JP2009248209A - Method of estimating thermal displacement of machine tool - Google Patents

Method of estimating thermal displacement of machine tool Download PDF

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JP2009248209A
JP2009248209A JP2008096481A JP2008096481A JP2009248209A JP 2009248209 A JP2009248209 A JP 2009248209A JP 2008096481 A JP2008096481 A JP 2008096481A JP 2008096481 A JP2008096481 A JP 2008096481A JP 2009248209 A JP2009248209 A JP 2009248209A
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temperature
equivalent
thermal displacement
setting
rotation speed
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JP4880634B2 (en
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Harumitsu Senda
治光 千田
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Okuma Corp
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Okuma Machinery Works Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To improve a thermal displacement estimating accuracy by correcting a set-equivalent heating value to eliminate the error of an estimated value. <P>SOLUTION: After a treatment for correcting a temperature-equivalent heating value is started and a time in which a rotating speed is three times a heating value changing time constant or higher is elapsed (S1), the difference between the reference temperature of a machine and the temperature near the bearing is calculated (S2) and the temperature-equivalent heat value is calculated according to an expression 1 (S3). The result is recorded with reference to the rotating speed (S4). When sufficient information for updating the preset set-equivalent heating value is provided (S5), the correction calculation for the set-equivalent heating value is performed according to an expression 2 (S6). Then the treatment is completed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、マシニングセンタ等の工作機械において、回転軸の熱変位を推定する熱変位推定方法に関するものである。   The present invention relates to a thermal displacement estimation method for estimating thermal displacement of a rotating shaft in a machine tool such as a machining center.

一般に、工作機械は、機械の特性上各部に熱源（例えば主軸の転がり軸受）を持っており、この熱源によって発生した熱が機械各部に伝わることで、機体の熱変位を引き起こす。機体の熱変位は加工精度に大きく影響するため、その防止対策として、従来から、発熱部を冷却する方法、或いは、機体温度情報から熱変位を推定して補正する方法が広く採用されている。   Generally, a machine tool has a heat source (for example, a rolling bearing of a main shaft) in each part due to the characteristics of the machine, and heat generated by this heat source is transmitted to each part of the machine, thereby causing thermal displacement of the machine body. Since the thermal displacement of the airframe greatly affects the machining accuracy, conventionally, a method of cooling the heat generating portion or a method of estimating and correcting the thermal displacement from the airframe temperature information has been widely adopted as a preventive measure.

後者の熱変位推定方法として、従来、本出願人は、特許文献１において、回転速度変化後の過渡状態から定常状態に至るまで、測定された温度変化を基に、回転時の相当発熱量を算出し、該算出値から熱変位を算出することで、あらゆる運転状況において熱変位を正確に推定する技術を提案している。さらに、特許文献２では、ムダ時間に対応するため発熱量が変化した後に、計測温度の複数回前との温度変化に基づいて相当発熱量を算出する方法を提案している。また、特許文献３では、過渡状態における温度と熱変位の時間応答が同様となるように時間或いは補正回数に応じて熱変位推定演算式の係数を変化させながら主軸の熱変位を求める熱変位推定演算を提案し、あらゆる運転状況において正確に補正することを提案している。これについては、特許文献４において、ムダ時間をキャンセルするため、温度及び熱変位の時間応答を等しくする関数で対応することを提案している。また、発熱量が急激に変化し、測定温度のムダ時間が大きい場合には、過渡状態の極初期において、温度変化が測定されない状態で、熱変位が発生する場合に、推定値に誤差が発生するという問題点に対して、予め設定した主軸回転速度と設定−相当発熱量の関係から、主軸回転速度変化前後での回転速度から算出される設定−相当発熱量と温度測定位置から算出される相当発熱量の差と回転速度変化後の経過時間から求めた補償量を、温度データに基づく温度−相当発熱量に加えることで、測定段階における測定ムダ時間を補償する提案をしている。   As a method for estimating the latter thermal displacement, in the past, the present applicant, in Patent Document 1, has calculated the amount of heat generated during rotation based on the measured temperature change from the transient state after the rotational speed change to the steady state. A technique for accurately estimating the thermal displacement in any driving situation by calculating and calculating the thermal displacement from the calculated value is proposed. Furthermore, Patent Document 2 proposes a method for calculating a corresponding heat generation amount based on a temperature change from a plurality of times before the measured temperature after the heat generation amount has changed in order to cope with waste time. Further, in Patent Document 3, thermal displacement estimation for obtaining the thermal displacement of the main shaft while changing the coefficient of the thermal displacement estimation formula according to the time or the number of corrections so that the time response of the temperature and the thermal displacement in the transient state is the same. Proposes computation and proposes to correct accurately in all driving situations. In order to cancel the waste time in Patent Document 4, it is proposed to deal with this with a function that equalizes the temperature and thermal displacement time responses. Also, if the amount of heat generation changes suddenly and the waste time of the measured temperature is large, an error will occur in the estimated value when thermal displacement occurs in the very early stage of the transient state without temperature change being measured. To solve the problem, the setting is calculated from the rotation speed before and after the change in the spindle rotation speed from the relationship between the preset spindle rotation speed and the setting-equivalent heating value. A proposal has been made to compensate the measurement waste time in the measurement stage by adding a compensation amount obtained from the difference between the equivalent heat generation amount and the elapsed time after the rotation speed change to the temperature-equivalent heat generation amount based on the temperature data.

