JP2016109237A - Cage for non-circulation type ball screw and non-circulation type ball screw, and manufacturing method of cage for non-circulation type ball screw - Google Patents

Cage for non-circulation type ball screw and non-circulation type ball screw, and manufacturing method of cage for non-circulation type ball screw Download PDF

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JP2016109237A
JP2016109237A JP2014248668A JP2014248668A JP2016109237A JP 2016109237 A JP2016109237 A JP 2016109237A JP 2014248668 A JP2014248668 A JP 2014248668A JP 2014248668 A JP2014248668 A JP 2014248668A JP 2016109237 A JP2016109237 A JP 2016109237A
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cage
ball screw
ball
screw
divided
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和史 山本
Kazufumi Yamamoto
和史 山本
一成 宮崎
Kazunari Miyazaki
一成 宮崎
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NSK Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a cage for a non-circulation type ball screw which improves the processing accuracy and the positional accuracy of individual ball attachment parts even if the number of windings is increased, and can improve productivity, and its manufacturing method.SOLUTION: This cage 20 is constituted of a group of two cylindrical divided components 21, 22 which are divided along an axial direction. The two divided components 21, 22 have spiral protrusions 23 which are spirally formed along a screw shaft 1 or a screw groove of a nut 2, the spiral protrusions 23 are formed while protruding toward the outside rather than a cylindrical external peripheral face of the cage 20, and a plurality of ball-holding ball attachment parts 24 are protrusively arranged from internal peripheral face sides of the divided components 21, 22 along the spiral protrusions 23.SELECTED DRAWING: Figure 2

Description

本発明は、半導体機械、射出成型機および一般搬送装置等に用いられる、ボールが循環しない構造の非循環式ボールねじに係り、特に、この種の非循環式ボールねじの保持器に関する。   The present invention relates to a non-circulating ball screw having a structure in which a ball does not circulate, which is used in a semiconductor machine, an injection molding machine, a general transfer device, and the like, and more particularly to a retainer for this type of non-circulating ball screw.

非循環式ボールねじは、外周面に螺旋状のねじ溝が形成されたねじ軸と、ねじ軸のねじ溝に対向する螺旋状のねじ溝が内周面に形成されたナットとを、保持器で保持された複数のボールを介して螺合させている（例えば特許文献１ないし２参照）。   The non-circulating ball screw includes a screw shaft having a spiral thread groove formed on the outer peripheral surface and a nut having a spiral thread groove formed on the inner peripheral surface opposite to the screw groove of the screw shaft. (See, for example, Patent Documents 1 and 2).

特開２００２−１３０４１６号公報（図６）Japanese Patent Laid-Open No. 2002-130416 (FIG. 6) 実開平５−８１０４号公報（図３）Japanese Utility Model Publication No. 5-8104 (FIG. 3)

ところで、特許文献１、２では、一体形成された薄肉円筒形の保持器に、複数のボール装填部用の穴が形成されている。特に、特許文献１記載の技術では、ボールがねじ軸のねじ溝を離れて外側に脱落するのを防ぐために、ボール装填部が単純な穴ではなく、保持器の外周側に凸となる突出部を形成してボールの脱落を防止する構造が提案されている。
しかしながら、特許文献１ないし２に記載の保持器は、一体形成された薄肉円筒形の保持器に対してボール装填部用の穴を複数形成しているため、一つ一つの穴を成型もしくは切削加工するのは非常に困難である。 By the way, in Patent Documents 1 and 2, a plurality of holes for ball loading portions are formed in an integrally formed thin cylindrical cage. In particular, in the technique described in Patent Document 1, in order to prevent the ball from leaving the thread groove of the screw shaft and falling outside, the ball loading portion is not a simple hole but a protruding portion that protrudes toward the outer peripheral side of the cage. A structure has been proposed in which the ball is prevented from falling off.
However, since the cages described in Patent Documents 1 and 2 have a plurality of holes for the ball loading portion formed in the integrally formed thin cylindrical cage, each hole is molded or cut. It is very difficult to process.

特に、特許文献１に開示されるような、突出部が一体形成された薄肉円筒形の保持器を形成するためには、円筒部の内面側から「裏座ぐり」という特殊な加工が必要である。そのため、ボールねじの巻き数が少ない場合であれば制作可能ではあるものの、巻き数が増えるにつれて制作の難易度が極めて高くなるとともに、生産性を上げることが一層困難となり、製作費が非常に高価になるという問題がある。また、難加工であることから、個々の穴の加工精度や位置精度が悪い場合には、保持器とボールとの間の摩擦が大きくなるという問題もある。
そこで、本発明は、このような問題点に着目してなされたものであって、巻き数が増える場合であっても、個々のボール装填部の加工精度や位置精度を向上させるとともに、生産性を向上させ得る非循環式ボールねじ用保持器および非循環式ボールねじ、並びに非循環式ボールねじ用保持器の製造方法を提供することを課題とする。 In particular, in order to form a thin cylindrical retainer integrally formed with a protruding portion as disclosed in Patent Document 1, a special process of “back facing” is required from the inner surface side of the cylindrical portion. is there. Therefore, although it is possible to produce if the number of turns of the ball screw is small, the difficulty of production becomes extremely high as the number of turns increases, and it becomes more difficult to increase productivity, and the production cost is very expensive. There is a problem of becoming. In addition, since it is difficult to process, there is a problem that friction between the cage and the ball increases when the processing accuracy or position accuracy of each hole is poor.
Therefore, the present invention has been made paying attention to such a problem, and even when the number of windings is increased, the processing accuracy and position accuracy of each ball loading portion are improved and productivity is increased. It is an object of the present invention to provide a non-circulating ball screw cage, a non-circulating ball screw, and a method for manufacturing a non-circulating ball screw cage.

