JP2007263192A - Deflector type ball screw - Google Patents

Deflector type ball screw Download PDF

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Publication number
JP2007263192A
JP2007263192A JP2006087129A JP2006087129A JP2007263192A JP 2007263192 A JP2007263192 A JP 2007263192A JP 2006087129 A JP2006087129 A JP 2006087129A JP 2006087129 A JP2006087129 A JP 2006087129A JP 2007263192 A JP2007263192 A JP 2007263192A
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Japan
Prior art keywords
piece
groove
ball
ball screw
type ball
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JP2006087129A
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Japanese (ja)
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Yasushi Tateishi
康司 立石
Hirakazu Yoshida
平和 吉田
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NTN Corp
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NTN Corp
NTN Toyo Bearing Co Ltd
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Priority to JP2006087129A priority Critical patent/JP2007263192A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a deflector type ball screw for actualizing smooth ball circulation by restricting the grove width of a connection groove of a deflector member. <P>SOLUTION: The deflector type ball screw comprises the deflector member 5 fitted to a deflector window 6 provided in a shell portion of a nut 3 and having the connection groove 7 using a rolling passage as a circuit. The connection groove 7 of the deflector member 5 is connected corresponding to a screw groove 3a adjacent to the nut 3 and formed into an approximately S-shaped curve with the angle of an opening portion 7a of the connection grove 7 smoothly rounded. Its groove width W is set in a range of 1.10Dw≤W≤1.20Dw, where Dw is the outer diameter of a ball 4. Thus, the deflector type ball screw actualizes smooth ball circulation without disturbing the behavior of the ball 4 being circulated, even when a machining or assembling error occurs in the deflector member 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、放電加工機やタッピングセンター等の各種工作機械、あるいは自動車の電動パワーステアリングやアクチュエータ等に使用されるボールねじに関し、特に、ボール循環部品である駒部材を使用した駒式ボールねじに関する。   The present invention relates to a ball screw used for various machine tools such as an electric discharge machine and a tapping center, or an electric power steering or an actuator of an automobile, and more particularly to a piece type ball screw using a piece member that is a ball circulation part. .

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、このねじ軸に外嵌され、内周面に螺旋状のねじ溝が形成されたナットと、対向する両ねじ溝により形成された転動路に収容された多数のボールと、転動路を周回経路とする循環機構とを備え、例えば、ナットを回転運動させることでねじ軸を直線運動させる運動変換機構として使用されている。   The ball screw is composed of a screw shaft having a helical thread groove formed on the outer peripheral surface, a nut externally fitted to the screw shaft, and a spiral screw groove formed on the inner peripheral surface, and both opposing screw grooves. It is equipped with a large number of balls accommodated in the formed rolling path and a circulation mechanism having the rolling path as a circuit path, and is used as a motion conversion mechanism that linearly moves the screw shaft by rotating the nut, for example. ing.

一般的にボールねじにはボールの循環機構が異なる種々の形式のものがあり、その一つに駒式と呼ばれるものがある。この駒式ボールねじは、ねじ溝の連結路を有し、転動路を周回経路とする循環用の駒部材がナットに装着されているもので、構成が比較的簡素で、かつコンパクトに構成できる利点がある。   Generally, there are various types of ball screws having different ball circulation mechanisms, and one of them is called a piece type. This piece-type ball screw has a threaded groove connection path, and a circulation piece member with a rolling path as a circulation path is attached to the nut. The structure is relatively simple and compact. There are advantages you can do.

このような駒式ボールねじの代表的な一例を図6および図7に示す。この駒式ボールねじは、ナット50の内周に小判形状をなす循環用の駒部材51を有する。駒部材51に設けられたバイパス路52は、ねじ軸53のねじ溝53aとナット50のねじ溝50aが対向してなす螺旋状のボール軌道路54の両側を連結し、無限循環回路55を構成している。そして、多数のボール56が無限循環回路55内に充填されており、ボール56は無限循環回路55内を無限循環する。   A typical example of such a piece-type ball screw is shown in FIGS. This piece-type ball screw has a circulation piece member 51 having an oval shape on the inner periphery of a nut 50. The bypass passage 52 provided in the piece member 51 connects both sides of the spiral ball raceway 54 formed by the screw groove 53a of the screw shaft 53 and the screw groove 50a of the nut 50 facing each other, thereby forming an infinite circulation circuit 55. is doing. A large number of balls 56 are filled in the endless circulation circuit 55, and the balls 56 endlessly circulate in the endless circulation circuit 55.

