JP2005133891A - Preload measuring method and device for bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preload measuring method and a preload measuring device for a bearing, capable of accurately detecting the preload even in a case when temperature difference between inner and out rings is large, or even in high-speed rotation. <P>SOLUTION: This method is applied to measure the preload of a rolling bearing 3 in a spindle device wherein a shaft 2 is rotatably supported to a housing 1 by the rolling bearing provided with a plurality of rolling elements 6 between the inner ring 4 and the outer ring 5 as bearing rings. Non-contact displacement measuring instruments 8A, 8B are mounted on a fixed-side member 1 of the housing 1 and the shaft 2. The non-contact displacement measuring instruments 8A, 8B measure, for example, the axial displacement of an end face of the inner ring 4 as a rotation-side bearing ring and the radial displacement of an outer-diameter face. The preload of the rolling bearing 3 is determined on the basis of results of the measurements of the axial displacement and the radial displacement. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

この発明は、工作機械等のスピンドル装置における主軸等を支持する軸受の予圧を測定する軸受の予圧測定方法および予圧測定装置、並びに予圧調整装置に関する。   The present invention relates to a bearing preload measuring method, a preload measuring apparatus, and a preload adjusting apparatus for measuring a preload of a bearing that supports a main shaft or the like in a spindle apparatus such as a machine tool.

工作機械のスピンドル装置では、加工精度の向上、加工効率の向上のために、高剛性、高回転が要求され、軸受の予圧管理が重要となる。スピンドル装置の予圧量測定に関しては、内外輪の相対的軸方向変位量（相対位置）を測定し、予め定めた変位量（または相対位置）と異なったときに、油圧の予圧付与機構で予圧を加減し、予め定めた変位量に維持するという方法が提案されている（例えば、特許文献１、特許文献２）。
特開平１０−８９３５５号公報 特開２０００−２３７９０２号公報 In a spindle device of a machine tool, high rigidity and high rotation are required to improve machining accuracy and machining efficiency, and bearing preload management is important. When measuring the amount of preload of the spindle device, the relative axial displacement (relative position) of the inner and outer rings is measured, and when it differs from the predetermined amount of displacement (or relative position), preload is applied by the hydraulic preload application mechanism. A method of adjusting and maintaining a predetermined amount of displacement has been proposed (for example, Patent Document 1 and Patent Document 2).
Japanese Patent Laid-Open No. 10-89355 JP 2000-237902 A

上記従来の測定方法は、軸受予圧量として内外輪の軸方向の相対位置だけを測定し、その測定結果で制御しようとしている。しかし、実際にはスピンドルが回転すると、(1) 軸受内外輪の温度差や、(2) 遠心力による内輪の拡径が原因となって、軸受内輪は径方向に膨張する。そのため、外輪との相対位置が小さくなり、軸受の予圧量は大きくなる。このように、軸方向の変位量を測定するだけでは、正確に予圧量を測定することができず、したがって予圧量の適切な調整が難しい。特に高速回転時は、上記内外輪の温度差や遠心力による影響が大きくなり、これに伴って予圧量測定の誤差が大きくなる。   In the above conventional measurement method, only the relative position in the axial direction of the inner and outer rings is measured as the bearing preload amount, and control is made based on the measurement result. However, in reality, when the spindle rotates, the bearing inner ring expands in the radial direction due to (1) temperature difference between the inner and outer rings of the bearing and (2) expansion of the inner ring due to centrifugal force. Therefore, the relative position with respect to the outer ring is reduced, and the preload amount of the bearing is increased. As described above, the preload amount cannot be accurately measured only by measuring the axial displacement amount, and therefore it is difficult to appropriately adjust the preload amount. In particular, at the time of high-speed rotation, the influence of the temperature difference between the inner and outer rings and the centrifugal force increases, and accordingly, the error in the preload measurement increases.

この発明の目的は、内外輪の温度差が大きい場合や、高速回転の場合にも、予圧量を精度良く検出することのできる軸受の予圧測定方法および予圧測定装置を提供することである。
この発明の他の目的は、スピンドル装置の運転状況に応じた予圧量の調整がリアルタイムで適切に行える軸受の予圧調整装置を提供することである。 An object of the present invention is to provide a bearing preload measuring method and a preload measuring apparatus capable of accurately detecting the amount of preload even when the temperature difference between the inner and outer rings is large or when the rotation speed is high.
Another object of the present invention is to provide a bearing preload adjusting device that can appropriately adjust the preload amount in accordance with the operating condition of the spindle device in real time.

この発明の軸受の予圧測定方法は、軌道輪である内輪と外輪間に複数の転動体を配した転がり軸受によりハウジングに対して軸を回転自在に支持したスピンドル装置において、上記転がり軸受の予圧量を測定する方法である。この予圧測定方法は、上記ハウジングおよび軸のうちの固定側の部材に取付けられた非接触変位測定機により、上記転がり軸受の回転側軌道輪の端面の軸方向変位量、および回転側軌道輪の軸受内側となる周面の径方向変位量を測定し、これら軸方向変位量および径方向変位量の測定結果を用いて、転がり軸受の予圧量を求めることを特徴とする。上記軸方向変位量および径方向変位量は、例えば軸受組込時に予圧を零とした状態に対する変位量である。非接触変位測定機は、軸方向変位量の測定用のものと、径方向変位量の測定用のものとを設けても良く、また一つで軸方向と径方向の両方の変位量を測定できるものを用いても良い。
この方法によると、回転側軌道輪の軸方向変位量だけでなく、径方向変位量を測定し、両変位量の測定結果から予圧量を求めるため、内外輪間の温度差が大きい場合や、高速回転の場合にも、その温度差による熱膨張量の差、および遠心力による回転側軌道輪の径の変化による予圧量の変化を測定できて、予圧量を精度良く測定することができる。なお、軸方向変位量の測定と径方向変位量の測定とは、別々の時機に行っても良い。例えば、軸方向の変位量の測定を軸受組込み時に行い、径方向の変位量の測定は軸受運転時に行い、両変位量から予圧量を計算するようにしても良い。 The bearing preload measuring method according to the present invention is a spindle device in which a shaft is rotatably supported with respect to a housing by a rolling bearing in which a plurality of rolling elements are arranged between an inner ring and an outer ring which are raceways. Is a method of measuring. This preload measurement method uses a non-contact displacement measuring machine attached to a fixed member of the housing and shaft, and the amount of axial displacement of the end surface of the rotating bearing ring of the rolling bearing, and of the rotating bearing ring. It is characterized in that the amount of radial displacement of the peripheral surface on the inner side of the bearing is measured, and the preload amount of the rolling bearing is obtained using the measurement results of the axial direction displacement amount and the radial direction displacement amount. The axial displacement amount and the radial displacement amount are, for example, displacement amounts with respect to a state in which the preload is zero when the bearing is assembled. Non-contact displacement measuring machines may be provided for measuring axial displacement and for measuring radial displacement, and measure both axial and radial displacement by one. What can be used may be used.
According to this method, not only the axial displacement amount of the rotating raceway, but also the radial displacement amount is measured, and the preload amount is obtained from the measurement result of both displacement amounts. Even in the case of high-speed rotation, the difference in thermal expansion due to the temperature difference and the change in the preload amount due to the change in the diameter of the rotating raceway due to the centrifugal force can be measured, and the preload amount can be measured with high accuracy. The measurement of the axial displacement amount and the measurement of the radial displacement amount may be performed at different times. For example, the axial displacement amount may be measured when the bearing is incorporated, and the radial displacement amount may be measured during the bearing operation, and the preload amount may be calculated from both displacement amounts.

