JPH10118877A - Feed screw mechanism - Google Patents
Feed screw mechanismInfo
- Publication number
- JPH10118877A JPH10118877A JP29797096A JP29797096A JPH10118877A JP H10118877 A JPH10118877 A JP H10118877A JP 29797096 A JP29797096 A JP 29797096A JP 29797096 A JP29797096 A JP 29797096A JP H10118877 A JPH10118877 A JP H10118877A
- Authority
- JP
- Japan
- Prior art keywords
- screw shaft
- feed screw
- bearing
- feed
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
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- Transmission Devices (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、工作機械や三次元
測定機などの精密機械における送りねじ機構に関し、特
に駆動に基づき発生する熱対策のため、送りねじ軸に予
張力を付与する送りねじ機構に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed screw mechanism for a precision machine such as a machine tool or a coordinate measuring machine, and more particularly, to a feed screw for applying a pretension to a feed screw shaft in order to take measures against heat generated by driving. Regarding the mechanism.
【０００２】[0002]
【従来の技術】工作機械や三次元測定機などの精密機械
における一般的な送りねじ機構は、ねじ部のピッチを若
干短くした送りねじ軸の両端を基台に固定した軸受によ
り支持し、送りねじ軸の一方の軸端に螺着したナットを
締め込むことにより前記送りねじ軸に予張力を付与し
て、送りねじ軸のねじ部のピッチを正規寸法まで引き伸
ばすような構造を採用している。これによつて、送りね
じ軸の駆動時に発生する熱膨張に基づく前記ねじ軸の応
力が、予張力（引張応力）で吸収されてねじ部のピッチ
が変動せず、送りねじ機構の送り精度や剛性を高く維持
することができるようにされていた。2. Description of the Related Art A general feed screw mechanism in a precision machine such as a machine tool or a coordinate measuring machine supports a feed screw shaft in which a pitch of a screw portion is slightly shortened and supported by bearings having both ends fixed to a base. The feed screw shaft is pre-tensioned by tightening a nut screwed to one shaft end of the screw shaft, and the pitch of the thread portion of the feed screw shaft is extended to a regular size. . Thereby, the stress of the screw shaft based on the thermal expansion generated when the feed screw shaft is driven is absorbed by the pretension (tensile stress), so that the pitch of the screw portion does not fluctuate. The rigidity was kept high.
【０００３】近年、加工速度の向上に伴い、送りねじ機
構における送り速度の高速化を図る必要が生じている
が、上述したようなナツトの締め込みにより送りねじ軸
に予張力を付与する構造では、送りねじ機構の高速駆動
時には熱膨張により送りねじ軸が予想以上に伸びて、送
りねじ軸に所定の引張応力を超えた応力が発生した場
合、送りねじ軸に付与した予張力が抜けてしまい、送り
ねじ機構の送り精度や剛性が低下するといった問題があ
った。In recent years, it has become necessary to increase the feed speed of the feed screw mechanism with the improvement of the processing speed. However, in the structure in which the feed screw shaft is pretensioned by tightening the nut as described above. When the feed screw mechanism is driven at high speed, the feed screw shaft extends more than expected due to thermal expansion, and if a stress exceeding the predetermined tensile stress is generated on the feed screw shaft, the pretension applied to the feed screw shaft is lost. However, there has been a problem that the feed accuracy and rigidity of the feed screw mechanism are reduced.
【０００４】このような問題点を解決する技術として、
本願出願人による特開平８−９０３７９号公報に開示し
たような「送りねじ機構」が知られている。この公知技
術は、図４（前記の送りねじ機構を工作機械の送り軸に
適用したときの実施形態の要部側断面図）を参照して、
ボールねじ軸１の両端をベース（基台）３に対し軸受支
持し、その一方側軸受(図示せず)をベース３及びボール
ねじ軸１に対し軸線方向に固定すると共に、前記ボール
ねじ軸１の他方側自由端に螺着されたロックナット５に
より、当該軸端側のアンギュラコンタクト軸受（以下、
「ベアリング」という）７を内、外輪を介してベアリン
グの保持ケース（以下、「ベアリングケース」という）
９に対し軸線方向に押圧し、前記ベアリング７の外輪を
ベース３に固定したベアリングケース９の段付側面に係
止させる一方、前記ロックナット５を締め込む反作用と
して、ボールねじ軸１に予張力を付与するものである。As a technique for solving such a problem,
A "feed screw mechanism" as disclosed in Japanese Patent Application Laid-Open No. Hei 8-90379 by the present applicant is known. This known technique is described with reference to FIG. 4 (a sectional side view of a main part of an embodiment when the above-described feed screw mechanism is applied to a feed shaft of a machine tool).
Both ends of the ball screw shaft 1 are bearing-supported with respect to a base (base) 3, and one side bearing (not shown) is axially fixed with respect to the base 3 and the ball screw shaft 1. The lock nut 5 screwed to the free end on the other side of the shaft allows the angular contact bearing on the shaft end side (hereinafter, referred to as an angular contact bearing).
A bearing holding case 7 (hereinafter referred to as a "bearing case") via an inner and an outer ring.
9, the outer ring of the bearing 7 is locked to the stepped side surface of the bearing case 9 fixed to the base 3, while the lock nut 5 is tightened to prevent the ball screw shaft 1 from being pretensioned. Is given.