駒部材51は、上面57上にバイパス路52が形成されている。このバイパス路52の両端には出入り口52a、52bが形成され、これらの出入り口52a、52bによりバイパス路52はボール軌道路54の両端部とそれぞれ繋がっている。また、出入り口52aから出入り口52bにかけて出入り通路58a、中間通路59、出入り通路58bが順番に連なってバイパス路52を形成しており、中間通路59と各出入り通路58a、58bの接触部分が折れ曲がって略Zの字形をなしている。また、これらの出入り通路58a、中間通路59、出入り通路58bは、上面57上でそれぞれ直線状をなしている。そして、中間通路59が、出入り口52aと出入り口52bとの間に挟まれたねじ軸53のねじ山60を乗り越えている。   The piece member 51 has a bypass path 52 formed on the upper surface 57. Entrances 52a and 52b are formed at both ends of the bypass 52, and the bypass 52 is connected to both ends of the ball raceway 54 by these entrances 52a and 52b. In addition, the entrance / exit passageway 58a, the intermediate passageway 59, and the entrance / exit passageway 58b are connected in order from the entrance / exit 52a to the entrance / exit 52b to form the bypass passage 52. Z-shaped. In addition, the entrance / exit passage 58 a, the intermediate passage 59, and the entrance / exit passage 58 b are respectively linear on the upper surface 57. Then, the intermediate passage 59 gets over the screw thread 60 of the screw shaft 53 sandwiched between the doorway 52a and the doorway 52b.

また、ねじ軸53に対する出入り通路58a、58bの各リード角θ1は、ねじ軸53に対するボール軌道路54のリード角δと同じ値αに構成されている。したがって、出入り口52a、52bの前後で、ボール軌道路54のリード角δと、出入り通路58a、58bの各リード角θ1との差は0度となっている。さらに、ねじ軸53に対する中間通路59のリード角θ2の値はβとなっており、α―βの絶対値は40度以下に構成されている。これにより、駒部材51にボール56から大きな力が働いて駒部材51が破損するのが防止されると共に、ボール56に駒部材51から大きな力が働いてボール56がバイパス路52内で詰まることが防止され、バイパス路52内で詰まったボール56から大きな力が駒部材51に働いて駒部材51が破損するのが防止される。
特開2004−36789号公報
Each lead angle θ1 of the access passages 58a and 58b with respect to the screw shaft 53 is configured to have the same value α as the lead angle δ of the ball raceway 54 with respect to the screw shaft 53. Therefore, the difference between the lead angle δ of the ball raceway 54 and the lead angles θ1 of the entrance / exit passages 58a and 58b is 0 degree before and after the entrances 52a and 52b. Furthermore, the value of the lead angle θ2 of the intermediate passage 59 with respect to the screw shaft 53 is β, and the absolute value of α−β is configured to be 40 degrees or less. As a result, it is possible to prevent the piece member 51 from being damaged due to a large force acting on the piece member 51 from the ball 56 and to cause the ball 56 to be clogged in the bypass passage 52 due to a large force acting on the ball 56 from the piece member 51. Thus, it is possible to prevent the piece member 51 from being damaged by a large force acting on the piece member 51 from the balls 56 clogged in the bypass passage 52.
JP 2004-36789 A

然しながら、このような従来の駒式ボールねじにおいて、駒部材51の配置角度、すなわち、駒部材51のバイパス路52を構成する出入り通路58a、中間通路59、出入り通路58bの各リード角の差が40度以内に規制され、バイパス路52の出入り口52a、52bの前後で、ボール軌道路54のリード角と、出入り通路58a、58bのリード角との差を40度以内として規制されているが、バイパス路52自体の溝幅がばらついた場合、ボール56がバイパス路52内で干渉して詰ったり、逆にバイパス路52内で千鳥配列になってスムーズなボール循環が行われない恐れがある。   However, in such a conventional piece type ball screw, the arrangement angle of the piece member 51, that is, the difference between the lead angles of the entry / exit passage 58 a, the intermediate passage 59 and the entry / exit passage 58 b constituting the bypass passage 52 of the piece member 51 is Although regulated within 40 degrees, the difference between the lead angle of the ball raceway 54 and the lead angle of the entrance / exit paths 58a, 58b before and after the entrances 52a, 52b of the bypass path 52 is regulated to be within 40 degrees. If the groove width of the bypass path 52 itself varies, the balls 56 may interfere and clog in the bypass path 52, or conversely, the balls 56 may become staggered in the bypass path 52 and smooth ball circulation may not be performed.

本発明は、このような事情に鑑みてなされたもので、駒部材における連結溝の溝幅を規制し、スムーズなボール循環が得られる駒式ボールねじを提供することを目的としている。   The present invention has been made in view of such circumstances, and an object of the present invention is to provide a piece-type ball screw that regulates the groove width of a connecting groove in a piece member and can obtain a smooth ball circulation.