この予圧測定方法は、より詳しくは次のように測定する。一般に、スピンドル装置に組み込んだ例えば２個の転がり軸受に予圧を与える場合、軸受の内輪または外輪を軸方向に押し、軸受隙間が無くなった状態を予圧量零とし、これからさらに軸方向に押し込み、この押し込み量を基に計算から軸受組込み時の予圧量を得ることができる。また、スピンドル装置を運転すると、遠心力による回転側の軌道輪（例えば内輪）の膨張や、回転に対する抵抗から発熱し熱膨張を生じるため、径方向に寸方変化が生じて予圧量が変化する。   More specifically, the preload measurement method is measured as follows. In general, when preload is applied to, for example, two rolling bearings incorporated in a spindle device, the inner ring or outer ring of the bearing is pushed in the axial direction, the state where there is no bearing clearance is set to zero preload amount, and then pushed further in the axial direction. The amount of preload at the time of assembling the bearing can be obtained from the calculation based on the pushing amount. In addition, when the spindle device is operated, heat is generated due to expansion of the rotating raceway (for example, the inner ring) due to centrifugal force or resistance to rotation, and thermal expansion occurs. .

この予圧測定方法は、上記のようにスピンドル装置の固定側、つまり内輪回転であればハウジング、外輪回転であれば軸に、軸方向および径方向の非接触変位測定機を取付けておく。このように各非接触変位測定機を取付けておき、上記の軸受組込み時の軸受の隙間が無くなった状態からの各変位量を測定する。例えば、軸受隙間が零からさらに軸方向に押し込んだときの軸方向の押し込み量を測定する。また、運転時の回転側軌道輪の軸受内側となる周面の径方向変位量を測定する。軸受内側となる周面は、回転側軌道輪が内輪であれば外径面、外輪であれば内径面である。これらの軸方向変位量および径方向変位量の測定値を、測定値利用時よりも前に予め設定しておいた所定の関係式等の関係設定データに従い、計算プログラム等を用いて予圧量へ変換し、両者を加えた値を、運転時の予圧量として算出することができる。予め設定する関係設定データは、計算または実験等で求めておくことができる。なお、運転時においても非接触変位測定機により軸方向の変位量を測定し、予圧測定データとして用いるようにしても良い。   In this preload measuring method, as described above, non-contact displacement measuring machines in the axial direction and the radial direction are attached to the fixed side of the spindle device, that is, the housing for inner ring rotation and the shaft for outer ring rotation. Thus, each non-contact displacement measuring machine is attached, and each displacement amount is measured from a state in which there is no bearing clearance when the bearing is incorporated. For example, the amount of pushing in the axial direction when the bearing gap is pushed further in the axial direction from zero is measured. In addition, the amount of radial displacement of the circumferential surface inside the bearing of the rotating raceway during operation is measured. The peripheral surface that is the inner side of the bearing is an outer diameter surface if the rotation-side race is an inner ring, and an inner diameter surface if the outer ring is an outer ring. The measured values of these axial displacements and radial displacements are converted into the preload amount using a calculation program or the like according to the relationship setting data such as a predetermined relational equation set before using the measured values. A value obtained by converting and adding both can be calculated as a preload amount during operation. The relationship setting data set in advance can be obtained by calculation or experiment. Even during operation, the amount of axial displacement may be measured with a non-contact displacement measuring instrument and used as preload measurement data.

この発明の軸受の予圧測定装置は、軌道輪である内輪と外輪間に複数の転動体を配した転がり軸受によりハウジングに対して軸を回転自在に支持したスピンドル装置において、上記転がり軸受の予圧量を測定する装置であって、上記ハウジングおよび軸のうちの固定側の部材にそれぞれ取付けられて、上記転がり軸受の回転側軌道輪の端面の軸方向変位量、および回転側軌道輪の軸受内側となる周面の径方向変位量をそれぞれ測定する軸方向および径方向の非接触変位測定機を備えることを特徴とする。
この構成の予圧測定装置によると、この発明の予圧測定方法を実施することができ、それにより、内外輪の温度差が大きい場合や、高速回転の場合にも、予圧量を精度良く検出することができる。 A bearing preload measuring device according to the present invention is a spindle device in which a shaft is rotatably supported with respect to a housing by a rolling bearing in which a plurality of rolling elements are arranged between an inner ring and an outer ring which are raceways. Measuring the amount of axial displacement of the end surface of the rotating bearing ring of the rolling bearing, and the inside of the bearing of the rotating bearing ring. And a non-contact displacement measuring device in the axial direction and the radial direction for measuring the amount of radial displacement of the peripheral surface.
According to the preload measuring device of this configuration, the preload measuring method of the present invention can be carried out, whereby the preload amount can be accurately detected even when the temperature difference between the inner and outer rings is large or in the case of high speed rotation. Can do.

