JP2008281063A - Ball screw mechanism - Google Patents

Ball screw mechanism Download PDF

Info

Publication number
JP2008281063A
JP2008281063A JP2007124643A JP2007124643A JP2008281063A JP 2008281063 A JP2008281063 A JP 2008281063A JP 2007124643 A JP2007124643 A JP 2007124643A JP 2007124643 A JP2007124643 A JP 2007124643A JP 2008281063 A JP2008281063 A JP 2008281063A
Authority
JP
Japan
Prior art keywords
nut
peripheral surface
groove
ball screw
ball
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.)
Pending
Application number
JP2007124643A
Other languages
Japanese (ja)
Inventor
Daisaku Kawada
大作 川田
Koji Hashimoto
橋本　　浩司
Manabu Horikoshi
学 堀越
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NSK Ltd
Original Assignee
NSK Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NSK Ltd filed Critical NSK Ltd
Priority to JP2007124643A priority Critical patent/JP2008281063A/en
Publication of JP2008281063A publication Critical patent/JP2008281063A/en
Pending legal-status Critical Current

Links

Images

Landscapes

  • Transmission Devices (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a ball screw mechanism capable of eliminating waste upon machining, enhancing riliability of the ball screw mechanism, and capable of increasing the degree of freedom in manufacture. <P>SOLUTION: A circulation passage 2b is directly formed on an inner peripheral surface of a nut 2, and a female screw groove 2a and the circulation passage 2b can be smoothly connected and a step can be dispensed with as shown in Fig.9, and thereby, abnormal noise or operation torque fluctuation (hooking) can be prevented even when a ball 3 passes through a space between the female screw groove 2a and the circulation passage 2b, and deterioration in the service life can be restrained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、一般産業用機械に組付けられたり、或いは自動車、船舶等に使用されたりするボールねじ機構に関するものである。   The present invention relates to a ball screw mechanism that is assembled to a general industrial machine or used in automobiles, ships, and the like.

近年、車両等の省力化が進み、例えば自動車のトランスミッションやパーキングブレーキなどを手動でなく、電動モータの力により行うシステムが開発されている。そのような用途に用いる電動アクチュエータには、電動モータから伝達される回転運動を高効率で軸線方向運動に変換するために、ボールねじ機構が用いられる場合がある。   In recent years, labor saving of vehicles and the like has progressed, and for example, a system has been developed in which a transmission, a parking brake, and the like of an automobile are performed not by hand but by the power of an electric motor. An electric actuator used for such an application may use a ball screw mechanism in order to convert the rotational motion transmitted from the electric motor into the axial motion with high efficiency.

しかるに、通常、ボールねじ機構は、ねじ軸と、ナットと、両者間に形成された転走路内を転動するボールとからなるが、いわゆるコマ式のボールねじ機構においては、転走路の一端から他端へとボールを戻すために、コマをナットに取り付けている（特許文献１参照）。又、ナットの雌ねじ溝は、螺旋状に刃物を形成したタップ工具を用いてナットの内周面を切削加工することで形成できる（特許文献２参照）。
特開平１１−２７０６４８号公報 特開２００５−６９２６５号公報 However, normally, the ball screw mechanism is composed of a screw shaft, a nut, and a ball that rolls in a rolling path formed between the two. In the so-called top-type ball screw mechanism, the ball screw mechanism starts from one end of the rolling path. In order to return the ball to the other end, a top is attached to the nut (see Patent Document 1). The female thread groove of the nut can be formed by cutting the inner peripheral surface of the nut using a tap tool in which a blade is formed in a spiral shape (see Patent Document 2).
JP 11-270648 A JP 2005-69265 A

しかるに、従来技術の製造方法によれば、
（１）加工されるナット内周面においては、実際にボールが挿入されて使用される部分以外に雌ねじ溝の切削が行われ、不必要な加工が行われている。
（２）加工されるナット内周面においては、実際にボールが挿入されて使用される転走路以外の部分（不使用溝という）にもついても雌ねじ溝の切削が行われるが、ボールねじ組立の際に、かかる不使用溝に誤ってボールが挿入されると、ボールが詰まって作動不良を起こす恐れがある。
（３）タップ工具の切り歯は、ナットに最初に挿入する側の先端から後方に向かって徐々に切削量を増して行くようなテーパ状になっている為、工具の径方向及び軸方向寸法が増大し、加工機及び加工法に制約が伴うという問題がある。 However, according to the prior art manufacturing method,
(1) On the inner peripheral surface of the nut to be processed, the internal thread groove is cut in addition to the portion where the ball is actually inserted and used, and unnecessary processing is performed.
(2) On the inner peripheral surface of the nut to be machined, the internal thread groove is also cut on the part other than the rolling path where the ball is actually inserted and used (referred to as an unused groove). In this case, if the ball is mistakenly inserted into the unused groove, the ball may be clogged, resulting in malfunction.
(3) The cutting teeth of the tap tool are tapered so that the amount of cutting gradually increases from the tip of the side that is first inserted into the nut toward the rear, so the radial and axial dimensions of the tool However, there is a problem that the processing machine and the processing method are restricted.

本発明は、かかる従来技術の問題点に鑑みてなされたものであり、加工の無駄を省き、ボールねじ機構の信頼性を高め、製造の自由度が向上するボールねじ機構の製造方法を提供することを目的とする。   The present invention has been made in view of the problems of the prior art, and provides a method of manufacturing a ball screw mechanism that eliminates processing waste, improves the reliability of the ball screw mechanism, and improves the degree of freedom in manufacturing. For the purpose.