上記課題を解決するために、本発明の一態様に係る非循環式ボールねじ用保持器は、外周面に螺旋状のねじ溝が形成されたねじ軸と、該ねじ軸に外嵌されて内周面に螺旋状のねじ溝が形成されたナットと、前記ねじ軸と前記ナットとの両ねじ溝間に転動自在に介装される複数のボールとを備えるととともに、前記複数のボールが循環しない構造を有する非循環式ボールねじに用いられ、前記複数のボールを一定間隔に保持する複数のボール装填部を有する保持器であって、当該保持器は、前記ねじ軸と前記ナットとの隙間内に遊挿し得る厚みを有する円筒形状をなすとともに、該円筒形状の軸方向に沿って二分割された二つの分割部品の組によって構成され、前記二つの分割部品は、前記ねじ軸または前記ナットのねじ溝に沿って螺旋状に形成された螺旋凸条部を有し、前記螺旋凸条部は、前記円筒形状の外周面よりも外側に向けて突出して形成されるとともに、当該螺旋凸条部に沿ってボール保持用の複数のボール装填部が各分割部品の内周面側から穿設されていることを特徴とする。   In order to solve the above problems, a cage for a non-circulating ball screw according to an aspect of the present invention includes a screw shaft having a spiral thread groove formed on an outer peripheral surface thereof, and an external fitting inside the screw shaft. A nut having a spiral thread groove formed on a peripheral surface, and a plurality of balls interposed between the threaded shafts of the screw shaft and the nut so as to be able to roll freely. A cage that is used in a non-circulating ball screw having a structure that does not circulate and has a plurality of ball loading portions that hold the plurality of balls at a constant interval, and the cage includes a screw shaft and a nut. A cylindrical shape having a thickness that can be loosely inserted into the gap, and a set of two divided parts divided into two along the axial direction of the cylindrical shape, the two divided parts being the screw shaft or the Helical shape along the thread of the nut The spiral ridge portion is formed to protrude outward from the outer peripheral surface of the cylindrical shape, and a plurality of balls for holding the ball along the spiral ridge portion. A ball loading portion is formed from the inner peripheral surface side of each divided part.

ここで、本発明の一態様に係る非循環式ボールねじ用保持器において、前記二つの分割部品相互は、円筒形状の端部またはその他の接触部分で結合されており、その結合部は、分割部品自身に形成された凹凸の係合もしくは加締め、または分割部品とは別個の結合用部品によって結合されていることは好ましい。
また、本発明の一態様に係る非循環式ボールねじ用保持器において、前記ボール装填部の先端部は、ドリル加工により、ボール装填部中のボールが外部に向けて脱落しないような円錐形状に穿設されていることは好ましい。
また、本発明の一態様に係る非循環式ボールねじ用保持器において、前記螺旋凸条部は、ナットのねじ溝と相似のオフセット形状に形成されていることは好ましい。 Here, in the non-circular ball screw retainer according to an aspect of the present invention, the two divided parts are coupled to each other at a cylindrical end portion or other contact portion, and the coupling portion is divided. It is preferable that the projections and recesses formed on the components themselves are engaged or crimped, or connected by separate connecting components from the divided components.
Further, in the non-circular ball screw retainer according to one aspect of the present invention, the tip of the ball loading portion has a conical shape so that the ball in the ball loading portion does not fall out toward the outside by drilling. It is preferable that it is perforated.
Moreover, in the non-circular ball screw retainer according to one aspect of the present invention, it is preferable that the spiral protrusion is formed in an offset shape similar to a thread groove of a nut.