特開２００６−０１５４６１号公報JP 2006-015461 A 特開２００７−０１５０９４号公報JP 2007-015094 A 特許第３１５１６５５号公報Japanese Patent No. 3151655 特許第３４２２４６２号公報Japanese Patent No. 3422462

ところが、これらの従来技術では、補償量算出のための基準となる設定−相当発熱量に回転速度に対する固定値を使用している。そのため、工作機械の環境温度変化により潤滑粘度が変化し回転速度に対する発熱量が変化した場合や、経時劣化による発熱量の変化があった場合に、設定−相当発熱量が実際と合わなくなり推定値に誤差が発生するという問題点があった。   However, in these conventional techniques, a fixed value with respect to the rotational speed is used for the setting-corresponding heat generation amount serving as a reference for calculating the compensation amount. Therefore, when the lubrication viscosity changes due to the environmental temperature change of the machine tool and the heat generation amount with respect to the rotation speed changes, or when there is a change in the heat generation amount due to deterioration over time, the setting-equivalent heat generation amount will not match the actual estimate There was a problem that an error occurred.

そこで、本発明では上記問題点を鑑み、回転速度に対する発熱量が変化した場合や、経時劣化による発熱量の変化があった場合であっても、設定−相当発熱量を修正して推定値の誤差をなくし、熱変位の推定精度を向上できる工作機械の熱変位推定方法の提供を課題とする。   Therefore, in view of the above problems, the present invention corrects the setting-equivalent heat generation amount by correcting the setting-equivalent heat generation amount even when the heat generation amount with respect to the rotation speed changes or when the heat generation amount changes due to deterioration over time. It is an object of the present invention to provide a thermal displacement estimation method for machine tools that can eliminate errors and improve thermal displacement estimation accuracy.

上記の課題を解決するために、請求項１に記載の発明は、工作機械の温度上昇をセンサで測定する段階と、測定した温度を数値化する段階と、数値化された温度データに基づき温度−相当発熱量を推定演算する段階と、該相当発熱量から熱変位を推定演算する段階と、予め設定した主軸回転速度と設定−相当発熱量の関係式をもとに主軸回転速度が変わる前の設定−相当発熱量の値と主軸回転速度が変化した後の設定−相当発熱量の値との差を求め、その差をもとに回転速度変化後の経過時間から求めた補償量を温度データに基づく温度−相当発熱量に加える段階とからなり、設定−相当発熱量の関係を、回転速度変化後で計測温度遅れ応答時定数の３倍以上経過した時間の温度−相当発熱量の値をもとに修正することを特徴とする。   In order to solve the above problems, the invention according to claim 1 is directed to a step of measuring a temperature rise of a machine tool with a sensor, a step of digitizing the measured temperature, and a temperature based on the digitized temperature data. -Estimating and calculating the equivalent heat value, Estimating and calculating thermal displacement from the equivalent heat value, Pre-set spindle speed and setting-Before changing the spindle speed based on the relational expression of equivalent heat value -The difference between the value of the equivalent calorific value and the setting after the spindle rotational speed changes-The value of the equivalent calorific value is obtained, and the compensation amount obtained from the elapsed time after the rotational speed change is calculated based on the difference. It consists of a step of adding to the temperature-equivalent calorific value based on the data, and the relationship between the setting and the equivalent calorific value is the temperature-equivalent calorific value at the time when more than three times the measured temperature delay response time constant has elapsed after the rotation speed change It is characterized by correcting based on

請求項２に記載の発明は、設定−相当発熱量の関係を、過去の複数回の値をもとに算出して修正することを特徴とする。   The invention according to claim 2 is characterized in that the relationship between the setting and the equivalent calorific value is calculated and corrected based on a plurality of past values.