【０００５】加えて、前記予力に基づきベアリングケー
ス９の段付側面に対し押圧されているベアリング７の外
輪と前記ベアリングケース９との間に皿ばね11を介装し
て、両者間を隔離するよう付勢している。その際、ロッ
クナット５の締め込みによりボールねじ軸１に付与した
予張力の方が、皿ばね11の撓みに基づく張力よりも大で
あるので、常態においては、ベアリングケース９と前記
ベアリング７の外輪とは圧接状態にある。上記機構にお
いては、ボールねじ軸１が熱膨張により過度に伸び、前
記ロックナット５の締め込みによって付与されていたボ
ールねじ軸１に対する予張力が抜けたときも、皿ばね11
による張力がボールねじ軸１に作用し、送りねじ機構の
送り精度や剛性が低下しない。In addition, a disc spring 11 is interposed between the outer ring of the bearing 7 pressed against the stepped side surface of the bearing case 9 based on the preload and the bearing case 9 to isolate the two. We are urging to do. At this time, since the pretension applied to the ball screw shaft 1 by tightening the lock nut 5 is larger than the tension based on the deflection of the disc spring 11, the bearing case 9 and the bearing 7 The outer ring is in pressure contact with the outer ring. In the above-mentioned mechanism, even when the ball screw shaft 1 is excessively stretched due to thermal expansion and the pretension applied to the ball screw shaft 1 given by tightening the lock nut 5 is released, the disc spring 11 can be used.
Does not act on the ball screw shaft 1, and the feed accuracy and rigidity of the feed screw mechanism do not decrease.
【０００６】[0006]
【発明が解決しようとする課題】上記公知の送りねじ機
構は、ベアリング７の外輪とベアリングケース９との間
に皿ばね11が介装されているため、ボールねじ軸１が熱
膨張によって過度に伸びたときには、ボールねじ軸１が
ベアリング７と一体になって移動し、前記ベアリング７
の外輪がベアリングケース９の内周面に対して滑動す
る。ところで、一般的にベアリングケース９は鋳物によ
り構成され、その内周面は中ぐり盤等により旋削加工を
行うため、良好な仕上面精度を望むことができない。
したがって、仕上面精度のあまり良くないベアリングケ
ース９の内周面とベアリング７の外輪との間で相対滑り
が生じることになり、熱膨張によるボールねじ軸１の円
滑な伸びを妨げるおそれがある。In the known feed screw mechanism described above, since the disc spring 11 is interposed between the outer ring of the bearing 7 and the bearing case 9, the ball screw shaft 1 is excessively expanded due to thermal expansion. When extended, the ball screw shaft 1 moves integrally with the bearing 7,
Of the bearing case 9 slides on the inner peripheral surface of the bearing case 9. By the way, the bearing case 9 is generally made of a casting, and its inner peripheral surface is turned by a boring machine or the like.
Therefore, relative slippage occurs between the inner peripheral surface of the bearing case 9 and the outer ring of the bearing 7, which have poor surface finish accuracy, and the smooth expansion of the ball screw shaft 1 due to thermal expansion may be hindered.
【０００７】そこで本発明は、過度な熱膨張の発生時に
送りねじ軸の伸びが円滑に行われると共に、送りねじ軸
の送り精度や剛性を高く維持することができる送りねじ
機構を提供することを目的とする。Accordingly, the present invention provides a feed screw mechanism capable of smoothly expanding the feed screw shaft when excessive thermal expansion occurs and maintaining high feed accuracy and rigidity of the feed screw shaft. Aim.
【０００８】[0008]
【課題を解決するための手段】本発明は、上述目的を達
成するために、以下に述べるとおりの各構成要件を具備
している。 （１） 送りねじ軸のねじ部のピッチを僅かに短めに作
製し、前記送りねじ軸に予張力を付与することにより、
前記ねじ部のねじのピツチを正規の寸法に保持して使用
する送りねじ機構において、前記送りねじ軸の両端を基
台に軸受支持し、前記送りねじ軸の一端側を前記送りね
じ軸の軸線方向に対して回転可能に固定すると共に、前
記送りねじ軸の他端側の先端に螺着したナットと前記他
端側の軸受の内輪との間に圧縮ばね手段を介在させ、前
記ナットを締め込み、前記送りねじ軸に予張力を付与し
て、前記送りねじ軸に引張応力を発生させ、前記送りね
じ軸の作動中の温度上昇に基づく熱膨張応力を前記引張
応力により、吸収するようにし、前記送りねじ軸の温度
上昇が過度で、前記熱膨張応力が前記引張応力を超えた
ときでも、前記圧縮ばね手段により前記送りねじ軸に軸
線方向の張力が付与するようにした送りねじ機構。The present invention has the following components in order to achieve the above object. (1) By making the pitch of the thread portion of the feed screw shaft slightly shorter and applying a pretension to the feed screw shaft,
In a feed screw mechanism that uses the screw pitch of the screw portion while maintaining the pitch of the screw at a regular size, both ends of the feed screw shaft are supported on a base and one end of the feed screw shaft is connected to the axis of the feed screw shaft. A compression spring is interposed between a nut screwed to the other end of the feed screw shaft and an inner ring of the bearing at the other end, and the nut is tightened. The feed screw shaft is pre-tensioned to generate a tensile stress in the feed screw shaft, and a thermal expansion stress based on a temperature rise during operation of the feed screw shaft is absorbed by the tensile stress. A feed screw mechanism in which the compression spring means applies axial tension to the feed screw shaft even when the temperature of the feed screw shaft rises excessively and the thermal expansion stress exceeds the tensile stress.
