JP5541054B2 - Physical quantity measuring device for rotating members - Google Patents

Physical quantity measuring device for rotating members Download PDF

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JP5541054B2
JP5541054B2 JP2010224219A JP2010224219A JP5541054B2 JP 5541054 B2 JP5541054 B2 JP 5541054B2 JP 2010224219 A JP2010224219 A JP 2010224219A JP 2010224219 A JP2010224219 A JP 2010224219A JP 5541054 B2 JP5541054 B2 JP 5541054B2
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一宇 田中
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Description

この発明は、フライス盤、マシニングセンタ等の各種工作機械の主軸の如く、荷重を受けつつ高速で回転する回転軸等の回転部材に加わる荷重、或いはこの回転部材の変位量等の物理量を測定する為の、回転部材用物理量測定装置の改良に関する。具体的には、通常運転時に於ける測定精度を確保しつつ、非常時に適切な対応を行い易い構造を実現する事を目的としている。   This invention is for measuring a physical quantity such as a load applied to a rotating member such as a rotating shaft rotating at a high speed while receiving a load, or a physical quantity such as a displacement amount of the rotating member, such as a spindle of various machine tools such as a milling machine and a machining center. The present invention relates to an improvement of a physical quantity measuring device for rotating members. Specifically, an object is to realize a structure that facilitates an appropriate response in an emergency while ensuring measurement accuracy during normal operation.

工作機械の主軸は、先端部に刃物等の工具を固定した状態で高速回転し、加工台上に固定した被加工物に、切削等の加工を施す。前記主軸を回転自在に支持したヘッドは、この被加工物の加工の進行に伴って、所定方向に所定量だけ移動し、この被加工物を、所定の寸法及び形状に加工する。この様な加工作業時、前記ヘッドの移動速度を適正にする事が、加工能率を確保しつつ、前記工具の耐久性及び前記被加工物の品質を確保する為に必要である。前記移動速度が速過ぎると、前記工具に無理な力が加わり、この工具の耐久性が著しく損なわれるだけでなく、前記被加工物の表面性状が悪化したり、著しい場合にはこの被加工物に亀裂等の損傷が発生する。逆に、前記移動速度が遅過ぎると、前記被加工物の加工能率が徒に悪化する。   The spindle of the machine tool rotates at a high speed with a tool such as a blade fixed at the tip, and performs processing such as cutting on the workpiece fixed on the processing table. The head that rotatably supports the main shaft moves by a predetermined amount in a predetermined direction as the workpiece is processed, and processes the workpiece into a predetermined size and shape. In such a machining operation, it is necessary to make the moving speed of the head appropriate in order to ensure the durability of the tool and the quality of the workpiece while ensuring the machining efficiency. If the moving speed is too high, an excessive force is applied to the tool, and not only the durability of the tool is remarkably deteriorated, but also the surface property of the workpiece is deteriorated or, in the case of remarkable, the workpiece. Damage such as cracks occurs. On the contrary, when the moving speed is too slow, the processing efficiency of the workpiece is easily deteriorated.

前記ヘッドの移動速度の適正値は一定ではなく、工具の種類（大きさ）、被加工物の材質や形状により大きく変わる為、前記移動速度を一定としたまま、この移動速度を適正値に維持する事は難しい。この為、前記工具を固定した主軸に加わる荷重を測定する事により、前記移動速度を適正値に調節する事が、従来から知られている。即ち、工具により被加工物に切削等の加工を施す際には、加工抵抗により、この工具及びこの工具を固定した主軸に荷重が加わる。この加工抵抗、延いてはこの主軸に加わる荷重は、前記移動速度が速くなる程大きくなり、逆に、この移動速度が遅くなる程小さくなる。そこで、前記荷重が所定範囲に収まる様に、前記移動速度を調節すれば、この移動速度を適正範囲に収める事ができる。   The appropriate value of the moving speed of the head is not constant, but varies greatly depending on the type (size) of the tool and the material and shape of the workpiece. Therefore, the moving speed is kept constant while keeping the moving speed constant. It is difficult to do. For this reason, it is conventionally known that the moving speed is adjusted to an appropriate value by measuring the load applied to the main spindle to which the tool is fixed. That is, when a work such as cutting is performed on a workpiece with a tool, a load is applied to the tool and the main shaft to which the tool is fixed due to processing resistance. The machining resistance, and hence the load applied to the main shaft, increases as the moving speed increases, and conversely decreases as the moving speed decreases. Therefore, if the moving speed is adjusted so that the load falls within a predetermined range, the moving speed can be kept within an appropriate range.

又、この移動速度等、他の条件を同じとした場合に前記荷重は、前記工具の切削性（切れ味）が劣化する程大きくなる。そこで、前記移動速度との関係で前記荷重の大小を観察すれば、前記工具が寿命に達した事を知る事ができて、寿命に達した不良工具で加工を継続する事による、歩留まりの悪化を防止できる。又、前記荷重を、前記移動速度等、他の加工条件と関連付けて継続的に観察する事により、最適な加工条件を見出して、省エネルギ化や工具の長寿命化に繋げる事もできる。更に、継続的観察により、工具破損等の事故発生時に、その原因を特定する事もできる。   In addition, when other conditions such as the moving speed are the same, the load increases as the cutting property (sharpness) of the tool deteriorates. Therefore, by observing the magnitude of the load in relation to the moving speed, it is possible to know that the tool has reached the end of its life, and deterioration in yield due to continuing processing with a defective tool that has reached the end of its life. Can be prevented. In addition, by continuously observing the load in association with other machining conditions such as the moving speed, it is possible to find the optimum machining conditions and lead to energy saving and long tool life. Furthermore, by continuous observation, the cause of an accident such as tool breakage can be identified.

この様な目的で、工作機械の主軸等の回転軸に加わる荷重（切削抵抗）を測定する為の装置として従来から、例えば特許文献１に記載された構造のものが知られている。この特許文献１に記載された荷重測定装置は、水晶圧電式の荷重センサを複数個、荷重の作用方向に対して直列に配置し、これら各荷重センサの測定信号に基づいて、切削工具を支持固定した回転軸に加わる荷重（切削抵抗）を測定する様に構成している。この様な特許文献１に記載された荷重測定装置の場合、高価な水晶圧電式の荷重センサを使用する為、荷重測定装置全体としてのコストが嵩む事が避けられない。   For such a purpose, a device having a structure described in Patent Document 1, for example, is conventionally known as a device for measuring a load (cutting resistance) applied to a rotating shaft such as a main shaft of a machine tool. The load measuring apparatus described in Patent Document 1 includes a plurality of quartz piezoelectric type load sensors arranged in series with respect to the direction of load application, and supports a cutting tool based on measurement signals of these load sensors. The load (cutting resistance) applied to the fixed rotating shaft is measured. In the case of such a load measuring device described in Patent Document 1, since an expensive quartz piezoelectric load sensor is used, it is inevitable that the cost of the load measuring device as a whole increases.

一方、特許文献２〜４には、水晶圧電式の荷重センサに比べて低コストで調達できる、磁気式の被検出リングとセンサとにより構成する、荷重測定装置付転がり軸受ユニットに関する発明が記載されている。例えば特許文献２の段落［００６６］〜［００６８］には、図８に示す様な被検出リング（トーンホイール或いはエンコーダ）１を使用して、この被検出リング１を同心に支持した回転部材の軸方向に関する変位量、延いてはこの回転部材に加わるアキシアル荷重を測定する技術が記載されている。後述する本発明の実施の形態の構造は、前記被検出リング１と同様の特性を有する被検出リングを使用して、工作機械の主軸の軸方向変位量、更に必要に応じてこの主軸に加わるアキシアル荷重を測定するものである。そこで、先ず、前記被検出リング１の形状、並びに、この被検出リング１を使用して、軸方向変位量及びアキシアル荷重を測定する原理に就いて説明する。   On the other hand, Patent Documents 2 to 4 describe inventions related to a rolling bearing unit with a load measuring device, which includes a magnetic detection ring and a sensor, which can be procured at a lower cost than a quartz piezoelectric load sensor. ing. For example, in paragraphs [0066] to [0068] of Patent Document 2, a detected ring (tone wheel or encoder) 1 as shown in FIG. 8 is used, and a rotating member that supports the detected ring 1 concentrically is used. A technique for measuring the amount of displacement in the axial direction and thus the axial load applied to the rotating member is described. The structure of the embodiment of the present invention to be described later uses a detected ring having the same characteristics as the detected ring 1, and adds an axial displacement amount of the spindle of the machine tool, and further, if necessary, to this spindle. It measures the axial load. First, the shape of the ring to be detected 1 and the principle of measuring the axial displacement and the axial load using the ring to be detected 1 will be described.