請求項１、２の発明によれば、温度センサの時定数や取付位置によって生じる測定温度のムダ時間により、温度変化が測定される前に熱変位現象が発生する場合の補償に於いて、環境温度や経時劣化によって主軸の状態が変化し、回転速度に対する発熱量が変化した場合に特に優れた効果が期待でき、熱変位の推定精度を向上できるという優れた効果を奏する。また、設定−相当発熱量の修正に用いる温度−相当発熱量において、回転速度変更後の修正値を求めるまでの時間を短くできる。   According to the first and second aspects of the invention, in the compensation in the case where the thermal displacement phenomenon occurs before the temperature change is measured due to the waste time of the measurement temperature caused by the time constant of the temperature sensor and the mounting position, A particularly excellent effect can be expected when the state of the main shaft changes due to temperature and deterioration with time, and the amount of heat generated with respect to the rotational speed changes, and the excellent effect of improving the accuracy of thermal displacement estimation can be achieved. Further, it is possible to shorten the time required to obtain the corrected value after changing the rotation speed in the setting—the temperature used for correcting the equivalent heating value—the equivalent heating value.

以下に、本発明の熱変位推定方法を図面に基づいて詳細に説明する。図１はマシニングセンタにおける主軸回転速度の経時変化を示している。図２は図１の運転条件下における主軸の実際の熱変位、図３は測定温度の経時変化の一例である。図２の熱変位は非接触式変位センサを用いて１０秒間隔で測定し、図３の温度は主軸軸受の近傍に設置した温度センサで測定したものである。ここでは本発明の特徴を明らかにするために、同じ種類の主軸において十分な慣らし運転を行った後１５０００ｍｉｎ−１で運転した場合の軸受の温度変化を測定する統計調査を行った。図４は計４４台を測定した統計調査結果である。これより軸受の温度変化は４．０〜６．５℃の範囲で分布し、平均５．１３℃、標準偏差０．５８８℃であったことから、組立直後においても組立状況や環境温度状態の影響で発熱量が変化していることが分かる。これより回転速度と設定−相当発熱量の関係は、全ての機械や状況において必ずしも同じ係数にならないことを示している。 Below, the thermal displacement estimation method of this invention is demonstrated in detail based on drawing. FIG. 1 shows the change over time of the spindle rotation speed in the machining center. FIG. 2 shows an actual thermal displacement of the main shaft under the operating conditions of FIG. 1, and FIG. 3 shows an example of a change in measured temperature with time. The thermal displacement in FIG. 2 is measured at intervals of 10 seconds using a non-contact displacement sensor, and the temperature in FIG. 3 is measured with a temperature sensor installed in the vicinity of the main shaft bearing. Here, in order to clarify the features of the present invention, a statistical survey was performed to measure the temperature change of the bearing when the same type of spindle was operated at 15000 min −1 after sufficient running-in. FIG. 4 shows the results of a statistical survey of a total of 44 units. From this, the temperature change of the bearing is distributed in the range of 4.0-6.5 ° C, and the average was 5.13 ° C and the standard deviation was 0.588 ° C. It can be seen that the calorific value changes due to the influence. Thus, the relationship between the rotational speed and the setting-equivalent heat generation amount indicates that the coefficient is not necessarily the same in all machines and situations.

