を新たな指標として信頼性は高まるものの、カメラ等の付加装置が必要となってコストアップに繋がってしまう。   However, when the invention related to such a warm-up operation is adopted for the bearing diagnosis, in the invention of Patent Document 3, the amount of heat generated varies when a bearing is abnormal because the temperature threshold is simply used as a guideline for terminating the warm-up operation. If the temperature in the steady state changes, the timing of terminating the warm-up operation becomes inappropriate, and accurate bearing diagnosis cannot be performed. In the invention of Patent Document 4, although the reliability is improved using the tip position of the tool as a new index, an additional device such as a camera is required, which leads to an increase in cost.

そこで、本発明は、適切な暖機運転時間を低コストで決定して不必要な暖機運転時間を解消でき、効率的な軸受の異常診断が可能となる工作機械における軸受診断前の暖機運転時間の決定方法及び工作機械を提供することを目的としたものである。   Accordingly, the present invention provides a warm-up operation before a bearing diagnosis in a machine tool, in which an appropriate warm-up operation time can be determined at low cost, unnecessary warm-up operation time can be eliminated, and an efficient bearing abnormality diagnosis can be performed. An object of the present invention is to provide a method for determining an operation time and a machine tool.

上記目的を達成するために、請求項1に記載の発明は、回転駆動する回転軸を軸受で軸支してなる回転軸装置と、前記回転軸の回転を制御する制御手段と、前記軸受の温度を検出する温度検出手段と、前記制御手段によって前記回転軸を所定の回転数で、且つ前記温度検出手段による検出温度が定常状態となるまでの時間で回転させる暖機運転を行った後、前記軸受の異常を検知する軸受診断を実行する軸受診断手段とを備えた工作機械において、前記暖機運転の時間を決定する方法であって、
前記軸受診断の実行前の通常運転時に、前記温度検出手段によって前記軸受の温度を検出する温度検出ステップと、
検出された前記軸受の温度変化と前記回転軸の回転数とに基づいて、前記通常運転時の温度時定数を算出する温度時定数算出ステップと、
算出された前記温度時定数を記憶する記憶ステップと、
前記暖機運転を行う際に、記憶された前記温度時定数に基づいて前記所定の回転数での前記暖機運転の時間を決定する時間決定ステップと、を実行することを特徴とする。
請求項2に記載の発明は、請求項1の構成において、前記温度検出ステップは、前記所定の回転数での通常運転時にのみ実行し、前記温度時定数算出ステップでは、前記所定の回転数での温度上昇変化から前記所定の回転数での温度時定数を算出することを特徴とする。
請求項3に記載の発明は、請求項1又は2の構成において、前記時間決定ステップでは、前記温度時定数から熱変位飽和時間を推定し、推定した前記熱変位飽和時間の任意の割合として前記暖機運転の時間を決定することを特徴とする。
請求項4に記載の発明は、請求項3の構成において、前記任意の割合は、89%以上であることを特徴とする。
上記目的を達成するために、請求項5に記載の発明は、回転駆動する回転軸を軸受で軸支してなる回転軸装置と、前記回転軸の回転を制御する制御手段と、前記軸受の温度を検出する温度検出手段と、前記制御手段によって前記回転軸を所定の回転数で、且つ前記温度検出手段による検出温度が定常状態となるまでの時間で回転させる暖機運転を行った後、前記軸受の異常を検知する軸受診断を実行する軸受診断手段とを備えた工作機械であって、
前記軸受診断の実行前の通常運転時に、前記温度検出手段によって前記軸受の温度を検出し、検出された前記軸受の温度変化と前記回転軸の回転数とに基づいて、前記通常運転時の温度時定数を算出する温度時定数算出手段と、
算出された前記温度時定数を記憶する記憶手段と、
前記暖機運転を行う際に、記憶された前記温度時定数に基づいて前記所定の回転数での前記暖機運転の時間を決定する時間決定手段と、を備えることを特徴とする。
請求項6に記載の発明は、請求項5の構成において、前記温度時定数算出手段では、前記所定の回転数での通常運転時にのみ前記軸受の温度を検出し、前記所定の回転数での温度上昇変化から前記所定の回転数での温度時定数を算出することを特徴とする。
請求項7に記載の発明は、請求項5又は6の構成において、前記時間決定手段は、前記温度時定数から熱変位飽和時間を推定し、推定した前記熱変位飽和時間の任意の割合で前記暖機運転の時間を決定することを特徴とする。
請求項8に記載の発明は、請求項7の構成において、前記任意の割合は、89%以上であることを特徴とする。
Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 is a rotating shaft device in which a rotating shaft that is rotationally driven is supported by a bearing, control means for controlling rotation of the rotating shaft, After performing a warm-up operation of rotating the rotating shaft at a predetermined rotation speed by the control unit and the temperature detected by the temperature detecting unit to a steady state, In a machine tool comprising: a bearing diagnosis unit that performs a bearing diagnosis that detects an abnormality of the bearing, a method of determining the time of the warm-up operation,
During normal operation before the execution of the bearing diagnosis, a temperature detection step of detecting the temperature of the bearing by the temperature detection means,
A temperature time constant calculating step of calculating the temperature time constant during the normal operation based on the detected temperature change of the bearing and the rotation speed of the rotating shaft;
A storing step of storing the calculated temperature time constant;
When performing the warm-up operation, a time determining step of determining the time of the warm-up operation at the predetermined rotation speed based on the stored temperature time constant is performed.