第１の本発明のボールねじ機構の製造方法は、外周面に雄ねじ溝を形成したねじ軸と、
前記ねじ軸を包囲するように配置され且つ内周面に雌ねじ溝を形成したナットと、
対向する両ねじ溝間に形成された転走路に沿って転動自在に配置された複数のボールと、を有するボールねじ機構の製造方法において、
前記ナットの雌ねじ溝は、前記雌ねじ溝に対応する形状の刃物を有する工具を、自転させつつ公転させて切削加工することを特徴とする。 A manufacturing method of a ball screw mechanism according to a first aspect of the present invention includes:
A nut disposed so as to surround the screw shaft and having an internal thread formed on an inner peripheral surface thereof;
In a manufacturing method of a ball screw mechanism having a plurality of balls arranged to roll along a rolling path formed between both screw grooves facing each other,
The female thread groove of the nut is characterized in that a tool having a cutter having a shape corresponding to the female thread groove is revolved and cut while being revolved.

第２の本発明のボールねじ機構の製造方法は、外周面に雄ねじ溝を形成したねじ軸と、
前記ねじ軸を包囲するように配置され且つ内周面に雌ねじ溝を形成したナットと、
対向する両ねじ溝間に形成された転走路に沿って転動自在に配置された複数のボールと、を有するボールねじ機構の製造方法において、
前記ナットの循環路は、塑性加工により前記ナットの内周面に形成されることを特徴とする。 A manufacturing method of a ball screw mechanism according to a second aspect of the present invention includes a screw shaft having a male screw groove formed on an outer peripheral surface,
A nut disposed so as to surround the screw shaft and having an internal thread formed on an inner peripheral surface thereof;
In a manufacturing method of a ball screw mechanism having a plurality of balls arranged to roll along a rolling path formed between both screw grooves facing each other,
The nut circulation path is formed on the inner peripheral surface of the nut by plastic working.

第１の本発明によれば、前記ナットの雌ねじ溝は、前記雌ねじ溝に対応する形状の刃物を有する工具を、自転させつつ公転させて切削加工するので、一般的なタップ工具を用いる場合と比較し、ボールが転送する雌ねじ溝以外の切削加工を極力抑制できるので、加工時間が短縮され、刃物の損耗を抑制できる。又、一般的なタップ工具では外径がナットの内径より大きいため、加工の自由度が制限されるが、本発明の刃物は、例えば比較的細い回転軸の外周に一つ形成すれば足りるので、これにより加工の自由度を増大させることができる。更に、組み付け時において、従来のタップ工具にて形成される不使用溝のような部位を極力形成することなく加工できるので、ボールが誤って挿入されやすい部位を減らすことにより誤組等の不具合を回避できる。尚、「雌ねじ溝に対応する形状の刃物」とは、刃物の切削面が雌ねじ溝の断面形状に一致するか、それに近似する形状を有することをいう。   According to the first aspect of the present invention, the female thread groove of the nut revolves and cuts a tool having a blade having a shape corresponding to the female thread groove, so that a general tap tool is used. In comparison, cutting processing other than the female thread groove transferred by the ball can be suppressed as much as possible, so that the processing time can be shortened and wear of the blade can be suppressed. In addition, since the outer diameter of a general tap tool is larger than the inner diameter of the nut, the degree of freedom of processing is limited. However, it is sufficient to form one cutter of the present invention on the outer periphery of a relatively thin rotating shaft, for example. As a result, the degree of freedom of processing can be increased. Furthermore, when assembling, parts such as unused grooves formed by conventional tap tools can be processed without forming as much as possible. Can be avoided. Note that “the blade having a shape corresponding to the female screw groove” means that the cutting surface of the blade has a shape that matches or approximates the cross-sectional shape of the female screw groove.

前記ナットの循環路は、塑性加工により前記ナットの内周面に形成されると好ましい。   The circulation path of the nut is preferably formed on the inner peripheral surface of the nut by plastic working.

例えば、コマ式ボールねじ機構では、一般に循環溝が成形されているコマをナットへ組付けることが行われる。しかるに、コマ式ボールねじ機構では、ボールが転送する雌ねじ溝と、コマに成形された循環溝との間に段差が生じることが避けられず、結果として、無視できない異音、作動トルク変動、寿命低下が発生する恐れがある。これに対し本発明によれば、コマを用いることなく、ナットの内周面に循環溝を直接形成するので、循環溝と雌ねじ溝との間に段差が形成されることがなく、滑らかに接続できるので、循環溝と雌ねじ溝との間をボールが通過しても、異音や作動トルク変動を生じることがなく、また寿命低下等を抑制することができる。   For example, in a piece type ball screw mechanism, a piece in which a circulation groove is formed is generally assembled to a nut. However, in the top-type ball screw mechanism, it is inevitable that a step is generated between the female screw groove to which the ball is transferred and the circulation groove formed in the top, and as a result, abnormal noise, operating torque fluctuation, and life that cannot be ignored. Decrease may occur. On the other hand, according to the present invention, the circulation groove is formed directly on the inner peripheral surface of the nut without using a piece, so that a step is not formed between the circulation groove and the female screw groove, and the connection is made smoothly. Therefore, even if the ball passes between the circulation groove and the female screw groove, no abnormal noise or fluctuation in operating torque is generated, and a reduction in life can be suppressed.

前記ナットの循環路は、前記雌ねじ溝と同時に焼入処理されると好ましい。   The circulation path of the nut is preferably subjected to a quenching process simultaneously with the female screw groove.