この発明の予圧測定装置において、主軸の前部を支持する転がり軸受の前側の端面の軸方向変位量を測定する非接触変位測定機と、主軸の後部を支持する転がり軸受の後ろ側の端面の軸方向変位量を測定する非接触変位測定機とを設けても良い。前後両側の軸受の軸方向変位量を測定することで、より一層精度の良い予圧量測定が行える。
径方向変位量を測定する非接触変位測定機についても、上記前後の転がり軸受に対して設けることが好ましい。これにより、さらに精度の良い予圧量測定が行える。 In the preload measuring device according to the present invention, a non-contact displacement measuring machine that measures the amount of axial displacement of the front end surface of the rolling bearing that supports the front portion of the main shaft, and the rear end surface of the rolling bearing that supports the rear portion of the main shaft. You may provide the non-contact displacement measuring device which measures the amount of axial displacement. By measuring the amount of axial displacement of the bearings on both the front and rear sides, it is possible to perform a more accurate preload measurement.
A non-contact displacement measuring machine that measures the radial displacement is also preferably provided for the front and rear rolling bearings. Thereby, a more accurate preload amount measurement can be performed.

この発明の軸受の予圧調整装置は、内輪と外輪の間に複数の転動体を配した転がり軸受によりハウジングに対して軸を回転自在に支持したスピンドル装置において、上記転がり軸受の予圧量を調整する装置であって、この発明の予圧測定方法または装置を適用したものである。この予圧調整装置は、上記ハウジングに設置され転がり軸受に指令値に対応した予圧を付与可能な予圧付与装置と、上記ハウジングにそれぞれ取付けられ、上記転がり軸受の内輪の端面の軸方向変位量および内輪の外径面の径方向変位量をそれぞれ測定する軸方向および径方向の非接触変位測定機と、これら非接触変位測定機の出力である内輪端面の軸方向変位量および内輪外径面の径方向変位量から、関係設定データに従って上記予圧付与装置に、予圧量が設定範囲内に維持されるように動作指令を与える予圧量制御装置とを備える。上記予圧付与装置は、例えば、別の手段で与えられた予圧を減じることで、指令値に対応した予圧を付与するものとされる。   A bearing preload adjusting device according to the present invention adjusts a preload amount of the rolling bearing in a spindle device in which a shaft is rotatably supported with respect to a housing by a rolling bearing in which a plurality of rolling elements are arranged between an inner ring and an outer ring. An apparatus to which the preload measuring method or apparatus of the present invention is applied. The preload adjusting device includes a preload applying device that is installed in the housing and can apply a preload corresponding to a command value to the rolling bearing, and an axial displacement amount and an inner ring of the end surface of the inner ring of the rolling bearing that are attached to the housing. Axial and radial non-contact displacement measuring machines that measure the radial displacement of the outer diameter surface of the inner ring, and the axial displacement of the inner ring end face and the diameter of the inner ring outer diameter surface, which are the outputs of these non-contact displacement measuring machines A preload amount control device that gives an operation command to the preload applying device so as to maintain the preload amount within a set range according to the relationship setting data from the direction displacement amount. For example, the preload applying device applies a preload corresponding to the command value by reducing the preload applied by another means.

この構成の予圧調整装置によると、非接触変位測定機で測定し、その測定値に応じて予圧付与装置で予圧の加減を行うため、スピンドル装置の運転状況に応じた予圧量の調整がリアルタイムで行える。この場合に、軸方向変位量および径方向変位量を用いて予圧量を測定するため、内外輪の温度差が大きい場合や、高速回転の場合にも、精度良く予圧調整することができる。
なお、予圧量制御装置において、軸方向変位量および径方向変位量から関係設定データに従って上記動作指令を生成することについては、軸方向変位量および径方向変位量を予圧値に換算してから上記動作指令の指令量を生成するようにしても、また予圧値に換算することなく、直接に動作指令の指令量を生成するようにしても良い。 According to the preload adjusting device of this configuration, since the preload is measured by the non-contact displacement measuring machine and the preload is adjusted by the preload applying device according to the measured value, the preload amount can be adjusted in real time according to the operation state of the spindle device. Yes. In this case, since the amount of preload is measured using the amount of axial displacement and the amount of radial displacement, it is possible to accurately adjust the preload even when the temperature difference between the inner and outer rings is large or at high speed rotation.
In the preload amount control device, the operation command is generated from the axial displacement amount and the radial displacement amount according to the relationship setting data. After converting the axial displacement amount and the radial displacement amount into the preload value, the above-described operation command is generated. The command amount of the operation command may be generated, or the command amount of the operation command may be directly generated without converting to the preload value.

この発明の軸受の予圧測定方法および予圧測定装置は、ハウジングおよび軸のうちの固定側の部材に、軸方向および径方向の非接触変位測定機を取付け、これら非接触変位測定機により、転がり軸受の回転側軌道輪の端面の軸方向変位量、および回転側軌道輪の軸受内側となる周面の径方向変位量を測定し、これら軸方向変位量および径方向変位量の測定結果を用いて、上記転がり軸受の予圧量を求めるため、内外輪の温度差が大きい場合や、高速回転の場合にも、予圧量を精度良く検出することのできる。
この発明の軸受の予圧調整装置は、軸方向および径方向の非接触変位測定機と、その軸方向変位量および径方向変位量から、関係設定データに従って予圧付与装置に予圧量が設定範囲内に維持されるように動作指令を与える予圧量制御装置とを備えたものであるため、内外輪の温度差が大きい場合や、高速回転の場合にも、スピンドル装置の運転状況に応じた予圧量の適切な調整がリアルタイムで行える。 A bearing preload measuring method and a preload measuring apparatus according to the present invention are provided with a non-contact displacement measuring device in an axial direction and a radial direction attached to a member on a fixed side of a housing and a shaft. Measure the amount of axial displacement of the end face of the rotating raceway and the amount of radial displacement of the circumferential surface inside the bearing of the rotating raceway, and use the measurement results of these axial displacement and radial displacement. Since the preload amount of the rolling bearing is obtained, the preload amount can be accurately detected even when the temperature difference between the inner and outer rings is large or when the rotation speed is high.
According to the bearing preload adjusting device of the present invention, the preload amount is within the set range in the preload applying device according to the relationship setting data based on the non-contact displacement measuring device in the axial direction and the radial direction, and the axial displacement amount and the radial displacement amount. This is equipped with a preload amount control device that gives an operation command so that the preload amount can be adjusted according to the operation status of the spindle device even when the temperature difference between the inner and outer rings is large or at high speed rotation. Appropriate adjustments can be made in real time.