係る目的を達成すべく、本発明のうち請求項1に記載の発明は、外周面に螺旋状のねじ溝が形成されたねじ軸と、このねじ軸に外嵌され、内周面に螺旋状のねじ溝が形成されたナットと、対向する両ねじ溝により形成される転動路に収容された複数のボールと、前記ナットの胴部に穿設された駒窓に嵌合され、前記転動路を周回経路とする連結溝が形成された駒部材とを備えた駒式ボールねじにおいて、前記駒部材の連結溝が、前記ナットの隣接するねじ溝に合致するように接続され、略S字状に湾曲して形成されると共に、当該連結溝の溝幅が、前記ボールの外径の1.10〜1.20の範囲に設定されている。   In order to achieve such an object, the invention according to claim 1 of the present invention includes a screw shaft having a spiral thread groove formed on the outer peripheral surface thereof, and is externally fitted to the screw shaft and spirally formed on the inner peripheral surface. And a plurality of balls accommodated in a rolling path formed by opposing screw grooves, and a piece window drilled in a body portion of the nut, and the rolling In the piece type ball screw provided with a piece member in which a connecting groove having a circulation path as a circulation path is formed, the connecting groove of the piece member is connected so as to coincide with an adjacent screw groove of the nut, and approximately S The connecting groove is formed in a curved shape, and the width of the connecting groove is set in the range of 1.10 to 1.20 of the outer diameter of the ball.

このように、ナットの胴部に穿設された駒窓に嵌合され、転動路を周回経路とする連結溝が形成された駒部材を備えた駒式ボールねじにおいて、駒部材の連結溝が、ナットの隣接するねじ溝に合致するように接続され、略S字状に湾曲して形成されると共に、当該連結溝の溝幅が、ボールの外径の1.10〜1.20の範囲に設定されているので、駒部材の加工誤差や組立誤差が生じても、ボールの循環においてその挙動を阻害することなくスムーズなボール循環が得られる駒式ボールねじを提供することができる。   Thus, in the piece-type ball screw having the piece member that is fitted to the piece window formed in the trunk portion of the nut and has the connection groove having the rolling path as the circulation path, the piece member connection groove Are connected so as to match the adjacent thread grooves of the nut and are formed to be curved in a substantially S shape, and the groove width of the connecting groove is 1.10 to 1.20 of the outer diameter of the ball. Therefore, even if a piece member processing error or assembly error occurs, it is possible to provide a piece type ball screw that can obtain a smooth ball circulation without hindering the behavior of the ball circulation.

好ましくは、請求項2に記載の発明のように、前記連結溝の開口部における角部が滑らかに丸められていれば、連結溝にボールがスムーズに進入することができる。   Preferably, as in the second aspect of the invention, if the corners of the opening of the connecting groove are smoothly rounded, the ball can smoothly enter the connecting groove.

また、請求項3に記載の発明のように、前記ナットにおけるねじ溝の断面がゴシックアーク形状に形成されていれば、ボールとの接触角が大きくとれると共に、アキシアルすきまが小さく設定でき、軸方向荷重に対する剛性が高くなり、かつ振動の発生を抑制することができる。   In addition, if the cross section of the thread groove in the nut is formed in a Gothic arc shape as in the invention described in claim 3, the contact angle with the ball can be increased, the axial clearance can be set small, and the axial direction The rigidity with respect to a load becomes high and generation | occurrence | production of a vibration can be suppressed.

また、請求項4に記載の発明のように、前記駒窓が円形に形成され、駒部材の断面がこれに対応して断面が略円形に形成されていれば、駒窓の加工が容易となると共に、駒部材の位置決め作業が簡便化できる。   Further, if the piece window is formed in a circular shape and the cross section of the piece member is formed in a substantially circular shape corresponding to this, the piece window can be easily processed. In addition, the positioning work of the piece member can be simplified.

また、請求項5に記載の発明のように、前記駒部材が焼結合金からMIMによって成形されていれば、加工度が高く複雑な形状であっても容易に、かつ精度良く所望の形状・寸法に成形することができる。   Further, as in the invention described in claim 5, if the piece member is formed from a sintered alloy by MIM, even if it has a high workability and a complicated shape, the desired shape / Can be molded to dimensions.

本発明に係る駒式ボールねじは、外周面に螺旋状のねじ溝が形成されたねじ軸と、このねじ軸に外嵌され、内周面に螺旋状のねじ溝が形成されたナットと、対向する両ねじ溝により形成される転動路に収容された複数のボールと、前記ナットの胴部に穿設された駒窓に嵌合され、前記転動路を周回経路とする連結溝が形成された駒部材とを備えた駒式ボールねじにおいて、前記駒部材の連結溝が、前記ナットの隣接するねじ溝に合致するように接続され、略S字状に湾曲して形成されると共に、当該連結溝の溝幅が、前記ボールの外径の1.10〜1.20の範囲に設定されているので、駒部材の加工誤差や組立誤差が生じても、ボールの循環においてその挙動を阻害することなくスムーズなボール循環が得られる駒式ボールねじを提供することができる。   The piece ball screw according to the present invention includes a screw shaft having a helical thread groove formed on the outer peripheral surface, a nut externally fitted to the screw shaft, and a spiral screw groove formed on the inner peripheral surface, A plurality of balls accommodated in a rolling path formed by opposing screw grooves, and a connecting groove that is fitted to a piece window drilled in a body portion of the nut and has the rolling path as a circulation path. In the piece type ball screw provided with the formed piece member, the connecting groove of the piece member is connected so as to match the adjacent screw groove of the nut, and is formed to be curved in a substantially S shape. Since the groove width of the connecting groove is set in the range of 1.10 to 1.20 of the outer diameter of the ball, even if a piece member processing error or assembly error occurs, its behavior in the circulation of the ball A piece-type ball screw that provides smooth ball circulation without obstructing Door can be.