コマ式ボールねじ機構では、コマをナットへ組付ける場合には製造コストを押える目的で、コマ本体をカシメなどで塑性変形させて、ナットに固定することが行われることが多い（特開２００１−２８９３０１号公報参照）。従って、コマは塑性変形しやすいように、硬度をある程度下げる必要が生じる。一方、コマに成形された循環溝は、一般的に硬度をあげることが、ボールねじ機構の高速性能や寿命にとって良いとされている。従って硬度を上げるとカシメがしにくくなり、硬度を下げるとボールねじ機構の高速性能や寿命が低下するという相反する問題がある。これに対し本発明によれば、コマを用いることなく、ナットの内周面に循環溝を直接形成するので、ナット本体を焼入処理する際に同時に循環路にも焼入処理が行われる為、ボールが転送する循環溝の硬度が上昇し、ボールねじの高速性能を高め長寿命化が向上することとなる。尚、焼入処理として高周波焼き入れを用いた場合、従来のようにコマの取り付け孔を有するナットにおいて、コマ孔周辺の局所オーバーヒートが発生する恐れがあるが、本発明によれば本来的にコマ孔がないため、このような不具合を回避できる。また、粒界酸化層を低減できるという利点もある。   In the top type ball screw mechanism, when the top is assembled to the nut, the top body is often plastically deformed by caulking or the like and fixed to the nut for the purpose of reducing the manufacturing cost (Japanese Patent Laid-Open No. 2001-2001). 289301). Therefore, it is necessary to lower the hardness to some extent so that the top is easily plastically deformed. On the other hand, the circulation groove formed in the top is generally considered to increase the hardness, which is good for the high-speed performance and life of the ball screw mechanism. Therefore, there is a conflicting problem that if the hardness is increased, it is difficult to crimp, and if the hardness is decreased, the high-speed performance and life of the ball screw mechanism are decreased. On the other hand, according to the present invention, the circulation groove is formed directly on the inner peripheral surface of the nut without using a piece, so that when the nut body is quenched, the circulation path is simultaneously quenched. As a result, the hardness of the circulation groove to which the ball is transferred is increased, and the high-speed performance of the ball screw is enhanced and the life is improved. When induction hardening is used as the quenching process, local overheating around the top hole may occur in the nut having the top mounting hole as in the conventional case. Since there is no hole, such a problem can be avoided. There is also an advantage that the grain boundary oxide layer can be reduced.

第２の本発明によれば、前記ナットの循環路は、塑性加工により前記ナットの内周面に形成されるので、容易に形成できると共に、前記雌ねじ溝に対応する形状の刃物を有する工具を、自転させつつ公転させて切削加工を併せて行うことで、前記循環路と前記雌ねじ溝とを段差なく接続させることができ、異音、作動トルク変動、寿命低下等を抑制することができる。   According to the second aspect of the present invention, since the circulation path of the nut is formed on the inner peripheral surface of the nut by plastic working, a tool having a blade having a shape corresponding to the female thread groove can be easily formed. By revolving while rotating and performing cutting together, the circulation path and the female thread groove can be connected without any step, and abnormal noise, operating torque fluctuation, life reduction, and the like can be suppressed.

次に、本発明の実施の形態を図面を参照して説明する。図１は、本実施の形態にかかる製造方法により製造したボールねじ機構の軸線方向断面図である。図２は、図１に示すナットをII-II線で切断して矢印方向に見た図である。図１において、不図示の被駆動部材に連結され、回転不能且つ軸線方向にのみ移動可能に支持されたねじ軸１の外周面には、雄ねじ溝１ａが形成されている。不図示のハウジングに対して回転のみ可能に支持された円筒状のナット２は、ねじ軸１を包囲するように配置され、内周面に、２列の雌ねじ溝２ａ（図２参照）と、各雌ねじ溝２ｂに接続する循環路２ｂとを形成している。複数のボール３が、対向する両ねじ溝間に形成された螺旋状の転走路内を転動し、循環路２ｂを介して戻るように配置されている。   Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an axial sectional view of a ball screw mechanism manufactured by the manufacturing method according to the present embodiment. FIG. 2 is a view of the nut shown in FIG. 1 taken along the line II-II and viewed in the direction of the arrow. In FIG. 1, a male screw groove 1a is formed on the outer peripheral surface of a screw shaft 1 connected to a driven member (not shown) and supported so as not to rotate but to move only in the axial direction. A cylindrical nut 2 supported so as to be rotatable only with respect to a housing (not shown) is disposed so as to surround the screw shaft 1, and has two rows of female screw grooves 2a (see FIG. 2) on the inner peripheral surface. A circulation path 2b connected to each female thread groove 2b is formed. A plurality of balls 3 are arranged so as to roll in a spiral rolling path formed between the opposing screw grooves and return via the circulation path 2b.

次に、本実施の形態にかかる製造方法について説明する。まず、ナットの素材であるフランジ付きの中空円筒部材の内周面に、循環溝を形成する。図３は、循環溝を形成する工程を示す図であり、図３（ａ）は中空円筒部材と金型の断面図、図３（ｂ）は図３（ａ）の構成を矢印IIIB方向に見た図であり、図３（ｃ）は図３（ｂ）の金型を矢印IIIC方向に見た図である。ここでは、図３に示すような金型Ｍを用いて鍛造加工を行う。金型Ｍは、中空円筒部材の内径より小径の外径を有する円筒状であって、その外表面に図３（ｂ）、（ｃ）に示すようなＳ字状の凸部Ｍａを２つ形成している。凸部Ｍａは、循環路２ｂの形状に対応している。   Next, the manufacturing method according to this embodiment will be described. First, a circulation groove is formed on the inner peripheral surface of a hollow cylindrical member with a flange, which is a nut material. FIG. 3 is a diagram showing a process of forming a circulation groove. FIG. 3 (a) is a sectional view of a hollow cylindrical member and a mold, and FIG. 3 (b) is a configuration of FIG. 3 (a) in the direction of arrow IIIB. FIG. 3C is a view of the mold shown in FIG. 3B as viewed in the direction of arrow IIIC. Here, forging is performed using a mold M as shown in FIG. The mold M has a cylindrical shape having an outer diameter smaller than the inner diameter of the hollow cylindrical member, and two S-shaped convex portions Ma as shown in FIGS. 3B and 3C are provided on the outer surface thereof. Forming. The convex portion Ma corresponds to the shape of the circulation path 2b.

