WO2021020263A1 - Roller screw unit - Google Patents

Roller screw unit Download PDF

Info

Publication number
WO2021020263A1
WO2021020263A1 PCT/JP2020/028380 JP2020028380W WO2021020263A1 WO 2021020263 A1 WO2021020263 A1 WO 2021020263A1 JP 2020028380 W JP2020028380 W JP 2020028380W WO 2021020263 A1 WO2021020263 A1 WO 2021020263A1
Authority
WO
WIPO (PCT)
Prior art keywords
nut
screw shaft
thread
screw
raceway surface
Prior art date
Application number
PCT/JP2020/028380
Other languages
French (fr)
Japanese (ja)
Other versions
WO2021020263A9 (en
Inventor
英二 社本
中村　隆
高橋　徹
喜大 濱田
弘幸 岸
Original Assignee
国立大学法人東海国立大学機構
Thk株式会社
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 国立大学法人東海国立大学機構, Thk株式会社 filed Critical 国立大学法人東海国立大学機構
Priority to JP2021536991A priority Critical patent/JPWO2021020263A1/ja
Publication of WO2021020263A1 publication Critical patent/WO2021020263A1/en
Publication of WO2021020263A9 publication Critical patent/WO2021020263A9/en

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/24—Elements essential to such mechanisms, e.g. screws, nuts

Definitions

  • the present invention relates to a rolling element screwing device such as a ball screw in which a rolling element is interposed between a screw shaft and a nut so that a rolling element can be rolled.
  • the ball screw is a rolling screw mechanism. That is, the ball screw includes a screw shaft, a nut, and a plurality of balls interposed between the screw shaft and the nut so as to be rollable. A spiral raceway surface is formed on the outer surface of the screw shaft. A spiral raceway surface facing the raceway surface of the screw shaft is formed on the inner surface of the nut. A ball is interposed between the raceway surface of the screw shaft and the raceway surface of the nut.
  • the shape of the raceway surface of the screw shaft and the raceway surface of the nut are both Gothic arch grooves.
  • the contact angle is set to 40 to 50 degrees (see Patent Document 1). This is so that the load can be received on both the outward and return paths of the nut.
  • the ball screw basically receives an axial load.
  • the contact angle is set to 40 to 50 degrees, so when an axial load acts on the ball screw, a load in the axial direction and the axial perpendicular direction (radial direction) is applied inside the ball screw. Occurs. Since the latter radial load does not help to receive the axial load, the conventional ball screw has a problem that the rated load in the axial direction is small. Further, since the radial position where the screw contacts the ball is smaller than the radial position where the nut contacts the ball, it has a convex curvature when viewed in the direction in which the raceway surface extends. Due to the curvature of the convex side, the area of elastic contact is reduced, and a large contact load cannot be received. That is, the conventional ball screw has a problem that the rated load is further reduced.
  • the ball comes into contact with the screw shaft and the Gothic arch groove of the nut at one point each, for a total of two points, and receives the load.
  • a third contact point is accompanied depending on whether the rotation is positive or reverse (see Non-Patent Document 1). Since slipping occurs instead of rolling at this third contact point, there is also a problem that friction loss increases and heat generation is large.
  • the ball screw generates heat, the screw shaft and nut cause metal expansion, which causes a change or deterioration in feed accuracy.
  • the present invention has been made in view of the above problems, and provides a rolling element screwing device which has a large rated load in the axial direction, generates little heat, and can suppress fluctuations in friction torque due to a free zone when the rolling direction is reversed.
  • the purpose is.
  • one aspect of the present invention includes a screw shaft having a spiral thread on the outer surface and a screw shaft raceway surface formed on the side surface of the screw thread, and a spiral nut on the inner surface.
  • a nut having a screw thread and having a nut raceway surface facing the screw shaft raceway surface formed on the side surface of the nut screw thread, and a rollable interposition between the screw shaft raceway surface and the nut raceway surface.
  • a rolling element screwing device including a plurality of rolling elements, wherein the outer diameter of the thread of the screw shaft is larger than the inner diameter of the nut thread of the nut.
  • a rolling element screw device that has a large rated load in the axial direction, generates less heat, and can suppress fluctuations in friction torque due to the free zone when the rolling direction is reversed.
  • FIG. 3A is a plan view of the rolling element screwing apparatus
  • FIG. 3B is a rolling element screwing apparatus which shows only the upper half of a nut
  • 3 (c) is a side view of FIG. 3 (b).
  • FIG. 1 is a cross-sectional view taken along the axis of the ball screw 1 as the rolling element screw device according to the first embodiment of the present invention.
  • FIG. 2 is an enlarged view of part II of FIG. 2 is a screw shaft, 2a is a screw shaft axis, 3 is a nut, and 5a and 5b are balls as rolling elements.