外周面に螺旋状のねじ溝が形成されたねじ軸と、このねじ軸に外嵌され、内周面に螺旋状のねじ溝が形成されたナットと、対向する両ねじ溝により形成される転動路に収容された複数のボールと、前記ナットの胴部に穿設された駒窓に嵌合され、前記転動路を周回経路とする連結溝が形成された駒部材とを備えた駒式ボールねじにおいて、前記駒部材の連結溝が、前記ナットの隣接するねじ溝に合致するように接続され、略S字状に湾曲して形成されると共に、当該連結溝の開口部における角部が滑らかに丸められ、その溝幅が、前記ボールの外径の1.10〜1.20の範囲に設定されている。   A screw shaft having a spiral thread groove formed on the outer peripheral surface, a nut externally fitted to the screw shaft and having a spiral thread groove formed on the inner peripheral surface, and a roller formed by both opposing screw grooves. A piece comprising a plurality of balls accommodated in a movement path, and a piece member that is fitted to a piece window formed in the trunk portion of the nut and has a connecting groove having the rolling path as a circulation path. In the type ball screw, the connecting groove of the piece member is connected to match the adjacent screw groove of the nut, is formed to be curved in a substantially S shape, and the corner portion at the opening of the connecting groove Are smoothly rounded, and the groove width is set in the range of 1.10 to 1.20 of the outer diameter of the ball.

以下、本発明の実施の形態を図面に基いて詳細に説明する。
図1は、本発明に係る駒式ボールねじの一実施形態を示し、(a)は平面図、(b)は縦断面図、図2は、本発明に係る駒部材の平面図、図3(a)は、図2の駒部材の他の実施態様を示す平面図、(b)は(a)のボールの挙動を示す説明図、図4は、図2の駒部材の比較例を示す平面図、図5(a)は、図4の他の実施態様を示す平面図、(b)は(a)のボールの挙動を示す説明図である。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an embodiment of a piece type ball screw according to the present invention, where (a) is a plan view, (b) is a longitudinal sectional view, and FIG. 2 is a plan view of the piece member according to the present invention. (A) is a top view which shows the other embodiment of the piece member of FIG. 2, (b) is explanatory drawing which shows the behavior of the ball | bowl of (a), FIG. 4 shows the comparative example of the piece member of FIG. FIG. 5A is a plan view showing another embodiment of FIG. 4, and FIG. 5B is an explanatory view showing the behavior of the ball in FIG.

この駒式ボールねじ1は、外周面に螺旋状のねじ溝2aが形成されたねじ軸2と、このねじ軸2に外嵌され、内周面に螺旋状のねじ溝3aが形成されたナット3と、対向する両ねじ溝2a、3aにより形成された転動路に収容された多数のボール4と、これらボール4の循環用部材となる駒部材5とを備えている。   This piece-type ball screw 1 includes a screw shaft 2 having a helical thread groove 2a formed on the outer peripheral surface, and a nut externally fitted to the screw shaft 2 and having a helical screw groove 3a formed on the inner peripheral surface. 3, a large number of balls 4 accommodated in a rolling path formed by both opposing screw grooves 2 a and 3 a, and a piece member 5 serving as a circulation member for these balls 4.

各ねじ溝2a、3aの断面形状は、サーキュラアーク形状であってもゴシックアーク形状であっても良いが、ここではボール4との接触角が大きくとれ、アキシアルすきまが小さく設定できるゴシックアーク形状に形成されている。これにより、軸方向荷重に対する剛性が高くなり、かつ振動の発生を抑制することができる。   The cross-sectional shape of each thread groove 2a, 3a may be a circular arc shape or a Gothic arc shape, but here, it has a Gothic arc shape that allows a large contact angle with the ball 4 and a small axial clearance. Is formed. Thereby, the rigidity with respect to an axial load becomes high and generation | occurrence | production of a vibration can be suppressed.