さらに、上記課題を解決するために、本発明の一態様に係る非循環式ボールねじは、本発明の一態様に係る非循環式ボールねじ用保持器を備えることを特徴とする。
さらに、上記課題を解決するために、本発明の一態様に係る非循環式ボールねじ用保持器の製造方法は、深絞りが可能な鋼製の板材（例えば冷間押し出し成形用のＳＰＣＣ材）を用い、その鋼製の板材をプレス成型して、前記非循環式ボールねじの螺旋状のねじ溝に対応する位置に沿って前記螺旋凸条部を押し出して成形するとともに、前記円筒形状の軸方向に沿って二分割された二つの分割部品それぞれに対応する半円筒形状に成形し、その半円筒形状に成形された二つの分割部品を組み合わせて円筒状の保持器とすることを特徴とする。 Furthermore, in order to solve the said subject, the non-circular ball screw which concerns on 1 aspect of this invention is equipped with the retainer for non-circular ball screws which concerns on 1 aspect of this invention, It is characterized by the above-mentioned.
Furthermore, in order to solve the said subject, the manufacturing method of the non-circulation type ball screw cage which concerns on 1 aspect of this invention is the steel board | plate material (for example, SPCC material for cold extrusion molding) in which deep drawing is possible. The steel plate material is press-molded, and the spiral ridge portion is extruded along a position corresponding to the spiral thread groove of the non-circulating ball screw, and the cylindrical shaft is formed. It is formed into a semi-cylindrical shape corresponding to each of two divided parts divided into two along the direction, and the two divided parts formed into the semi-cylindrical shape are combined to form a cylindrical cage. .

本発明のいずれか一の態様によれば、円筒形状の保持器を軸方向に沿って二分割された二つの分割部品によって構成し、二つの分割部品を組み合わせて円筒状の保持器とするので、分割部品を組み合わせる前の状態において、二分割された分割部品の内周面側を外に向けた状態とすることができる。そのため、円筒部の内側からの「裏座ぐり」を廃止し得て、巻き数が増える場合であっても、通常のドリル加工によって複数のボール装填部を穿設することができる。したがって、個々のボール装填部の穴の加工精度や位置精度を向上させるとともに、生産性を向上させることができる。   According to any one aspect of the present invention, the cylindrical cage is constituted by two divided parts divided into two along the axial direction, and the two divided parts are combined to form a cylindrical cage. In a state before the divided parts are combined, the inner peripheral surface side of the divided parts divided into two can be made to face outward. Therefore, the “back spot facing” from the inside of the cylindrical portion can be abolished, and even when the number of turns increases, a plurality of ball loading portions can be drilled by ordinary drilling. Therefore, it is possible to improve the processing accuracy and position accuracy of the holes of the individual ball loading sections and improve the productivity.

本発明の一態様に係る保持器を備える非循環式ボールねじの一実施形態を説明する模式図であり、同図では、軸線に沿った断面を示している。It is a mimetic diagram explaining one embodiment of a non-circular ball screw provided with a maintenance machine concerning one mode of the present invention, and shows the section along an axis. 図１に示す保持器の一実施形態を説明する図であり、同図（ａ）はその正面図、（ｂ）は右側面図である。It is a figure explaining one Embodiment of the holder | retainer shown in FIG. 1, The figure (a) is the front view, (b) is a right view. 図２（ａ）のＺ−Ｚ断面図である。It is ZZ sectional drawing of Fig.2 (a). 図２（ｂ）のＡ部拡大図である。It is the A section enlarged view of Drawing 2 (b). 螺旋凸条部に穿設されるボール装填部を説明する要部拡大図であり、同図（ａ）はその平面図、（ｂ）は正面図、（ｃ）は右側面図である。It is a principal part enlarged view explaining the ball | bowl loading part pierced by a spiral protruding item | line part, The figure (a) is the top view, (b) is a front view, (c) is a right view. 図２（ａ）のＢ部に装着される結合用部品を説明する図であり、同図（ａ）はその正面図、（ｂ）は右側面図である。It is a figure explaining the components for a coupling | bonding mounted | worn by the B section of Fig.2 (a), The same figure (a) is the front view, (b) is a right view. 螺旋凸条部およびこれに穿設されるボール装填部の変形例を説明するための平面図である。It is a top view for demonstrating the modification of a spiral protruding item | line part and the ball loading part pierced by this.

以下、本発明の一実施形態について、図面を適宜参照しつつ説明する。
図１に示すように、この非循環式ボールねじ１０は、外周面に螺旋状のねじ溝１ａが形成されたねじ軸１と、ねじ軸１のねじ溝１ａに対向する螺旋状のねじ溝２ａが内周面に形成されたナット２とを有する。ナット２は、機械構造用炭素鋼（ＪＩＳＧ４０５１）で作成されている。そして、ねじ軸１とナット２とが、保持器２０で保持された複数のボール３を介して螺合されている。保持器２０は、ねじ軸１とナット２との隙間内に遊挿し得る厚みを有する円筒形の薄肉部材であり、螺旋状のねじ溝１ａ、２ａに沿ってボール保持用の複数のボール装填部２４が形成され、複数のボール装填部２４によって、複数のボール３を対向するねじ溝１ａ、２ａ間に一定間隔に保持している。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.
As shown in FIG. 1, the non-circular ball screw 10 includes a screw shaft 1 having a spiral screw groove 1a formed on the outer peripheral surface, and a spiral screw groove 2a facing the screw groove 1a of the screw shaft 1. Has a nut 2 formed on the inner peripheral surface. The nut 2 is made of carbon steel for mechanical structure (JISG4051). Then, the screw shaft 1 and the nut 2 are screwed together via a plurality of balls 3 held by the cage 20. The cage 20 is a cylindrical thin-walled member having a thickness that can be loosely inserted into the gap between the screw shaft 1 and the nut 2, and a plurality of ball loading portions for holding the ball along the spiral thread grooves 1 a and 2 a. 24, and a plurality of ball loading portions 24 hold a plurality of balls 3 at regular intervals between the opposing thread grooves 1a, 2a.