  • a spiral thread 10 is provided on the outer surface of the screw shaft 2.
  • the thread 10 of the screw shaft 2 has a pair of left and right side surfaces 10b and 10c and a peak 10a (see FIG. 2).
  • a first screw shaft raceway surface 11 is formed on one side surface 10c of the thread 10 (the side surface on the right side of the thread 10 in FIG. 1).
  • a second screw shaft raceway surface 12 is formed on the other side surface 10b of the screw thread 10 (the left side surface of the screw thread 10 in FIG. 1).
  • the outer diameter of the thread 10 of the screw shaft 2, that is, the diameter of the virtual cylinder in contact with the peak 10a of the thread 10 is D1.
  • the nut 3 includes a first nut portion 3a and a second nut portion 3b that are connected in the axial direction.
  • the first nut portion 3a is provided with a hole 8a into which the screw shaft 2 is inserted.
  • a spiral nut thread 6a is formed on the inner surface of the hole 8a.
  • the nut thread 6a has a pair of left and right side surfaces 7b and 7c and a peak 7a (see FIG. 2).
  • a first nut raceway surface 21 facing the first screw shaft raceway surface 11 of the screw shaft 2 is formed on one (left side of FIG. 1) side surface 7b of the pair of side surfaces 7b and 7c of the nut thread 6a.
  • the first nut raceway surface 21 is formed only on one side surface 7b of the nut thread 6a (see FIG. 2).
  • a 1-nut raceway surface 21 may be formed on each of the pair of left and right side surfaces 7b and 7c of the nut thread 6a.
  • the second nut portion 3b is provided with a hole 8b into which the screw shaft 2 is inserted. Similar to the first nut portion 3a, a spiral nut thread 6b is formed on the inner surface of the hole 8b of the second nut portion 3b.
  • the nut thread 6b has a pair of left and right side surfaces and a ridge.
  • a second nut raceway surface 22 facing the second screw shaft raceway surface 12 of the screw shaft 2 is formed on the other side surface (on the right side in FIG. 1) of the pair of side surfaces of the nut screw thread 6b.
  • the second nut raceway surface 22 is formed only on the other side surface (on the right side of FIG. 1) of the nut thread 6b.
  • a second nut raceway surface 22 may be formed on each of the pair of side surfaces of the nut thread 6b.
  • the inner diameters of the nut threads 6a and 6b that is, the diameters of the virtual cylinders in contact with the peaks 7a of the nut threads 6a and 6b are all D2.
  • the outer diameter D1 of the thread 10 of the screw shaft 2 is larger than the inner diameter D2 of the nut threads 6a and 6b of the nut 3.
  • the nut threads 6a and 6b enter the thread 10 adjacent to the screw shaft 2.
  • the first ball 5a is interposed between the first screw shaft raceway surface 11 of the screw shaft 2 and the first nut raceway surface 21 of the first nut portion 3a.
  • the first ball 5a exists only on the first screw shaft raceway surface 11 side of the thread 10 of the screw shaft 2, and does not exist on the second screw shaft raceway surface 12 side.
  • a load is applied to the first ball 5a in only one direction (direction of arrow (1) in FIG. 1) acting on the first nut portion 3a.
  • a second ball 5b is interposed between the second screw shaft raceway surface 12 of the screw shaft 2 and the second nut raceway surface 22 of the nut 3.
  • the second ball 5b exists only on the second screw shaft raceway surface 12 side of the screw thread 10 of the screw shaft 2, and does not exist on the first screw shaft raceway surface 11 side.
  • a load is applied to the second ball 5b only in the other direction (direction of arrow (2) in FIG. 1) acting on the second nut portion 3b.
  • the shape of the first screw shaft raceway surface 11 formed on the thread 10 of the screw shaft 2 is formed in a circular arc groove having a single arc.
  • the radius of this circular arc groove is slightly larger than the radius of the first ball 5a.
  • the first screw shaft raceway surface 11 and the first ball 5a come into contact with each other at a point P1 at the bottom of the groove. Since the screw thread 10 has a lead angle, to be precise, the shape of the first screw shaft raceway surface 11 is formed in the circular arc groove in the right-angled cross-sectional view of the screw thread 10.
  • the shape of the first screw shaft raceway surface 11 may be a Gothic arch groove that contacts the first ball 5a at two points.
  • the side surface 10c of the screw thread 10 of the screw shaft 2 (the line connecting the side surface of the root portion 10-1 of the screw thread 10 in FIG. 2 and the side surface of the top portion 10-2) is the axis line 2a of the screw shaft 2 (in FIG. 2). It is inclined with respect to the line 2b orthogonal to the axis 2a parallel to the axis 2a of the screw shaft 2 in FIG. 1).