次に、図５のように主軸を回転させた場合の温度上昇と熱変位量の測定結果を図６に示す。さらに、式１は一定間隔の離散的に測定された温度上昇値に対して、温度−相当発熱量を求める伝達関数であり、実験に用いた機台の応答特性係数を代入し、式１’により求めた温度−相当発熱量の算出結果を図７に示す。ここでは、図５に示すように１３０００ｍｉｎ−１を基準とした温度上昇に対して温度−相当発熱量を算出したが、機械の基準温度に対する主軸軸受の近傍温度との差で温度−相当発熱量を算出してもよい。
ＴＸｎ＝ＴＹｎ−１＋（ＴＹｎ−ＴＹｎ−１）／αＴ 式１
ＴＸｎ：ｎ回目の温度−相当発熱量 ＴＹｎ：ｎ回目の温度変化
αＴ ：応答特性係数
ＴＸｎ＝ＴＹｎ−１＋（ＴＹｎ−ＴＹｎ−１）／０．９１ 式１’ Next, FIG. 6 shows the measurement results of temperature rise and thermal displacement when the main shaft is rotated as shown in FIG. Further, Equation 1 is a transfer function for obtaining temperature-equivalent calorific value with respect to temperature rise values measured discretely at regular intervals. Substituting the response characteristic coefficient of the machine base used in the experiment, Equation 1 ′ FIG. 7 shows the calculation result of the temperature-equivalent calorific value obtained by the above. Here, as shown in FIG. 5, the temperature-equivalent calorific value was calculated with respect to the temperature rise based on 13000 min −1 , but the temperature-equivalent calorific value is determined by the difference from the temperature near the spindle bearing with respect to the machine reference temperature. May be calculated.
TX n = TY n-1 + (TY n -TY n-1 ) / α T equation 1
TX n : n-th temperature-equivalent calorific value TY n : n-th temperature change α T : response characteristic coefficient TX n = TY n-1 + (TY n -TY n-1 ) /0.91 Equation 1 ′

ここで、主軸回転速度と設定−相当発熱量の関係式を式２に示す。
ＡＳ＝Ｃ・ＮＳ γ 式２
ＡＳ：回転速度と設定−発熱量の関係 Ｃ，γ：近似係数
ＮＳ：主軸指令回転速度 Here, a relational expression between the spindle rotation speed and the setting-equivalent heat generation amount is shown in Expression 2.
A S = C · N S γ Formula 2
A S : Relationship between rotational speed and setting-calorific value C, γ: Approximate coefficient N S : Spindle command rotational speed

回転速度が変化する前の設定−相当発熱量をＡｓ０、回転速度が変化した後での設定−相当発熱量をＡｓ１とすると、回転速度が変化する前と後での差 Ａｓｄは、式３で求めることができる。
ＡSｄ ＝ ＡS１−ＡS０ 式３
次に、式４を用いて回転速度変化後の経過時間から補償量を求め、式１のＴＸｎに加えることで、温度測定におけるムダ時間が補償された図８の結果を得る。
ＬＴｎ＝ Ａsｄ・ｅｘｐ（−ｔ／β） 式４
ＬＴｎ： 回転速度変化後ｎ回目の補償量
Ａsｄ ：回転速度が変化する前と後での差
ｔ：回転速度変化後の経過時間あるいは回転速度変化後の回数
β：温度検出の遅れを表す時定数
ここで、ＬＴｎが小さくなった場合には補償量の計算を終了することができる。 Assuming that the setting before the rotation speed is changed-the equivalent heating value is A s0 , and the setting after the rotation speed is changed-the equivalent heating value is A s1 , the difference Asd before and after the rotation speed is changed 3 can be obtained.
A Sd = A S1 −A S0 Formula 3
Next, the amount of compensation is obtained from the elapsed time after the rotation speed change using Equation 4, and added to TXn in Equation 1 to obtain the result of FIG. 8 in which the waste time in temperature measurement is compensated.
LT n = A sd · exp (−t / β) Equation 4
LT n : nth compensation amount A sd after rotation speed change: difference between before and after rotation speed change t: elapsed time after rotation speed change or number of times after rotation speed change β: temperature detection delay Time constant Here, when LT n becomes small, the calculation of the compensation amount can be terminated.

ところで、設定−相当発熱量は先に記しているとおり、組立状況や環境温度状態の影響で発熱量が変化するため、式２の近似係数Ｃは出荷時の既定値として設定することができない。そこで、近似係数Ｃを逐次変更することとする。具体的には、図６では温度変化、熱変位ともに飽和点に達していないのに対して、図７は回転速度変化後１分程度の短時間で飽和しているため、情報を得るのに都合がよいことが分かる。   By the way, the setting-equivalent calorific value, as described above, changes the calorific value due to the influence of the assembly condition and the environmental temperature state, and therefore the approximation coefficient C of Equation 2 cannot be set as a default value at the time of shipment. Therefore, the approximation coefficient C is sequentially changed. Specifically, in FIG. 6, neither the temperature change nor the thermal displacement has reached the saturation point, whereas FIG. 7 is saturated in a short time of about 1 minute after the rotation speed change. It turns out that it is convenient.