【０００９】[0009]
【作用】軸受の内輪とナットとの間に圧縮ばね手段を介
し送りねじ軸に対し軸線方向に予張力を付与して送りね
じ軸のねじ部のピッチを引き伸し、前記ピッチが正規の
寸法になるよう予張力を調整してナットを固定したの
で、送りねじ軸の作動中の発熱に基づく熱膨張応力を予
張力による引張応力中に吸収させると共に、所定温度を
超えて送りねじ軸が作動し予記張力が消失したのちには
圧縮ばね手段に基づく張力が作用して、軸受の内輪と送
りねじ軸の外周との間で相対滑理を生じさせるようにし
たので、送りねじ軸の軸受支持の安定を図ることがで
き、送り精度や剛性を高く維持する。The pre-tension is applied to the feed screw shaft in the axial direction between the inner ring of the bearing and the nut via a compression spring means to extend the pitch of the threaded portion of the feed screw shaft. The nut is fixed by adjusting the pre-tension so that the thermal expansion stress based on the heat generated during operation of the feed screw shaft is absorbed into the tensile stress by the pre-tension, and the feed screw shaft operates beyond the specified temperature. After the pre-tension is lost, the tension based on the compression spring means acts to cause relative lubrication between the inner ring of the bearing and the outer periphery of the feed screw shaft. Support stability can be achieved, and feed accuracy and rigidity are maintained high.
【００１０】[0010]
【発明の実施の形態】以下に、本発明の送りねじ機構の
一実施形態を図面に沿って説明するが、この実施形態を
構成する各要件は、本発明の出願当時の当業界における
技術レベルの範囲内で各種の変形が可能であるから、格
別の理由を示すことなく、以下に記載の実施形態の構成
のみに基づいて本発明の要旨を限定して解釈してはなら
ない。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a feed screw mechanism according to the present invention will be described below with reference to the drawings. Therefore, the gist of the present invention should not be construed as limiting the gist of the present invention based on only the configuration of the embodiment described below without showing a special reason.
【００１１】図１は、本発明の送りねじ機構を工作機械
の送り軸に適用したときの実施形態を示す一部切欠側断
面図で、図中、ベース（基台）３の左方側に固定された
送り軸駆動用モータ13の出力軸15端は、両端をベース３
に軸受支持したボールねじ（送りねじ）軸１の一端側と
突き合わされ、軸継手17により同心的に連結されてい
る。ボールねじ軸１の左方側の軸頚部（段付き嵌合軸
部）には、３個よりなるアンギュラコンタクト球軸受
（以下、「ベアリング」という）19及びスペーサ21が嵌
着され、その左方から前記ねじ軸１にロックナット23を
螺合、締結することにより、ベアリング19（内輪）とボ
ールねじ軸１とが一体的に連結される。FIG. 1 is a partially cutaway side sectional view showing an embodiment in which the feed screw mechanism of the present invention is applied to a feed shaft of a machine tool. In the drawing, a left side of a base (base) 3 is shown. The output shaft 15 end of the fixed feed shaft drive motor 13 has a base 3 at both ends.
One end of a ball screw (feed screw) shaft 1 supported by a bearing is abutted and connected concentrically by a shaft coupling 17. Three angular contact ball bearings (hereinafter, referred to as “bearings”) 19 and spacers 21 are fitted to the left and right shaft necks (stepped fitting shafts) of the ball screw shaft 1. By screwing and fastening the lock nut 23 to the screw shaft 1 from above, the bearing 19 (inner ring) and the ball screw shaft 1 are integrally connected.
【００１２】一方、前記ベアリング（外輪）19はベース
３の嵌合孔部に嵌着され、その左方からベアリング押え
25を係合しベース３にボルト止めすることにより、ベア
リング19（外輪）をベース３に一体的に連結している。
したがって、ボールねじ軸１の左側軸頚部は、ベース３
に対しベアリング19を介して回転自在かつ、軸線軸方向
には全く移動不可能（基準点位置）な支持型式を形成し
ている。On the other hand, the bearing (outer ring) 19 is fitted in a fitting hole of the base 3 and a bearing presser is provided from the left side thereof.
The bearing 19 (outer ring) is integrally connected to the base 3 by engaging the bolt 25 to the base 3 by engaging the engagement 25.
Therefore, the left side neck of the ball screw shaft 1 is
In contrast, a support type that is rotatable via a bearing 19 and that cannot be moved at all in the axial direction (reference point position) is formed.
【００１３】また、ボールねじ軸１の右方側において
は、ベース３に固定したベアリングケース９の内筒部に
嵌着した一対のアンギュラコンタクト球軸受（以下、
「ベアリング」という）７、スペーサ27、カラー10を挾
んだ一対の皿ばね11及び座金29が、この順序で前記ボー
ルねじ軸１の軸頚部（段付き嵌合軸部）に嵌着され、そ
の右方からロックナット５がボールねじ軸１に螺着され
ている。なお、前記ベアリングケース９は、ケース固定
用ボルトにより、そのフランジ部分でベース３に固定さ
れている。また、ベアリング７の外輪は、ベアリングケ
ース９の内筒部に強く嵌合、固着し、外力によっても簡
単には移動しない。On the right side of the ball screw shaft 1, a pair of angular contact ball bearings (hereinafter, referred to as “fittings”) fitted to the inner cylindrical portion of a bearing case 9 fixed to the base 3.