According to a second aspect of the present invention, in the configuration of the first aspect, the temperature detecting step is executed only during a normal operation at the predetermined rotational speed, and in the temperature time constant calculating step, the temperature detecting step is performed at the predetermined rotational speed. The temperature time constant at the predetermined rotation speed is calculated from the change in temperature rise.
According to a third aspect of the present invention, in the configuration according to the first or second aspect, in the time determining step, a thermal displacement saturation time is estimated from the temperature time constant, and the thermal displacement saturation time is estimated as an arbitrary ratio of the estimated thermal displacement saturation time. The time of the warm-up operation is determined.
According to a fourth aspect of the present invention, in the configuration of the third aspect, the arbitrary ratio is 89% or more.
In order to achieve the above object, an invention according to claim 5 is directed to a rotating shaft device in which a rotating shaft that is rotationally driven is supported by a bearing, control means for controlling rotation of the rotating shaft, After performing a warm-up operation of rotating the rotating shaft at a predetermined rotation speed by the control unit and the temperature detected by the temperature detecting unit to a steady state, A machine tool comprising: a bearing diagnosis unit that executes a bearing diagnosis for detecting an abnormality of the bearing,
During normal operation before the execution of the bearing diagnosis, the temperature of the bearing is detected by the temperature detecting unit, and the temperature during the normal operation is determined based on the detected temperature change of the bearing and the rotation speed of the rotating shaft. Temperature time constant calculating means for calculating a time constant,
Storage means for storing the calculated temperature time constant,
When the warm-up operation is performed, a time determination unit that determines the time of the warm-up operation at the predetermined rotation speed based on the stored temperature time constant is provided.
According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the temperature time constant calculating means detects the temperature of the bearing only during normal operation at the predetermined rotation speed, and detects the temperature at the predetermined rotation speed. A temperature time constant at the predetermined rotation speed is calculated from a change in temperature rise.
According to a seventh aspect of the present invention, in the configuration of the fifth or sixth aspect, the time determination means estimates a thermal displacement saturation time from the temperature time constant, and sets the thermal displacement saturation time at an arbitrary ratio of the estimated thermal displacement saturation time. The time of the warm-up operation is determined.
An eighth aspect of the present invention is characterized in that, in the configuration of the seventh aspect, the arbitrary ratio is 89% or more.

本発明によれば、通常運転時に取得した温度時定数に基づいて暖機運転時間を決定し、その暖機運転時間に従って暖機運転を行っているので、適切な暖機運転時間を低コストで決定して不必要な暖機運転時間を解消できる。よって、効率的な軸受の異常診断が可能となる。   According to the present invention, the warm-up operation time is determined based on the temperature time constant acquired during the normal operation, and the warm-up operation is performed according to the warm-up operation time. The determined warm-up operation time can be eliminated by the determination. Therefore, it is possible to efficiently diagnose the abnormality of the bearing.

工作機械の概略図である。It is a schematic diagram of a machine tool. 通常運転のフローチャートである。It is a flowchart of normal operation. 軸受診断のフローチャートである。It is a flowchart of a bearing diagnosis.