つまり設定−相当発熱量を求める場合には、熱変位や温度の飽和点まで待つことなく、短時間で必要な情報が得られることを示している。ここで必要な情報を得るまでの待ち時間としては、温度−相当発熱量の算出結果から回転速度変化に対するステップ応答として時定数を算出し、該時定数の3倍程度の時間が経過した以降の値を用いるとよい。また、近似係数の精度を高くするためには、回転速度に対する相当発熱量の値を複数点もとめ、式２にあてはめて最小二乗法などを用いて係数を決定することが望ましい。ここで使用する温度上昇は機械の基準温度に対する主軸軸受の近傍温度との差を用いる。   That is, when the setting-equivalent heat generation amount is obtained, it is shown that necessary information can be obtained in a short time without waiting for the thermal displacement or the temperature saturation point. Here, the waiting time until the necessary information is obtained is a time constant calculated as a step response to a change in rotational speed from the calculation result of the temperature-equivalent calorific value, and after about three times the time constant has elapsed. Use a value. In order to increase the accuracy of the approximation coefficient, it is desirable to obtain a plurality of values of the equivalent heat generation amount with respect to the rotation speed and apply the equation 2 to determine the coefficient using the least square method or the like. The temperature rise used here is the difference between the temperature near the spindle bearing and the reference temperature of the machine.

なお、この場合用いるデータは運転中に得られた情報であっても、特別に本目的のために設定する運転条件によって得られた結果、或いはその組合せの何れの場合でも良い。   It should be noted that the data used in this case may be information obtained during operation, a result obtained according to operation conditions specially set for this purpose, or a combination thereof.

次に、本発明をマシニングセンタに具体化した一実施形態を適宜図面に基づいて説明する。図９は立形マシニングセンタにおける熱変位補正システムを示すものであるが、これと同様のシステムを横形マシニングセンタに適用してもよい。マシニングセンタは、周知のように、主軸ヘッド１、コラム２、主軸３、ベッド４、移動テーブル５等から構成されている。主軸３の近傍にはその発熱温度を測定するための第１温度センサ６が取り付けられている（図１０参照）。ベッド４には基準温度を測定する第２温度センサ７が取り付けられている。   Next, an embodiment in which the present invention is embodied in a machining center will be described with reference to the drawings as appropriate. FIG. 9 shows a thermal displacement correction system in a vertical machining center, but a system similar to this may be applied to a horizontal machining center. As is well known, the machining center includes a spindle head 1, a column 2, a spindle 3, a bed 4, a moving table 5, and the like. A first temperature sensor 6 for measuring the heat generation temperature is attached in the vicinity of the main shaft 3 (see FIG. 10). A second temperature sensor 7 for measuring a reference temperature is attached to the bed 4.

温度測定装置８は各温度センサ６，７からのアナログ信号をデジタル信号に変換し、数値化された温度データを熱変位推定演算器９に出力する。記憶装置１０には補正パラメータ、および回転速度と設定−相当発熱量のパラメータが予め記憶されている。熱変位推定演算器９は温度データと補正パラメータとから熱変位を推定して補正値を算出する。そして、この補正値に基づいてＮＣ装置１１が周知の方法により位置補正を実行するようになっている。   The temperature measuring device 8 converts the analog signals from the temperature sensors 6 and 7 into digital signals, and outputs the digitized temperature data to the thermal displacement estimation calculator 9. The storage device 10 stores in advance correction parameters and parameters of rotation speed and setting-equivalent heat generation. The thermal displacement estimation calculator 9 estimates the thermal displacement from the temperature data and the correction parameter and calculates a correction value. Based on this correction value, the NC apparatus 11 executes position correction by a known method.