A bearing 7, a spacer 27, a pair of disc springs 11 sandwiching the collar 10, and a washer 29 are fitted to the shaft neck (stepped fitting shaft) of the ball screw shaft 1 in this order. A lock nut 5 is screwed to the ball screw shaft 1 from the right side. The bearing case 9 is fixed to the base 3 at its flange portion by case fixing bolts. Further, the outer ring of the bearing 7 is strongly fitted and fixed to the inner cylindrical portion of the bearing case 9 and does not easily move even by an external force.
【００１４】上記ボールねじ軸１の両端の軸受間、すな
わち、図１において左方側ベアリング19（ボールねじ軸
１の軸頚部、基準点位置を含む）と、右方側ベアリング
７との間は、図示していない公知のボール（送り）ねじ
を旋削したねじ軸が、連設されている。ただし、上記ボ
ールねじのピッチは、常温、自由長で、正規のピッチよ
りも僅かに短めに設定されている。Between the bearings at both ends of the ball screw shaft 1, that is, between the left bearing 19 (including the shaft neck of the ball screw shaft 1 and the reference point) and the right bearing 7 in FIG. A screw shaft obtained by turning a known ball (feed) screw (not shown) is continuously provided. However, the pitch of the ball screw is set to a normal temperature, a free length, and slightly shorter than a regular pitch.
【００１５】図２を参照して、送りねじ機構における前
記各部材間の軸線方向の位置関係を説明すると、ロック
ナット５をボールねじ軸１の右側自由端のねじ部に螺
合、締め込み、その側面により座金29、カラー10を含む
一対の皿ばね11（自由長）、スペーサ27及び一対のベア
リング７（内輪）をボールねじ軸１の左方側の基準点位
置方向に押圧、移動させ、前記ベアリング７の外輪側面
がベアリングケース９の内側段付部の側面に当接してい
る段階において、ベアリング７の内輪側面とボールねじ
軸１の軸頚部段付面との間には若干の隙間が存在する。
一対の皿ばね11は、カラー10を挾んで縮み代を具備し
て、すなわち、自由長を保持している。また、この時点
では、ボールねじ軸１の右方自由端のねじ部は、ロック
ナット５を螺合、締め込むのに充分な長さを有してい
る。Referring to FIG. 2, the axial positional relationship between the above members in the feed screw mechanism will be described. The lock nut 5 is screwed into the right free end of the ball screw shaft 1 and tightened. The side surface thereof presses and moves the washer 29, the pair of disc springs 11 (free length) including the collar 10, the spacer 27, and the pair of bearings 7 (the inner ring) in the direction of the reference point on the left side of the ball screw shaft 1. At the stage where the outer ring side surface of the bearing 7 is in contact with the side surface of the inner step portion of the bearing case 9, there is a slight gap between the inner ring side surface of the bearing 7 and the shaft neck portion step surface of the ball screw shaft 1. Exists.
The pair of disc springs 11 has a shrinkage allowance with the collar 10 interposed therebetween, that is, has a free length. At this time, the screw portion at the right free end of the ball screw shaft 1 has a length sufficient to screw and lock the lock nut 5.
【００１６】再び、図１を参照して、ロックナット５を
ボールねじ軸１の右方自由軸端のねじ部に螺着し左方側
の基準点位置方向にさらに締め込むときには、その軸線
方向締め込み力は、ベアリング７の外輪側面がベアリン
グケース９の内側段付部側面に当接しているため、ロッ
クナット５の座金29側面とベアリング７の内輪のスペー
サ27側面との間に嵌着されている一対の皿ばね11を圧縮
するように作用し、前記皿ばね11をカラー10の厚さ限度
まで撓ませる。その反作用で、ボールねじ軸１に対し基
準点位置からロックナット５方向に張力が発生する。そ
の状態から、さらにロックナット５を締め込めば、ロッ
クナット５の締め込み力はボールねじ軸１に対し軸線方
向に予張力を付与し、その結果、ねじ軸１を均質に伸ば
す。ここで、ロックナット５の締め込み力とボールねじ
軸１の軸線方向の伸びとは一般的に比例する。Referring again to FIG. 1, when the lock nut 5 is screwed into the threaded portion of the right free shaft end of the ball screw shaft 1 and further tightened in the direction of the left reference point, the axial direction Since the outer ring side surface of the bearing 7 is in contact with the inner stepped side surface of the bearing case 9, the tightening force is fitted between the washer 29 side surface of the lock nut 5 and the spacer 27 side surface of the inner ring of the bearing 7. This acts to compress the pair of disc springs 11, and deflects the disc springs 11 to the thickness limit of the collar 10. Due to the reaction, a tension is generated from the reference point position to the lock nut 5 with respect to the ball screw shaft 1. If the lock nut 5 is further tightened from that state, the tightening force of the lock nut 5 applies a pretension to the ball screw shaft 1 in the axial direction, and as a result, the screw shaft 1 is uniformly extended. Here, the tightening force of the lock nut 5 and the elongation in the axial direction of the ball screw shaft 1 are generally proportional.