前記被検出リング１は、鋼板等の磁性金属板を円筒状に形成して成るもので、それぞれが１対ずつの透孔２ａ、２ｂから成る、複数の被検出用特性変化組み合わせ部３、３を、周方向に関して等間隔に配置している。この様な各被検出用特性変化組み合わせ部３、３を構成する前記各透孔２ａ、２ｂの、前記被検出リング１の軸方向に対する傾斜方向は、互いに逆向きとしている。従って、前記各被検出用特性変化組み合わせ部３、３を構成する、それぞれ１対ずつの透孔２ａ、２ｂの周方向に関するピッチ（間隔）は、前記アキシアル荷重の測定方向に一致する、前記被検出面の幅方向に関して漸次変化している。この為、前記被検出リング１のうち、被検出面である外周面の磁気特性は、前記各透孔２ａ、２ｂの存在により、円周方向に関して変化している。又、この円周方向に関して前記磁気特性が変化するパターン（後述するパルス周期比δ／Ｌに対応する、円周方向に亙る特性変化状況）は、前記測定すべきアキシアル荷重の作用方向に関する位置である、前記被検出リング１の軸方向位置が異なると、互いに異なるものとなる。   The ring to be detected 1 is formed by forming a magnetic metal plate such as a steel plate in a cylindrical shape, and each of the plurality of detected characteristic change combination parts 3 and 3 is composed of a pair of through holes 2a and 2b. Are arranged at equal intervals in the circumferential direction. The inclination directions of the through holes 2a and 2b constituting the detected characteristic change combination portions 3 and 3 with respect to the axial direction of the detected ring 1 are opposite to each other. Therefore, the pitches (intervals) in the circumferential direction of the pair of through holes 2a and 2b that constitute the detected characteristic change combination portions 3 and 3 respectively correspond to the measurement direction of the axial load. It gradually changes in the width direction of the detection surface. For this reason, the magnetic characteristics of the outer peripheral surface, which is the detected surface, of the detected ring 1 change in the circumferential direction due to the presence of the through holes 2a and 2b. Further, the pattern in which the magnetic characteristics change with respect to the circumferential direction (the characteristic change situation in the circumferential direction corresponding to a pulse period ratio δ / L described later) is a position related to the acting direction of the axial load to be measured. If the axial positions of the detected rings 1 are different, they are different from each other.

上述の様な被検出リング１は、工作機械の主軸の如き回転部材の一部に、この回転部材と同心に（この回転部材の回転中心と共通する回転中心を有する状態で）固定する。又、この回転部材に隣接する部分に設けられた静止部材の一部で前記被検出リング１の外周面に対向する部分にセンサを設けている。これら被検出リング１の外周面とセンサの検出部とは、微小隙間を介して近接対向させており、この被検出リング１の回転に伴って前記センサの出力信号が変化する様にしている。この為に、例えばこのセンサとして、ホール素子、磁気抵抗素子等の磁気検出素子と永久磁石とを組み合わせた、磁気検知式のものを使用する。   The detected ring 1 as described above is fixed to a part of a rotating member such as a main shaft of a machine tool concentrically with the rotating member (in a state having a rotation center common to the rotation center of the rotating member). In addition, a sensor is provided in a part of the stationary member provided in a part adjacent to the rotating member and facing the outer peripheral surface of the ring 1 to be detected. The outer peripheral surface of the ring 1 to be detected and the detection part of the sensor are closely opposed to each other through a minute gap so that the output signal of the sensor changes with the rotation of the ring 1 to be detected. For this purpose, for example, a magnetic detection type sensor in which a magnetic detection element such as a Hall element or a magnetoresistive element and a permanent magnet are combined is used as this sensor.

前記回転部材と共に前記被検出リング１が回転すると、前記センサがこの被検出リングの外周面を走査する。この被検出面の磁気特性は、前述の様に、前記各透孔２ａ、２ｂの存在により円周方向に変化している為、前記被検出リング１の回転に伴って前記センサの出力信号が変化する。例えば、このセンサの検出部がこの被検出リング１の外周面のうち、図９の（Ａ）の鎖線イ位置を走査すると、このセンサの出力信号が、この図９の（Ｂ）に示す様に変化する。この図９の（Ｂ）で、円周方向に隣り合う１対の透孔２ａ、２ｂに基づいて発生する１対のパルス間の周期を部分周期δ1とする。又、円周方向に隣り合う１対の被検出用特性変化組み合わせ部３、３のうちで、互いに対応する（傾斜方向が同じである）透孔２ａ、２ａ（又は２ｂ、２ｂ）に基づいて発生する１対のパルス間の周期を全周期Ｌ1とする。前記センサの検出部が前記鎖線イ位置を走査する場合には、前記部分周期δ1と前記全周期Ｌ1との比であるパルス周期比δ1／Ｌ1は、比較的小さな（０に近い）値となる。これに対して、前記センサの検出部が図９の（Ａ）の鎖線ロ位置を走査すると、このセンサの出力信号が、この図９の（Ｃ）に示す様に変化する。そして、部分周期δ2と全周期Ｌ2との比（パルス周期比δ2／Ｌ2）は、比較的大きな（１に近い）値となる。以上の説明では、走査位置に伴ってパルス周期比の大小が変化する方向が、分子となる部分周期δとして、同じ被検出用特性変化組み合わせ部３を構成する１対の透孔２ａ、２ｂに関するパルス間の周期を採用した場合に就いて述べた。分子となる部分周期として、円周方向に隣り合う被検出用特性変化組み合わせ部３、３を構成し、互いに逆方向に傾斜した（円周方向に隣り合う）１対の透孔２ａ、２ｂに関するパルスの周期を採用した場合には、前記パルス周期比の大小が変位する方向が、上述した場合とは逆になる。 When the detected ring 1 rotates together with the rotating member, the sensor scans the outer peripheral surface of the detected ring. As described above, the magnetic characteristics of the surface to be detected change in the circumferential direction due to the presence of the through holes 2a and 2b, so that the output signal of the sensor changes as the detection ring 1 rotates. Change. For example, when the detection unit of the sensor scans the position of the chain line a in FIG. 9A on the outer peripheral surface of the ring 1 to be detected, the output signal of the sensor is as shown in FIG. 9B. To change. In the FIG. 9 (B), a pair of through holes 2a adjacent to each other in the circumferential direction, 2b to the period between a pair of pulses with sub-periods [delta] 1 generated based on. In addition, based on the through holes 2a, 2a (or 2b, 2b) corresponding to each other (in the same inclination direction) among the pair of detected characteristic change combination portions 3, 3 adjacent to each other in the circumferential direction. A period between a pair of generated pulses is defined as a total period L 1 . When the detection unit of the sensor scans the chain line a position, the pulse period ratio δ 1 / L 1 , which is the ratio of the partial period δ 1 and the total period L 1 , is relatively small (close to 0). ) Value. On the other hand, when the detection unit of the sensor scans the position of the chain line in FIG. 9A, the output signal of the sensor changes as shown in FIG. 9C. The ratio between the partial period δ 2 and the total period L 2 (pulse period ratio δ 2 / L 2 ) is a relatively large value (close to 1). In the above description, the direction in which the magnitude of the pulse period ratio changes with the scanning position is related to the pair of through holes 2a and 2b constituting the same detected characteristic change combination unit 3 as the partial period δ that becomes a molecule. The case where the period between pulses was adopted was described. Concerning the pair of through holes 2a, 2b that constitute the characteristic change combination portions 3 and 3 for detection adjacent to each other in the circumferential direction as the partial period that becomes a molecule and are inclined in opposite directions (adjacent to the circumferential direction). When the pulse period is adopted, the direction in which the magnitude of the pulse period ratio is displaced is opposite to that described above.