  • the width of the root portion 10-1 of the thread 10 of the screw shaft 2 is wider than the width of the top portion 10-2. Even if the side surface 10c is inclined, the first screw shaft raceway surface 11 makes point contact with the first ball 5a at the point P1 at the bottom of the groove. That is, the contact angle ⁇ described later is maintained in the vicinity of 90 °.
  • the arc length of the first screw shaft raceway surface 11 from the point P1 to the groove end N1 on the root portion 10-1 side is the arc length from the point P1 to the top of the first screw shaft raceway surface 11. It is longer than the arc length up to the groove end N2 on the 10-2 side (upper side of FIG. 2).
  • the groove width of the first screw shaft raceway surface 11 of the screw shaft 2 (the region represented by the central angle ⁇ 1 in FIG. 2) is an allowable surface pressure of 4200 MPa at the contact point P1 between the first ball 5a and the first screw shaft raceway surface 11. It is desirable that the contact long axis radius (the region represented by the central angle ⁇ 2 in FIG. 2) does not deviate from the groove width when
  • the side surface 10b of the thread 10 of the screw shaft 2 is inclined in the direction opposite to the side surface 10c.
  • a second screw shaft raceway surface 12 is formed on the side surface 10b of the screw thread 10.
  • the shape of the second screw shaft raceway surface 12 is formed in a circular arc groove having a single arc, similarly to the first screw shaft raceway surface 11.
  • the screw thread 10 is formed symmetrically.
  • the shape of the first nut raceway surface 21 formed on the nut thread 6a of the first nut portion 3a is also formed in a circular arc groove having a single arc.
  • the radius of the circular arc groove is slightly larger than the radius of the first ball 5a, like the first screw shaft raceway surface 11.
  • the first nut raceway surface 21 and the first ball 5a come into contact with each other at a point P2 at the bottom of the groove. Since the nut thread 6a has a lead angle, to be precise, the shape of the first nut raceway surface 21 is formed in the circular arc groove in the right-angled cross-sectional view of the nut thread 6a.
  • the shape of the first nut raceway surface 21 may be a Gothic arch groove that contacts the first ball 5a at two points.
  • an allowable surface pressure of 4200 MPa acts on the contact point P2 between the first ball 5a and the first nut raceway surface 21 as in the case of the first screw shaft raceway surface 11. At that time, it is desirable to set so that the contact semimajor axis does not deviate from the groove width.
  • the side surface 7b of the nut thread 6a of the first nut portion 3a is also inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2.
  • the width of the root portion 6-1 of the nut thread 6a is wider than the width of the top portion 6-2.
  • the first nut raceway surface 21 makes point contact with the first ball 5a at the point P2 at the bottom of the groove. That is, the contact angle ⁇ described later is maintained in the vicinity of 90 °. Therefore, the arc length of the first nut raceway surface 21 from the point P2 to the groove end M1 on the root portion 6-1 side (upper side in FIG. 2) is the arc length from the point P2 to the top portion 6-2 of the first nut raceway surface 21. It is longer than the arc length up to the groove end M2 on the side (lower side of FIG. 2).
  • the side surface 7c of the nut thread 6a of the first nut portion 3a is inclined in the direction opposite to the side surface 7b.
  • the first nut raceway surface 21 is not formed on the side surface 7c of the nut thread 6a.
  • the angle ⁇ formed by the line connecting the contact P1 and the contact P2 and the line 2b orthogonal to the axis 2a of the screw shaft 2, that is, the contact angle ⁇ is in the range of 90 ° ⁇ 30 °, preferably in the range of 90 ° ⁇ 20 °. , And more preferably set in the range of 90 ° ⁇ 10 °.
  • the contact angle ⁇ is a line connecting the bottoms of the Gothic arch groove for convenience.
  • the nut thread 6b of the second nut portion 3b is formed symmetrically with the nut thread 6a of the first nut portion 3a.
  • a spacer 4 as a preload applying means for applying the preload to the first ball 5a and the second ball 5b.
  • the spacer 4 pushes the first nut portion 3a in one direction (direction of the arrow (1) in FIG. 1), and compresses the first rolling element between the first nut portion 3a and the screw shaft 2. Further, the spacer 4 pushes the second nut portion 3b in the other direction (direction of the arrow (2) in FIG. 1), and compresses the second rolling element between the second nut portion 3b and the screw shaft 2.
  • a spring may be used instead of the spacer 4.
  • the nut 3 may be a single nut in which the first nut portion 3a and the second nut portion 3b are integrated. By shifting the nut thread 6a of the first nut portion 3a and the nut thread 6b of the second nut portion 3b at the central portion of the single nut, preload can be applied to the first ball 5a and the second ball 5b. ..