保持器２０は、図２に示すように、その円筒形状の軸方向に沿って二分割された二つの分割部品２１，２２の組によって構成されている。ここで、この保持器２０の分割構造は、例えば特許文献１に記載されるような巻き数の途中で保持器を追加するために設けるものではなく、軸直角断面において、中心Ｏを通る軸線Ｄ（図２（ｂ）参照）に沿って略蒲鉾型となる半円弧状となるように１８０度の位置で二分割し、その二分割された二つの分割部品２１，２２を組み合わせて円筒状の保持器２０としている。   As shown in FIG. 2, the cage 20 is configured by a set of two divided parts 21 and 22 that are divided into two along the axial direction of the cylindrical shape. Here, the split structure of the cage 20 is not provided for adding a cage in the middle of the number of windings as described in Patent Document 1, for example, and the axis D passing through the center O in the cross section perpendicular to the axis. (Refer to FIG. 2 (b)) is divided into two parts at a position of 180 degrees so as to form a semi-circular arc shape that is substantially saddle-shaped, and the two divided parts 21 and 22 are combined to form a cylindrical shape. The cage 20 is used.

二つの分割部品２１，２２は、同図（ａ）に示すように、ねじ軸１またはナット２のねじ溝１ａ、２ａに沿って、互いを組み合わせたときに連続する螺旋状に形成された螺旋凸条部２３を有する。螺旋凸条部２３は、図３に示すように、円筒形状をなす保持器２０の外周面２０ｇよりも外側に向けて突出して形成され、その突出する断面形状は、ねじ溝２ａに干渉しないように、ボール３よりも僅かに小さい凸の半円弧２３ｒとされるとともに、凸の半円弧２３ｒの頂部が平面２３ｔとされている。   As shown in FIG. 2A, the two divided parts 21 and 22 are spirals formed in a continuous spiral shape when they are combined with each other along the screw grooves 1a and 2a of the screw shaft 1 or the nut 2. It has a ridge 23. As shown in FIG. 3, the spiral ridge 23 is formed to protrude outward from the outer peripheral surface 20g of the cylindrical retainer 20, and the protruding cross-sectional shape does not interfere with the screw groove 2a. In addition, a convex semicircular arc 23r slightly smaller than the ball 3 is formed, and the top of the convex semicircular arc 23r is a flat surface 23t.

ここで、二つの分割部品２１，２２は、深絞りが可能な鋼製の板材を用い、鋼製の板材をその巻き取り材から所望の寸法に切断し、その切断した鋼製の板材をプレス成型して制作されている。各分割部品２１，２２のプレス成型工程は、非循環式ボールねじ１０の螺旋状のねじ溝１ａ、２ａに対応する位置に沿って螺旋凸条部２３を押し出して成形する螺旋凸条部成形工程と、円筒形状の軸方向に沿って二分割された二つの分割部品２１，２２それぞれに対応する半円筒形状に成形する半円筒形状成形工程とを含む。   Here, the two divided parts 21 and 22 use a steel plate material that can be deep drawn, cut the steel plate material from the winding material to a desired size, and press the cut steel plate material It is produced by molding. The press molding process of each of the divided parts 21 and 22 is a spiral ridge forming process in which the spiral ridge 23 is extruded and molded along a position corresponding to the spiral thread grooves 1a and 2a of the non-circulating ball screw 10. And a semi-cylindrical forming step of forming a semi-cylindrical shape corresponding to each of the two divided parts 21 and 22 divided into two along the axial direction of the cylindrical shape.

そして、二つの分割部品２１，２２に対し、図４および図５に示すように、螺旋凸条部２３に沿ってボール保持用の複数のボール装填部２４を、各分割部品２１，２２の内周面側からドリル加工により形成している。特に、ボール装填部２４の先端部２４ｓは、ドリルＫによる穿設により、ボール装填部中のボールが外部に向けて脱落しないように、先端（装填部の底）が円錐形状に穿設され、収容するボール３の外周面にボール装填部２４が線接触するようになっている。   As shown in FIG. 4 and FIG. 5, a plurality of ball loading portions 24 for holding a ball are provided along the spiral ridge portion 23 with respect to the two divided components 21 and 22. It is formed by drilling from the peripheral surface side. In particular, the tip 24s of the ball loading unit 24 is drilled with a drill K so that the tip (bottom of the loading unit) is drilled in a conical shape so that the ball in the ball loading unit does not fall out. The ball loading portion 24 is in line contact with the outer peripheral surface of the ball 3 to be accommodated.