次に、熱変位補正システムについて、図１１をもとに説明する。まず、熱変位補正プログラムが開始されると、温度センサ６，７による温度測定が実行される（Ｓ１１）。そして、この間に主軸３の回転数が変化する（Ｓ１２）とカウンタがスタート（Ｓ１３）し、式３にて回転速度が変化する前の設定−相当発熱量Ａｓ0と回転速度が変化した後の設定−相当発熱量をＡｓ１との差Ａｓｄを算出する。ムダ時間補償量が小さくない間は、式４にて補償量を演算（Ｓ１６）し、式１による相当発熱量演算（Ｓ１７）に加算される。その後、熱変位相当温度変化を演算（Ｓ１８）し、熱変位量に換算（Ｓ１９）され、ＮＣ装置１１が補正処理（Ｓ２０）を行う。 Next, a thermal displacement correction system will be described with reference to FIG. First, when the thermal displacement correction program is started, temperature measurement is performed by the temperature sensors 6 and 7 (S11). During this time, when the rotational speed of the main shaft 3 changes (S12), the counter starts (S13), and the setting before the rotational speed is changed in Equation 3—the equivalent heating value As 0 and the rotational speed is changed. The difference A sd from the setting-equivalent heat generation amount to A s1 is calculated. While the waste time compensation amount is not small, the compensation amount is calculated by Equation 4 (S16) and added to the equivalent calorific value calculation (S17) by Equation 1. Thereafter, a temperature change corresponding to the thermal displacement is calculated (S18), converted into a thermal displacement amount (S19), and the NC device 11 performs a correction process (S20).

次に、本発明のフローチャートを示す図１２をもとに説明する。温度−相当発熱量の修正を行う処理がはじまり、回転速度が発熱量変化時定数の３倍以上の時間が経過(Ｓ１)すると、機械の基準温度に対する軸受近傍の温度との差を算出し（Ｓ２）式１に基づく補償量を用いた演算により温度−相当発熱量の算出を行う（Ｓ３）。その結果を回転速度との関係で記録する（Ｓ４）。予め設定した設定−相当発熱量の更新に十分な情報が得られる（Ｓ５）と式２により設定−相当発熱量の修正演算（Ｓ６）が行われ、処理を完了する。そして、この修正演算結果に相当する補正量が演算器９からＮＣ装置１１に出力され、該装置１１によって位置補正が実行される。   Next, a description will be given based on FIG. 12 showing a flowchart of the present invention. When the process of correcting the temperature-equivalent heat generation starts and the time when the rotational speed is more than 3 times the heat generation change time constant has elapsed (S1), the difference between the reference temperature of the machine and the temperature near the bearing is calculated ( S2) Temperature-equivalent heat generation is calculated by calculation using the compensation amount based on Equation 1 (S3). The result is recorded in relation to the rotation speed (S4). When sufficient information for updating the preset setting-equivalent calorific value is obtained (S5), the setting-corresponding calorific value correction calculation (S6) is performed according to Equation 2, and the processing is completed. Then, a correction amount corresponding to the correction calculation result is output from the calculator 9 to the NC device 11, and position correction is executed by the device 11.

このように、本発明の熱変位推定方法を採用した上記実施例のマシニングセンタによれば、環境温度や経時劣化によって主軸の状態が変化し、回転速度に対する発熱量が変化した場合であっても、設定−相当発熱量の関係を、回転速度変化後で計測温度遅れ応答時定数の３倍以上経過した時間の温度−相当発熱量の値をもとに修正することで、熱変位の推定精度を向上できるという優れた効果を奏する。また、設定−相当発熱量の修正に用いる温度−相当発熱量において、回転速度変更後の修正値を求めるまでの時間が短いメリットもある。   As described above, according to the machining center of the above embodiment adopting the thermal displacement estimation method of the present invention, even when the state of the main shaft changes due to environmental temperature or deterioration with time, and the amount of heat generated with respect to the rotational speed changes, By correcting the relationship between the setting and the equivalent heating value based on the temperature-equivalent heating value at the time when more than three times the measured temperature delay response time constant has elapsed after the rotation speed change, the estimated accuracy of thermal displacement can be improved. There is an excellent effect that it can be improved. In addition, there is an advantage that the time required to obtain the corrected value after the rotation speed change is short in the setting-temperature used for correcting the equivalent heating value-equivalent heating value.