  • first nut portion 3a and the second nut portion 3b are arranged in opposite directions from the state shown in FIG. 1, that is, the first nut portion 3a is arranged on the right side and the second nut portion 3b is arranged on the left side. Preload may be applied to the first ball 5a and the second ball 5b so that the nut portion 3a and the second nut portion 3b pull each other.
  • FIG. 3 shows the circulation structure of the ball screw 1 of the present embodiment.
  • 3 (a) is a plan view of the ball screw 1
  • FIG. 3 (b) is a side view of the ball screw 1 showing only the upper half of the nut 3
  • FIG. 3 (c) is a view taken along the line c of FIG. 3 (b). Is.
  • the first nut portion 3a is provided with two return pipes 23 connected to one end and the other end of the circulation path.
  • the return pipe 23 scoops up the first ball 5a that rolls to one end of the circulation path and returns it to the other end of the circulation path.
  • the second nut portion 3b is provided with, for example, two rows of 2.5 winding circulation paths.
  • the second nut portion 3b is also provided with two return pipes 25 connected to one end and the other end of the circulation path.
  • Reference numeral 24 denotes a key for stopping the rotation of the first nut portion 3a and the second nut portion 3b.
  • the number of turns and the number of rows of the circulation path are examples, and are set appropriately according to the rated load.
  • a circulation method instead of the return pipe method, a circulation method such as a spinning top type, an end cap type, an end deflector type, or a return plate type may be adopted.
  • the contact angle ⁇ can be set to an angle advantageous for receiving the load in the axial direction, and since the contact area between the balls 5a and 5b and the screw shaft 2 is large, the rated load in the axial direction can be increased.
  • the contact area between the screw shaft and the ball is small, but the contact area between the nut and the ball is large. Therefore, the rated load is determined on the smaller screw shaft side.
  • the difference in contact area between the two is reduced or eliminated, so that the rated load becomes large.
  • the balls 5a and 5b roll.
  • the angle formed by the two lines connecting the two contact points P1 and P2 and the ball center O is approximately 180. It becomes a degree. Therefore, slippage (friction) can be reduced, and heat generation of the ball screw due to friction can be suppressed.
  • a first screw shaft raceway surface 11 and a second screw shaft raceway surface 12 are formed on each of the pair of side surfaces 10b and 10c of the screw thread 10 of the screw shaft 2, and the first ball 5a of the first nut portion 3a is attached to the screw shaft 2 Since the second ball 5b of the second nut portion 3b is provided only on the second screw shaft raceway surface 12 side of the screw shaft 2, the lead angle of the screw shaft 2 is reduced. be able to. Further, a preload can be applied to the first ball 5a and the second ball 5b.
  • the screw shaft raceway surfaces 11 and 12 are on the side surfaces 10b and 10c of the screw thread 10. Is easy to process.
  • the grindstone T for grinding the first screw shaft raceway surface 11 is broken down from the solid line by inclining the side surfaces 10b and 10c of the thread 10 of the screw shaft 2 from the solid line in the figure as shown by the broken line.
  • the first screw shaft raceway surface 11 can be ground on the peripheral surface T1 of the grindstone T.
  • FIG. 5 is a cross-sectional view of a ball screw 31 as a rolling element screw device according to a second embodiment of the present invention.
  • 2 is a screw shaft
  • 2a is a screw shaft axis
  • 3 is a nut
  • 3a is a first nut portion
  • 3b is a second nut portion
  • 5a is a first ball
  • 5b is a second ball
  • 4 is a spacer. Since the basic configuration of the ball screw 31 of the second embodiment is the same as that of the ball screw 1 of the first embodiment, the same reference numerals are given and the description thereof will be omitted.
  • the side surfaces 10b and 10c of the screw thread 10 of the screw shaft 2 are inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2, whereas the second embodiment
  • the side surfaces 10b and 10c of the thread 10 of the screw shaft 2 are parallel to the line 2b orthogonal to the axis 2a of the screw shaft 2.
  • the side surfaces 7b and 7c of the nut threads 6a and 6b of the nut 3 are inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2.
  • the side surfaces 7b and 7c of the nut threads 6a and 6b of the nut 3 are parallel to the line 2b orthogonal to the axis 2a of the screw shaft 2.
  • FIG. 6 is a cross-sectional view of a ball screw 40 as a rolling element screw device according to a third embodiment of the present invention.
  • 41 is a screw shaft
  • 41a is a screw shaft axis
  • 42 is a nut
  • 43 is a ball.
  • the ball screw 1 of the first embodiment and the ball screw 31 of the second embodiment are configured so that the ball screws 1 and 31 can receive loads in two directions of the outward path and the return path, but the third embodiment.