本実施形態では、上述のようにして形成された二つの半円筒形状の分割部品２１，２２を、図２（ａ）に示すように、互いの端部Ｒを対向させて組み合わせて円筒状の保持器２０としている。なお、同図では、同図の正面中央に位置するボール装填部２４について詳細図示（図５（ａ）参照）し、他の箇所のボール装填部２４については簡略に図示しているが、全て同様のドリル加工が施されている。   In this embodiment, as shown in FIG. 2A, the two semi-cylindrical divided parts 21 and 22 formed as described above are combined with their end portions R facing each other to form a cylindrical shape. The cage 20 is used. In addition, in the same figure, the ball loading part 24 located in the front center of the figure is shown in detail (see FIG. 5A), and the ball loading parts 24 in other places are illustrated in a simplified manner. A similar drilling process is applied.

そして、二つの分割部品２１，２２相互は、円筒形状の軸方向両端部Ｂで結合されており、その結合部は、図６に示す、分割部品とは別個の結合用部品３０によって結合されている。結合用部品３０は、図６に示すように、円環状の部材の一部に、径方向に沿って貫通するすり割り溝３１を形成してなる略Ｃ型に形成された抱き締め部材である。すり割り溝３１が形成された箇所には、すり割り溝３１とは直交する方向から、一方の端部に座繰り穴３２が形成されるとともに、他方の端部に座繰り穴３２と同軸に雌ねじ３３が形成されている。結合用部品３０の内周３０ｎの直径は、保持器２０の両端部２０ｔ（図２（ａ）参照）の直径とインロー嵌合する寸法に形成されている。   The two divided parts 21 and 22 are coupled with each other at both ends B in the axial direction of the cylindrical shape, and the coupled part is coupled by a coupling part 30 shown in FIG. Yes. As shown in FIG. 6, the coupling component 30 is a hugging member formed in a substantially C shape in which a slit groove 31 penetrating in the radial direction is formed in a part of an annular member. A countersink hole 32 is formed at one end from the direction perpendicular to the slot 31 at a location where the slot 31 is formed, and coaxial with the countersink 32 at the other end. An internal thread 33 is formed. The diameter of the inner periphery 30n of the coupling component 30 is formed so as to fit into the diameters of both end portions 20t of the cage 20 (see FIG. 2A).

これにより、分割部品２１，２２を組み合わせてなる保持器２０の両端部２０ｔそれぞれに結合用部品３０をはめ込み、不図示の締めねじを座繰り穴３２の側から挿入して雌ねじ３３に締め込むことで円筒形状の軸方向両端部Ｂで二つの分割部品２１，２２相互を抱き締めして、二つの分割部品２１，２２相互を結合している。なお、結合用部品３０の外周３０ｍの直径は、装着時のボール３の頂部よりも外周側に位置するような大径とされている。   As a result, the coupling component 30 is fitted into each of the both ends 20t of the cage 20 formed by combining the divided components 21 and 22, and a tightening screw (not shown) is inserted from the side of the counterbore 32 and tightened into the female screw 33. The two divided parts 21 and 22 are held together at both ends B in the axial direction of the cylindrical shape, and the two divided parts 21 and 22 are connected to each other. In addition, the diameter of the outer periphery 30m of the coupling component 30 is set to a large diameter so as to be positioned on the outer peripheral side from the top of the ball 3 at the time of mounting.

次に、上記非循環式ボールねじ１０の保持器２０の作用・効果について説明する。
この非循環式ボールねじ１０は、所定の移動範囲内において、ねじ軸１とナット２との相対的な回転運動により、複数のボール３はその軌道であるねじ溝１ａ、２ａに沿って移動するが、個々のボール３は保持器２０の各ボール装填部２４に保持された状態で転動するため、各ボール３は所定の間隔を保たれて相互の接触が防止される。 Next, the operation and effect of the cage 20 of the non-circular ball screw 10 will be described.
In the non-circular ball screw 10, a plurality of balls 3 move along the screw grooves 1 a and 2 a, which are the tracks, by a relative rotational movement between the screw shaft 1 and the nut 2 within a predetermined movement range. However, since the individual balls 3 roll while being held by the respective ball loading portions 24 of the holder 20, the respective balls 3 are kept at a predetermined interval to prevent mutual contact.

ここで、保持器２０とボール３との間にも「滑り摩擦」が生じるため、相互の接触面積を可及的に減らすことが望ましい。特に、「滑り摩擦」が大きくなると、保持器２０が非循環式ボールねじ１０の軸方向に少しずつずれて、最終的には、ナット２から保持器２０が分離してしまう。そのため、この種の非循環式ボールねじでは、保持器とボール相互の摩擦を如何に減らせるかが重要である。   Here, since “sliding friction” also occurs between the cage 20 and the ball 3, it is desirable to reduce the mutual contact area as much as possible. In particular, when “sliding friction” increases, the cage 20 is gradually shifted in the axial direction of the non-circulating ball screw 10, and finally the cage 20 is separated from the nut 2. Therefore, in this type of non-circular ball screw, it is important how the friction between the cage and the ball can be reduced.