マシニングセンタにおける主軸回転速度の経時変化を示す特性図である。It is a characteristic view which shows the time-dependent change of the spindle rotational speed in the machining center. 主軸熱変位の経時変化を示す特性図である。It is a characteristic view which shows a time-dependent change of a spindle thermal displacement. 主軸温度の経時変化を示す特性図である。It is a characteristic view which shows a time-dependent change of spindle temperature. 主軸温度上昇のばらつきを示す分布図である。It is a distribution map which shows the dispersion | variation in a spindle temperature rise. 主軸回転速度の経時変化を示す特性図である。It is a characteristic view which shows a time-dependent change of a spindle rotational speed. 主軸の熱変位及び温度上昇値の経時変化を示す特性図である。It is a characteristic view which shows the time-dependent change of the thermal displacement of a main axis | shaft and a temperature rise value. 測定温度から算出される温度−相当発熱量を示す特性図である。It is a characteristic figure which shows temperature-equivalent calorific value computed from measurement temperature. ムダ時間補償の相当発熱量を示す特性図である。It is a characteristic view which shows the equivalent calorific value of waste time compensation. 本発明の方法が実施される立形マシニングセンタの熱変位補正システムを示す概略図である。It is the schematic which shows the thermal displacement correction | amendment system of a vertical machining center with which the method of this invention is implemented. 温度センサの設置箇所を例示する主軸ヘッドの詳細図である。It is detail drawing of the spindle head which illustrates the installation location of a temperature sensor. マシニングセンタの温度をもとに熱変位を推定し、補正する方法を示すフローチャートである。It is a flowchart which shows the method of estimating and correcting a thermal displacement based on the temperature of a machining center. 温度−相当発熱量をもとに設定−温度発熱量の修正をおこなうフローチャートである。It is a flowchart which corrects setting-temperature calorific value based on temperature-corresponding calorific value.

符号の説明Explanation of symbols

１・・主軸ヘッド、３・・主軸、４・・ベッド、６・・第１温度センサ、７・・第２温度センサ、８・・温度測定装置、９・・熱変位推定演算器、１０・・記憶装置、１１・・ＮＣ装置。   1 .... Spindle head, 3 .... Spindle, 4 .... Bed, 6 .... First temperature sensor, 7 .... Second temperature sensor, 8 .... Temperature measuring device, 9 .... Thermal displacement estimation calculator, 10.・ Storage device, 11 ・ ・ NC device.

Claims (2)

工作機械の温度上昇をセンサで測定する段階と、測定した温度を数値化する段階と、数値化された温度データに基づき温度−相当発熱量を推定演算する段階と、該相当発熱量から熱変位を推定演算する段階と、予め設定した主軸回転速度と設定−相当発熱量の関係式をもとに主軸回転速度が変わる前の設定−相当発熱量の値と主軸回転速度が変化した後の設定−相当発熱量の値との差を求め、その差をもとに回転速度変化後の経過時間から求めた補償量を温度データに基づく温度−相当発熱量に加える段階とからなり、
設定−相当発熱量の関係を、回転速度変化後で計測温度遅れ応答時定数の３倍以上経過した時間の温度−相当発熱量の値をもとに修正する、
ことを特徴とする工作機械の熱変位推定方法。 A step of measuring the temperature rise of the machine tool with a sensor, a step of digitizing the measured temperature, a step of estimating a temperature-equivalent heat generation based on the digitized temperature data, and a thermal displacement from the equivalent heat generation Estimating and calculating, and setting before changing the spindle rotation speed based on the relationship between the preset spindle rotation speed and setting-equivalent heating value-setting after changing the equivalent heating value and spindle rotation speed -Finding the difference from the value of the equivalent calorific value, and adding the compensation amount obtained from the elapsed time after the rotation speed change based on the difference to the temperature-equivalent calorific value based on the temperature data,
Correct the setting-equivalent calorific value relationship based on the temperature-equivalent calorific value at the time when more than three times the measured temperature delay response time constant has elapsed after the rotation speed change.
A method for estimating thermal displacement of a machine tool. 設定−相当発熱量の関係を、過去の複数回の値をもとに算出して修正する、
請求項１に記載の工作機械の熱変位推定方法。 The setting-equivalent calorific value relationship is calculated and corrected based on the past multiple values.
The thermal displacement estimation method for a machine tool according to claim 1.
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JP2015030083A (en) * 2013-08-07 2015-02-16 株式会社ジェイテクト Method for determining linear expansion coefficient of each member in machine tool and thermal displacement correction device of machine tool

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