この発明の第１の実施形態を図１と共に説明する。図１は、この軸受の予圧測定装置を装備したスピンドル装置の断面図である。このスピンドル装置は、マシニングセンタや、フライス盤、研削盤等の工作機械に用いられるものであり、ハウジング１に軸２が前後の軸受３により回転自在に支持されている。軸２は、前端に工具（図示せず）を差し込んで取り付ける工具取付部１５を有している。前後の軸受３は、それぞれ軌道輪である内輪４と外輪５の間に複数の転動体６を介在させた転がり軸受であり、保持器７で保持されている。軸受３は軸方向の予圧が可能な軸受であり、アンギュラ玉軸受、深溝玉軸受、またはテーパころ軸受等が用いられる。図示の例では、アンギュラ玉軸受が用いられている。   A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of a spindle device equipped with this bearing preload measuring device. This spindle device is used for a machine tool such as a machining center, a milling machine, or a grinding machine. A shaft 2 is rotatably supported by a housing 1 by front and rear bearings 3. The axis | shaft 2 has the tool attachment part 15 which inserts and attaches a tool (not shown) to the front end. The front and rear bearings 3 are rolling bearings in which a plurality of rolling elements 6 are interposed between an inner ring 4 and an outer ring 5 that are raceways, and are held by a cage 7. The bearing 3 is a bearing capable of axial preload, and an angular ball bearing, a deep groove ball bearing, a tapered roller bearing, or the like is used. In the illustrated example, an angular ball bearing is used.

各軸受３の外輪５は、ハウジング１の内径面に嵌合し、前後の軸受３の外輪５の間に外輪間座９が介在している。前側の軸受３の外輪５の前側端面、および後ろ側の軸受３の後ろ側端面は、それぞれハウジング１に設けられた段面１ｂ，１ｃに係合している。
各軸受３の内輪４は、軸２の外径面に嵌合し、前後の軸受３の内輪４の間に内輪間座１０が介在している。前側の軸受３の内輪４の前側の端面は、軸２の前端に設けられた大径部２ａに隣接する段面２ｂに係合している。後ろ側の軸受３の内輪４の後ろ側の端面は、軸２の後端に設けられた雄ねじ部２ｄに螺合したナット１１により、内輪押付け用間座１２を介して押し付けられている。 The outer ring 5 of each bearing 3 is fitted to the inner diameter surface of the housing 1, and an outer ring spacer 9 is interposed between the outer rings 5 of the front and rear bearings 3. The front end surface of the outer ring 5 of the front bearing 3 and the rear end surface of the rear bearing 3 are engaged with step surfaces 1 b and 1 c provided in the housing 1, respectively.
The inner ring 4 of each bearing 3 is fitted to the outer diameter surface of the shaft 2, and an inner ring spacer 10 is interposed between the inner rings 4 of the front and rear bearings 3. The front end surface of the inner ring 4 of the front bearing 3 is engaged with a step surface 2 b adjacent to the large diameter portion 2 a provided at the front end of the shaft 2. The rear end surface of the inner ring 4 of the rear bearing 3 is pressed through an inner ring pressing spacer 12 by a nut 11 screwed into a male screw portion 2d provided at the rear end of the shaft 2.

軸受３の外輪５に対する内輪４の軸方向および径方向の位置を測定するために、非接触変位測定機８を、スピンドル装置の熱の影響および遠心力の影響を受けない非回転側であるハウジング１に固定する。非接触変位測定機８としては、内輪４の端面の軸方向の変位量を測定する非接触変位測定機８Ａと、内輪４の外径面の径方向の変位量を測定する非接触変位測定機８Ｂとを設けている。これら非接触変位測定機８Ａ，８Ｂは、前側の軸受３に対して設けているが、後ろ側の軸受３に対して設けても良い。   In order to measure the axial and radial positions of the inner ring 4 with respect to the outer ring 5 of the bearing 3, the non-contact displacement measuring machine 8 is a non-rotating side housing that is not affected by the heat of the spindle device and the centrifugal force. Fix to 1. The non-contact displacement measuring machine 8 includes a non-contact displacement measuring machine 8A that measures the amount of axial displacement of the end face of the inner ring 4, and a non-contact displacement measuring machine that measures the amount of radial displacement of the outer diameter surface of the inner ring 4. 8B. These non-contact displacement measuring machines 8A and 8B are provided for the front bearing 3, but may be provided for the rear bearing 3.

軸方向の非接触変位測定機８Ａは、ハウジング１の前端の内径面に設けられた切欠状部内に固定されている。径方向の非接触変位測定機８Ｂは、ハウジング１の上記段面１ｂに設けられた切欠状部内に固定されている。図１の例では、径方向の非接触変位測定機８Ｂの取付側の軸受３は、内輪４の幅を外輪５よりも広げることにより、径方向の非接触変位測定機８Ｂを、内輪４の外径面に対して垂直方向に配置可能としている。非接触変位測定機８Ｂのリード線は、ハウジング１に設けられた導出孔から外部に引き出されている。内輪幅を広げる代わりに、例えば図９に示すように、外輪５に非接触変位測定機８Ｂの一部または全体が入る切欠状部１３を設けても良い。このように、内輪幅を広げるか、または外輪５に切欠状部１３を設けることで、径方向の非接触変位測定機８Ｂを内輪外径面に対して垂直方向に対向させることができるため、前後の軸受３を背面合わせおよび正面合わせのいずれの向きに配置しても、測定値を同様に取り扱うことができる。なお、図１において、径方向の非接触変位測定機８Ｂを内輪４の外径面に対して斜めに向けることで、内外輪４，５の幅を同一幅としても良い。   The axial non-contact displacement measuring machine 8 </ b> A is fixed in a notch-like portion provided on the inner diameter surface of the front end of the housing 1. The non-contact displacement measuring device 8B in the radial direction is fixed in a notch-like portion provided on the step surface 1b of the housing 1. In the example of FIG. 1, the bearing 3 on the mounting side of the radial non-contact displacement measuring machine 8B expands the width of the inner ring 4 more than the outer ring 5 to change the radial non-contact displacement measuring machine 8B of the inner ring 4. It can be arranged in a direction perpendicular to the outer diameter surface. The lead wire of the non-contact displacement measuring instrument 8B is drawn out from the lead-out hole provided in the housing 1. Instead of widening the inner ring width, for example, as shown in FIG. 9, a notch-shaped portion 13 into which a part or the whole of the non-contact displacement measuring machine 8B enters the outer ring 5 may be provided. In this way, by increasing the inner ring width or by providing the outer ring 5 with the notch 13, the radial non-contact displacement measuring instrument 8B can be opposed to the inner ring outer diameter surface in the vertical direction. Even if the front and rear bearings 3 are arranged in either the back-to-back or front-to-front orientation, the measured values can be handled in the same manner. In FIG. 1, the inner and outer rings 4 and 5 may have the same width by directing the radial non-contact displacement measuring device 8 </ b> B obliquely with respect to the outer diameter surface of the inner ring 4.