これに対し、本実施形態においては、ドリルＫによる加工後のボール装填部２４は、ドリル加工によって先端（装填部の底）２４ｓが、ボール装填部中のボールが外部に向けて脱落しないような円錐形状に形成されているので、ボール３の外周面にボール装填部２４が線接触する。これにより、可及的に少ない摩擦により非循環式ボールねじ１０を作動させることができる。なお、本実施形態では、結合用部品３０の外周３０ｍの直径が、装着時のボール３の頂部よりも外周側に位置するような大径とされているので、保持器２０が非循環式ボールねじ１０の軸方向にずれてしまった場合のストッパを兼ねるようになっている。   On the other hand, in this embodiment, the ball loading unit 24 after being processed by the drill K is such that the tip (bottom of the loading unit) 24s does not fall off the ball in the ball loading unit toward the outside by drilling. Since it is formed in a conical shape, the ball loading portion 24 comes into line contact with the outer peripheral surface of the ball 3. As a result, the non-circulating ball screw 10 can be operated with as little friction as possible. In the present embodiment, since the diameter of the outer periphery 30m of the coupling component 30 is such a large diameter as to be positioned on the outer peripheral side with respect to the top of the ball 3 at the time of mounting, the cage 20 is a non-circulating ball. It also serves as a stopper when it is displaced in the axial direction of the screw 10.

そして、多数のボール装填部２４に対するドリル加工は、非常に繊細な加工となるが、本実施形態の保持器２０であれば、保持器２０の軸線に沿った二分割構造を有するので、二つの分割部品２１，２２とされた個々の保持器構成部に対して、その内周面２０ｎの側を外に向けた状態とし、内周面２０ｎの側から容易にドリル加工を施すことができる。そのため、巻き数が増える場合であっても、生産性を向上させつつ、ボール装填部２４に対する所期のドリル加工を、加工精度や位置精度を良く行える。したがって、可及的に少ない摩擦により非循環式ボールねじ１０を作動させることができる保持器２０を提供することができる。   The drilling process for the large number of ball loading units 24 is very delicate. However, the cage 20 of the present embodiment has a two-part structure along the axis of the cage 20, With respect to the individual retainer constituting portions which are the divided parts 21 and 22, the inner peripheral surface 20n can be easily drilled from the inner peripheral surface 20n with the inner peripheral surface 20n facing outward. Therefore, even when the number of windings increases, the desired drilling process for the ball loading unit 24 can be performed with good processing accuracy and positional accuracy while improving productivity. Therefore, it is possible to provide the cage 20 that can operate the non-circular ball screw 10 with as little friction as possible.

以上説明したように、本実施形態の非循環式ボールねじ用保持器および非循環式ボールねじ、並びに非循環式ボールねじ用保持器の製造方法によれば、巻き数が増える場合であっても、個々のボール装填部の加工精度や位置精度を向上させるとともに、生産性を向上させることができる。
なお、本発明に係る非循環式ボールねじ用保持器および非循環式ボールねじ、並びに非循環式ボールねじ用保持器の製造方法は、上記実施形態に限定されるものではなく、本発明の趣旨を逸脱しなければ種々の変形が可能である。 As described above, according to the manufacturing method of the non-circulating ball screw retainer and the non-circulating ball screw and the non-circulating ball screw retainer according to the present embodiment, even when the number of turns increases. In addition to improving the processing accuracy and position accuracy of the individual ball loading sections, it is possible to improve productivity.
The non-circulating ball screw retainer and the non-circulating ball screw according to the present invention, and the method for producing the non-circulating ball screw retainer are not limited to the above-described embodiments, and the gist of the present invention. Various modifications are possible without departing from the above.

例えば、上記実施形態では、二つの分割部品２１，２２相互が、結合用部品３０によって抱き締めにより結合された例で説明したが、これに限らず、円筒形状の端部またはその他の接触部分で二つの分割部品２１，２２相互が結合されており、その結合部は、分割部品自身に形成された凹凸の係合もしくは加締め、または分割部品とは別個の結合用部品によって結合するようにしてもよい。
また、上記実施形態では、ドリル加工後のボール装填部２４が、ボール外周面に線接触する例で説明したが、これに限らず、螺旋凸条部２３を、ナット２のねじ溝２ａと相似のオフセット形状に形成し、図７に示すように、ボール装填部２４の底の形状がボール外周面に点接触するように構成してもよい。 For example, in the above-described embodiment, the example in which the two divided parts 21 and 22 are coupled to each other by the coupling part 30 has been described. However, the present invention is not limited to this. The two divided parts 21 and 22 are coupled to each other, and the coupling part may be coupled by engaging or crimping the unevenness formed on the divided parts themselves, or by coupling parts separate from the divided parts. Good.
In the above-described embodiment, the example in which the ball loading portion 24 after drilling is in line contact with the outer peripheral surface of the ball has been described. As shown in FIG. 7, the bottom shape of the ball loading portion 24 may be configured to make point contact with the outer peripheral surface of the ball.