かかる金型Ｍを中空円筒部材Ｎの内部に挿入して、その内周面の上部に凸部Ｍａを当接させ、更に金型Ｍの両端を支持した状態で、中空円筒部材Ｎを金型Ｍに向かってプレス（Ｐ）し、鍛造加工を行う。すると、図４に示すように、凸部Ｍａが中空円筒部材Ｎの内周面に転写され、くぼんだ２つの循環路２ｂが形成される。   The mold M is inserted into the hollow cylindrical member N, the convex portion Ma is brought into contact with the upper part of the inner peripheral surface thereof, and the both ends of the mold M are supported, and the hollow cylindrical member N is fixed to the mold. Press (P) toward M and perform forging. Then, as shown in FIG. 4, the convex portion Ma is transferred to the inner peripheral surface of the hollow cylindrical member N, and two recessed circulation paths 2b are formed.

次に、循環路２ｂを形成した中空円筒部材Ｎの内周面に、雌ねじ溝を形成する。図５は、雌ねじ溝を形成する工程を示す図である。ここでは、図５に示すような切削工具Ｔを用いて切削加工を行う。切削工具Ｔは、回転軸Ｔａの外周に、刃物Ｔｂを形成している。刃物Ｔｂの切削面（周方向に対向する面）は、雌ねじ溝２ａの形状に一致する。回転軸Ｔａは、その軸線Ｏ回りに回転（図５（ｂ）のＡ）するが、それとは独立して偏心軸Ｑ回りに公転（図５（ｂ）のＢ）する。尚、このように切削工具Ｔを自転及び公転させる機構としては、例えば遊星歯車機構（不図示）の遊星歯車に回転軸Ｔａを連結した構成が考えられるが、それに限られない。   Next, a female thread groove is formed on the inner peripheral surface of the hollow cylindrical member N in which the circulation path 2b is formed. FIG. 5 is a diagram illustrating a process of forming the female thread groove. Here, cutting is performed using a cutting tool T as shown in FIG. The cutting tool T forms a blade Tb on the outer periphery of the rotation axis Ta. The cutting surface (surface facing the circumferential direction) of the blade Tb matches the shape of the female thread groove 2a. The rotation axis Ta rotates around the axis O (A in FIG. 5B), but independently revolves around the eccentric axis Q (B in FIG. 5B). As a mechanism for rotating and revolving the cutting tool T in this way, for example, a configuration in which the rotation shaft Ta is connected to a planetary gear of a planetary gear mechanism (not shown) is conceivable, but not limited thereto.

この切削加工を行う場合、中空円筒部材Ｎの端面近辺では自転する刃物の公転軌道を、自転する刃物Ｔｂが中空円筒部材Ｎの内周面に接触しないよう公転軌道中心よりに逃がすことが必要となる。更に図５に示すように、切削工具Ｔの回転軸Ｔａを所定の軸線方向位置で半径方向外方にシフトさせ、雌ねじ溝２ａのピッチで軸線方向に送り出しながら公転させつつ、より速い速度で自転させることで、３６０度未満の螺旋状の雌ねじ溝２ａを、中空円筒部材Ｎの内周面に切削形成することができる。このとき、循環路２ｂに軸線方向位置及び位相を合わせることで、図６に示すように、各循環路２ｂが雌ねじ溝２ａの両端に接続するように形成できる。図５に示す切削工具Ｔでは、２本の雌ねじ溝２ａを形成するために、同じ中空円筒部材Ｎについて２回切削加工することになるが、回転軸Ｔａ上に刃物Ｔｂを２つ形成すれば、一度の切削加工で形成できる。   When performing this cutting process, it is necessary to let the revolving trajectory of the rotating tool near the end surface of the hollow cylindrical member N escape from the center of the revolving track so that the rotating tool Tb does not contact the inner peripheral surface of the hollow cylindrical member N. Become. Further, as shown in FIG. 5, the rotational axis Ta of the cutting tool T is shifted radially outward at a predetermined axial position, and revolved while being sent out in the axial direction at the pitch of the female thread groove 2a, and rotated at a higher speed. By doing so, the helical female thread groove 2a of less than 360 degrees can be cut and formed on the inner peripheral surface of the hollow cylindrical member N. At this time, by aligning the axial position and phase with the circulation path 2b, as shown in FIG. 6, each circulation path 2b can be connected to both ends of the female thread groove 2a. In the cutting tool T shown in FIG. 5, in order to form the two female thread grooves 2a, the same hollow cylindrical member N is cut twice, but if two blades Tb are formed on the rotation axis Ta. It can be formed by a single cutting process.

次に、循環路２ｂ及び雌ねじ溝２ａを形成した中空円筒部材Ｎの内周面に、焼入処理を行う。図７は、高周波焼入の処理工程を示す図である。ここでは、図７に示すように、中空円筒状部材Ｎの内部にコイルＣを配置し、高周波電源ＥからコイルＣに高周波電流を流す事で、中空円筒状部材Ｎの内周面に高周波焼入れを行う。以上の工程により、ナット２を製造することができる。   Next, a quenching process is performed on the inner peripheral surface of the hollow cylindrical member N in which the circulation path 2b and the female thread groove 2a are formed. FIG. 7 is a diagram illustrating a process of induction hardening. Here, as shown in FIG. 7, the coil C is disposed inside the hollow cylindrical member N, and high-frequency hardening is applied to the inner peripheral surface of the hollow cylindrical member N by flowing a high-frequency current from the high-frequency power source E to the coil C. I do. The nut 2 can be manufactured by the above process.

本実施の形態によれば、中空円筒状部材Ｎにコマの取り付け孔を形成していないので、オーバーヒートの熱処理不具合等が無く、高周波焼入れを行うのに適している。また中空円筒状部材Ｎの内周面に一度に焼入れを行うことで、耐摩耗性に優れた雌ねじ溝２ａ及び循環路２ｂを形成でき、その場合に粒界酸化を抑制できる。   According to the present embodiment, since the top mounting holes are not formed in the hollow cylindrical member N, there is no overheating heat treatment defect and the like, which is suitable for induction hardening. Further, by quenching the inner peripheral surface of the hollow cylindrical member N at a time, the female thread groove 2a and the circulation path 2b having excellent wear resistance can be formed, and in this case, grain boundary oxidation can be suppressed.