軸方向の非接触変位測定機８Ａと径方向の非接触変位測定機８Ｂとは、同じ種類，規格のものを用いても良く、また種類や規格を異ならせても良い。
これら非接触変位測定機８Ａ，８Ｂとしては、対向する表面位置の変位が非接触で検出できるものであれば良く、例えば渦電流式変位センサや、レーザ測長機、または静電容量式変位センサ等を用いることができる。渦電流式変位センサを用いた場合、非接触変位測定機８Ａ，８Ｂと検出対象面との間にグリース等の介在物があっても、影響されずに精度良く測定することができる。 The non-contact displacement measuring device 8A in the axial direction and the non-contact displacement measuring device 8B in the radial direction may be of the same type and standard, or may be different in type and standard.
These non-contact displacement measuring devices 8A and 8B may be any devices that can detect the displacement of the opposing surface positions in a non-contact manner. For example, an eddy current displacement sensor, a laser length measuring device, or a capacitance displacement sensor. Etc. can be used. When an eddy current displacement sensor is used, even if there are inclusions such as grease between the non-contact displacement measuring machines 8A and 8B and the detection target surface, it can be measured accurately without being affected.

このスピンドル装置における予圧測定方法を説明する。ナット１１を軽く締めて各部品の隙間を無くした状態、すなわち前後の軸受３の予圧が零の状態で、軸方向の非接触変位測定機８Ａにより内輪４の対向する端面の軸方向位置を測定し、この予圧が零の軸方向位置を原点とする。その後、ナット１１を締めて、軸受３に予圧を与えた時の内輪４の軸方向位置変化量を測定する。ナット１１の締め付け前後の内輪軸方向位置の差が、内外輪４，５の転走面および転動体６の弾性変位量であり、この変位量から軸受３の予圧量を算出することができる。   A preload measuring method in this spindle apparatus will be described. In the state where the nut 11 is lightly tightened to eliminate the gap between the parts, that is, the preload of the front and rear bearings 3 is zero, the axial position of the opposite end face of the inner ring 4 is measured by the axial non-contact displacement measuring machine 8A. The axial position where this preload is zero is the origin. Thereafter, the nut 11 is tightened, and the axial position change amount of the inner ring 4 when the preload is applied to the bearing 3 is measured. The difference in the position of the inner ring in the axial direction before and after tightening the nut 11 is the amount of elastic displacement of the rolling surfaces of the inner and outer rings 4 and 5 and the rolling elements 6, and the amount of preload of the bearing 3 can be calculated from this amount of displacement.

次に、スピンドル装置を運転すると、軸受３の内輪輪４，５の温度差および遠心力による内輪４の膨張のために、内輪４が拡径する。その変位量を径方向の非接触変位測定機８Ｂで測定し、この値から、予圧の変化量を求めることができる。
径方向の非接触変位測定機８Ｂにより得られた軸受予圧変化量に、軸方向の非接触変位測定機８Ａで得られた運転前の予圧量を加えることにより、運転時の予圧量を算出することができる。 Next, when the spindle device is operated, the inner ring 4 expands due to the temperature difference between the inner rings 4 and 5 of the bearing 3 and the expansion of the inner ring 4 due to centrifugal force. The displacement amount is measured by the radial non-contact displacement measuring instrument 8B, and the change amount of the preload can be obtained from this value.
The preload amount during operation is calculated by adding the preload amount before operation obtained by the axial noncontact displacement measuring device 8A to the bearing preload change amount obtained by the noncontact displacement measuring device 8B in the radial direction. be able to.

図２は、転がり軸受における上記軸方向変位量と予圧量の関係を示すグラフであり、図３は遠心力と熱膨張による径方向変位量と予圧量の関係を示すグラフである。いずれも一般的な傾向を示す概念図である。このように予め判っている各変位量と予圧量の変化の関係を用いることで、軸方向変位量および径方向変位量の測定値から予圧量の変化を測定することができる。   FIG. 2 is a graph showing the relationship between the axial displacement amount and the preload amount in a rolling bearing, and FIG. 3 is a graph showing the relationship between the radial displacement amount and the preload amount due to centrifugal force and thermal expansion. Each is a conceptual diagram showing a general tendency. As described above, by using the relationship between each displacement amount and the change in the preload amount that is known in advance, the change in the preload amount can be measured from the measured values of the axial displacement amount and the radial displacement amount.

図４は、この発明の他の実施形態を示す。この実施形態は、図１に示す第１の実施形態において、前側の軸受３に対する非接触変位測定機８Ａ，８Ｂに加えて、後ろ側の軸受３における内輪４の端面の軸方向変位量を測定する非接触変位測定機８Ｃを加えたものである。   FIG. 4 shows another embodiment of the present invention. In this embodiment, in the first embodiment shown in FIG. 1, in addition to the non-contact displacement measuring machines 8A and 8B for the front bearing 3, the axial displacement amount of the end face of the inner ring 4 in the rear bearing 3 is measured. The non-contact displacement measuring machine 8C is added.

スピンドル装置を運転すると、軸受３の内外輪４，５の温度差のため、ハウジング１と軸２にも温度差を生じる。その結果、軸２が伸びて内外輪４，５の軸方向位置が変化し、予圧量が変化する。
軸方向に加わる荷重が零の場合は、前後の軸受３が均等に内外輪４，５の軸方向位置の変化を生じるが、実際のスピンドル装置には、切削荷重等により軸２に軸方向荷重が加わる。その場合、内外輪４，５の軸方向位置を測定する非接触変位測定機８Ａが１個では、前後２個の軸受３の予圧量を正確に測定・算出することが困難である。
しかし、この実施形態のように、前後の軸受３，４のそれぞれに１個ずつ非接触変位測定機８Ａ，８Ｃを設けることで、より正確に予圧量を算出することができる。 When the spindle device is operated, a temperature difference occurs between the housing 1 and the shaft 2 due to a temperature difference between the inner and outer rings 4 and 5 of the bearing 3. As a result, the shaft 2 extends, the axial positions of the inner and outer rings 4 and 5 change, and the amount of preload changes.
When the load applied in the axial direction is zero, the front and rear bearings 3 change the axial position of the inner and outer rings 4 and 5 evenly. However, in an actual spindle device, the axial load is applied to the shaft 2 due to cutting load or the like. Will be added. In that case, it is difficult to accurately measure and calculate the preload amount of the two front and rear bearings 3 with one non-contact displacement measuring machine 8A that measures the axial positions of the inner and outer rings 4 and 5.
However, the preload amount can be calculated more accurately by providing one non-contact displacement measuring machine 8A, 8C for each of the front and rear bearings 3, 4 as in this embodiment.