  • the ball screw 40 of the form is configured so that the ball screw 40 can receive a load in one direction (downward on the Z axis indicated by the arrow (3) in FIG. 6).
  • the screw shaft 41 is arranged in the Z-axis direction. Then, rattling is prevented from occurring due to the gravity of a movable body (not shown) attached to the nut 42.
  • the screw shaft raceway surface 45 is formed on the side surface of the spiral thread 44 of the screw shaft 41.
  • a nut raceway surface 47 facing the screw shaft raceway surface 45 is formed on the side surface of the spiral nut thread 46 of the nut 42.
  • a plurality of balls 43 are interposed between the screw shaft raceway surface 45 and the nut raceway surface 47 so as to be rollable.
  • the outer diameter of the thread 44 of the screw shaft 41 is larger than the inner diameter of the nut thread 46 of the nut 42, and the contact angle is set in the range of 90 ° ⁇ 30 °.
  • the rated load in the axial direction is large, the heat generation is small, and the rolling direction. Fluctuations in friction torque due to the free zone during reversal can also be suppressed.
  • the ball is used as the rolling element, but a roller may be used as the rolling element.

Abstract

Provided is a roller screw unit that has a large rated load in an axial direction, generates little heat, and is capable of suppressing fluctuations of friction torque caused due to a free zone obtained when a rolling direction is reversed. A spiral thread (10) is provided on an outer surface of a screw shaft (2). Spiral nut threads (6a, 6b) are provided on an inner surface of a nut (3). An outer diameter (D1) of the thread (10) of the screw shaft (2) is set to be greater than an inner diameter (D2) of the nut threads (6a, 6b) of the nut (3). Screw shaft raceway surfaces (11, 12) are formed on respective side surfaces of the thread (10) of the screw shaft (2). Nut raceway surfaces (21, 22) opposing the screw shaft raceway surfaces (11, 12) are formed on respective side surfaces of the nut threads (6a, 6b) of the nut (3). A plurality of rollers (5a, 5b) are interposed in a rollable manner between the screw shaft raceway surfaces (11, 12) and the nut raceway surfaces (21, 22).

Description

転動体ねじ装置Roller screw device
　本発明は、ねじ軸とナットとの間に転がり運動可能に転動体を介在させたボールねじ等の転動体ねじ装置に関する。 The present invention relates to a rolling element screwing device such as a ball screw in which a rolling element is interposed between a screw shaft and a nut so that a rolling element can be rolled.
　工作機械等の産業用機械は、内部に送り駆動機構を持っている。送り駆動機構には、ボールねじが多用されている。ボールねじは、送り駆動機構を通して産業用機械の性能を支配する重要な機械要素になっている。 Industrial machines such as machine tools have a feed drive mechanism inside. Ball screws are often used in the feed drive mechanism. The ball screw has become an important mechanical element that governs the performance of industrial machines through the feed drive mechanism.
　ボールねじは、ねじ機構を転がり化したものである。すなわち、ボールねじは、ねじ軸と、ナットと、ねじ軸とナットとの間に転がり運動可能に介在する複数のボールと、を備える。ねじ軸の外面には、螺旋状の軌道面が形成される。ナットの内面には、ねじ軸の軌道面に対向する螺旋状の軌道面が形成される。ねじ軸の軌道面とナットの軌道面との間には、ボールが介在される。 The ball screw is a rolling screw mechanism. That is, the ball screw includes a screw shaft, a nut, and a plurality of balls interposed between the screw shaft and the nut so as to be rollable. A spiral raceway surface is formed on the outer surface of the screw shaft. A spiral raceway surface facing the raceway surface of the screw shaft is formed on the inner surface of the nut. A ball is interposed between the raceway surface of the screw shaft and the raceway surface of the nut.
　従来のボールねじにおいて、ねじ軸の軌道面とナットの軌道面の形状は、いずれもゴシックアーチ溝である。そして、接触角は４０～５０度に設定される（特許文献１参照）。ナットの往路も復路も荷重を受けられるようにするためである。 In the conventional ball screw, the shape of the raceway surface of the screw shaft and the raceway surface of the nut are both Gothic arch grooves. The contact angle is set to 40 to 50 degrees (see Patent Document 1). This is so that the load can be received on both the outward and return paths of the nut.