以下、本発明の実施の形態を図面に基づいて説明する。
図1は、工作機械の一例を示す概略図で、この工作機械は、工具を回転させる回転軸装置としての主軸装置に用いられる軸受を診断する。
工作機械1において、2は主軸装置で、主軸ハウジング3内には、先端に工具5が装着されて図示しない主軸モータで回転する回転軸としての主軸4が、軸受(ここでは転動体が玉であるボールベアリング)6,6によって軸支されている。7は主軸4の回転速度を検出する回転速度検出器で、主軸ハウジング3には、軸受6,6の近傍にプローブを挿入させた温度センサ8が設けられている。主軸4の主軸モータは、工作機械1の送り軸モータ等も制御する制御手段としての制御装置9によって制御される。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a machine tool. This machine tool diagnoses a bearing used in a spindle device as a rotating shaft device for rotating a tool.
In the machine tool 1, reference numeral 2 denotes a spindle device. In a spindle housing 3, a spindle 4 having a tool 5 mounted at its tip and serving as a rotating shaft rotated by a spindle motor (not shown) is provided with a bearing (here, a rolling element is a ball). Ball bearings) 6,6. Reference numeral 7 denotes a rotation speed detector for detecting the rotation speed of the main shaft 4. The main shaft housing 3 is provided with a temperature sensor 8 having a probe inserted near the bearings 6, 6. The spindle motor of the spindle 4 is controlled by a control device 9 as a control unit that also controls a feed shaft motor of the machine tool 1 and the like.

10は、軸受診断手段としての軸受診断装置で、回転速度検出器7からの回転検出信号と温度センサ8からの温度検出信号とが入力される計測装置11と、主軸4の回転数及び温度が入力されて軸受特性や後述する温度時定数等を算出する温度時定数算出手段及び時間決定手段としての演算装置12と、演算装置12で算出された軸受特性や温度時定数等が記憶される記憶手段としての記憶装置13とが設けられている。記憶装置13には軸受診断時の診断プログラム等も格納される。14は、演算装置12での軸受診断結果が表示される表示装置である。ここでは温度センサ8及び計測装置11が温度検出手段となる。   Reference numeral 10 denotes a bearing diagnostic device as bearing diagnostic means, which is a measuring device 11 to which a rotation detection signal from the rotation speed detector 7 and a temperature detection signal from the temperature sensor 8 are input, and that the rotation speed and the temperature of the main shaft 4 are measured. An arithmetic unit 12 as a temperature time constant calculating unit and a time determining unit which are input and calculate a bearing characteristic, a temperature time constant described later, and the like, and a storage in which the bearing characteristic, the temperature time constant, and the like calculated by the arithmetic unit 12 are stored. A storage device 13 as means is provided. The storage device 13 also stores a diagnostic program and the like at the time of bearing diagnosis. Reference numeral 14 denotes a display device on which the result of the bearing diagnosis by the arithmetic unit 12 is displayed. Here, the temperature sensor 8 and the measuring device 11 serve as temperature detecting means.

以上の如く構成された工作機械1における通常運転を図2のフローチャートに基づいて説明する。
まず、S1で主軸回転指令が制御装置9に入力されると、S2で制御装置9は主軸モータを制御して指令された回転数で主軸4を回転させ、S3では加工プログラムによって送り軸等が制御されて加工が行われる。
加工中は、S4で、主軸4の回転数が軸受診断用に予め指定された回転数か否かを確認し、指定回転数でなければ、そのままS5で加工プログラムの終了を確認するまで加工を継続する。
The normal operation of the machine tool 1 configured as described above will be described based on the flowchart of FIG.
First, when a spindle rotation command is input to the control device 9 in S1, the control device 9 controls the spindle motor to rotate the spindle 4 at the commanded rotation speed in S2. Processing is performed under control.
During machining, it is checked in step S4 whether the rotational speed of the spindle 4 is the rotational speed specified in advance for bearing diagnosis. If not, the machining is continued until the end of the machining program is confirmed in step S5. continue.

一方、S4の判別で指定回転数が確認されると、S6で、温度センサ8によって軸受6の温度を検出し、計測装置11を介して記憶装置13に検出温度の変化を記録する(温度検出ステップ)。
そして、S7では、演算装置12が、記録された検出温度の上昇変化から現在の回転数での温度時定数を算出する(温度時定数算出ステップ)。この温度時定数τは、例えば初期温度から定常状態となった温度までの温度差の63.2%や50%の時点の時間として算出される。
次に、S8で、算出した温度時定数を回転数と共に記憶装置13に保存し(記憶ステップ)、S5に戻る。ここで加工終了でなければS4で指定回転数を確認し、指定回転数であればS6以下の処理を実行する。よって、指定回転数での軸受温度の記録と温度時定数の算出、保存は、加工終了まで繰り返され、データが更新されることになる。
On the other hand, when the designated rotation speed is confirmed in the determination in S4, the temperature of the bearing 6 is detected by the temperature sensor 8 in S6, and the change in the detected temperature is recorded in the storage device 13 via the measuring device 11 (temperature detection). Steps).
Then, in S7, the arithmetic unit 12 calculates a temperature time constant at the current rotational speed from the recorded increase in the detected temperature (temperature time constant calculation step). The temperature time constant τ is calculated, for example, as a time at 63.2% or 50% of the temperature difference from the initial temperature to the temperature in the steady state.
Next, in S8, the calculated temperature time constant is stored in the storage device 13 together with the number of rotations (storage step), and the process returns to S5. Here, if the machining is not completed, the designated rotation speed is confirmed in S4, and if it is the designated rotation speed, the processing in S6 and thereafter is executed. Therefore, the recording of the bearing temperature and the calculation and storage of the temperature time constant at the specified number of rotations are repeated until the processing is completed, and the data is updated.