円筒状のナット3の胴部には、内外の周面に貫通してねじ溝3aの一部を切欠き、断面が小判型の駒窓6が穿設されている。そして、この駒窓6に対応して断面が小判型に形成された駒部材5が嵌合されている。駒部材5の内方には、ねじ溝3aの隣合う1周分同士を連結する連結溝7が形成され、この連結溝7とねじ溝3aの略1周の部分とでボール4の転動路を構成している。転動路内の内外のねじ溝2a、3a間に介在された多数のボール4はねじ溝2a、3aに沿って転動し、駒部材5の連結溝7に案内されながらねじ軸2のねじ山を乗り越えて隣接するねじ溝3aに戻り、再びねじ溝2a、3aに沿って転動する。なお、ここでは、小判型の駒窓6および駒部材5を例示したが、これに限らず、図示はしないが、断面が円形のものであっても良い。これにより駒窓の加工が容易となると共に、駒部材の位置決め作業が簡便化できる。   The cylindrical nut 3 is formed with a piece window 6 that penetrates the inner and outer peripheral surfaces, cuts a part of the thread groove 3a, and has an oval cross section. A piece member 5 whose cross section is formed in an oval shape corresponding to the piece window 6 is fitted. A connecting groove 7 is formed on the inner side of the piece member 5 to connect adjacent ones of the screw grooves 3a, and the ball 4 rolls between the connecting groove 7 and the substantially one part of the screw groove 3a. Constitutes the road. A large number of balls 4 interposed between the inner and outer screw grooves 2 a and 3 a in the rolling path roll along the screw grooves 2 a and 3 a, and are guided by the connecting groove 7 of the piece member 5. The mountain passes over the mountain, returns to the adjacent screw groove 3a, and rolls along the screw grooves 2a and 3a again. In addition, although the oval-shaped piece window 6 and the piece member 5 were illustrated here, it is not restricted to this, Although illustration is not carried out, a cross section may be circular. This facilitates processing of the piece window and simplifies the positioning operation of the piece member.

駒部材5はSCM415等の浸炭材から切削加工によって形成され、駒窓6に嵌挿した後、加締治具(図示せず)を使用して駒窓6の縁部側に塑性変形させて形成した加締部8によってナット3に固定されている。   The piece member 5 is formed by cutting from a carburized material such as SCM415, and is inserted into the piece window 6 and then plastically deformed to the edge side of the piece window 6 using a crimping jig (not shown). The formed caulking portion 8 is fixed to the nut 3.

駒部材5の材料としては、浸炭材以外にも、Niが3.0〜10.0wt%含有し、加工性、耐食性に優れた材料(日本粉末冶金工業規格のFEN8)か、Cが0.07wt%、Crが17wt%、Niが4wt%、Cuが4wt%、残りがFe等からなる析出硬化系ステンレスSUS630、あるいは、金属粉末を可塑状に調整し、射出成形機で成形される焼結合金であっても良い。SUS630は、固溶化熱処理で硬さを適切に上げることができ、強靭性と高硬度を確保することができる。   As the material of the piece member 5, in addition to the carburized material, Ni is contained in an amount of 3.0 to 10.0 wt% and excellent in workability and corrosion resistance (FEN8 of Japanese Powder Metallurgy Industry Standard), or C is 0.1. Precipitation hardening stainless steel SUS630 consisting of 07 wt%, Cr 17 wt%, Ni 4 wt%, Cu 4 wt% and the rest made of Fe or the like, or a heat-bonded metal powder adjusted to a plastic shape and molded by an injection molding machine It can be gold. SUS630 can appropriately increase hardness by solution heat treatment, and can ensure toughness and high hardness.

なお、駒部材5を浸炭材で形成する場合は、浸炭焼入れによって表面硬さが30〜40HRCの範囲になるように硬化処理されると共に、高周波テンパー装置を用いて、加締部8となる外端部が焼戻しされ、表面硬さが15〜30HRCの範囲になるように設定されている。これにより、加締部8の靭性が高くなると共に、駒部材5をナット3に加締固定する際に割れ等が発生するのを防止することができる。   In addition, when forming the piece member 5 with a carburizing material, it is hardened by carburizing and quenching so that the surface hardness is in a range of 30 to 40 HRC, and the outer portion that becomes the crimping portion 8 using a high-frequency temper device. The end is tempered and the surface hardness is set to be in the range of 15 to 30 HRC. Thereby, the toughness of the caulking portion 8 is increased, and cracks and the like can be prevented from occurring when the piece member 5 is caulked and fixed to the nut 3.

また、射出成形機で成形される焼結合金の場合、この射出成形に際して、まず、金属粉と、プラスチックおよびワックスからなるバインダとを混練機で混練し、その混練物をペレット状に造粒すると共に、造粒したペレットを金型内に加熱溶融状態で押し込む、所謂MIM(Metal Injection Molding)により成形される。これにより、加工度が高く複雑な形状であっても容易に、かつ精度良く所望の形状・寸法に成形することができる。   In the case of a sintered alloy formed by an injection molding machine, at the time of injection molding, first, metal powder and a binder made of plastic and wax are kneaded by a kneader, and the kneaded product is granulated into a pellet. At the same time, it is molded by so-called MIM (Metal Injection Molding), in which the granulated pellets are pushed into the mold in a heated and melted state. Thereby, even if it is a complicated shape with a high degree of processing, it can be easily and accurately formed into a desired shape and size.