何れにしても、前記センサの出力信号に関するパルス周期比δ／Ｌは、このセンサの検出部が走査する、前記被検出リング１の外周面の軸方向位置により変化する。そして、この軸方向位置は、被検出リングを固定した回転部材の軸方向変位により変化する。又、この回転部材が、予圧を付与された転がり軸受により回転自在に支持されていた場合、この回転部材の軸方向変位量は、この回転部材に加わるアキシアル荷重の大きさに応じて変化する。言い換えれば、この回転部材に加わるアキシアル荷重と、この回転部材の軸方向変位量との間には、反復・再現性のある相関関係が存在する。そして、この相関関係は、転がり軸受の分野で広く知られている弾性接触理論により計算で求められる他、実験によっても求められる。従って、前記センサの出力信号を処理する為の演算器に、前記相関関係を勘案した、前記アキシアル荷重を算出する為の式を組み込んだソフトウェアをインストールしておけば、前記演算器により、前記パルス周期比δ／Ｌに基づいて、前記回転部材に加わるアキシアル荷重を算出できる。   In any case, the pulse cycle ratio δ / L related to the output signal of the sensor changes depending on the axial position of the outer peripheral surface of the ring 1 to be detected, which is scanned by the detection unit of the sensor. And this axial position changes with the axial displacement of the rotating member which fixed the to-be-detected ring. Further, when the rotating member is rotatably supported by a rolling bearing to which a preload is applied, the axial displacement amount of the rotating member changes according to the magnitude of the axial load applied to the rotating member. In other words, there is a reproducible and reproducible correlation between the axial load applied to the rotating member and the axial displacement of the rotating member. And this correlation is calculated | required not only by calculation by the elastic contact theory widely known in the field of a rolling bearing but also by experiment. Therefore, if software that incorporates an equation for calculating the axial load in consideration of the correlation is installed in an arithmetic unit for processing the output signal of the sensor, the arithmetic unit calculates the pulse. Based on the cycle ratio δ / L, an axial load applied to the rotating member can be calculated.

例えば、前記回転部材を工作機械の主軸とし、外周面に図８〜９に示す様な被検出用特性変化組み合わせ部３、３を形成した被検出リング１を前記主軸に外嵌固定すると共に、工作機械のハウジング（主軸頭）にセンサを支持固定すれば、この主軸に加わるアキシアル荷重を測定可能になる。そして、この主軸の移動速度を適正範囲に収めたり、この主軸の先端部に支持した工具の寿命を判定したり、最適な加工条件を求めて省エネルギ化や工具の長寿命化に繋げたり、事故発生時にその原因を特定したりできる。   For example, the rotating member is a main shaft of a machine tool, and the detected ring 1 having the detected characteristic change combination portions 3 and 3 as shown in FIGS. If the sensor is supported and fixed to the housing (spindle head) of the machine tool, the axial load applied to the spindle can be measured. And the movement speed of this spindle is kept within the proper range, the life of the tool supported on the tip of this spindle is judged, and the optimum machining conditions are obtained, leading to energy saving and long tool life, The cause of an accident can be identified.

ところで、上述の様にして、例えば主軸に加わるアキシアル荷重を測定する為の測定装置を構成した場合でも、信頼性の高い測定を行う場合には、前記センサの出力信号や、この出力信号を処理して軸方向変位を表す信号とした処理信号に、フィルタリング処理を施す必要がある。即ち、この出力信号中には、様々なノイズが混入する為、このノイズを除去してから前記演算器に送り込むか、或いは、この演算器による処理を施した処理信号中のノイズを除去しないと、このノイズに起因して、前記アキシアル荷重等の測定値に、無視できない程の誤差を生じる可能性がある。そこで、前記センサから前記演算器に前記出力信号を送る為の、又は、この演算器による処理を施した処理信号を送る為の信号伝達回路の途中に適宜のフィルタを設け、前記出力信号又はこの処理信号中に混入したノイズを除去する事が望ましい。この様な場合に使用できるフィルタとしては、ローパスフィルタ、バンドパスフィルタ、適応フィルタ等が、採用可能である。   By the way, as described above, for example, even when a measuring device for measuring an axial load applied to the spindle is configured, when performing highly reliable measurement, the output signal of the sensor or the output signal is processed. Thus, it is necessary to perform a filtering process on the processed signal that represents the axial displacement. That is, since various noises are mixed in this output signal, this noise must be removed before being sent to the computing unit or the noise in the processed signal processed by this computing unit must be removed. Due to this noise, an error that cannot be ignored may occur in the measured value of the axial load or the like. Therefore, an appropriate filter is provided in the middle of a signal transmission circuit for sending the output signal from the sensor to the computing unit, or for sending a processing signal processed by the computing unit, and the output signal or the It is desirable to remove noise mixed in the processed signal. As a filter that can be used in such a case, a low-pass filter, a band-pass filter, an adaptive filter, or the like can be used.

例えば、ローパスフィルタを使用する事により、前記被検出用特性変化組み合わせ部３、３を形成した被検出リング１の回転によっては出現しない様な高周波成分を、前記出力信号中より除去してから、前記演算器に送り込む。但し、ローパスフィルタは、カットオフ周波数により、検出可能な（通過して前記演算器又はこの演算器よりも後方に設けられる制御器に送り込まれる）出力信号の周波数レンジが変わるだけでなく、応答性も変わる。即ち、カットオフ周波数が低いローパスフィルタの場合には、比較的周波数の低いノイズまで除去できる為、ノイズがアキシアル荷重の測定結果に及ぼす悪影響を、解消乃至僅少に抑えて、信頼性の高い測定を行える代わりに、応答性が悪い。これに対して、カットオフ周波数が高いローパスフィルタの場合には、応答性が良好である代わりに、比較的周波数の低いノイズを通過させる為、ノイズがアキシアル荷重の測定値に悪影響を及ぼし易く、測定結果の信頼性確保が難しくなる。例えば、周波数が１０Ｈｚのノイズ成分が存在する場合に、カットオフ周波数が８〜９Ｈｚ程度である、カットオフ周波数が低いローパスフィルタを使用すれば、前記ノイズ成分を除去して、測定結果の信頼性確保を図れる。   For example, by using a low-pass filter, high frequency components that do not appear due to rotation of the detected ring 1 forming the detected characteristic change combination units 3 and 3 are removed from the output signal, Send to the computing unit. However, the low-pass filter not only changes the frequency range of the output signal that can be detected (passed and sent to the arithmetic unit or a controller provided behind the arithmetic unit) depending on the cut-off frequency, but also has responsiveness. Will also change. In other words, in the case of a low-pass filter with a low cut-off frequency, noise with a relatively low frequency can be removed, so that the adverse effect of noise on the measurement result of the axial load can be eliminated or suppressed to a high level and highly reliable measurement can be performed. In spite of being able to do it, responsiveness is poor. On the other hand, in the case of a low-pass filter with a high cut-off frequency, instead of having a good response, noise with a relatively low frequency is allowed to pass through, so that the noise tends to adversely affect the measured axial load value. It becomes difficult to ensure the reliability of measurement results. For example, when a noise component having a frequency of 10 Hz exists, if a low-pass filter having a cut-off frequency of about 8 to 9 Hz and a low cut-off frequency is used, the noise component is removed, and the reliability of the measurement result Secure it.

工作機械の主軸の回転速度は運転状況に伴って変化し、ノイズ成分の周波数に関してもそれに伴って変化する場合がある。この場合でもカットオフ周波数可変式のローパスフィルタを使用し、前記主軸の回転速度に応じてこのカットオフ周波数を変化させれば、通常の運転状態である限り、ノイズ成分を除去して、測定結果の信頼性確保を図れる。又、通常運転時には、測定結果に関して信頼性を確保する事が重要で、特に高い応答性を確保する必要はなく、ローパスフィルタの応答性が悪い事は、特に問題とはならない。以上の事から明らかな通り、主軸の移動速度を適正範囲に収めたり、工具の寿命を判定したり、省エネルギ化や工具の長寿命化に繋げたりする為には、前記ローパスフィルタとして、特に応答性の高いものを使用する必要はない。   The rotational speed of the spindle of the machine tool changes with the operating condition, and the frequency of the noise component may change with it. Even in this case, if the cut-off frequency variable low-pass filter is used and the cut-off frequency is changed in accordance with the rotation speed of the main shaft, the noise component is removed and the measurement result is maintained as long as the normal operation state. Ensuring reliability. Further, during normal operation, it is important to ensure reliability with respect to the measurement result, and it is not necessary to ensure particularly high responsiveness, and the low response of the low-pass filter is not particularly problematic. As apparent from the above, in order to keep the moving speed of the spindle within an appropriate range, to determine the tool life, and to save energy and extend the tool life, the low-pass filter is particularly It is not necessary to use a highly responsive one.