【００１７】上述のようなロックナット５の締め込みに
基づくボールねじ軸１の均質な伸びにより、常温におい
て僅かに短く設定したボールねじ軸１の送りねじ部の個
々のピッチが引き伸ばされ、その結果、送りねじ部の各
ピッチが正規寸法のピッチとなる。送りねじ機構の駆動
時、熱的平衡状態に近づくにしたがって、温度上昇によ
るボールねじ軸１の軸線方向の熱膨張が前記ねじ軸１を
伸ばす方向に働くが、その熱応力はロックナット５の締
め込みによりねじ軸１に付与した予張力で発生する引張
応力と相殺するだけで、送りねじ部のピッチの寸法に影
響を及ぼすことはない。Due to the uniform elongation of the ball screw shaft 1 based on the tightening of the lock nut 5 as described above, the individual pitch of the feed screw portion of the ball screw shaft 1 set slightly short at normal temperature is elongated, and as a result, Each pitch of the feed screw portion is a pitch of a regular size. When the feed screw mechanism is driven, the thermal expansion in the axial direction of the ball screw shaft 1 due to a rise in temperature acts in the direction of extending the screw shaft 1 as the temperature approaches a thermal equilibrium state. It does not affect the pitch dimension of the feed screw portion only by offsetting with the tensile stress generated by the pretension applied to the screw shaft 1 by the insertion.
【００１８】また、高速駆動時等の送りねじ機構の過負
荷駆動のためにボールねじ軸１の熱的平衡状態が破れ
て、ボールねじ軸１が通常の駆動時の温度よりも上昇し
軸線方向の伸びが生じた場合、ロックナット５の締め込
みによりボールねじ軸１に付与した予張力がゼロに近付
くが、前記皿ばね11の撓みによるボールねじ軸１の張力
が軸線方向に働いているから、前記ボールねじ軸１の軸
線方向の伸びは、その張力に吸収されることになり、ボ
ールねじ軸１の軸受支持の安定性を維持することができ
る。その際、ボールねじ軸１の伸縮は、ベアリングケー
ス９に嵌着されたベアリング７の内輪とねじ軸１の軸頚
部の外径との間の仕上げ精度の高い滑動面により行われ
るから、精度の高い軸受支持が可能となる。Further, the thermal equilibrium state of the ball screw shaft 1 is broken due to overload driving of the feed screw mechanism at the time of high-speed driving or the like, so that the temperature of the ball screw shaft 1 rises above the normal driving temperature and the axial When the lock nut 5 is tightened, the pretension applied to the ball screw shaft 1 approaches zero, but the tension of the ball screw shaft 1 due to the bending of the disc spring 11 acts in the axial direction. The extension of the ball screw shaft 1 in the axial direction is absorbed by the tension, so that the stability of the bearing support of the ball screw shaft 1 can be maintained. At this time, the expansion and contraction of the ball screw shaft 1 is performed by a highly accurate sliding surface between the inner ring of the bearing 7 fitted to the bearing case 9 and the outer diameter of the shaft neck of the screw shaft 1. High bearing support is possible.
【００１９】これを、図３を参照して説明すると、同図
は横軸を発熱、膨脹に基づくボールねじ軸１の伸びを採
り、縦軸をボールねじ軸１に掛かる張力（予張力）とし
たグラフで、本実施態様おいては、さきに述べたよう
に、ボールねじ軸１に掛かる張力（予張力）とロックナ
ット５による締め込み力及び、皿ばね11の撓みに基づく
ばね力の和とは釣り合っている。図で、常温、初期値の
Ａ点においては、ロックナット５を基準点位置方向に締
め込み一対の皿ばね11をカラー10の厚さまで撓ませた
上、さらにロックナット５を締め込んでボールねじ軸１
に掛かる張力（予張力）を増加させてボールねじ軸１を
軸線方向に均等に引き伸ばし、あらかじめ僅かに短かく
設定したボールねじ軸１の送りねじ部の個々のピッチを
正規の寸法にまで引き伸ばした状態（図１参照）を示し
ている。This will be described with reference to FIG. 3. In FIG. 3, the horizontal axis represents the elongation of the ball screw shaft 1 due to heat generation and expansion, and the vertical axis represents the tension (pretension) applied to the ball screw shaft 1. In this embodiment, the sum of the tension (pre-tension) applied to the ball screw shaft 1, the tightening force by the lock nut 5, and the spring force based on the deflection of the disc spring 11 is described in this embodiment. Is balanced. In the figure, at a normal temperature and an initial value point A, the lock nut 5 is tightened in the direction of the reference point to deflect the pair of disc springs 11 to the thickness of the collar 10, and then the lock nut 5 is further tightened to tighten the ball screw. Axis 1
The ball screw shaft 1 is stretched uniformly in the axial direction by increasing the tension (pretension) applied to the ball screw, and the individual pitches of the feed screw portions of the ball screw shaft 1 set in advance to be slightly shorter are stretched to regular dimensions. The state (see FIG. 1) is shown.