特に、従来のボールねじ機構で用いられているチューブやコマ等の循環部材は、一般的に熱処理が行われていないから、長期間にわたりボールねじを作動すると磨耗し、循環不良の原因となる。これに対し、本実施の形態によれば、雌ねじ溝２ａのみならず循環路２ｂにも焼入れを同時に行うことができるので、耐摩耗性を確保すると同時に粒界酸化を抑制できるので、長寿命が期待できる。   In particular, circulating members such as tubes and pieces used in conventional ball screw mechanisms are generally not heat-treated, and thus wear when operated for a long period of time, causing poor circulation. On the other hand, according to the present embodiment, not only the female thread groove 2a but also the circulation path 2b can be quenched at the same time, so that the wear resistance can be ensured and the grain boundary oxidation can be suppressed at the same time. I can expect.

図８は、比較例にかかるコマ式ボールねじ機構の軸線直交方向断面図であり、図９は、図８の構成をIX-IX線で切断して矢印方向に見た図であるが、３次元的奥行きは廃止し、模式的に表している。図１０は、図１に示す本実施の形態の構成をIX-IX線で切断して矢印方向に見た図であるが、３次元的奥行きは廃止し、模式的に表している。図８，９に示す比較例は、ナット２の取り付け孔２ｃに、循環路４ａを有するコマ４を組み付けている点のみが異なる。   8 is a cross-sectional view in the direction orthogonal to the axis of the top type ball screw mechanism according to the comparative example, and FIG. 9 is a view of the configuration of FIG. The dimensional depth is abolished and is shown schematically. FIG. 10 is a view of the configuration of the present embodiment shown in FIG. 1 taken along the line IX-IX and viewed in the direction of the arrow, but the three-dimensional depth is abolished and schematically shown. The comparative example shown in FIGS. 8 and 9 is different only in that the top 4 having the circulation path 4 a is assembled in the mounting hole 2 c of the nut 2.

ねじ軸１の雄ねじ溝１ａとナット２の雌ねじ溝２ａにより形成される転送路は、ボール３の外径にほぼ近似した螺旋状の空間となる。よって図８に示すように、循環路４ａをコマ４に形成して、ナット２’に組み付けた場合、循環路４ａの導入部は、ナット２の雌ねじ溝２ａよりも径方向で外方に逃げていなくてはならず、それにより雌ねじ溝２ａと循環路４ａとの間には段差Δが生じる。コマ４を別部材とすると、段差Δを０にする事は一般的には困難である。これに対し、本実施の形態によれば、循環路２ｂはナット２の内周面に直接形成されるため、図９に示すように、雌ねじ溝２ａと循環路２ｂとの間（図１０のＤ部）を滑らかに接続し、段差を設けないようにできるので、雌ねじ溝２ａと循環溝２ｂとの間をボール３が通過しても、異音や作動トルク変動（ひっかかり等）を生じることがなく、また寿命低下等を抑制することができる。   The transfer path formed by the male screw groove 1 a of the screw shaft 1 and the female screw groove 2 a of the nut 2 is a spiral space that is approximately approximate to the outer diameter of the ball 3. Therefore, as shown in FIG. 8, when the circulation path 4 a is formed in the top 4 and assembled to the nut 2 ′, the introduction portion of the circulation path 4 a escapes outward in the radial direction from the female thread groove 2 a of the nut 2. As a result, a step Δ is formed between the female screw groove 2a and the circulation path 4a. If the top 4 is a separate member, it is generally difficult to set the step Δ to 0. On the other hand, according to the present embodiment, the circulation path 2b is formed directly on the inner peripheral surface of the nut 2, so as shown in FIG. 9, between the female thread groove 2a and the circulation path 2b (see FIG. 10). D portion) can be connected smoothly and no step is provided, so that even if the ball 3 passes between the female thread groove 2a and the circulation groove 2b, abnormal noise and fluctuations in operating torque (such as catching) may occur. In addition, it is possible to suppress a decrease in service life.

更に、比較例の構成では、図８に示すように、ナット２’の内周面には軸線方向にわたって雌ねじ溝２ａが形成される。かかる場合、軸線方向における取り付け孔２ｃ、２ｃの間に形成された雌ねじ溝（不要溝）２ａ’と、それに対向する雄ねじ溝１ａとの間に、点線で示すようにボール３を誤って組み付けると、ボール３が転送できずにねじ軸１とナット２がロックしてしまう恐れがある。これに対し本実施の形態によれば、図９に示すように、軸線方向における循環溝２ｂ、２ｂの間に雌ねじ溝を形成しないので、ボール３が誤って組み付けられる余地がなく、作動不良を招く恐れがない。   Furthermore, in the configuration of the comparative example, as shown in FIG. 8, a female thread groove 2a is formed on the inner peripheral surface of the nut 2 'in the axial direction. In such a case, if the ball 3 is mistakenly assembled between the female screw groove (unnecessary groove) 2a ′ formed between the mounting holes 2c and 2c in the axial direction and the male screw groove 1a opposed to the female screw groove 2a ′, as shown by a dotted line. The ball 3 cannot be transferred and the screw shaft 1 and the nut 2 may be locked. On the other hand, according to the present embodiment, as shown in FIG. 9, since the female thread groove is not formed between the circulation grooves 2b and 2b in the axial direction, there is no room for the ball 3 to be mistakenly assembled, resulting in malfunction. There is no fear of inviting.

図１１は、変形例にかかる循環溝を形成する工程を示す図であり、図１１（ａ）は中空円筒部材と金型の断面図、図１１（ｂ）は図１１（ａ）の構成を矢印XIB方向に見た図である。図３に示す工程の場合、金型Ｍの両端のみを支持しているので、プレス圧Ｐが強大であると金型Ｍが撓み、循環溝を精度良く転写形成できない恐れがある。   FIG. 11 is a diagram illustrating a process of forming a circulation groove according to a modification. FIG. 11A is a cross-sectional view of a hollow cylindrical member and a mold, and FIG. 11B is a configuration of FIG. It is the figure seen in the arrow XIB direction. In the case of the process shown in FIG. 3, since both ends of the mold M are supported, if the press pressure P is high, the mold M may bend and the circulation groove may not be accurately transferred.