ここで、本実施形態では、図2に示すように、駒部材5の連結溝7は、ナット3の隣接するねじ溝3aに合致するように接続され、ねじ溝3a、3a間を滑らかに接続するようにS字状に湾曲して形成されている。そして、連結溝7の溝幅Wが所定の範囲に設定されると共に、連結溝7の開口部7aにおける角部が滑らかに丸められている。   Here, in this embodiment, as shown in FIG. 2, the connecting groove 7 of the piece member 5 is connected so as to match the adjacent screw groove 3a of the nut 3, and smoothly connects between the screw grooves 3a and 3a. As shown, it is curved in an S shape. The groove width W of the connecting groove 7 is set within a predetermined range, and the corners of the opening 7a of the connecting groove 7 are smoothly rounded.

本出願人は、加工方法や組立方法に鑑み、駒部材5における連結溝7の溝幅Wを種々検証した結果、ボール4の外径をDwとした場合、1.10Dw≦W≦1.20Dwの範囲に設定するのが好ましいとした。そして、溝幅Wの下限値、W=1.10Dwと設定した場合、例えば、ボール4の外径Dwが3.175mmにおいては、連結溝7の溝幅Wが略3.5mmとなって、連結溝7とボール4とのすきまeが片側で略0.16mmとなる。これは駒部材5を切削加工によって形成した場合の加工公差±0.07〜0.10を考慮しても、ボール4が連結溝7内に進入および転動するのに充分なすきまeを確保することができる。   As a result of various verifications of the groove width W of the connecting groove 7 in the piece member 5 in view of the processing method and the assembling method, the applicant has 1.10 Dw ≦ W ≦ 1.20 Dw when the outer diameter of the ball 4 is Dw. It is preferable to set the value within the range. When the lower limit of the groove width W is set to W = 1.10 Dw, for example, when the outer diameter Dw of the ball 4 is 3.175 mm, the groove width W of the connecting groove 7 is approximately 3.5 mm. The clearance e between the connecting groove 7 and the ball 4 is approximately 0.16 mm on one side. This ensures a sufficient clearance e for the ball 4 to enter and roll into the connecting groove 7 even when machining tolerance ± 0.07 to 0.10 when the piece member 5 is formed by cutting is taken into consideration. can do.

一方、図3(a)に示すように、連結溝7の溝幅Wを上限値、すなわち、W=1.20Dwと設定した場合、溝幅Wが略3.5mmとなって、すきまeが片側で略0.31mmとなる。この場合、(b)に示すように、ボール4の中心線軌跡が屈曲して僅かに千鳥配列になるものの、楔現象でボール4をロックさせてボール4の挙動を阻害することはなく、スムーズなボール循環が得られる。   On the other hand, as shown in FIG. 3A, when the groove width W of the connecting groove 7 is set to an upper limit value, that is, W = 1.20 Dw, the groove width W is approximately 3.5 mm, and the clearance e is It is approximately 0.31 mm on one side. In this case, as shown in (b), although the center line trajectory of the ball 4 is bent and slightly staggered, the ball 4 is locked by the wedge phenomenon and the behavior of the ball 4 is not hindered. A good ball circulation.

これに対して、連結溝7の溝幅Wを1.10Dwよりも小さく設定した場合、例えば、図4に示すように、W=1.03Dwと設定した場合、溝幅Wが略3.27mmとなって、すきまeが片側で略0.05mmとなる。これでは、加工寸法のバラツキによって連結溝7の開口部7aに進入してきたボール4が干渉する恐れがあり、スムーズなボール循環は期待できない。   On the other hand, when the groove width W of the connecting groove 7 is set to be smaller than 1.10 Dw, for example, as shown in FIG. 4, when W is set to 1.03 Dw, the groove width W is approximately 3.27 mm. Thus, the clearance e is approximately 0.05 mm on one side. In this case, the balls 4 entering the opening 7a of the connecting groove 7 may interfere with each other due to variations in processing dimensions, and smooth ball circulation cannot be expected.

また、連結溝7の溝幅Wを1.20Dwよりも大きく設定した場合、例えば、図5(a)に示すように、W=1.30Dwと設定した場合、開口部7aの溝幅Wが略4.13mmとなって、すきまeが片側で略0.48mmとなる。これでは、開口部7aにボール4が干渉することはないが、(b)に示すように、ボール4の中心線軌跡が屈曲して千鳥配列になってボール4同士が競り合い、その接触部分で高い面圧が発生し、ボール4がスムーズに転動できないばかりでなく、楔現象でボール4をロックさせてボール4の挙動を阻害することになる。   Further, when the groove width W of the connecting groove 7 is set larger than 1.20 Dw, for example, as shown in FIG. 5A, when W = 1.30 Dw, the groove width W of the opening 7a is It is about 4.13 mm, and the clearance e is about 0.48 mm on one side. In this case, the ball 4 does not interfere with the opening 7a. However, as shown in (b), the center line locus of the ball 4 is bent to form a staggered arrangement, and the balls 4 compete with each other. A high surface pressure is generated, and not only the ball 4 cannot roll smoothly, but also the ball 4 is locked by the wedge phenomenon, thereby inhibiting the behavior of the ball 4.