【００２０】いま、送りねじ機構を駆動したとき、ボー
ルねじ軸１の送りねじ部と送りねじ部に螺合するナット
部との間で発生する摩擦熱や、その他の発熱により、送
りねじ機構の温度が上昇してボールねじ軸１が熱膨張応
力を発生すると前記の張力を相殺してボールねじ軸１の
内部応力（引張応力）は、図中、Ａ−Ｂ線に沿ってＤ点
方向に向かって減少するするが、その間、ロックナット
５の締め込み固定位置、皿ばね11の撓みの変動はないか
ら、このためボールねじ軸１の送りねじ部の各ピッチが
規定の寸法から変動することはない。ボールねじ軸１が
軸線方向に膨脹して、その張力がＢ点まで低下すると、
Ｂ点におけるボールねじ軸１の内部応力は、皿ばね11の
撓みによるばね力による張力と同等となる。Now, when the feed screw mechanism is driven, frictional heat generated between the feed screw portion of the ball screw shaft 1 and the nut portion screwed to the feed screw portion, and other heat, cause the feed screw mechanism to rotate. When the temperature rises and the ball screw shaft 1 generates thermal expansion stress, the above-mentioned tension is canceled out, and the internal stress (tensile stress) of the ball screw shaft 1 is changed in the direction of point D along the line AB in the drawing. In the meantime, there is no change in the tightening position of the lock nut 5 and the deflection of the disc spring 11 during this time. Therefore, each pitch of the feed screw portion of the ball screw shaft 1 fluctuates from a specified dimension. There is no. When the ball screw shaft 1 expands in the axial direction and its tension decreases to the point B,
The internal stress of the ball screw shaft 1 at the point B becomes equal to the tension due to the spring force due to the bending of the disc spring 11.
【００２１】本実施態様においては、駆動時におけるボ
ールねじ軸１の摩擦熱やその他の要因による発熱により
ねじ軸１の温度が常温から徐々に上昇し、送りねじ機構
に発生する熱と、放、拡散する熱とが釣合いを保ち送り
ねじ機構が熱的平衡状態になってボールねじ軸１が略、
一定の作動温度を維持している場合に、ねじ軸１の送り
ねじ部のピッチが正規の寸法になるように、皿ばね11の
撓み力、ロックナット５の締め付け力の和を調整（図３
におけるＡ−Ｂ線参照）している。とはいうものの、送
りねじ機構の高速駆動中等、過酷な動作が続いて通常の
熱的平衡状態が破れさらに温度上昇して、ボールねじ軸
１がさらに熱膨張をする場合に備え、ロックナット５の
締め付け力に基づく内部応力が消失しても皿ばね11の撓
み量を残すようにし、これにより、ねじ軸１の軸線方向
に若干の張力を維持している。図３におけるＢ−Ｃ線
は、そのときボールねじ軸１に掛かる張力の変動を示す
ものである。すなわち、皿ばね11の撓み力によって送り
ねじ機構の過度な温度上昇の場合にも、ボールねじ軸１
の張力をゼロにすることなく、前記ねじ軸１を安定、か
つ確実に軸受支持することができる。In this embodiment, the temperature of the screw shaft 1 gradually increases from room temperature due to frictional heat of the ball screw shaft 1 during driving and heat generated by other factors. The spread screw keeps balance and the feed screw mechanism is in thermal equilibrium, and the ball screw shaft 1 is approximately
When the constant operating temperature is maintained, the sum of the bending force of the disc spring 11 and the tightening force of the lock nut 5 is adjusted so that the pitch of the feed screw portion of the screw shaft 1 becomes a regular size (FIG. 3).
Line AB). Nevertheless, the lock nut 5 is used in case that the ball screw shaft 1 is further thermally expanded due to continued severe operation such as during high-speed driving of the feed screw mechanism, breaking the normal thermal equilibrium state and further increasing the temperature. Thus, even if the internal stress based on the tightening force disappears, the amount of deflection of the disc spring 11 is left, thereby maintaining a slight tension in the axial direction of the screw shaft 1. The line BC in FIG. 3 shows the fluctuation of the tension applied to the ball screw shaft 1 at that time. That is, even if the temperature of the feed screw mechanism rises excessively due to the bending force of the disc spring 11, the ball screw shaft
The screw shaft 1 can be stably and reliably supported as a bearing without reducing the tension of the screw shaft to zero.
【００２２】この場合、ボールねじ軸１のロックナット
５側の軸頚部を軸受支持するベアリング７の両（外、内
輪）側面は、ベアリングケース９の段付側面とスペーサ
27、皿ばね11及び、座金29を介してロックナット５とに
より、ベース３またはベアリングケース９に（見かけ
上）固着され、ねじ軸１に対して軸線方向に移動するこ
とはないから、ボールねじ軸１の熱膨張によりボールね
じ軸１が軸線方向に伸びると、皿ばね11とカラー10の間
に隙間が生じて皿ばね11の撓み量が減少し、ロックナッ
ト５側のねじ軸１の軸頚部がベアリング７の内輪に対し
て滑動する。In this case, both (outer and inner) side surfaces of the bearing 7 for supporting the shaft neck of the ball screw shaft 1 on the lock nut 5 side are formed with the stepped side surface of the bearing case 9 and the spacer.