但し、非常時の対応を適切に行わせる為には、前記ローパスフィルタとして応答性が高いものを使用する必要がある。例えば、主軸の移動速度が速過ぎたり、主軸の移動方向が不正であったりした場合には、この主軸の先端部に支持固定した工具が被加工物に衝突する可能性がある。そして、衝突した場合には、前記主軸に、瞬間的に過大な荷重（ピーク荷重）が加わる。前記衝突により工作機械の各部が損傷するのを防止する為には、このピーク荷重を検出して、この衝突の直後に前記主軸を緊急停止させる必要がある。この様な場合には、前記ローパスフィルタの応答性が高い事が必要になる。更に、緊急停止が間に合わない等により工作機械が故障した場合には、この工作機械のユーザーからの要請により、同じくメーカーの技術者が対応する事になる。その際、主軸から工具が取り外されていた上、ユーザー側の作業者からメーカー側の技術者への状況説明が適切に行われないと、メーカー側の技術者が故障の原因を特定できず、適切な修理等を行えなくなる可能性がある。この様な場合にも、前記主軸に加わる荷重の情報がメモリに記録されていれば、メーカー側の技術者が故障の原因を特定して、適切な修理等を行い易くなる。この様な場合にも、前記メモリに前記ピーク荷重を記録する為には、前記ローパスフィルタの応答性が高い事が必要になる。以上の事から明らかな通り、工具が被加工物に衝突する様な、非常時の対応を適切に行わせる為には、前記ローパスフィルタとして応答性が高いものを使用する必要がある。   However, in order to appropriately deal with an emergency, it is necessary to use a low-response filter as the low-pass filter. For example, when the moving speed of the main shaft is too fast or the moving direction of the main shaft is incorrect, there is a possibility that the tool supported and fixed at the tip of the main shaft collides with the workpiece. When a collision occurs, an excessive load (peak load) is momentarily applied to the main shaft. In order to prevent each part of the machine tool from being damaged by the collision, it is necessary to detect the peak load and to stop the spindle immediately after the collision. In such a case, it is necessary that the response of the low-pass filter is high. In addition, when a machine tool breaks down due to an emergency stop, etc., the manufacturer's engineer will respond to the request from the machine tool user. At that time, if the tool was removed from the main spindle and the situation from the user side worker to the manufacturer side engineer was not properly explained, the manufacturer side engineer could not identify the cause of the failure, There is a possibility that proper repair etc. cannot be performed. Even in such a case, if the information on the load applied to the main shaft is recorded in the memory, it becomes easier for the manufacturer's engineer to identify the cause of the failure and perform appropriate repairs. Even in such a case, in order to record the peak load in the memory, it is necessary that the responsiveness of the low-pass filter is high. As is clear from the above, it is necessary to use a filter with high responsiveness as the low-pass filter in order to appropriately deal with an emergency such that the tool collides with the workpiece.

特開２００２−１８７０４８号公報JP 2002-187048 A 特開２００６−３１７４２０号公報JP 2006-317420 A 特開２００８−３９１５５号公報JP 2008-39155 A 特開２００８−６４７３１号公報JP 2008-64731 A

本発明は、上述の様な事情に鑑みて、例えば工作機械の主軸に加わるアキシアル荷重を測定するのに利用した場合に、通常運転時には測定値の信頼性を十分に確保でき、しかも、非常時には迅速且つ適切な対応を可能にできる回転部材用物理量測定装置を実現すべく発明したものである。   In view of the circumstances as described above, the present invention can sufficiently ensure the reliability of measured values during normal operation, for example, when used to measure the axial load applied to the spindle of a machine tool, and in an emergency. The present invention has been invented to realize a physical quantity measuring device for a rotating member that can quickly and appropriately respond.

本発明の回転部材用物理量測定装置は、ハウジングと、回転部材と、被検出リングと、センサと、演算器とを備える。
このうちのハウジングは、例えば工作機械の主軸頭（ヘッド）等であり、回転しない。
又、前記回転部材は、例えば工作機械の主軸であり、それぞれが予圧を付与された複数の転がり軸受により前記ハウジングの内側に、回転自在に支持されている。
又、前記被検出リングは、前記回転部材の一部に支持固定されたもので、この回転部材と同心の被検出面を有する。
又、前記センサは、検出部をこの被検出面に対向させた状態で、前記ハウジングに支持されている。
更に、前記演算器は、前記センサの出力信号を処理するもので、この出力信号の位相に関する情報に基づいて、前記回転部材に関する物理量を求める機能を有する。 The physical quantity measuring device for a rotating member of the present invention includes a housing, a rotating member, a ring to be detected, a sensor, and an arithmetic unit.
Among these, the housing is, for example, a spindle head (head) of a machine tool and does not rotate.
The rotating member is, for example, a main shaft of a machine tool, and is rotatably supported inside the housing by a plurality of rolling bearings each provided with a preload.
The detected ring is supported and fixed to a part of the rotating member, and has a detected surface concentric with the rotating member.
The sensor is supported by the housing in a state where the detection portion faces the detected surface.
Furthermore, the computing unit processes an output signal of the sensor, and has a function of obtaining a physical quantity related to the rotating member based on information related to the phase of the output signal.

特に、本発明の回転部材用物理量測定装置に於いては、前記演算器が前記出力信号を処理した処理信号を取り出す為の処理信号取り出し部分、又は、前記センサから前記演算器に前記出力信号を送る出力信号送信部分に、それぞれが前記処理信号又はこの出力信号を後方に送る機能を備えた複数の信号伝達回路を、互いに並列に設けている。又、これら各信号伝達回路に、これら各信号伝達回路中を送られる前記処理信号又は前記出力信号中に含まれるノイズを除去する為のフィルタを設けている。そして、これら各信号伝達回路中に設けた各フィルタの特性を、互いに異ならせている。   In particular, in the physical quantity measuring device for a rotating member according to the present invention, a processing signal extraction portion for extracting a processing signal obtained by processing the output signal by the arithmetic unit, or the output signal from the sensor to the arithmetic unit. A plurality of signal transmission circuits each having a function of sending the processing signal or the output signal backward are provided in parallel in the output signal transmission portion to be sent. Each of these signal transmission circuits is provided with a filter for removing noise contained in the processing signal or the output signal sent through the signal transmission circuit. The characteristics of the filters provided in the signal transmission circuits are different from each other.

上述の様な本発明の回転部材用物理量測定装置を実施する場合に好ましくは、請求項２に記載した発明の様に、前記処理信号又は前記出力信号に対応する物理量を、前記各信号伝達回路を送られるこの処理信号又はこの出力信号毎に、経過時間と関連付けて記録するメモリを備える。   Preferably, when the physical quantity measuring device for a rotating member of the present invention as described above is implemented, the physical quantity corresponding to the processing signal or the output signal is converted into each signal transmission circuit as in the invention described in claim 2. For each processing signal or output signal sent to the memory, a memory is provided which records in association with the elapsed time.

又、上述の様な本発明の回転部材用物理量測定装置を実施する場合に、具体的には、請求項３に記載した発明の様に、前記被検出リングの被検出面に複数の被検出用特性変化組み合わせ部を、周方向に関して等間隔に、それぞれ前記物理量の測定方向に一致する前記被検出面の幅方向に形成する。そして、前記各被検出用特性変化組み合わせ部は、この幅方向に対する傾斜方向が互いに異なる１対の特性変化部を、前記被検出リングの周方向に離隔した状態で設けたものとする。
又、前記センサは、前記各被検出用特性変化組み合わせ部を構成する前記各特性変化部が前記検出部が対向する部分を通過する瞬間に、出力信号を変化させるものとする。
更に、前記演算器は、円周方向に隣り合う１対の特性変化部に基づいて発生する１対のパルス間の周期である部分周期と、円周方向に隣り合う１対の被検出用特性変化組み合わせ部の対応する特性変化部に基づいて発生する、別の１対のパルス間の周期である全周期との比であるパルス周期比に基づいて、前記物理量を求める。 Further, when the physical quantity measuring device for a rotating member of the present invention as described above is implemented, specifically, as in the invention described in claim 3, a plurality of detected objects are detected on the detected surface of the detected ring. The characteristic change combination portions are formed at equal intervals in the circumferential direction in the width direction of the detected surface that coincides with the measurement direction of the physical quantity. Each of the detected characteristic change combination parts is provided with a pair of characteristic change parts having different inclination directions with respect to the width direction in a state of being separated in the circumferential direction of the detected ring.
Further, the sensor changes the output signal at the moment when each of the characteristic changing parts constituting each of the detected characteristic changing combination parts passes through a portion where the detecting part faces.
Further, the computing unit includes a partial period which is a period between a pair of pulses generated based on a pair of characteristic changing portions adjacent in the circumferential direction, and a pair of characteristics to be detected adjacent in the circumferential direction. The physical quantity is obtained on the basis of a pulse period ratio that is a ratio with respect to the entire period that is a period between another pair of pulses that is generated based on the corresponding characteristic changing part of the change combination part.