このように本実施形態では、連結溝7の溝幅Wが、1.10Dw≦W≦1.20Dwの範囲に設定されると共に、連結溝7の開口部7aにおける角部が滑らかに丸められているので、駒部材5の加工誤差や組立誤差が生じても、ボール4の循環においてその挙動を阻害することなくスムーズなボール循環が得られる駒式ボールねじを提供することができる。   As described above, in this embodiment, the groove width W of the connecting groove 7 is set in the range of 1.10 Dw ≦ W ≦ 1.20 Dw, and the corner portion of the opening 7 a of the connecting groove 7 is smoothly rounded. Therefore, even if a processing error or assembly error of the piece member 5 occurs, it is possible to provide a piece type ball screw that can obtain a smooth ball circulation without disturbing the behavior of the ball 4 in the circulation.

以上、本発明の実施の形態について説明を行ったが、本発明はこうした実施の形態に何等限定されるものではなく、あくまで例示であって、本発明の要旨を逸脱しない範囲内において、さらに種々なる形態で実施し得ることは勿論のことであり、本発明の範囲は、特許請求の範囲の記載によって示され、さらに特許請求の範囲に記載の均等の意味、および範囲内のすべての変更を含む。   The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

本発明に係る駒式ボールねじは、自動車の電動アクチュエータ等に使用される駒式ボールねじに適用することができる。   The piece type ball screw according to the present invention can be applied to a piece type ball screw used for an electric actuator of an automobile or the like.

(a)は、本発明に係る駒式ボールねじの一実施形態を示す平面図である。 (b)は、同上縦断面図である。(A) is a top view which shows one Embodiment of the piece-type ball screw which concerns on this invention. (B) is a longitudinal cross-sectional view same as the above. 本発明に係る駒部材の平面図である。It is a top view of the piece member concerning the present invention. (a)は、図2の駒部材の他の実施態様を示す平面図である。 (b)は、(a)のボールの挙動を示す説明図である。(A) is a top view which shows the other embodiment of the piece member of FIG. (B) is explanatory drawing which shows the behavior of the ball | bowl of (a). 図2の駒部材の比較例を示す平面図である。It is a top view which shows the comparative example of the piece member of FIG. (a)は、図4の他の実施態様を示す平面図である。 (b)は、(a)のボールの挙動を示す説明図である。(A) is a top view which shows the other embodiment of FIG. (B) is explanatory drawing which shows the behavior of the ball | bowl of (a). 従来の駒式ボールねじを示す斜視図である。It is a perspective view which shows the conventional piece type ball screw. 同上、要部断面図である。It is a principal part sectional drawing same as the above.

符号の説明Explanation of symbols

1・・・・・・・・・・駒式ボールねじ
2・・・・・・・・・・ねじ軸
2a、3a・・・・・・ねじ溝
3・・・・・・・・・・ナット
4・・・・・・・・・・ボール
5・・・・・・・・・・駒部材
5a・・・・・・・・・連結溝
6・・・・・・・・・・駒窓
7・・・・・・・・・・連結溝
7a・・・・・・・・・開口部
8・・・・・・・・・・加締部
50・・・・・・・・・ナット
50a、53a・・・・ねじ溝
51・・・・・・・・・駒部材
52・・・・・・・・・バイパス路
52a、52b・・・・出入り口
53・・・・・・・・・ねじ軸
54・・・・・・・・・ボール軌道路
55・・・・・・・・・無限循環回路
56・・・・・・・・・ボール
57・・・・・・・・・上面
58a、58b・・・・出入り通路
59・・・・・・・・・中間通路
60・・・・・・・・・ねじ山
Dw・・・・・・・・・ボールの外径
e・・・・・・・・・・連結溝とボールとのすきま
W・・・・・・・・・・連結溝の溝幅
δ・・・・・・・・・・ボール軌道路のリード角
θ1・・・・・・・・・出入り通路のリード角
θ2・・・・・・・・・中間通路のリード角
1 ······ Poma type ball screw 2 ·············· Screw shafts 2a, 3a Nut 4 ... Ball 5 ... Piece member 5a ... Connection groove 6 ... Piece Window 7 ... Connection groove 7a ... Opening 8 ... Caulking part 50 ... Nut 50a, 53a ··· Thread groove 51 ······ Piece member 52 ············ Bypass passage 52a, 52b ··· Entrance / exit 53 ··· .... Screw shaft 54 ... Ball raceway 55 ... Endless circuit 56 ... Ball 57 ...・ Upper surfaces 58a, 58b ... ・ Access passage 59 ... Passage 60 ... Thread Dw ... Ball outer diameter e ... Clearance W between connecting groove and ball W ... ·········· groove width δ of the connecting groove ········ Lead angle θ1 of the ball raceway ············· Lead angle θ2 of the access path ... Lead angle of intermediate passage

Claims (5)