これに対し本変形例では、中空円筒部材Ｎの中央に孔Ｎａを形成し、ここを通した支持柱ＳＣで金型Ｍの中央を更に支持するようにしている。従って、金型Ｍは両端と中央の三点で支持されるため、例えプレス圧Ｐが強大であっても金型Ｍの撓みが顕著に減少し、循環溝を精度良く転写形成できる。尚、本変形例で用いる中空円筒部材Ｎは、２つの雌ねじ溝２ａの間において、これらに連通しないようにして孔Ｎａが形成されるため、ここからボール３が脱落する恐れはない。孔Ｎａは、ボールねじ機構の使用中、不図示の蓋部材で遮蔽されても良い。   On the other hand, in this modification, a hole Na is formed in the center of the hollow cylindrical member N, and the center of the mold M is further supported by the support column SC passing therethrough. Therefore, since the mold M is supported at three points, both ends and the center, even if the press pressure P is high, the bending of the mold M is remarkably reduced, and the circulation groove can be transferred and formed with high accuracy. Since the hollow cylindrical member N used in this modification is formed with a hole Na so as not to communicate with the two female screw grooves 2a, there is no possibility that the ball 3 will drop out. The hole Na may be shielded by a lid member (not shown) during use of the ball screw mechanism.

以上、本発明を実施の形態を参照して説明してきたが、本発明は上記実施の形態に限定して解釈されるべきではなく、適宜変更・改良が可能であることはもちろんである。   The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate.

本実施の形態であるボールねじ機構の軸線方向断面図である。It is an axial direction sectional view of the ball screw mechanism which is this embodiment. 図１に示すナットをII-II線で切断して矢印方向に見た図である。It is the figure which cut | disconnected the nut shown in FIG. 1 by the II-II line | wire, and looked at the arrow direction. 図３（ａ）は中空円筒部材と金型の断面図、図３（ｂ）は図３（ａ）の構成を矢印IIIB方向に見た図であり、図３（ｃ）は図３（ｂ）の金型を矢印IIIC方向に見た図である。3A is a cross-sectional view of the hollow cylindrical member and the mold, FIG. 3B is a view of the configuration of FIG. 3A viewed in the direction of the arrow IIIB, and FIG. 3C is FIG. 3) is a view of the mold in the direction of arrow IIIC. 図４（ａ）は、中空円筒部材の鍛造加工後における軸線方向断面図であり、図４（ｂ）は、中空円筒部材の鍛造加工後における斜視図である。4A is a cross-sectional view in the axial direction after forging the hollow cylindrical member, and FIG. 4B is a perspective view after forging the hollow cylindrical member. 図５（ａ）は、中空円筒部材の切削加工の状態を示す斜視図であり、図５（ｂ）は、図５（ａ）に示す中空円筒部材と切削工具を矢印VA方向に見た図である。Fig.5 (a) is a perspective view which shows the state of the cutting process of a hollow cylindrical member, FIG.5 (b) is the figure which looked at the hollow cylindrical member and cutting tool shown to Fig.5 (a) in the arrow VA direction. It is. 図６（ａ）は、中空円筒部材の切削加工後における軸線方向断面図であり、図６（ｂ）は、中空円筒部材の切削加工後における斜視図である。FIG. 6A is an axial sectional view after the hollow cylindrical member is cut, and FIG. 6B is a perspective view after the hollow cylindrical member is cut. 中空円筒部材の焼入処理の状態を示す軸線方向断面図である。It is an axial direction sectional view showing the state of quenching processing of a hollow cylindrical member. 比較例にかかるコマ式ボールねじ機構の軸線直交方向断面図である。It is a cross-sectional view in the direction perpendicular to the axis of the top ball screw mechanism according to the comparative example. 図８の構成をIX-IX線で切断して矢印方向に見た図である。It is the figure which cut | disconnected the structure of FIG. 8 by the IX-IX line, and looked at the arrow direction. 図１に示す本実施の形態の構成をIX-IX線で切断して矢印方向に見た図である。It is the figure which cut | disconnected the structure of this Embodiment shown in FIG. 1 by the IX-IX line and looked at the arrow direction. 図１１（ａ）は中空円筒部材と金型の断面図、図１１（ｂ）は図１１（ａ）の構成を矢印XIB方向に見た図である。FIG. 11A is a cross-sectional view of the hollow cylindrical member and the mold, and FIG. 11B is a view of the configuration of FIG. 11A viewed in the direction of the arrow XIB.

符号の説明Explanation of symbols

１ ねじ軸
２ ナット
３ ボール
Ｎ 中空円筒部材
Ｔ 切削工具
Ｃ コイル
Ｅ 高周波電源 1 Screw shaft 2 Nut 3 Ball N Hollow cylindrical member T Cutting tool C Coil E High frequency power supply

Claims (4)