又、本発明の回転部材用物理量測定装置を実施する場合に、具体的には、請求項４に記載した発明の様に、前記被検出面を、前記被検出リングの外周面とする。又、前記物理量を、前記回転部材の軸方向に加わるアキシアル荷重とする。
更には、請求項５に記載した発明の様に、前記各フィルタを、カットオフ周波数が互いに異なる、複数種類のローパスフィルタとする。 Further, when the physical quantity measuring device for a rotating member according to the present invention is implemented, specifically, the detected surface is the outer peripheral surface of the detected ring as in the invention described in claim 4. The physical quantity is an axial load applied in the axial direction of the rotating member.
Furthermore, as in the invention described in claim 5, each of the filters is a plurality of types of low-pass filters having different cutoff frequencies.

上述の様に構成する本発明の回転部材用物理量測定装置によれば、例えば工作機械の主軸に加わるアキシアル荷重を測定するのに適用した場合に、通常運転時には測定値の信頼性を十分に確保でき、しかも、非常時には、迅速且つ適切な対応を行える。
例えば、各信号伝達回路に、カットオフ周波数が互いに異なるローパスフィルタを設置し、通常運転時にはカットオフ周波数が低いローパスフィルタを通過した処理信号又は出力信号に基づく測定値により回転部材の運転状態を制御すれば、この測定値に関する信頼性を確保しつつ、この回転部材を安定して運転できる。これに対して、カットオフ周波数が高いローパスフィルタを通過した処理信号又は出力信号に基づく測定値により前記回転部材の運転を制御したり、この測定値を記録しておけば、非常事態が発生した瞬間に、この回転部材の運転を迅速に停止したり、前記測定値を、故障の原因特定等に利用できる。 According to the physical quantity measuring device for a rotating member of the present invention configured as described above, for example, when applied to measure an axial load applied to the spindle of a machine tool, sufficient reliability of measured values is ensured during normal operation. In addition, it is possible to respond quickly and appropriately in an emergency.
For example, low-pass filters with different cut-off frequencies are installed in each signal transmission circuit, and the operating state of the rotating member is controlled by measured values based on processing signals or output signals that have passed through the low-pass filter with low cut-off frequencies during normal operation. Then, the rotating member can be stably operated while ensuring the reliability related to the measured value. On the other hand, if the operation of the rotating member is controlled by a measured value based on a processing signal or an output signal that has passed through a low-pass filter having a high cutoff frequency, or if this measured value is recorded, an emergency has occurred. In an instant, the operation of the rotating member can be quickly stopped, and the measured value can be used for identifying the cause of the failure.

本発明の対象となる構造の１例を示す断面図。Sectional drawing which shows one example of the structure used as the object of this invention. 図１のＸ部拡大図。The X section enlarged view of FIG. 被検出リングを取り出して示す斜視図。The perspective view which takes out and shows a to-be-detected ring. センサユニットを取り出して、先端のセンサ装着部を被覆していない状態（Ａ）と被覆した状態（Ｂ）とで示す斜視図。The perspective view which takes out a sensor unit and shows with the state (A) which is not covering the sensor mounting part of the front-end | tip, and the state (B) which covered. センサ部分を略示する模式図。The schematic diagram which shows a sensor part schematically. センサの出力信号を演算器に送る信号伝達回路部分を示す回路図。The circuit diagram which shows the signal transmission circuit part which sends the output signal of a sensor to a calculator. センサの出力信号の波形と、この出力信号が第一のフィルタを通過した後の波形と、同じく第二のフィルタを通過した後の波形とを示す線図。The diagram which shows the waveform of the output signal of a sensor, the waveform after this output signal passes the 1st filter, and the waveform after passing the 2nd filter similarly. 従来から知られている被検出リングの斜視図。The perspective view of the to-be-detected ring conventionally known. この被検出リングを利用してアキシアル荷重を測定できる理由を説明する為の模式図。The schematic diagram for demonstrating the reason which can measure an axial load using this to-be-detected ring.

図１〜６により、本発明の実施の形態の１例に就いて説明する。本例の構造は、工作機械の主軸４に加わるアキシアル荷重を測定する構造に本発明を適用した場合に就いて示している。この為に本例の構造では、工作機械のハウジング（主軸頭）５の内径側に前記主軸４を、多列転がり軸受ユニット６により回転自在に支持すると共に、電動モータ７により、前記主軸４を回転駆動自在としている。前記多列転がり軸受ユニット６を構成する複数個の転がり軸受８ａ〜８ｄのうち、先端寄りに配置した２個の転がり軸受８ａ、８ｂと、基端寄りに配置した２個の転がり軸受８ｃ、８ｄとには、互いに逆向きの接触角を付与すると共に、これら各転がり軸受８ａ〜８ｄに、予圧を付与している。これにより、前記主軸４を前記ハウジング５に対して、ラジアル荷重及び両方向のアキシアル荷重を支承する状態で、がたつきなく、回転自在に支持している。前記工作機械の運転時には、前記主軸４の先端部（図１の左端部）に固定した工具（図示省略）を、高速で回転しつつ被加工物に押し付け、この被加工物に、切削等の加工を施す。この様にして加工を施す際に、前記主軸４には、この被加工物に前記工具を押し付ける事の反作用として、各方向の荷重が加わる。図１に示した本例の構造では、このうち、前記主軸４の軸方向に一致する、前記アキシアル荷重に基づく、この主軸４の軸方向の変位量（更に必要に応じてこのアキシアル荷重）を求められる様にしている。   1 to 6, an example of the embodiment of the present invention will be described. The structure of this example is shown when the present invention is applied to a structure for measuring an axial load applied to the spindle 4 of the machine tool. For this reason, in the structure of this example, the main shaft 4 is rotatably supported by the inner diameter side of the housing (main shaft head) 5 of the machine tool by the multi-row rolling bearing unit 6, and the main shaft 4 is supported by the electric motor 7. It can be freely rotated. Among the plurality of rolling bearings 8a to 8d constituting the multi-row rolling bearing unit 6, two rolling bearings 8a and 8b arranged near the distal end and two rolling bearings 8c and 8d arranged near the proximal end. In addition to applying contact angles opposite to each other, a preload is applied to each of the rolling bearings 8a to 8d. As a result, the main shaft 4 is supported rotatably with respect to the housing 5 in a state in which a radial load and an axial load in both directions are supported. During operation of the machine tool, a tool (not shown) fixed to the tip end portion (left end portion in FIG. 1) of the main spindle 4 is pressed against the workpiece while rotating at high speed, and the workpiece is subjected to cutting or the like. Apply processing. When machining is performed in this manner, a load in each direction is applied to the main shaft 4 as a reaction of pressing the tool against the workpiece. In the structure of this example shown in FIG. 1, the displacement amount in the axial direction of the main shaft 4 based on the axial load, which coincides with the axial direction of the main shaft 4 (and this axial load if necessary). I am asking for it.