図５は、スピンドル装置に軸受の予圧調整装置２０を設けた実施形態を示す。この実施形態は、図４に示す実施形態において、予圧付与装置２１と、予圧量制御装置２２とを設けたものである。これら予圧付与装置２１および予圧量制御装置２２と、上記非接触変位測定機８Ａ〜８Ｃとで予圧調整装置２０が構成される。   FIG. 5 shows an embodiment in which a bearing preload adjusting device 20 is provided in the spindle device. In this embodiment, a preload applying device 21 and a preload control device 22 are provided in the embodiment shown in FIG. The preload applying device 21 and the preload control device 22 and the non-contact displacement measuring machines 8A to 8C constitute a preload adjusting device 20.

予圧付与装置２１は、指令値に対応した予圧を軸受３に付与可能な装置であり、ハウジング１に設置されている。予圧付与装置２１は、例えば、円周方向複数箇所に設けられた油圧シリンダからなり、そのシリンダ本体がハウジング１に設置されてピストンロッドで軸受３の外輪５の端面を押すものとされる。予圧付与装置２１は、例えばハウジング１に組み込まれて全周に連続したリング状の油圧室およびピストンを有するものであっても良い。この実施形態における予圧付与装置２１は、ナット１１の締め付けにより与えた予圧を、外輪４の端面の押し付けによって弱めることで、予圧量を指令値に対応した値に対応するものとされる。予圧は、スピンドル装置の運転によって上がるため、予圧付与装置２１は、上記のように別に与えられている予圧を下げるものとすることで、大荷重の付与が不要で、簡易な構成のもので済む。なお、図４において、予圧付与装置２１と非接触変位測定機８Ｃを同じ断面上に示してあるが、予圧付与装置２１が円周方向複数箇所の油圧シリンダである場合、その油圧シリンダと非接触変位測定機８Ｃとは互いに円周方向にずれた位置に配置する。   The preload applying device 21 is a device that can apply a preload corresponding to the command value to the bearing 3, and is installed in the housing 1. The preload applying device 21 is composed of, for example, hydraulic cylinders provided at a plurality of locations in the circumferential direction. The cylinder body is installed in the housing 1 and pushes the end surface of the outer ring 5 of the bearing 3 with a piston rod. The preload applying device 21 may include, for example, a ring-shaped hydraulic chamber and a piston that are incorporated in the housing 1 and are continuous around the entire circumference. The preload applying device 21 in this embodiment is configured to correspond to a value corresponding to the command value by weakening the preload applied by tightening the nut 11 by pressing the end face of the outer ring 4. Since the preload is increased by the operation of the spindle device, the preload applying device 21 reduces the preload applied separately as described above, so that it is not necessary to apply a large load and a simple configuration is sufficient. . In FIG. 4, the preload applying device 21 and the non-contact displacement measuring device 8C are shown on the same cross section. However, when the preload applying device 21 is a hydraulic cylinder at a plurality of locations in the circumferential direction, the preload applying device 21 is not in contact with the hydraulic cylinder. The displacement measuring device 8C is arranged at a position shifted from each other in the circumferential direction.

予圧量制御装置２２は、各非接触変位測定機８Ａ〜８Ｃの出力である内輪端面の軸方向変位量および内輪外径面の径方向変位量から、関係設定データに従って、予圧付与装置２１に予圧量が設定範囲内に維持されるように動作指令を与える装置である。予圧量制御装置２２は、上記設定関係データである予圧量と軸方向変位量の関係、および予圧量と径方向変位量の関係を記憶したデータベース２２ａと、上記各測定値をデータベース２２ａに記憶された設定関係データと比較して予圧量調整のための動作量を演算する動作量演算手段２２ｂとを備える。予圧付与装置２１が油圧シリンダである場合、予圧量制御装置２２には、動作量演算手段２２ｂで演算された出力に従って油圧を制御する油圧制御機器２２ｃが設けられる。   The preload amount control device 22 preloads the preload application device 21 according to the relation setting data from the axial displacement amount of the inner ring end face and the radial displacement amount of the outer diameter surface of the inner ring, which are outputs of the non-contact displacement measuring machines 8A to 8C. It is a device that gives an operation command so that the amount is maintained within a set range. The preload amount control device 22 stores the relationship between the preload amount and the axial displacement amount and the relationship between the preload amount and the radial displacement amount, which are the setting relationship data, and the measured values in the database 22a. The operation amount calculating means 22b for calculating the operation amount for adjusting the preload amount in comparison with the set relation data. When the preload application device 21 is a hydraulic cylinder, the preload amount control device 22 is provided with a hydraulic control device 22c that controls the hydraulic pressure according to the output calculated by the operation amount calculation means 22b.

この構成の場合、予圧量制御装置２２のデータベース２２ａを使って、各非接触変位測定機８Ａ〜８Ｃから得られた変位量から予圧量を算出することができる。予圧量制御装置２２は、運転中の予圧量が設定された予圧量を外れた場合に、動作指令を出力し、その動作指令により、油圧シリンダからなる予圧付与装置２１によって軸受外輪５を軸方向に押し、軸受３間の外輪４間の距離を調整することによって、適正な予圧範囲内に戻す。そのため、リアルタイムで予圧量を検出して、常時適正な予圧量で運転できるスピンドル装置を構成することができる。   In the case of this configuration, the preload amount can be calculated from the displacement amounts obtained from the non-contact displacement measuring machines 8A to 8C using the database 22a of the preload amount control device 22. When the preload amount during operation deviates from the set preload amount, the preload amount control device 22 outputs an operation command, and in response to the operation command, the preload applying device 21 including a hydraulic cylinder causes the bearing outer ring 5 to move in the axial direction. To the proper preload range by adjusting the distance between the outer rings 4 between the bearings 3. Therefore, it is possible to configure a spindle device that can detect a preload amount in real time and can always operate with an appropriate preload amount.