外周面に雄ねじ溝を形成したねじ軸と、
前記ねじ軸を包囲するように配置され、内周面に雌ねじ溝と、前記雌ねじ溝の両端を連結する循環路とを形成したナットと、
対向する両ねじ溝間に形成された転走路に沿って転動自在に配置された複数のボールと、を有するボールねじ機構の製造方法において、
前記ナットの雌ねじ溝は、前記雌ねじ溝に対応する形状の刃物を有する工具を、自転させつつ公転させて切削加工することを特徴とするボールねじ機構の製造方法。 A screw shaft having a male screw groove formed on the outer peripheral surface;
A nut that is disposed so as to surround the screw shaft, and has a female screw groove formed on an inner peripheral surface thereof, and a circulation path that connects both ends of the female screw groove;
In a manufacturing method of a ball screw mechanism having a plurality of balls arranged to roll along a rolling path formed between both screw grooves facing each other,
The method of manufacturing a ball screw mechanism, wherein the female screw groove of the nut is formed by revolving and cutting a tool having a cutter having a shape corresponding to the female screw groove. 前記ナットの循環路は、塑性加工により前記ナットの内周面に形成されることを特徴とする請求項１に記載のボールねじ機構の製造方法。   The ball screw mechanism manufacturing method according to claim 1, wherein the nut circulation path is formed on an inner peripheral surface of the nut by plastic working. 前記ナットの循環路は、前記雌ねじ溝と同時に焼入処理されることを特徴とする請求項２に記載のボールねじ機構の製造方法。   The ball screw mechanism manufacturing method according to claim 2, wherein the nut circulation path is hardened simultaneously with the female screw groove. 外周面に雄ねじ溝を形成したねじ軸と、
前記ねじ軸を包囲するように配置され且つ内周面に雌ねじ溝を形成したナットと、
対向する両ねじ溝間に形成された転走路に沿って転動自在に配置された複数のボールと、を有するボールねじ機構の製造方法において、
前記ナットの循環路は、塑性加工により前記ナットの内周面に形成されることを特徴とするボールねじ機構の製造方法。 A screw shaft having a male screw groove formed on the outer peripheral surface;
A nut disposed so as to surround the screw shaft and having an internal thread formed on an inner peripheral surface thereof;
In a manufacturing method of a ball screw mechanism having a plurality of balls arranged to roll along a rolling path formed between both screw grooves facing each other,
A method of manufacturing a ball screw mechanism, wherein the nut circulation path is formed on an inner peripheral surface of the nut by plastic working.
JP2007124643A 2007-05-09 2007-05-09 Ball screw mechanism Pending JP2008281063A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007124643A JP2008281063A (en) 2007-05-09 2007-05-09 Ball screw mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2007124643A JP2008281063A (en) 2007-05-09 2007-05-09 Ball screw mechanism

Related Child Applications (2)

Application Number Title Priority Date Filing Date
JP2011252136A Division JP2012037057A (en) 2011-11-18 2011-11-18 Ball screw mechanism
JP2011252137A Division JP5282810B2 (en) 2011-11-18 2011-11-18 Ball screw mechanism

Publications (1)

Publication Number Publication Date
JP2008281063A true JP2008281063A (en) 2008-11-20

Family

ID=40142058

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2007124643A Pending JP2008281063A (en) 2007-05-09 2007-05-09 Ball screw mechanism

Country Status (1)

Country Link
JP (1) JP2008281063A (en)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011114728A1 (en) 2010-03-17 2011-09-22 日本精工株式会社 Ball screw, manufacturing method of nut for ball screw
WO2011122053A1 (en) * 2010-03-31 2011-10-06 日本精工株式会社 Ball screw and method for manufacturing ball screw nut
JP2011220375A (en) * 2010-04-05 2011-11-04 Nsk Ltd Method for manufacturing ball screw
JP2011231925A (en) * 2010-04-05 2011-11-17 Nsk Ltd Method for manufacturing of ball screw nut
WO2012017672A1 (en) 2010-08-04 2012-02-09 日本精工株式会社 Ball screw and method for manufacturing ball screw nut
CN101774120B (en) * 2009-12-29 2012-02-15 广州文冲船厂有限责任公司 Device for installing tail shaft nuts of ship
WO2012066693A1 (en) 2010-11-15 2012-05-24 日本精工株式会社 Ball screw
JP2012139722A (en) * 2011-01-06 2012-07-26 Nsk Ltd Method of manufacturing nut for ball screw
JP2012149734A (en) * 2011-01-20 2012-08-09 Nsk Ltd Method for manufacturing ball screw
JP2012159191A (en) * 2011-01-14 2012-08-23 Nsk Ltd Nut for ball screw, manufacturing method of nut for ball screw
JP2012163116A (en) * 2011-02-03 2012-08-30 Nsk Ltd Nut for ball screw, and method for manufacturing the same
JP2012180539A (en) * 2011-02-28 2012-09-20 Nsk Ltd Method for manufacturing nut for ball screw, and nut for ball screw
JP2013076463A (en) * 2011-09-15 2013-04-25 Nsk Ltd Ball screw
JP2013076464A (en) * 2011-09-16 2013-04-25 Nsk Ltd Method of manufacturing ball screw nut
JP2013076462A (en) * 2011-09-15 2013-04-25 Nsk Ltd Ball screw actuator
JP2013079689A (en) * 2011-10-04 2013-05-02 Nsk Ltd Method for manufacturing ball screw and nut for ball screw
JP2014062570A (en) * 2012-09-20 2014-04-10 Nsk Ltd Method of manufacturing nut for ball screw
JP2016142377A (en) * 2015-02-04 2016-08-08 Ntn株式会社 Top-type ball screw and its manufacturing method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006105388A (en) * 2004-09-09 2006-04-20 Nsk Ltd Method of manufacturing ball screw mechanism
JP2006275139A (en) * 2005-03-29 2006-10-12 Nsk Ltd Ball screw mechanism
JP2007092968A (en) * 2005-09-30 2007-04-12 Nsk Ltd Manufacturing method for nut

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006105388A (en) * 2004-09-09 2006-04-20 Nsk Ltd Method of manufacturing ball screw mechanism
JP2006275139A (en) * 2005-03-29 2006-10-12 Nsk Ltd Ball screw mechanism
JP2007092968A (en) * 2005-09-30 2007-04-12 Nsk Ltd Manufacturing method for nut