そして、軸受6の異常を検知する軸受診断は、図3のフローチャートによって実行される。
まず、S11で、診断開始指令が図示しない入力装置によって軸受診断装置10に入力されると、S12では、主軸4が、軸受診断用の指定回転数であるか否かが判別される。ここで指定回転数でなければ、S13で制御装置9によって指定回転数に変更する。そして、再びS12で指定回転数であることが確認されると、S14では、記憶装置13に保存されている指定回転数と温度時定数とを参照して演算装置12が暖機運転時間を算出する(時間決定ステップ)。この暖機運転時間は、温度時定数から熱変位飽和時間を推定し、推定した熱変位飽和時間の任意の割合として決定される。例えば、温度時定数τが、初期の温度差の63.2%変化までの時間として取得されており、任意の割合が89%であれば、暖機運転時間は、(τ/0.632)×0.89で決定される。
よって、S15では、制御装置9が、こうして算出された暖機運転時間に従い、暖機運転を開始する。
S16で、算出した暖機運転時間の経過が確認されると、S17で暖機運転を終了してS18で軸受診断を開始する。
The bearing diagnosis for detecting the abnormality of the bearing 6 is executed according to the flowchart of FIG.
First, in S11, when a diagnosis start command is input to the bearing diagnosis device 10 by an input device (not shown), in S12, it is determined whether or not the main shaft 4 is at a designated rotational speed for bearing diagnosis. Here, if it is not the designated rotation speed, the control device 9 changes the rotation speed to the designated rotation speed in S13. When it is confirmed again at S12 that the rotation speed is the specified rotation speed, at S14, the arithmetic unit 12 calculates the warm-up operation time with reference to the specified rotation speed and the temperature time constant stored in the storage device 13. (Time determination step). This warm-up operation time is determined as an arbitrary ratio of the estimated thermal displacement saturation time by estimating the thermal displacement saturation time from the temperature time constant. For example, the temperature time constant τ is acquired as the time until a 63.2% change in the initial temperature difference, and if an arbitrary ratio is 89%, the warm-up operation time is (τ / 0.632). × 0.89.
Therefore, in S15, the control device 9 starts the warm-up operation according to the warm-up operation time thus calculated.
When the elapse of the calculated warm-up operation time is confirmed in S16, the warm-up operation is terminated in S17 and the bearing diagnosis is started in S18.

この軸受診断は、例えば、主軸モータへの通電を停止させて惰性回転を行い、主軸4の停止が確認されるまで回転数と温度とを計測し、計測した回転数に基づき、摩擦トルクや転がり速度、軸受予圧等を算出して軸受特性を求め、その軸受特性を記憶装置13に予め記憶した基準の軸受特性と比較して異常の有無を判定することで行われる。
診断の結果、S19で軸受6が異常と判定したら、S20で表示装置14にその旨を表示して異常発生を報知し、異常がなければ異常診断を終了する。
In this bearing diagnosis, for example, inertia rotation is performed by stopping power supply to the spindle motor, and the rotation speed and temperature are measured until the stop of the spindle 4 is confirmed. Based on the measured rotation speed, friction torque and rolling are determined. This is performed by calculating a speed, a bearing preload, and the like to obtain a bearing characteristic, and comparing the bearing characteristic with a reference bearing characteristic stored in advance in the storage device 13 to determine whether there is an abnormality.
As a result of the diagnosis, if it is determined in S19 that the bearing 6 is abnormal, the fact is displayed on the display device 14 to notify the occurrence of the abnormality in S20, and if there is no abnormality, the abnormality diagnosis is ended.