特開２０１５－１０８４００号公報JP-A-2015-108400
　ボールねじは、基本的に軸方向の荷重を受けるものである。しかし、従来のボールねじにおいては、接触角が４０～５０度に設定されるので、ボールねじに軸方向の荷重が働くと、ボールねじの内部に軸方向と軸直角方向（半径方向）の荷重が発生する。後者の半径方向の荷重は、軸方向の荷重を受けるのに何の役にも立っていないので、従来のボールねじには、軸方向の定格荷重が小さいという課題がある。さらに、ねじがボールに接する半径位置は、ナットがボールに接する半径位置に比べて小さいため、軌道面が伸びる方向に見ると凸側の曲率を持つ。この凸側の曲率によって弾性接触の面積が減少し、大きな接触荷重を受けることができない。すなわち、従来のボールねじには、さらに定格荷重が小さくなるという課題がある。 The ball screw basically receives an axial load. However, in the conventional ball screw, the contact angle is set to 40 to 50 degrees, so when an axial load acts on the ball screw, a load in the axial direction and the axial perpendicular direction (radial direction) is applied inside the ball screw. Occurs. Since the latter radial load does not help to receive the axial load, the conventional ball screw has a problem that the rated load in the axial direction is small. Further, since the radial position where the screw contacts the ball is smaller than the radial position where the nut contacts the ball, it has a convex curvature when viewed in the direction in which the raceway surface extends. Due to the curvature of the convex side, the area of elastic contact is reduced, and a large contact load cannot be received. That is, the conventional ball screw has a problem that the rated load is further reduced.
　また、従来のボールねじにおいては、ボールはねじ軸及びナットのゴシックアーチ溝とそれぞれ１点、合計２点で接触して荷重を受ける。しかし、ねじがナットに対して回転している状態では、回転の正又は逆に依存して第３の接触点を伴う（非特許文献１参照）。この第３の接触点では転がりではなく滑りを生じるため、摩擦損失が増大し発熱が大きいという課題もある。ボールねじが発熱すると、ねじ軸やナットが金属膨張を起こすので、送り精度の変化、悪化を招く。 Also, in the conventional ball screw, the ball comes into contact with the screw shaft and the Gothic arch groove of the nut at one point each, for a total of two points, and receives the load. However, in the state where the screw is rotating with respect to the nut, a third contact point is accompanied depending on whether the rotation is positive or reverse (see Non-Patent Document 1). Since slipping occurs instead of rolling at this third contact point, there is also a problem that friction loss increases and heat generation is large. When the ball screw generates heat, the screw shaft and nut cause metal expansion, which causes a change or deterioration in feed accuracy.
　さらに、従来のボールねじにおいては、ボールの転がり方向反転時に、ボールと軌道面との接触状態が３点接触状態→２点接触状態→３点接触状態に変化するので、２点接触状態に起因して摩擦トルクが低下する所謂フリーゾーンが発生するという課題もある。このフリーゾーンは、運動反転時の軌跡制御誤差の補正を複雑・困難にしている。 Further, in the conventional ball screw, when the rolling direction of the ball is reversed, the contact state between the ball and the raceway surface changes from the 3-point contact state to the 2-point contact state to the 3-point contact state, which is caused by the 2-point contact state. Therefore, there is also a problem that a so-called free zone in which the friction torque is reduced is generated. This free zone complicates and makes it difficult to correct the trajectory control error at the time of motion reversal.
　本発明は、上記の課題を鑑みてなされたものであり、軸方向の定格荷重が大きく、発熱が少なく、転がり方向反転時のフリーゾーンによる摩擦トルクの変動も抑制できる転動体ねじ装置を提供することを目的とする。 The present invention has been made in view of the above problems, and provides a rolling element screwing device which has a large rated load in the axial direction, generates little heat, and can suppress fluctuations in friction torque due to a free zone when the rolling direction is reversed. The purpose is.
　上記課題を解決するために、本発明の一態様は、外面に螺旋状のねじ山を有し、前記ねじ山の側面にねじ軸軌道面が形成されるねじ軸と、内面に螺旋状のナットねじ山を有し、前記ナットねじ山の側面に前記ねじ軸軌道面に対向するナット軌道面が形成されるナットと、前記ねじ軸軌道面と前記ナット軌道面との間に転がり可能に介在する複数の転動体と、を備え、前記ねじ軸の前記ねじ山の外径が前記ナットの前記ナットねじ山の内径よりも大きい転動体ねじ装置である。 In order to solve the above problems, one aspect of the present invention includes a screw shaft having a spiral thread on the outer surface and a screw shaft raceway surface formed on the side surface of the screw thread, and a spiral nut on the inner surface. A nut having a screw thread and having a nut raceway surface facing the screw shaft raceway surface formed on the side surface of the nut screw thread, and a rollable interposition between the screw shaft raceway surface and the nut raceway surface. A rolling element screwing device including a plurality of rolling elements, wherein the outer diameter of the thread of the screw shaft is larger than the inner diameter of the nut thread of the nut.
　本発明によれば、軸方向の定格荷重が大きく、発熱が少なく、転がり方向反転時のフリーゾーンによる摩擦トルクの変動も抑制できる転動体ねじ装置が得られる。 According to the present invention, it is possible to obtain a rolling element screw device that has a large rated load in the axial direction, generates less heat, and can suppress fluctuations in friction torque due to the free zone when the rolling direction is reversed.