図６は、この発明のさらに他の実施形態を示す。この実施形態は、図１に示す第１の実施形態において、前側の軸受３に対する非接触変位測定機８Ａ，８Ｂに加えて、後ろ側の軸受３に対して、内輪４の端面の軸方向変位量を測定する非接触変位測定機８Ｃ、および内輪４の外径面の径方向変位量を測定する非接触変位測定機８Ｄを設けたものである。
このように、前後の軸受３に、共に軸方向の非接触変位測定機８Ａ，８Ｃ、および径方向の非接触変位測定機８Ｂ，８Ｄを設けた場合、前後の軸受３の温度や他の環境の違いに応じて、より精度良く予圧量の測定が行える。 FIG. 6 shows still another embodiment of the present invention. In this embodiment, in the first embodiment shown in FIG. 1, in addition to the non-contact displacement measuring machines 8A and 8B for the front bearing 3, the axial displacement of the end face of the inner ring 4 with respect to the rear bearing 3 is used. A non-contact displacement measuring machine 8C for measuring the amount and a non-contact displacement measuring machine 8D for measuring the radial displacement of the outer diameter surface of the inner ring 4 are provided.
As described above, when the front and rear bearings 3 are provided with the non-contact displacement measuring machines 8A and 8C in the axial direction and the non-contact displacement measuring machines 8B and 8D in the radial direction, the temperature of the front and rear bearings 3 and other environments. Depending on the difference, the amount of preload can be measured with higher accuracy.

図７は、この発明のさらに他の実施形態を示す。この実施形態は、図６に示す実施形態において、予圧調整装置２０Ａを設けたものである。予圧調整装置２０Ａは、予圧付与装置２１および予圧量制御装置２２と、各非接触変位測定機８Ａ〜８Ｄとでなる。予圧付与装置２１および予圧量制御装置２２は、４つの非接触変位測定機８Ａ〜８Ｄの測定値を用いること、およびデータベース２２ｂが４つの非接触変位測定機８Ａ〜８Ｄに対応するデータを有していること等、非接触変位測定機８Ａ〜８Ｄの個数，配置に対応する違いを除いて、図５に示す実施形態と同様である。だだし、この例では、外輪間座９が軸方向に対して弾性を持たせた弾性機能付き間座とされている。外輪間座９は、図示の例では、２つの分割外輪間座９ａに分割し、その間にＵ字状に湾曲した板ばね等からなるばね部材１４を介在させることで、弾性機能を有するものとされている。外輪間座９は、分割型とする代わりに、全体を高剛性ばね材等で構成しても良い。   FIG. 7 shows still another embodiment of the present invention. In this embodiment, a preload adjusting device 20A is provided in the embodiment shown in FIG. The preload adjusting device 20A includes a preload applying device 21, a preload control device 22, and non-contact displacement measuring machines 8A to 8D. The preload applying device 21 and the preload control device 22 use the measured values of the four non-contact displacement measuring machines 8A to 8D, and the database 22b has data corresponding to the four non-contact displacement measuring machines 8A to 8D. Except for the difference corresponding to the number and arrangement of the non-contact displacement measuring machines 8A to 8D, etc., it is the same as the embodiment shown in FIG. However, in this example, the outer ring spacer 9 is a spacer with an elastic function that is elastic in the axial direction. In the illustrated example, the outer ring spacer 9 is divided into two divided outer ring spacers 9a, and a spring member 14 made of a leaf spring or the like curved in a U shape is interposed between the outer ring spacers 9a and has an elastic function. Has been. The outer ring spacer 9 may be composed of a highly rigid spring material or the like instead of being divided.

この構成の場合、前後の軸受３に対してそれぞれ軸方向および径方向の非接触変位測定機８Ａ〜８Ｄを設け、その測定値に対応した制御を行うため、前後の軸受３に作用する環境等に大きな違いがあっても、精度良く予圧量の調整が行える。   In the case of this configuration, the non-contact displacement measuring machines 8A to 8D in the axial direction and the radial direction are provided for the front and rear bearings 3, respectively, and an environment acting on the front and rear bearings 3 is performed in order to perform control corresponding to the measured values. Even if there is a big difference, the amount of preload can be adjusted accurately.

なお、上記各実施形態では、前後に配置する軸受をそれぞれ１個ずつとしたが、例えば図８に示すように複数個ずつ配置しても良く、また前後のいずれかにつき、軸受３を複数配置しても良い。その場合、例えば図８に示されるように前側の各軸受３については前端の軸受３に対して、後ろ側の軸受３に対しては後端の軸受３に対して非接触変位測定機８Ａ〜８Ｄを配置する。   In each of the above embodiments, the number of bearings arranged at the front and rear is one, but a plurality of bearings may be arranged, for example, as shown in FIG. You may do it. In this case, for example, as shown in FIG. 8, the non-contact displacement measuring machines 8 </ b> A to 8 </ b> A to the front bearing 3 for the front bearings 3 and the rear bearing 3 to the rear bearing 3. Place 8D.

また、上記各実施形態は、いすれもハウジング１が固定側で、軸２が回転側である場合につき説明したが、ハウジング１が回転側で軸２が固定側である場合にも、この発明を適用することができる。その場合、非接触変位測定機は、固定側となる軸に取付け、回転側である外輪の端面および内径面の変位量を測定可能なように設置する。   In each of the above embodiments, the housing 1 is on the stationary side and the shaft 2 is on the rotating side. However, the present invention is also applicable to the case where the housing 1 is on the rotating side and the shaft 2 is on the stationary side. Can be applied. In that case, the non-contact displacement measuring machine is attached to the shaft on the fixed side and is installed so as to be able to measure the amount of displacement of the end surface and the inner diameter surface of the outer ring on the rotating side.