この為に本例の構造の場合には、前記主軸４の中間部先端寄り部分で、前記多列転がり軸受ユニット６を構成する転がり軸受８ｂ、８ｃ同士の間に、図３に示す様な被検出リング１ａを外嵌固定すると共に、前記ハウジング５に、図２、４に示す様なセンサユニット９を支持固定している。このうちの被検出リング１ａは、内輪間座を兼ねるもので、鋼等の磁性金属により造り、全体を円筒状としている。そして、被検出面である前記被検出リング１ａの外周面に、複数の被検出用特性変化組み合わせ部３ａ、３ａを、周方向に関して等間隔に形成している。これら各被検出用特性変化組み合わせ部３ａ、３ａは、前記被検出リング１ａの軸方向に対する傾斜方向が互いに異なる１対の特性変化部である、それぞれが直線状の凹溝１３ａ、１３ｂを、前記被検出リング１ａの周方向に離隔した状態で設けている。又、この様な凹溝１３ａ、１３ｂを形成した、この被検出リング１ａの外周面に、前記センサユニット９の検出部を近接対向させている。そして、このセンサユニット９の出力信号中に含まれる、パルスの間隔（パルス周期）に関する情報に基づいて、前記主軸４の軸方向に関する変位量を求め、更に必要に応じて、この主軸４に作用するアキシアル荷重を求める様にしている。   For this reason, in the case of the structure of the present example, the portion as shown in FIG. 3 is interposed between the rolling bearings 8b and 8c constituting the multi-row rolling bearing unit 6 at the portion near the tip of the intermediate portion of the main shaft 4. The detection ring 1a is externally fitted and fixed, and a sensor unit 9 as shown in FIGS. The detected ring 1a also serves as an inner ring spacer and is made of a magnetic metal such as steel and has a cylindrical shape as a whole. A plurality of detected characteristic change combination portions 3a and 3a are formed at equal intervals in the circumferential direction on the outer peripheral surface of the detected ring 1a which is a detected surface. Each of these detected characteristic change combination parts 3a, 3a is a pair of characteristic change parts having different inclination directions with respect to the axial direction of the detected ring 1a, each having a linear groove 13a, 13b, It is provided in a state of being separated in the circumferential direction of the ring to be detected 1a. Further, the detection portion of the sensor unit 9 is made to face and face the outer peripheral surface of the ring 1a to be detected in which such concave grooves 13a and 13b are formed. Then, based on the information about the pulse interval (pulse period) included in the output signal of the sensor unit 9, the displacement amount in the axial direction of the main shaft 4 is obtained, and if necessary, the displacement is applied to the main shaft 4. The axial load to be calculated is determined.

本例の回転部材用物理量測定装置の場合には、コスト低減及び小型化の面から、単一のセンサ１０の出力信号のパルス周期比δ／Ｌ（部分周期／全周期）により、前記被検出リング１ａ（を固定した前記主軸４）に関する物理量（軸方向に関する変位量とアキシアル荷重との一方又は双方）を求める様にしている。この為に使用する前記センサ１０は、前記被検出リング１ａの外周面に存在する、前記各凹溝１３ａ、１３ｂの存在に基づいて出力信号が変化するもので、ホールＩＣ、磁気抵抗素子等の磁気検出素子である。又、前記センサ１０の背面（前記被検出リング１ａの外周面と対向する検出部と反対側の面）に、永久磁石１１を配置し、これらセンサ１０と永久磁石１１とを、合成樹脂製のホルダ１２の先端部に包埋保持している。この永久磁石１１の着磁方向は、前記センサ１０が前記被検出リング１ａの被検出面に対向している方向とする。以上の構成を採用している為、これらセンサ１０と被検出リング１ａとの、この被検出リング１ａの軸方向に関する相対変位に伴って、前記パルス周期比δ／Ｌがずれる。このパルス周期比δ／Ｌに基づいて、前記主軸４に加わるアキシアル荷重を求める原理に就いては、前述の図８〜９で説明した通りである。即ち、前記センサの出力信号を演算器１４（図６参照）に送る。すると、この演算器１４が、予めインストールされたソフトウェア中の式により、前記パルス周期比δ／Ｌに基づいて、前記主軸４の軸方向に関する変位量を求め、更に、必要に応じて、この主軸４に加わるアキシアル荷重を求める。   In the case of the physical quantity measuring device for a rotating member of this example, from the viewpoint of cost reduction and miniaturization, the detected object is obtained by the pulse cycle ratio δ / L (partial cycle / full cycle) of the output signal of the single sensor 10. A physical quantity (one or both of the displacement amount and the axial load in the axial direction) related to the ring 1a (the main shaft 4 to which the ring 1a is fixed) is obtained. The sensor 10 used for this purpose has an output signal that changes based on the presence of the concave grooves 13a and 13b existing on the outer peripheral surface of the detected ring 1a. It is a magnetic detection element. A permanent magnet 11 is disposed on the back surface of the sensor 10 (the surface opposite to the detection portion facing the outer peripheral surface of the detected ring 1a), and the sensor 10 and the permanent magnet 11 are made of synthetic resin. It is embedded and held at the tip of the holder 12. The permanent magnet 11 is magnetized in the direction in which the sensor 10 faces the detection surface of the detection ring 1a. Since the above configuration is employed, the pulse cycle ratio δ / L is shifted with the relative displacement between the sensor 10 and the detected ring 1a in the axial direction of the detected ring 1a. The principle of determining the axial load applied to the main shaft 4 based on the pulse cycle ratio δ / L is as described above with reference to FIGS. That is, the output signal of the sensor is sent to the calculator 14 (see FIG. 6). Then, the computing unit 14 obtains a displacement amount in the axial direction of the spindle 4 based on the pulse cycle ratio δ / L by an expression in software installed in advance, and further, if necessary, the spindle The axial load applied to 4 is obtained.

特に、本例の回転部材用物理量測定装置の場合には、図６に示す様に、前記演算器１４が前記出力信号を処理した処理信号を取り出す為の処理信号取り出し部分に、１対の信号伝達回路１５ａ、１５ｂを、互いに並列に設けている。これら両信号伝達回路１５ａ、１５ｂは、それぞれが前記処理信号を、前記工作機械の制御器に向けて後方に送る機能を備えている。即ち、本例の場合には、前記演算器１４が前記センサ１０からの出力信号に基づいて、前記被検出リング１ａの、軸方向に関する変位量を算出し、この変位量を表す処理信号を、前記工作機械の制御器に送る様にしている。この処理信号が表す、前記被検出リング１ａの軸方向に関する変位量と、前記主軸４に加わるアキシアル荷重との間には相関関係があるので、前記制御器は、この変位量に基づいて直接、或は、この変位量を前記アキシアル荷重に換算してから、前記主軸４の送り速度を調節したり、事故発生時には、この主軸４を緊急停止させる。   In particular, in the case of the physical quantity measuring device for a rotating member of this example, as shown in FIG. 6, a pair of signals is provided in the processing signal extraction portion for extracting the processing signal obtained by processing the output signal by the computing unit 14. Transmission circuits 15a and 15b are provided in parallel with each other. Each of these signal transmission circuits 15a and 15b has a function of sending the processing signal backward to the controller of the machine tool. That is, in the case of this example, the computing unit 14 calculates a displacement amount in the axial direction of the detected ring 1a based on an output signal from the sensor 10, and a processing signal representing this displacement amount is calculated. This is sent to the controller of the machine tool. Since there is a correlation between the displacement amount in the axial direction of the detected ring 1a represented by this processing signal and the axial load applied to the main shaft 4, the controller directly based on this displacement amount, Alternatively, the amount of displacement is converted into the axial load, and then the feed speed of the spindle 4 is adjusted, or the spindle 4 is urgently stopped when an accident occurs.

又、前記両信号伝達回路１５ａ、１５ｂの途中に、それぞれローパスフィルタ１６ａ、１６ｂを設けている。これら両ローパスフィルタ１６ａ、１６ｂは、何れも、前記処理信号のうち、設定値（カットオフ周波数）よりも低い周波数成分のみを前記制御器に向けて送り出す（前記処理信号中から、設定値以上の周波数成分を除去する）ものであるが、カットオフ周波数が互いに異なる。即ち、一方のローパスフィルタ１６ａのカットオフ周波数は比較的低い（例えば５Ｈｚ程度である）のに対して、他方のローパスフィルタ１６ｂのカットオフ周波数は比較的高い（例えば２０Ｈｚ程度である）。   Further, low-pass filters 16a and 16b are provided in the middle of the signal transmission circuits 15a and 15b, respectively. Both of these low-pass filters 16a and 16b send out only a frequency component lower than a set value (cut-off frequency) out of the processed signal to the controller (from the processed signal, a value equal to or higher than the set value). Frequency components are removed), but the cut-off frequencies are different from each other. That is, the cut-off frequency of one low-pass filter 16a is relatively low (for example, about 5 Hz), while the cut-off frequency of the other low-pass filter 16b is relatively high (for example, about 20 Hz).