本発明の第１の実施形態の転動体ねじ装置の軸線に沿った断面図である。It is sectional drawing along the axis of the rolling element screwing apparatus of 1st Embodiment of this invention. 図１のII部拡大図である。It is an enlarged view of the part II of FIG. 第１の実施形態の転動体ねじ装置の循環構造を示す図である（図３（ａ）は転動体ねじ装置の平面図、図３（ｂ）はナットの上側半分のみを示す転動体ねじ装置の側面図、図３（ｃ）は図３（ｂ）のｃ矢視図）。It is a figure which shows the circulation structure of the rolling element screwing apparatus of 1st Embodiment (FIG. 3A is a plan view of the rolling element screwing apparatus, and FIG. 3B is a rolling element screwing apparatus which shows only the upper half of a nut. 3 (c) is a side view of FIG. 3 (b). ねじ山の側面の傾き砥石の傾きの関係を示す概念図である。It is a conceptual diagram which shows the relationship of the inclination of the side surface of a screw thread, and the inclination of a grindstone. 本発明の第２の実施形態の転動体ねじ装置の軸線に沿った断面図である。It is sectional drawing along the axis of the rolling element screw device of the 2nd Embodiment of this invention. 本発明の第３の実施形態の転動体ねじ装置の軸線に沿った断面図である。It is sectional drawing along the axis of the rolling element screwing apparatus of 3rd Embodiment of this invention.
　以下、添付図面に基づいて、本発明の実施形態の転動体ねじ装置を説明する。ただし、本発明の転動体ねじ装置は種々の形態で具体化することができ、本明細書に記載される実施形態に限定されるものではない。本実施形態は、明細書の開示を十分にすることによって、当業者が発明の範囲を十分に理解できるようにする意図をもって提供されるものである。
　（第１の実施形態） Hereinafter, the rolling element screwing device according to the embodiment of the present invention will be described with reference to the accompanying drawings. However, the rolling element screwing device of the present invention can be embodied in various forms, and is not limited to the embodiments described in the present specification. The present embodiment is provided with the intention of allowing those skilled in the art to fully understand the scope of the invention by adequately disclosing the specification.
(First Embodiment)
　図１は、本発明の第１の実施形態の転動体ねじ装置としてのボールねじ１の軸線に沿った断面図である。図２は、図１のII部拡大図である。２はねじ軸、２ａはねじ軸の軸線、３はナット、５ａ，５ｂは転動体としてのボールである。 FIG. 1 is a cross-sectional view taken along the axis of the ball screw 1 as the rolling element screw device according to the first embodiment of the present invention. FIG. 2 is an enlarged view of part II of FIG. 2 is a screw shaft, 2a is a screw shaft axis, 3 is a nut, and 5a and 5b are balls as rolling elements.
　図１に示すように、ねじ軸２の外面には、螺旋状のねじ山１０が設けられる。ねじ軸２のねじ山１０は、左右一対の側面１０ｂ，１０ｃと、山頂１０ａと、を有する（図２参照）。ねじ山１０の一方の側面１０ｃ（図１のねじ山１０の右側の側面）には、第１ねじ軸軌道面１１が形成される。ねじ山１０の他方の側面１０ｂ（図１のねじ山１０の左側の側面）には、第２ねじ軸軌道面１２が形成される。ねじ軸２のねじ山１０の外径、すなわちねじ山１０の山頂１０ａに接する仮想的な円筒の直径はＤ１である。 As shown in FIG. 1, a spiral thread 10 is provided on the outer surface of the screw shaft 2. The thread 10 of the screw shaft 2 has a pair of left and right side surfaces 10b and 10c and a peak 10a (see FIG. 2). A first screw shaft raceway surface 11 is formed on one side surface 10c of the thread 10 (the side surface on the right side of the thread 10 in FIG. 1). A second screw shaft raceway surface 12 is formed on the other side surface 10b of the screw thread 10 (the left side surface of the screw thread 10 in FIG. 1). The outer diameter of the thread 10 of the screw shaft 2, that is, the diameter of the virtual cylinder in contact with the peak 10a of the thread 10 is D1.