The ball screw 11 is fixed (apparently) to the base 3 or the bearing case 9 by the lock nut 5 through the disc spring 11 and the washer 29, and does not move in the axial direction with respect to the screw shaft 1. When the ball screw shaft 1 extends in the axial direction due to the thermal expansion of the shaft 1, a gap is formed between the disc spring 11 and the collar 10, the bending amount of the disc spring 11 decreases, and the shaft of the screw shaft 1 on the lock nut 5 side. The neck slides with respect to the inner ring of the bearing 7.
【００２３】一般に軸頚部の加工は、旋削加工等により
高精度精密加工が可能であるし、既成品として市場に流
通しているベアリング７の内輪の径寸法、内径面も精密
加工されているから、両者面間の滑動は円滑であり、熱
膨張、収縮によるボールねじ軸１の移動はスムーズに行
われる。このため、送りねじ機構の機能に不測の外乱が
入るおそれがない。送りねじ機構の稼働時において、ボ
ールねじ軸１が熱膨張、収縮する場合にも、常にねじ軸
１の両軸頚部の軸受支持が確実に行われるから、ボール
ねじ軸１の送り精度や、剛性を維持する。また、ボール
ねじ軸１の軸頚部とベアリング７の内輪と間に滑動面が
生じるが、滑動面の仕上げ精度が極めて良好であるた
め、前記滑動面は長期の使用に耐え、滑動に基づく局所
的摩耗が生じることがない。Generally, the machining of the shaft neck can be performed with high precision and precision by turning or the like, and the diameter and inner diameter of the inner ring of the bearing 7 which is commercially available as a ready-made product are also precision-machined. The sliding between the two surfaces is smooth, and the movement of the ball screw shaft 1 due to thermal expansion and contraction is performed smoothly. For this reason, there is no possibility that an unexpected disturbance enters the function of the feed screw mechanism. During operation of the feed screw mechanism, even when the ball screw shaft 1 thermally expands and contracts, the bearing support of the both necks of the screw shaft 1 is always reliably performed. To maintain. In addition, a sliding surface is formed between the neck portion of the ball screw shaft 1 and the inner ring of the bearing 7, but the finishing accuracy of the sliding surface is extremely good. No wear occurs.
【００２４】[0024]
【発明の効果】本発明の送りねじ機構によれば、熱膨張
により、送りねじ軸に過度の伸びが発生しても、その伸
びを円滑に吸収することができる。また、送りねじ軸に
安定した張力を常に付与することができ、送り精度や剛
性を高く維持する。送りねじ軸の軸受支持の静剛性及び
動剛性が向上して、ガタの発生や固有振動の低下を起こ
し難い、送りねじ機構を提供することができる。等々、
従来装置では、期待することができない、格別な作用、
効果を奏することができる。According to the feed screw mechanism of the present invention, even if an excessive elongation occurs in the feed screw shaft due to thermal expansion, the elongation can be smoothly absorbed. In addition, a stable tension can always be applied to the feed screw shaft, and feed accuracy and rigidity are kept high. It is possible to provide a feed screw mechanism in which the static rigidity and the dynamic rigidity of the bearing support of the feed screw shaft are improved, and the occurrence of backlash and a decrease in natural vibration hardly occur. And so on,
Special effects that cannot be expected with conventional equipment,
The effect can be achieved.
【図１】本発明の送りねじ機構を工作機械の送り軸に適
用したときの実施形態を示す一部切欠側断面図である。FIG. 1 is a partially cutaway side sectional view showing an embodiment when a feed screw mechanism of the present invention is applied to a feed shaft of a machine tool.
【図２】図１におけるナット締付調整前の状態を示す要
部側断面図である。FIG. 2 is a sectional side view of a main part showing a state before a nut tightening adjustment in FIG.
【図３】本発明における送りねじ軸の張力と伸びとの関
係を示す線図である。FIG. 3 is a diagram showing a relationship between tension and elongation of a feed screw shaft in the present invention.
【図４】従来の送りねじ機構を工作機械の送り軸に適用
したときの実施形態を示す要部側断面図である。FIG. 4 is a side sectional view of a main part showing an embodiment when a conventional feed screw mechanism is applied to a feed shaft of a machine tool.