このように、上記形態の工作機械1及び暖機運転時間の決定方法によれば、通常運転時に取得した温度時定数に基づいて暖機運転時間を決定し、その暖機運転時間に従って暖機運転を行っているので、適切な暖機運転時間を低コストで決定して不必要な暖機運転時間を解消できる。よって、効率的な軸受の異常診断が可能となる。   As described above, according to the machine tool 1 and the method for determining the warm-up operation time of the embodiment, the warm-up operation time is determined based on the temperature time constant acquired during the normal operation, and the warm-up operation is performed according to the warm-up operation time. Therefore, an appropriate warm-up operation time can be determined at low cost, and unnecessary warm-up operation time can be eliminated. Therefore, it is possible to efficiently diagnose the abnormality of the bearing.

なお、上記形態では、通常運転時の指定回転数の場合にのみ温度時定数を算出するようにしているが、全ての回転数の場合に温度時定数を算出するようにしてもよい。
また、温度時定数から推定した熱変位飽和時間から暖機運転時間を決定する割合は、89%に限らず、それより高い割合としてもよく、割合でなく熱変位飽和時間をそのまま暖機運転時間とすることもできる。
さらに、回転軸としては工具を回転させる主軸に限らず、ワークを把持して回転させる回転軸装置であっても本発明による暖機運転時間の決定及び軸受診断は可能である。
In the above embodiment, the temperature time constant is calculated only at the designated rotation speed during normal operation, but the temperature time constant may be calculated at all rotation speeds.
The rate at which the warm-up operation time is determined from the thermal displacement saturation time estimated from the temperature time constant is not limited to 89%, but may be a higher rate. It can also be.
Further, the rotary shaft is not limited to the main shaft for rotating the tool, and a rotary shaft device for gripping and rotating a work can determine the warm-up operation time and diagnose a bearing according to the present invention.

1・・工作機械、2・・主軸装置、3・・主軸ハウジング、4・・主軸、5・・工具、6・・軸受、7・・回転速度検出器、8・・温度センサ、9・・制御装置、10・・軸受診断装置、11・・計測装置、12・・演算装置、13・・記憶装置、14・・表示装置。   1. Machine tool, 2. Spindle device, 3. Spindle housing, 4. Spindle, 5. Tool, 6. Bearing, 7. Rotation speed detector, 8. Temperature sensor, 9. Control device, 10 ... Bearing diagnostic device, 11 ... Measurement device, 12 ... Computing device, 13 ... Storage device, 14 ... Display device.

Claims (8)