また、上記実施形態では、保持器２０の二つの分割部品２１，２２は、深絞りが可能な鋼製の板材を用いた例で説明したが、これに限らず、二つの分割部品２１，２２を、鉄系材料よりも硬度が低い合成樹脂材料または軟質金属材料から形成してもよい。
二つの分割部品２１，２２を軟質金属材料から形成する場合、軟質金属材料表面の摩擦係数をより小さくする表面処理を施すことが望ましい。軟質金属材料表面の摩擦係数をより小さくする表面処理としては、例えばリン酸マンガン、もしくは二硫化モリブデンの単層、または、下地をリン酸マンガンとし表層に二硫化モリブデン被膜を形成する二層構造とすることができる。 Moreover, in the said embodiment, although the two division | segmentation parts 21 and 22 of the holder | retainer 20 demonstrated in the example using the steel board | plate material which can be deep-drawn, it is not restricted to this, Two division | segmentation parts 21 and 22 are used. May be formed from a synthetic resin material or a soft metal material having a lower hardness than the iron-based material.
When the two divided parts 21 and 22 are formed of a soft metal material, it is desirable to perform a surface treatment that makes the friction coefficient of the surface of the soft metal material smaller. As a surface treatment for reducing the friction coefficient of the surface of the soft metal material, for example, a single layer of manganese phosphate or molybdenum disulfide, or a two-layer structure in which the underlying layer is manganese phosphate and a molybdenum disulfide film is formed on the surface layer. can do.

ここで、鉄系材料よりも硬度が低い材料としては、上記ナット２の素材である機械構造用炭素鋼（ＪＩＳＧ４０５１）の生の状態以下の硬度が望ましい。軟質金属材料であれば、ロックウェル硬さで、ＨＲＣ２０以下の軟質金属材料が好ましく、例えば、金（Ａｕ）、銀（Ａｇ）、銅（Ｃｕ）、ニッケル（Ｎｉ）、鉛（Ｐｂ）、亜鉛（Ｚｎ）、すず（Ｓｎ）、インジウム（Ｉｎ）、またはこれらを用いた合金などの金属材料が挙げられる。また、合成樹脂材料としては、例えば、四フッ化エチレン樹脂（ＰＴＦＥ）などのフッ素樹脂、アクリル樹脂、シリコーン樹脂、ポリウレタン樹脂などが挙げられる。   Here, as a material whose hardness is lower than that of the iron-based material, a hardness equal to or less than a raw state of the carbon steel for mechanical structure (JISG4051) which is a material of the nut 2 is desirable. If it is a soft metal material, a soft metal material having a Rockwell hardness of HRC 20 or less is preferable. For example, gold (Au), silver (Ag), copper (Cu), nickel (Ni), lead (Pb), zinc A metal material such as (Zn), tin (Sn), indium (In), or an alloy using the same can be given. Examples of the synthetic resin material include a fluororesin such as tetrafluoroethylene resin (PTFE), an acrylic resin, a silicone resin, and a polyurethane resin.

１ ねじ軸
２ ナット
３ ボール
１０ 非循環式ボールねじ
２０ 保持器
２１ 第一の分割部品
２２ 第二の分割部品
２３ 螺旋凸条部
２４ ボール装填部
３０ 結合用部品
３１ すり割り溝
３２ 座繰り穴
３３ 雌ねじ
Ｋ ドリル DESCRIPTION OF SYMBOLS 1 Screw shaft 2 Nut 3 Ball 10 Non-circulation type ball screw 20 Cage 21 1st division | segmentation part 22 2nd division | segmentation part 23 Spiral protruding part 24 Ball loading part 30 Parts for connection 31 Slot groove 32 Countersink hole 33 Female thread K drill

Claims (6)