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101774120B (en) * 2009-12-29 2012-02-15 广州文冲船厂有限责任公司 Device for installing tail shaft nuts of ship
WO2011114728A1 (en) 2010-03-17 2011-09-22 日本精工株式会社 Ball screw, manufacturing method of nut for ball screw
JP5418667B2 (en) * 2010-03-17 2014-02-19 日本精工株式会社 Ball screw and ball screw nut manufacturing method
KR101414381B1 (en) * 2010-03-17 2014-07-01 닛본 세이고 가부시끼가이샤 Ball screw, manufacturing method of nut for ball screw
CN102906457A (en) * 2010-03-17 2013-01-30 日本精工株式会社 Ball screw, manufacturing method of nut for ball screw
US9737926B2 (en) 2010-03-17 2017-08-22 Nsk Ltd. Ball screw and manufacturing method of nut for ball screw
JP5708638B2 (en) * 2010-03-31 2015-04-30 日本精工株式会社 Method for manufacturing ball screw nut and ball screw
CN102869463A (en) * 2010-03-31 2013-01-09 日本精工株式会社 Ball screw and method for manufacturing ball screw nut
WO2011122053A1 (en) * 2010-03-31 2011-10-06 日本精工株式会社 Ball screw and method for manufacturing ball screw nut
KR101450986B1 (en) * 2010-03-31 2014-10-22 닛본 세이고 가부시끼가이샤 Ball screw and method for manufacturing ball screw nut
US8950283B2 (en) 2010-03-31 2015-02-10 Nsk Ltd. Method for manufacturing nut for ball screw and ball screw
JP2011231925A (en) * 2010-04-05 2011-11-17 Nsk Ltd Method for manufacturing of ball screw nut
JP2011220375A (en) * 2010-04-05 2011-11-04 Nsk Ltd Method for manufacturing ball screw
WO2012017672A1 (en) 2010-08-04 2012-02-09 日本精工株式会社 Ball screw and method for manufacturing ball screw nut
JP6015444B2 (en) * 2010-08-04 2016-10-26 日本精工株式会社 Manufacturing method of nut for ball screw
EP2551051A4 (en) * 2010-08-04 2017-12-20 NSK Ltd. Ball screw and method for manufacturing ball screw nut
CN103228953A (en) * 2010-11-15 2013-07-31 日本精工株式会社 Ball screw
WO2012066693A1 (en) 2010-11-15 2012-05-24 日本精工株式会社 Ball screw
JP5569592B2 (en) * 2010-11-15 2014-08-13 日本精工株式会社 Ball screw
JP2012139722A (en) * 2011-01-06 2012-07-26 Nsk Ltd Method of manufacturing nut for ball screw
JP2012159191A (en) * 2011-01-14 2012-08-23 Nsk Ltd Nut for ball screw, manufacturing method of nut for ball screw
JP2012149734A (en) * 2011-01-20 2012-08-09 Nsk Ltd Method for manufacturing ball screw
JP2012163116A (en) * 2011-02-03 2012-08-30 Nsk Ltd Nut for ball screw, and method for manufacturing the same
JP2012180539A (en) * 2011-02-28 2012-09-20 Nsk Ltd Method for manufacturing nut for ball screw, and nut for ball screw
JP2013076462A (en) * 2011-09-15 2013-04-25 Nsk Ltd Ball screw actuator
JP2013076463A (en) * 2011-09-15 2013-04-25 Nsk Ltd Ball screw
JP2013076464A (en) * 2011-09-16 2013-04-25 Nsk Ltd Method of manufacturing ball screw nut
JP2013079689A (en) * 2011-10-04 2013-05-02 Nsk Ltd Method for manufacturing ball screw and nut for ball screw
JP2014062570A (en) * 2012-09-20 2014-04-10 Nsk Ltd Method of manufacturing nut for ball screw
JP2016142377A (en) * 2015-02-04 2016-08-08 Ntn株式会社 Top-type ball screw and its manufacturing method
WO2016125825A1 (en) * 2015-02-04 2016-08-11 Ntn株式会社 Bridge-type ball screw and method for manufacturing same
CN107250613A (en) * 2015-02-04 2017-10-13 Ntn株式会社 Bridge-type ball-screw and its manufacture method
CN107250613B (en) * 2015-02-04 2020-03-03 Ntn株式会社 Method for manufacturing bridge type ball screw
US10677328B2 (en) 2015-02-04 2020-06-09 Ntn Corporation Bridge-type ball screw and manufacturing method thereof

Similar Documents

Publication Publication Date Title
JP2008281063A (en) Ball screw mechanism
EP2392837B1 (en) Ball screw apparatus and electric power steering apparatus
JP2007092968A (en) Manufacturing method for nut
JP2006220249A (en) Electric linear actuator
JP6365796B1 (en) Track groove processing method, ball screw device, machine and vehicle manufacturing method
JP5282810B2 (en) Ball screw mechanism
JP4640135B2 (en) Ball screw and ball screw nut manufacturing method
JP2005083549A (en) Ball screw nut and its manufacturing method
JP2006275139A (en) Ball screw mechanism
JP2014109319A (en) Ball screw mechanism
WO2006033397A1 (en) Ball screw mechanism
JP2012037057A (en) Ball screw mechanism
JP5998511B2 (en) Ball screw manufacturing method
CN114127440B (en) Worm shaft, worm reducer, and method for manufacturing worm shaft
JP2007111740A (en) Method for forming screw thread and screw thread in ball screw thread
JP2008157374A (en) Ball screw mechanism
JP2012077914A (en) Ball screw mechanism
JP4784132B2 (en) Ball screw mechanism
JP2008215422A (en) Ball screw for actuator and its screw grooving method
JP5772586B2 (en) Ball screw nut
JP2006346684A (en) Infeed form rolling die, and screw shaft of ball screw mechanism
JP2011094790A (en) Ball screw, method and die for manufacturing the same
JP4775629B2 (en) Ball screw mechanism
JP2010270916A (en) Ball screw mechanism
JP2014062570A (en) Method of manufacturing nut for ball screw

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20100420

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20110921

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20110922

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20111118

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20120508

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20120710

A911 Transfer of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20120718

A912 Removal of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A912

Effective date: 20120824