この発明の第１の実施形態にかかる軸受の予圧測定装置を備えたスピンドル装置の断面図である。It is sectional drawing of the spindle apparatus provided with the preload measuring apparatus of the bearing concerning 1st Embodiment of this invention. 軸方向変位量と予圧量の関係を示すグラフである。It is a graph which shows the relationship between the amount of axial direction displacement, and the amount of preload. 径方向変位量と予圧量の関係を示すグラフである。It is a graph which shows the relationship between the amount of radial direction displacement, and the amount of preload. この発明の他の実施形態にかかる予圧測定装置を備えたスピンドル装置の断面図である。It is sectional drawing of the spindle apparatus provided with the preload measuring apparatus concerning other embodiment of this invention. この発明のさらに他の実施形態にかかる予圧調整装置を備えたスピンドル装置の断面図である。It is sectional drawing of the spindle apparatus provided with the preload adjusting apparatus concerning further another embodiment of this invention. この発明のさらに他の実施形態にかかる予圧測定装置を備えたスピンドル装置の断面図である。It is sectional drawing of the spindle apparatus provided with the preload measuring apparatus concerning further another embodiment of this invention. この発明のさらに他の実施形態にかかる予圧調整装置を備えたスピンドル装置の断面図である。It is sectional drawing of the spindle apparatus provided with the preload adjusting apparatus concerning further another embodiment of this invention. この発明のさらに他の実施形態にかかる予圧測定装置を備えたスピンドル装置の断面図である。It is sectional drawing of the spindle apparatus provided with the preload measuring apparatus concerning further another embodiment of this invention. 非接触変位測定機取付用の切欠状部を設けた軸受の部分斜視図である。It is a fragmentary perspective view of the bearing which provided the notch-shaped part for non-contact displacement measuring machine attachment.

符号の説明Explanation of symbols

１…ハウジング
２…軸
３…軸受
４…内輪
５…外輪
６…転動体
８…非接触変位測定機
８Ａ〜８Ｄ…非接触変位測定機
２０…予圧調整装置
２１…予圧付与装置 ２２…予圧量制御装置 DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Shaft 3 ... Bearing 4 ... Inner ring 5 ... Outer ring 6 ... Rolling element 8 ... Non-contact displacement measuring machine 8A-8D ... Non-contact displacement measuring machine 20 ... Preload adjusting device 21 ... Preload imparting device 22 ... Preload amount control apparatus

Claims (4)

軌道輪である内輪と外輪間に複数の転動体を配した転がり軸受によりハウジングに対して軸を回転自在に支持したスピンドル装置において、上記転がり軸受の予圧量を測定する方法であって、上記ハウジングおよび軸のうちの固定側の部材に取付けられた非接触変位測定機により、上記転がり軸受の回転側軌道輪の端面の軸方向変位量、および回転側軌道輪の軸受内側となる周面の径方向変位量を測定し、これら軸方向変位量および径方向変位量の測定結果を用いて、上記転がり軸受の予圧量を求めることを特徴とする軸受の予圧測定方法。   In a spindle device in which a shaft is rotatably supported with respect to a housing by a rolling bearing in which a plurality of rolling elements are arranged between an inner ring and an outer ring, which are race rings, a method for measuring a preload amount of the rolling bearing, the housing And an axial displacement amount of the end face of the rotating bearing ring of the rolling bearing and a diameter of the peripheral surface on the inner side of the rotating bearing ring by a non-contact displacement measuring machine attached to a fixed member of the shaft. A bearing preload measurement method, comprising: measuring a direction displacement amount, and obtaining a preload amount of the rolling bearing using a measurement result of the axial direction displacement amount and the radial direction displacement amount. 軌道輪である内輪と外輪間に複数の転動体を配した転がり軸受によりハウジングに対して軸を回転自在に支持したスピンドル装置において、上記転がり軸受の予圧量を測定する装置であって、上記ハウジングおよび軸のうちの固定側の部材にそれぞれ取付けられて、上記転がり軸受の回転側軌道輪の端面の軸方向変位量、および回転側軌道輪の軸受内側となる周面の径方向変位量をそれぞれ測定する軸方向および径方向の非接触変位測定機を備えることを特徴とする軸受の予圧測定装置。   In a spindle device in which a shaft is rotatably supported with respect to a housing by a rolling bearing in which a plurality of rolling elements are arranged between an inner ring and an outer ring, which are raceways, a device for measuring a preload amount of the rolling bearing, the housing And the axial displacement amount of the end surface of the rotating bearing ring of the rolling bearing, and the radial displacement amount of the peripheral surface inside the bearing of the rotating bearing ring, respectively. A bearing preload measuring device comprising a non-contact displacement measuring device for measuring axial and radial directions. 請求項２において、前記軸の前部を支持する転がり軸受の前側の端面の軸方向変位量を測定する非接触変位測定機と、軸の後部を支持する転がり軸受の後ろ側の端面の軸方向変位量を測定する非接触変位測定機とを設けた軸受の予圧測定装置。   The non-contact displacement measuring machine for measuring the axial displacement amount of the front end face of the rolling bearing that supports the front portion of the shaft, and the axial direction of the rear end face of the rolling bearing that supports the rear portion of the shaft. A bearing preload measuring device provided with a non-contact displacement measuring device for measuring a displacement amount. 内輪と外輪の間に複数の転動体を配した転がり軸受によりハウジングに対して軸を回転自在に支持したスピンドル装置において、上記転がり軸受の予圧量を調整する装置であって、上記ハウジングに設置され転がり軸受に指令値に対応した予圧を付与可能な予圧付与装置と、上記ハウジングにそれぞれ取付けられ、上記転がり軸受の内輪の端面の軸方向変位量および内輪の外径面の径方向変位量をそれぞれ測定する軸方向および径方向の非接触変位測定機と、これら非接触変位測定機の出力である内輪端面の軸方向変位量および内輪外径面の径方向変位量から、関係設定データに従って上記予圧付与装置に、予圧量が設定範囲内に維持されるように動作指令を与える予圧量制御装置とを備えた軸受の予圧調整装置。   In a spindle device in which a shaft is rotatably supported with respect to a housing by a rolling bearing in which a plurality of rolling elements are arranged between an inner ring and an outer ring, the device adjusts a preload amount of the rolling bearing, and is installed in the housing. A preload applying device capable of applying a preload corresponding to a command value to the rolling bearing, and an axial displacement amount of the end surface of the inner ring of the rolling bearing and a radial displacement amount of the outer diameter surface of the inner ring, respectively. From the axial and radial non-contact displacement measuring devices to be measured, and the axial displacement amount of the inner ring end face and the radial displacement amount of the inner ring outer diameter surface which are the outputs of these non-contact displacement measuring devices, the above preload is determined according to the relation setting data. A preload adjusting device for a bearing, comprising: a preload amount control device for giving an operation command to the applying device so that the preload amount is maintained within a set range.

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