１ ボールねじ軸 ３ ベース ５ ロックナット ７ ベアリング（アンギュラコンタクト軸受） ９ ベアリングケース 10 カラー 11 皿ばね 19 ベアリング（アンギュラコンタクト軸受） 21 スペーサ 23 ロックナット 25 ベアリング押え 27 スペーサ 29 座金 1 Ball screw shaft 3 Base 5 Lock nut 7 Bearing (Angular contact bearing) 9 Bearing case 10 Collar 11 Belleville spring 19 Bearing (Angular contact bearing) 21 Spacer 23 Lock nut 25 Bearing presser 27 Spacer 29 Washer
Claims (1)
めに作製し、前記送りねじ軸に予張力を付与することに
より、前記ねじ部のねじのピツチを正規の寸法に保持し
て使用する送りねじ機構において、 前記送りねじ軸の両端を基台側に軸受支持し、 前記送りねじ軸の一端側を前記送りねじ軸の軸線方向に
対して回転可能に固定すると共に、 前記送りねじ軸の他端側の先端に螺着したナットと前記
他端側の軸受の内輪との間に圧縮ばね手段を介在させ、
前記ナットを締め込み、前記送りねじ軸に予張力を付与
して、前記送りねじ軸に引張応力を発生させ、 銭機送りねじ軸の作動中の温度上昇に基づく熱膨張応力
を前記引張応力により吸収するようにし、 前記送りねじ軸の温度上昇が過度で、前記熱膨張応力が
前記引張応力を超えたときでも、前記圧縮ばね手段によ
り前記送りねじ軸に軸線方向の張力が付与するようにし
たことを特徴とする送りねじ機構。1. A pitch of a screw portion of a feed screw shaft is made slightly shorter and a pretension is applied to the feed screw shaft so that the pitch of the screw of the screw portion is maintained at a regular size. A feed screw mechanism, wherein both ends of the feed screw shaft are supported on a base side, and one end of the feed screw shaft is rotatably fixed in the axial direction of the feed screw shaft; Compression spring means is interposed between the nut screwed to the tip on the other end side and the inner ring of the bearing on the other end side,
The nut is tightened, a pretension is applied to the feed screw shaft to generate a tensile stress in the feed screw shaft, and a thermal expansion stress based on a temperature rise during the operation of the feed screw shaft is changed by the tensile stress. Even if the temperature rise of the feed screw shaft is excessive and the thermal expansion stress exceeds the tensile stress, the tension of the feed screw shaft is applied in the axial direction by the compression spring means. A feed screw mechanism, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29797096A JP3535327B2 (en) | 1996-10-22 | 1996-10-22 | Feed screw mechanism |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29797096A JP3535327B2 (en) | 1996-10-22 | 1996-10-22 | Feed screw mechanism |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10118877A true JPH10118877A (en) | 1998-05-12 |
| JP3535327B2 JP3535327B2 (en) | 2004-06-07 |
Family
ID=17853459
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29797096A Expired - Lifetime JP3535327B2 (en) | 1996-10-22 | 1996-10-22 | Feed screw mechanism |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3535327B2 (en) |
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| JP2007285351A (en) * | 2006-04-13 | 2007-11-01 | Nsk Ltd | Ball screw |
| CN103143971A (en) * | 2013-03-01 | 2013-06-12 | 江苏松野数控科技有限公司 | Pre-drawing structure of ball screw |
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| CN105817939A (en) * | 2016-04-15 | 2016-08-03 | 江苏润德精密机械有限公司 | Transmission shaft structure and vertical machining center with transmission shaft structure |
| CN106122409A (en) * | 2016-06-27 | 2016-11-16 | 芜湖市海联机械设备有限公司 | A kind of ball screw bearing arrangement |
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| CN114198409A (en) * | 2022-01-19 | 2022-03-18 | 浙江优特轴承有限公司 | Lead screw supporting bearing assembly |
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| JP6094347B2 (en) * | 2013-04-11 | 2017-03-15 | 日本精工株式会社 | Lock nut for ball screw device and ball screw device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007285351A (en) * | 2006-04-13 | 2007-11-01 | Nsk Ltd | Ball screw |
| CN103143971A (en) * | 2013-03-01 | 2013-06-12 | 江苏松野数控科技有限公司 | Pre-drawing structure of ball screw |
| CN105479237A (en) * | 2016-01-18 | 2016-04-13 | 南通国盛机电集团有限公司 | Lead screw prestretching structure |
| CN105817939A (en) * | 2016-04-15 | 2016-08-03 | 江苏润德精密机械有限公司 | Transmission shaft structure and vertical machining center with transmission shaft structure |
| CN106122409A (en) * | 2016-06-27 | 2016-11-16 | 芜湖市海联机械设备有限公司 | A kind of ball screw bearing arrangement |
| CN108300518A (en) * | 2018-04-03 | 2018-07-20 | 山西阳煤化工机械（集团）有限公司 | Gasification furnace fin panel casing series internals support device |
| CN108581582A (en) * | 2018-06-25 | 2018-09-28 | 中山市捷上同程数控机床有限公司 | A kind of lead screw pretension fixing device |
| CN112846827A (en) * | 2020-12-25 | 2021-05-28 | 津上精密机床（浙江）有限公司 | Machine tool for small workpieces and method for improving precision of machine tool |
| CN114198409A (en) * | 2022-01-19 | 2022-03-18 | 浙江优特轴承有限公司 | Lead screw supporting bearing assembly |
| CN114654484A (en) * | 2022-02-28 | 2022-06-24 | 哈尔滨工业大学 | Scissors instrument suitable for big difference in temperature and cut-out design of preventing escaping |
| CN114654484B (en) * | 2022-02-28 | 2024-03-29 | 哈尔滨工业大学 | Scissors tool suitable for design of big difference in temperature and cut anti-escape |
| CN114738364A (en) * | 2022-04-02 | 2022-07-12 | 浙江中通汽车零部件有限公司 | Bearing nut with bearing clearance accurate adjustment and automatic anti-loosening and locking functions |
| CN114738364B (en) * | 2022-04-02 | 2023-08-15 | 浙江中通汽车零部件有限公司 | Bearing nut with bearing clearance accurate adjustment and automatic anti-loosening locking function |
| CN115435057A (en) * | 2022-08-29 | 2022-12-06 | 苏州德扬数控机械有限公司 | Lead screw prestretches structure |
| CN115435057B (en) * | 2022-08-29 | 2023-09-22 | 苏州德扬数控机械有限公司 | Lead screw prestretching structure |
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|---|---|
| JP3535327B2 (en) | 2004-06-07 |
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