上述の様に、カットオフ周波数が互いに異なるローパスフィルタ１６ａ、１６ｂを設けた、前記両信号伝達回路１５ａ、１５ｂを送られる処理信号のうち、カットオフ周波数が低いローパスフィルタ１６ａを設けた信号伝達回路１５ａを送られる第一の処理信号は、例えば前記工作機械の主軸４の送り速度を制御したり、この主軸４の先端部に固定した工具の寿命を判定する為に利用する。これに対して、カットオフ周波数が高いローパスフィルタ１６ｂを設けた信号伝達回路１５ｂを送られる第二の処理信号は、例えば、前記工作機械の運転時の事故の有無を見張る為に利用する。この為に、この第二の処理信号を（好ましくは前記第一の処理信号と合わせて）、前記工作機械の制御器に付属させたメモリに、経過時間（運転時刻）と関連付けて記録する。   As described above, the signal transmission circuit provided with the low-pass filter 16a having a low cut-off frequency among the processing signals sent to the signal transmission circuits 15a and 15b provided with the low-pass filters 16a and 16b having different cut-off frequencies. The first processing signal sent to 15a is used, for example, to control the feed speed of the spindle 4 of the machine tool or to determine the life of a tool fixed to the tip of the spindle 4. On the other hand, the second processing signal sent to the signal transmission circuit 15b provided with the low-pass filter 16b having a high cut-off frequency is used, for example, to monitor whether there is an accident during the operation of the machine tool. For this purpose, this second processing signal (preferably together with the first processing signal) is recorded in a memory attached to the controller of the machine tool in association with the elapsed time (operation time).

上述の様に構成する本例の構造によれば、工作機械の主軸４に加わるアキシアル荷重に基づく軸方向変位を測定する事に関して、通常運転時には測定値の信頼性を十分に確保でき、しかも、非常時には、迅速且つ適切な対応を行える。先ず、前記軸方向変位の測定値の信頼性確保に関しては、通常運転時に、前記カットオフ周波数が低いローパスフィルタ１６ａを通過した第一の処理信号に基づいて前記軸方向変位を算出する事により、実現できる。この点に就いて、前記主軸４に、図７の実線αで示す様な軸方向変位が生じた場合に就いて説明する。尚、図７の実線αは、厳密には前記主軸４の実際の軸方向変位そのものを示すものではなく、この実際の軸方向変位を、本例の物理量測定装置とは異なる、高精度ではあるが高価な別のセンサ（小野測器社製／接触式変位計／ＧＳ−７７１０Ａ）により測定した結果を示している。この測定結果には、不可避な誤差が含まれてはいるものの、その誤差の程度は非常に小さい。この為、以下の説明では、前記実線αを、前記主軸４の実際の軸方向変位を示す信号として取り扱う事にする。この主軸４に、この実線αで示す様な軸方向変位が生じた場合に、前記センサ１０の出力信号に基づいて前記演算器１４が算出した、前記主軸４の軸方向変位を表す信号（図７には図示せず）中に、許容範囲を超える様な大きなノイズが混入している場合には、その信号をそのまま前記主軸４の送り量等の制御に利用しても、適切な制御を行えない。但し、この様な場合でも、前記第一の処理信号は、図７の破線βに示す様に平滑化されたものとなり、混入していたノイズがほぼ除去されたものとなる。従って、前記第一の処理信号を前記主軸４の送り量等の制御に利用すれば、適切な制御を行える。   According to the structure of this example configured as described above, the reliability of the measured value can be sufficiently ensured during normal operation with respect to measuring the axial displacement based on the axial load applied to the spindle 4 of the machine tool, In the event of an emergency, a quick and appropriate response can be made. First, for ensuring the reliability of the measurement value of the axial displacement, by calculating the axial displacement based on a first processing signal that has passed through the low-pass filter 16a having a low cutoff frequency during normal operation, realizable. This point will be described when the main shaft 4 is displaced in the axial direction as indicated by the solid line α in FIG. Note that the solid line α in FIG. 7 does not strictly indicate the actual axial displacement of the main shaft 4, but the actual axial displacement is different from the physical quantity measuring apparatus of this example and has high accuracy. Shows the result of measurement by another expensive sensor (Ono Sokki Co., Ltd./contact displacement meter / GS-7710A). Although this measurement result includes an inevitable error, the degree of the error is very small. Therefore, in the following description, the solid line α is handled as a signal indicating the actual axial displacement of the main shaft 4. When the main shaft 4 is displaced in the axial direction as indicated by the solid line α, a signal representing the axial displacement of the main shaft 4 calculated by the computing unit 14 based on the output signal of the sensor 10 (FIG. 7) (not shown in FIG. 7), when a large noise exceeding the allowable range is mixed, even if the signal is used for controlling the feed amount of the spindle 4 as it is, appropriate control is performed. I can't. However, even in such a case, the first processed signal is smoothed as indicated by a broken line β in FIG. 7, and the mixed noise is substantially removed. Therefore, if the first processing signal is used for controlling the feed amount of the main spindle 4, appropriate control can be performed.

但し、図７の実線αと破線βとの立ち上がり部（横軸で２４秒の近傍部分）を比較すれば分かる様に、前記カットオフ周波数が低いローパスフィルタ１６ａを通過した、前記第一の処理信号は、実際の軸方向変位を示す信号に対する応答遅れが大きくなる（レスポンスが悪い）。この為、この第一の処理信号によっては、非常時に迅速且つ適切な対応を行う事は難しい。即ち、前記主軸４の先端部に設けた工具が被加工物に勢い良く衝突する等によりこの主軸４に衝撃荷重が加わる様な事故が発生すると、この主軸４の軸方向位置が、前記立ち上がり部で表される様に、急激に変化する。故障時にこの主軸４を緊急停止させたり、或いは、修理作業の際に事故の原因を特定したりする為には、前記立ち上がり部で表される急激な変化を検出する必要がある。ところが、この立ち上がり部で前記実線αと前記破線βとのずれが大きくなっている事から分かる様に、前記第一の処理信号では、前記事故の際に適切な対応が難しい場合が考えられる。   However, as can be seen by comparing the rising portion (the vicinity of 24 seconds on the horizontal axis) of the solid line α and the broken line β in FIG. 7, the first processing that has passed through the low-pass filter 16a having a low cutoff frequency. The response delay with respect to the signal indicating the actual axial displacement increases (the response is poor). For this reason, it is difficult to respond promptly and appropriately in an emergency depending on the first processing signal. That is, when an accident occurs such that an impact load is applied to the main shaft 4 due to the tool provided at the tip of the main shaft 4 colliding with the workpiece vigorously, the axial position of the main shaft 4 is changed to the rising portion. As shown, it changes rapidly. In order to make an emergency stop of the spindle 4 at the time of failure or to specify the cause of an accident during repair work, it is necessary to detect a sudden change represented by the rising portion. However, as can be seen from the large deviation between the solid line α and the broken line β at the rising portion, it may be difficult to appropriately deal with the first processing signal in the event of the accident.

そこで、本例の構造の場合には、前記第二の処理信号に基づいて、前記事故の際の対応を行う様にしている。カットオフ周波数が高い前記ローパスフィルタ１６ｂを設けた信号伝達回路１５ｂを送られる、前記第二の処理信号は、図７の鎖線γで示す様に変化する。この図７の実線αと鎖線γとの立ち上がり部を比較すれば分かる様に、前記カットオフ周波数が高いローパスフィルタ１６ｂを通過した、前記第二の処理信号は、前記第一の処理信号（破線β）に比べてノイズの除去量が少なくなってはいるものの、ノイズのレベルは許容範囲内に収められており、しかも実際の軸方向変位を示す信号に対する応答遅れが小さい（レスポンスが良い）。この為、この第二の処理信号によって、非常時に、緊急停止等の、迅速且つ適切な対応を行う事が可能になる。又、この第二の処理信号を、前記制御器に付属したメモリに記録しておけば、修理作業の際に事故の原因を特定する事が容易になる。   Therefore, in the case of the structure of the present example, a response in the event of the accident is performed based on the second processing signal. The second processing signal sent through the signal transmission circuit 15b provided with the low-pass filter 16b having a high cut-off frequency changes as indicated by a chain line γ in FIG. As can be seen by comparing the rising portions of the solid line α and the chain line γ in FIG. 7, the second processed signal that has passed through the low-pass filter 16 b having a high cutoff frequency is the first processed signal (broken line). Although the amount of noise removal is smaller than β), the noise level is within the allowable range, and the response delay with respect to the signal indicating the actual axial displacement is small (good response). For this reason, the second processing signal enables quick and appropriate response such as emergency stop in an emergency. If this second processing signal is recorded in the memory attached to the controller, it becomes easy to identify the cause of the accident during repair work.