回転駆動する回転軸を軸受で軸支してなる回転軸装置と、前記回転軸の回転を制御する制御手段と、前記軸受の温度を検出する温度検出手段と、前記制御手段によって前記回転軸を所定の回転数で、且つ前記温度検出手段による検出温度が定常状態となるまでの時間で回転させる暖機運転を行った後、前記軸受の異常を検知する軸受診断を実行する軸受診断手段とを備えた工作機械において、前記暖機運転の時間を決定する方法であって、
前記軸受診断の実行前の通常運転時に、前記温度検出手段によって前記軸受の温度を検出する温度検出ステップと、
検出された前記軸受の温度変化と前記回転軸の回転数とに基づいて、前記通常運転時の温度時定数を算出する温度時定数算出ステップと、
算出された前記温度時定数を記憶する記憶ステップと、
前記暖機運転を行う際に、記憶された前記温度時定数に基づいて前記所定の回転数での前記暖機運転の時間を決定する時間決定ステップと、
を実行することを特徴とする工作機械における軸受診断前の暖機運転時間の決定方法。
A rotating shaft device that supports a rotating shaft that is rotationally driven by a bearing, a control unit that controls the rotation of the rotating shaft, a temperature detecting unit that detects the temperature of the bearing, and the control unit that controls the rotating shaft. Bearing diagnosis means for executing a bearing diagnosis for detecting an abnormality of the bearing after performing a warm-up operation of rotating at a predetermined rotation speed and for a time until the temperature detected by the temperature detection means reaches a steady state. A method for determining a time of the warm-up operation in a machine tool provided with:
During normal operation before the execution of the bearing diagnosis, a temperature detection step of detecting the temperature of the bearing by the temperature detection means,
A temperature time constant calculating step of calculating the temperature time constant during the normal operation based on the detected temperature change of the bearing and the rotation speed of the rotating shaft;
A storing step of storing the calculated temperature time constant;
When performing the warm-up operation, a time determination step of determining the time of the warm-up operation at the predetermined rotation speed based on the stored temperature time constant,
And determining the warm-up operation time before the bearing diagnosis in the machine tool.
前記温度検出ステップは、前記所定の回転数での通常運転時にのみ実行し、
前記温度時定数算出ステップでは、前記所定の回転数での温度上昇変化から前記所定の回転数での温度時定数を算出することを特徴とする請求項1に記載の工作機械における軸受診断前の暖機運転時間の決定方法。
The temperature detection step is executed only during normal operation at the predetermined rotation speed,
The said temperature time constant calculation step calculates the temperature time constant at the said predetermined rotation speed from the temperature rise change at the said predetermined rotation speed, The bearing before the bearing diagnosis in the machine tool of Claim 1 characterized by the above-mentioned. How to determine the warm-up operation time.
前記時間決定ステップでは、前記温度時定数から熱変位飽和時間を推定し、推定した前記熱変位飽和時間の任意の割合として前記暖機運転の時間を決定することを特徴とする請求項1又は2に記載の工作機械における軸受診断前の暖機運転時間の決定方法。   The time determination step estimates a thermal displacement saturation time from the temperature time constant, and determines the warm-up operation time as an arbitrary ratio of the estimated thermal displacement saturation time. 3. The method for determining a warm-up operation time before bearing diagnosis in a machine tool according to item 1. 前記任意の割合は、89%以上であることを特徴とする請求項3に記載の工作機械における軸受診断前の暖機運転時間の決定方法。   The method according to claim 3, wherein the arbitrary ratio is 89% or more. 回転駆動する回転軸を軸受で軸支してなる回転軸装置と、前記回転軸の回転を制御する制御手段と、前記軸受の温度を検出する温度検出手段と、前記制御手段によって前記回転軸を所定の回転数で、且つ前記温度検出手段による検出温度が定常状態となるまでの時間で回転させる暖機運転を行った後、前記軸受の異常を検知する軸受診断を実行する軸受診断手段とを備えた工作機械であって、
前記軸受診断の実行前の通常運転時に、前記温度検出手段によって前記軸受の温度を検出し、検出された前記軸受の温度変化と前記回転軸の回転数とに基づいて、前記通常運転時の温度時定数を算出する温度時定数算出手段と、
算出された前記温度時定数を記憶する記憶手段と、
前記暖機運転を行う際に、記憶された前記温度時定数に基づいて前記所定の回転数での前記暖機運転の時間を決定する時間決定手段と、
を備えることを特徴とする工作機械。
A rotating shaft device that supports a rotating shaft that is rotationally driven by a bearing, a control unit that controls the rotation of the rotating shaft, a temperature detecting unit that detects the temperature of the bearing, and the control unit that controls the rotating shaft. Bearing diagnosis means for executing a bearing diagnosis for detecting an abnormality of the bearing after performing a warm-up operation of rotating at a predetermined rotation speed and for a time until the temperature detected by the temperature detection means reaches a steady state. Machine tool with
During normal operation before the execution of the bearing diagnosis, the temperature of the bearing is detected by the temperature detecting unit, and the temperature during the normal operation is determined based on the detected temperature change of the bearing and the rotation speed of the rotating shaft. Temperature time constant calculating means for calculating a time constant,
Storage means for storing the calculated temperature time constant,
When performing the warm-up operation, time determining means for determining the time of the warm-up operation at the predetermined rotation speed based on the stored temperature time constant,
A machine tool comprising:
前記温度時定数算出手段では、前記所定の回転数での通常運転時にのみ前記軸受の温度を検出し、前記所定の回転数での温度上昇変化から前記所定の回転数での温度時定数を算出することを特徴とする請求項5に記載の工作機械。   The temperature time constant calculating means detects the temperature of the bearing only during normal operation at the predetermined rotation speed, and calculates a temperature time constant at the predetermined rotation speed from a change in temperature rise at the predetermined rotation speed. The machine tool according to claim 5, wherein 前記時間決定手段は、前記温度時定数から熱変位飽和時間を推定し、推定した前記熱変位飽和時間の任意の割合で前記暖機運転の時間を決定することを特徴とする請求項5又は6に記載の工作機械。   The said time determination means estimates the thermal displacement saturation time from the said temperature time constant, and determines the time of the warm-up operation at an arbitrary ratio of the estimated thermal displacement saturation time. A machine tool according to claim 1. 前記任意の割合は、89%以上であることを特徴とする請求項7に記載の工作機械。   The machine tool according to claim 7, wherein the arbitrary ratio is 89% or more.
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