外周面に螺旋状のねじ溝が形成されたねじ軸と、該ねじ軸に外嵌されて内周面に螺旋状のねじ溝が形成されたナットと、前記ねじ軸と前記ナットとの両ねじ溝間に転動自在に介装される複数のボールとを備えるととともに、前記複数のボールが循環しない構造を有する非循環式ボールねじに用いられ、前記複数のボールを一定間隔に保持する複数のボール装填部を有する保持器であって、
当該保持器は、前記ねじ軸と前記ナットとの隙間内に遊挿し得る厚みを有する円筒形状をなすとともに、該円筒形状の軸方向に沿って二分割された二つの分割部品の組によって構成され、
前記二つの分割部品は、前記ねじ軸または前記ナットのねじ溝に沿って螺旋状に形成された螺旋凸条部を有し、
前記螺旋凸条部は、前記円筒形状の外周面よりも外側に向けて突出して形成されるとともに、当該螺旋凸条部に沿ってボール保持用の複数のボール装填部が各分割部品の内周面側から穿設されていることを特徴とする非循環式ボールねじ用保持器。 A screw shaft having a helical thread groove formed on the outer peripheral surface, a nut externally fitted to the screw shaft and having a helical thread groove formed on the inner peripheral surface, and both screws of the screw shaft and the nut A plurality of balls that are interposed between the grooves so as to be freely rollable, and that are used for a non-circulating ball screw having a structure in which the plurality of balls do not circulate, and that hold the plurality of balls at a constant interval. A cage having a ball loading section of
The retainer has a cylindrical shape having a thickness that can be loosely inserted into a gap between the screw shaft and the nut, and is configured by a set of two divided parts that are divided into two along the axial direction of the cylindrical shape. ,
The two divided parts have spiral ridges formed spirally along the threaded shaft of the screw shaft or the nut,
The spiral ridges are formed so as to protrude outward from the outer peripheral surface of the cylindrical shape, and a plurality of ball loading portions for holding a ball along the spiral ridges are provided on the inner periphery of each divided component. A retainer for a non-circulating ball screw, wherein the retainer is drilled from the surface side. 前記二つの分割部品相互は、円筒形状の端部またはその他の接触部分で結合されており、
その結合部は、分割部品自身に形成された凹凸の係合もしくは加締め、または分割部品とは別個の結合用部品によって結合されている請求項１に記載の非循環式ボールねじ用保持器。 The two divided parts are connected to each other at a cylindrical end or other contact part,
The non-circulating ball screw retainer according to claim 1, wherein the coupling portion is coupled by engagement or caulking of unevenness formed on the divided component itself, or by a coupling component separate from the divided component. 前記ボール装填部の先端部は、ドリル加工により、ボール装填部中のボールが外部に向けて脱落しないような円錐形状に穿設されている請求項１または２に記載の非循環式ボールねじ用保持器。   3. The non-circulating ball screw according to claim 1, wherein a tip portion of the ball loading portion is drilled into a conical shape so that a ball in the ball loading portion does not fall out toward the outside by drilling. Cage. 前記螺旋凸条部は、ナットのねじ溝と相似のオフセット形状に形成されている請求項１〜３のいずれか一項に記載の非循環式ボールねじ用保持器。   The non-circular ball screw retainer according to any one of claims 1 to 3, wherein the spiral protrusion is formed in an offset shape similar to a screw groove of a nut. 請求項１〜４のいずれか一項に記載の非循環式ボールねじ用保持器を備えることを特徴とする非循環式ボールねじ。   A non-circular ball screw comprising the retainer for a non-circular ball screw according to any one of claims 1 to 4. 請求項１〜４のいずれか一項に記載の非循環式ボールねじ用保持器を製造する方法であって、
深絞りが可能な鋼製の板材を用い、
その鋼製の板材をプレス成型して、前記非循環式ボールねじの螺旋状のねじ溝に対応する位置に沿って前記螺旋凸条部を押し出して成形するとともに、前記円筒形状の軸方向に沿って二分割された二つの分割部品それぞれに対応する半円筒形状に成形し、
その半円筒形状に成形された二つの分割部品を組み合わせて円筒状の保持器とすることを特徴とする非循環式ボールねじ用保持器の製造方法。 A method for producing a non-circulating ball screw cage according to any one of claims 1 to 4,
Using a steel plate that can be deep drawn,
The steel plate material is press-molded, and the spiral ridges are extruded along a position corresponding to the spiral thread groove of the non-circulating ball screw, and along the cylindrical axial direction. Molded into a semi-cylindrical shape corresponding to each of the two divided parts,
A method of manufacturing a non-circulating ball screw cage, comprising combining two divided parts formed in a semi-cylindrical shape into a cylindrical cage.
JP2014248668A 2014-12-09 2014-12-09 Cage for non-circulation type ball screw and non-circulation type ball screw, and manufacturing method of cage for non-circulation type ball screw Pending JP2016109237A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000320557A (en) * 1999-05-11 2000-11-24 Nsk Ltd Retainer for split type rolling bearing
JP2002130416A (en) * 2000-10-13 2002-05-09 Shangyin Sci & Technol Co Ltd Cage type ball screw and its manufacturing method
JP2007247814A (en) * 2006-03-16 2007-09-27 Nsk Ltd Split type rolling bearing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000320557A (en) * 1999-05-11 2000-11-24 Nsk Ltd Retainer for split type rolling bearing
JP2002130416A (en) * 2000-10-13 2002-05-09 Shangyin Sci & Technol Co Ltd Cage type ball screw and its manufacturing method
JP2007247814A (en) * 2006-03-16 2007-09-27 Nsk Ltd Split type rolling bearing

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