図示の例では、互いにカットオフ周波数が異なる１対のローパスフィルタを、演算器と、工作機械の制御器との間に設けている。これに対して、ローパスフィルタ等の、それぞれが信号中に含まれるノイズを除去する為のフィルタを、センサと演算器との間に設ける事もできる。勿論、この場合には、センサと演算器との間に、それぞれがこのセンサの出力信号を演算器に送り込む為の、複数の信号伝達回路を、互いに並列に設ける。更に、各信号伝達回路の途中に設けるフィルタとしては、ローパスフィルタに限らず、バンドパスフィルタ、適応フィルタ等、ノイズ除去用の各種フィルタを採用できる。又、その出力信号或は処理信号がフィルタリングの対象となるセンサ、及び、このセンサの検出部をその被検出面に対向させる被検出リングは、図示の様な構造のものに限らず、前述の特許文献２〜４に記載された様な、各種構造のものを採用できる。更には、測定の対象となる変位や荷重に関しても、軸方向変位やアキシアル荷重に限らず、径方向変位やラジアル荷動とする事もできる。この場合には、被検出リングの被検出面を、軸方向側面とする。   In the illustrated example, a pair of low-pass filters having different cut-off frequencies are provided between the arithmetic unit and the machine tool controller. On the other hand, a filter such as a low-pass filter for removing noise included in each signal can be provided between the sensor and the arithmetic unit. Of course, in this case, a plurality of signal transmission circuits are provided in parallel with each other between the sensor and the computing unit, each for sending the output signal of the sensor to the computing unit. Further, the filter provided in the middle of each signal transmission circuit is not limited to the low-pass filter, and various filters for noise removal such as a band-pass filter and an adaptive filter can be employed. In addition, the sensor whose output signal or processing signal is to be filtered, and the detection ring that makes the detection part of this sensor face the detection surface are not limited to those of the structure shown in the figure. The thing of various structures as described in patent documents 2-4 can be adopted. Further, the displacement and load to be measured are not limited to the axial displacement and the axial load, but can be a radial displacement or a radial load. In this case, the detection surface of the detection ring is an axial side surface.

１、１ａ 被検出リング
２ａ、２ｂ 透孔
３、３ａ 被検出用特性変化組み合わせ部
４ 主軸
５ ハウジング
６ 多列転がり軸受ユニット
７ 電動モータ
８ａ、８ｂ、８ｃ、８ｄ 転がり軸受
９ センサユニット
１０ センサ
１１ 永久磁石
１２ ホルダ
１３ａ、１３ｂ 凹溝
１４ 演算器
１５ａ、１５ｂ 信号伝達回路
１６ａ、１６ｂ ローパスフィルタ DESCRIPTION OF SYMBOLS 1, 1a Detected ring 2a, 2b Through-hole 3, 3a Detected characteristic change combination part 4 Spindle 5 Housing 6 Multi-row rolling bearing unit 7 Electric motor 8a, 8b, 8c, 8d Rolling bearing 9 Sensor unit 10 Sensor 11 Permanent Magnet 12 Holder 13a, 13b Concave groove 14 Calculator 15a, 15b Signal transmission circuit 16a, 16b Low-pass filter

Claims (5)

回転しないハウジングと、それぞれが予圧を付与された複数の転がり軸受により、このハウジングの内側に回転自在に支持された回転部材と、この回転部材の一部に支持固定された、この回転部材と同心の被検出面を有する被検出リングと、検出部をこの被検出面に対向させた状態で前記ハウジングに支持されたセンサと、このセンサの出力信号を処理する演算器とを備え、この演算器は、この出力信号の位相に関する情報に基づいて、前記回転部材に関する物理量を求める機能を有するものである回転部材用物理量測定装置に於いて、
前記演算器が前記出力信号を処理した処理信号を取り出す為の処理信号取り出し部分、又は、前記センサから前記演算器に前記出力信号を送る出力信号送信部分に、それぞれが前記処理信号又はこの出力信号を後方に送る機能を備えた複数の信号伝達回路を、互いに並列に設けると共に、これら各信号伝達回路に、これら各信号伝達回路中を送られる前記処理信号又は前記出力信号中に含まれるノイズを除去する為のフィルタを設けており、これら各信号伝達回路中に設けた各フィルタの特性を互いに異ならせている事を特徴とする回転部材用物理量測定装置。 A rotating member that is rotatably supported inside the housing by a non-rotating housing and a plurality of rolling bearings, each of which is preloaded, and a concentric with the rotating member that is supported and fixed to a part of the rotating member A detection ring having a detection surface, a sensor supported by the housing in a state where the detection portion faces the detection surface, and an arithmetic unit that processes an output signal of the sensor. Is a physical quantity measuring device for a rotating member that has a function of obtaining a physical quantity related to the rotating member based on information on the phase of the output signal.
A processing signal extracting part for extracting a processing signal obtained by processing the output signal by the arithmetic unit, or an output signal transmitting part for transmitting the output signal from the sensor to the arithmetic unit, respectively, the processing signal or the output signal. A plurality of signal transmission circuits having a function of transmitting the signal to the rear are provided in parallel with each other, and the noise included in the processing signal or the output signal sent to each of these signal transmission circuits is provided to each of these signal transmission circuits. A physical quantity measuring device for a rotating member, characterized in that a filter for removal is provided, and the characteristics of the filters provided in the signal transmission circuits are different from each other. 前記処理信号又は前記出力信号に対応する物理量を、前記各信号伝達回路を送られるこの処理信号又はこの出力信号毎に、経過時間と関連付けて記録するメモリを備える、請求項１に記載した回転部材用物理量測定装置。   The rotating member according to claim 1, further comprising: a memory that records a physical quantity corresponding to the processing signal or the output signal in association with an elapsed time for each processing signal or each output signal sent to each signal transmission circuit. Physical quantity measuring device. 前記被検出リングの被検出面は、複数の被検出用特性変化組み合わせ部を、周方向に関して等間隔に、それぞれ前記物理量の測定方向に一致する前記被検出面の幅方向に形成しており、前記各被検出用特性変化組み合わせ部は、この幅方向に対する傾斜方向が互いに異なる１対の特性変化部を、前記被検出リングの周方向に離隔した状態で設けたものであり、
前記センサは、前記各被検出用特性変化組み合わせ部を構成する前記各特性変化部が前記検出部が対向する部分を通過する瞬間に出力信号を変化させるものであり、
前記演算器は、円周方向に隣り合う１対の特性変化部に基づいて発生する１対のパルス間の周期である部分周期と、円周方向に隣り合う１対の被検出用特性変化組み合わせ部の対応する特性変化部に基づいて発生する、別の１対のパルス間の周期である全周期との比であるパルス周期比に基づいて、前記物理量を求めるものである、請求項１〜２のうちの何れか１項に記載した回転部材用物理量測定装置。 The detected surface of the detected ring is formed with a plurality of detected characteristic change combination portions at equal intervals in the circumferential direction, respectively, in the width direction of the detected surface that matches the measurement direction of the physical quantity, Each of the detected characteristic change combination portions is provided with a pair of characteristic change portions whose inclination directions with respect to the width direction are different from each other in a state of being separated in the circumferential direction of the detected ring,
The sensor is configured to change an output signal at a moment when each of the characteristic changing units constituting the detected characteristic changing combination unit passes a portion where the detecting unit faces.
The computing unit includes a combination of a partial period that is a period between a pair of pulses generated based on a pair of characteristic change units adjacent in the circumferential direction, and a pair of characteristic change for detection adjacent in the circumferential direction. The physical quantity is obtained on the basis of a pulse period ratio that is a ratio between a total period that is a period between another pair of pulses that is generated based on a corresponding characteristic change part of the part. The physical quantity measuring device for a rotating member according to any one of 2. 前記被検出面が、前記被検出リングの外周面であり、前記物理量が、前記回転部材の軸方向に加わるアキシアル荷重である、請求項１〜３のうちの何れか１項に記載した回転部材用物理量測定装置。   The rotating member according to claim 1, wherein the detected surface is an outer peripheral surface of the detected ring, and the physical quantity is an axial load applied in an axial direction of the rotating member. Physical quantity measuring device. 前記各フィルタが、カットオフ周波数が互いに異なる、複数種類のローパスフィルタである、請求項１〜４のうちの何れか１項に記載した回転部材用物理量測定装置。   The physical quantity measuring device for a rotating member according to any one of claims 1 to 4, wherein each of the filters is a plurality of types of low-pass filters having different cutoff frequencies.
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