外周面に螺旋状のねじ溝が形成されたねじ軸と、
このねじ軸に外嵌され、内周面に螺旋状のねじ溝が形成されたナットと、
対向する両ねじ溝により形成される転動路に収容された複数のボールと、
前記ナットの胴部に穿設された駒窓に嵌合され、前記転動路を周回経路とする連結溝が形成された駒部材とを備えた駒式ボールねじにおいて、
前記駒部材の連結溝が、前記ナットの隣接するねじ溝に合致するように接続され、略S字状に湾曲して形成されると共に、当該連結溝の溝幅が、前記ボールの外径の1.10〜1.20の範囲に設定されていることを特徴とする駒式ボールねじ。
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 spiral thread groove formed on the inner peripheral surface;
A plurality of balls housed in a rolling path formed by opposing screw grooves;
In a piece-type ball screw provided with a piece member that is fitted to a piece window drilled in the trunk portion of the nut and has a connection groove having the rolling path as a circulation path,
The connecting groove of the piece member is connected so as to match the adjacent thread groove of the nut and is formed to be curved in a substantially S shape, and the groove width of the connecting groove is equal to the outer diameter of the ball. A piece type ball screw characterized by being set in a range of 1.10 to 1.20.
前記連結溝の開口部における角部が滑らかに丸められている請求項1に記載の駒式ボールねじ。   The piece type ball screw according to claim 1, wherein corners of the opening of the connecting groove are smoothly rounded. 前記ナットにおけるねじ溝の断面がゴシックアーク形状に形成されている請求項1または2に記載の駒式ボールねじ。   The piece type ball screw according to claim 1 or 2, wherein a cross section of a thread groove in the nut is formed in a Gothic arc shape. 前記駒窓が円形に形成され、駒部材の断面がこれに対応して断面が略円形に形成されている請求項1乃至3いずれかに記載の駒式ボールねじ。   The piece type ball screw according to any one of claims 1 to 3, wherein the piece window is formed in a circular shape, and a cross section of the piece member is formed in a substantially circular shape corresponding thereto. 前記駒部材が焼結合金からMIMによって成形されている請求項1乃至4いずれかに記載の駒式ボールねじ。   The piece type ball screw according to any one of claims 1 to 4, wherein the piece member is formed of a sintered alloy by MIM.
JP2006087129A 2006-03-28 2006-03-28 Deflector type ball screw Pending JP2007263192A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009057424A1 (en) * 2007-10-31 2009-05-07 Thk Co., Ltd. Rolling-body screw device
JP2011127719A (en) * 2009-12-18 2011-06-30 Showa Corp Ball screw device
US7992461B2 (en) * 2008-10-31 2011-08-09 Hiwin Technologies Corp. Circulating device for motion guide apparatus
JP2011196519A (en) * 2010-03-23 2011-10-06 Nsk Ltd Ball screw
JP2012167794A (en) * 2011-02-16 2012-09-06 Nsk Ltd Ball screw
JP2013255950A (en) * 2012-06-11 2013-12-26 Mura Technology:Kk Rotation converting mechanism and chuck device
US11506269B2 (en) 2016-11-14 2022-11-22 Nsk Ltd. Ball screw

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Publication number Priority date Publication date Assignee Title
JPS5077762A (en) * 1973-10-30 1975-06-25
JP2002235829A (en) * 2001-02-08 2002-08-23 Ntn Corp Ball screw and electric power steering device having the same
JP2004019905A (en) * 2002-06-20 2004-01-22 Nsk Ltd Linear drive actuator
JP2004204911A (en) * 2002-12-24 2004-07-22 Nsk Ltd Top type ball screw

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5077762A (en) * 1973-10-30 1975-06-25
JP2002235829A (en) * 2001-02-08 2002-08-23 Ntn Corp Ball screw and electric power steering device having the same
JP2004019905A (en) * 2002-06-20 2004-01-22 Nsk Ltd Linear drive actuator
JP2004204911A (en) * 2002-12-24 2004-07-22 Nsk Ltd Top type ball screw

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009057424A1 (en) * 2007-10-31 2009-05-07 Thk Co., Ltd. Rolling-body screw device
US8261627B2 (en) 2007-10-31 2012-09-11 Thk Co., Ltd. Rolling body screw device
JP5388857B2 (en) * 2007-10-31 2014-01-15 Thk株式会社 Rolling element screw device
US7992461B2 (en) * 2008-10-31 2011-08-09 Hiwin Technologies Corp. Circulating device for motion guide apparatus
JP2011127719A (en) * 2009-12-18 2011-06-30 Showa Corp Ball screw device
JP2011196519A (en) * 2010-03-23 2011-10-06 Nsk Ltd Ball screw
JP2012167794A (en) * 2011-02-16 2012-09-06 Nsk Ltd Ball screw
JP2013255950A (en) * 2012-06-11 2013-12-26 Mura Technology:Kk Rotation converting mechanism and chuck device
US11506269B2 (en) 2016-11-14 2022-11-22 Nsk Ltd. Ball screw
JP7302171B2 (en) 2016-11-14 2023-07-04 日本精工株式会社 ball screw

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