　ナット３は、軸方向に連結される第１ナット部３ａと第２ナット部３ｂを備える。第１ナット部３ａには、ねじ軸２が挿入される穴８ａが設けられる。穴８ａの内面には、螺旋状のナットねじ山６ａが形成される。ナットねじ山６ａは、ねじ山１０と同様に、左右一対の側面７ｂ，７ｃと、山頂７ａと、を有する（図２参照）。ナットねじ山６ａの一対の側面７ｂ，７ｃのうち一方の（図１の左側の）側面７ｂには、ねじ軸２の第１ねじ軸軌道面１１に対向する第１ナット軌道面２１が形成される。第１ナット軌道面２１は、ナットねじ山６ａの一方の側面７ｂのみに形成される（図２参照）。なお、ナットねじ山６ａの左右一対の側面７ｂ，７ｃのそれぞれに１ナット軌道面２１を形成してもよい。 The nut 3 includes a first nut portion 3a and a second nut portion 3b that are connected in the axial direction. The first nut portion 3a is provided with a hole 8a into which the screw shaft 2 is inserted. A spiral nut thread 6a is formed on the inner surface of the hole 8a. Like the screw thread 10, the nut thread 6a has a pair of left and right side surfaces 7b and 7c and a peak 7a (see FIG. 2). A first nut raceway surface 21 facing the first screw shaft raceway surface 11 of the screw shaft 2 is formed on one (left side of FIG. 1) side surface 7b of the pair of side surfaces 7b and 7c of the nut thread 6a. To. The first nut raceway surface 21 is formed only on one side surface 7b of the nut thread 6a (see FIG. 2). A 1-nut raceway surface 21 may be formed on each of the pair of left and right side surfaces 7b and 7c of the nut thread 6a.
　第２ナット部３ｂには、ねじ軸２が挿入される穴８ｂが設けられる。第２ナット部３ｂの穴８ｂの内面には、第１ナット部３ａと同様に、螺旋状のナットねじ山６ｂが形成される。ナットねじ山６ｂは、左右一対の側面と、山頂と、を有する。ナットねじ山６ｂの一対の側面のうち他方の（図１の右側の）側面には、ねじ軸２の第２ねじ軸軌道面１２に対向する第２ナット軌道面２２が形成される。第２ナット軌道面２２は、ナットねじ山６ｂの他方の（図１の右側の）側面のみに形成される。なお、ナットねじ山６ｂの一対の側面のそれぞれに第２ナット軌道面２２を形成してもよい。 The second nut portion 3b is provided with a hole 8b into which the screw shaft 2 is inserted. Similar to the first nut portion 3a, a spiral nut thread 6b is formed on the inner surface of the hole 8b of the second nut portion 3b. The nut thread 6b has a pair of left and right side surfaces and a ridge. A second nut raceway surface 22 facing the second screw shaft raceway surface 12 of the screw shaft 2 is formed on the other side surface (on the right side in FIG. 1) of the pair of side surfaces of the nut screw thread 6b. The second nut raceway surface 22 is formed only on the other side surface (on the right side of FIG. 1) of the nut thread 6b. A second nut raceway surface 22 may be formed on each of the pair of side surfaces of the nut thread 6b.
　ナットねじ山６ａ，６ｂの内径、すなわちナットねじ山６ａ，６ｂの山頂７ａに接する仮想的な円筒の直径は、いずれもＤ２である。ねじ軸２のねじ山１０の外径Ｄ１は、ナット３のナットねじ山６ａ，６ｂの内径Ｄ２よりも大きい。ナットねじ山６ａ，６ｂは、ねじ軸２の隣接するねじ山１０に入り込む。 The inner diameters of the nut threads 6a and 6b, that is, the diameters of the virtual cylinders in contact with the peaks 7a of the nut threads 6a and 6b are all D2. The outer diameter D1 of the thread 10 of the screw shaft 2 is larger than the inner diameter D2 of the nut threads 6a and 6b of the nut 3. The nut threads 6a and 6b enter the thread 10 adjacent to the screw shaft 2.
　ねじ軸２の第１ねじ軸軌道面１１と第１ナット部３ａの第１ナット軌道面２１との間には、第１ボール５ａが介在する。第１ボール５ａは、ねじ軸２のねじ山１０の第１ねじ軸軌道面１１側にのみ存在していて、第２ねじ軸軌道面１２側に存在していない。第１ボール５ａには、第１ナット部３ａに働く一方向（図１の矢印（１）方向）のみの荷重が負荷される。 The first ball 5a is interposed between the first screw shaft raceway surface 11 of the screw shaft 2 and the first nut raceway surface 21 of the first nut portion 3a. The first ball 5a exists only on the first screw shaft raceway surface 11 side of the thread 10 of the screw shaft 2, and does not exist on the second screw shaft raceway surface 12 side. A load is applied to the first ball 5a in only one direction (direction of arrow (1) in FIG. 1) acting on the first nut portion 3a.
　ねじ軸２の第２ねじ軸軌道面１２とナット３の第２ナット軌道面２２との間には、第２ボール５ｂが介在する。第２ボール５ｂは、ねじ軸２のねじ山１０の第２ねじ軸軌道面１２側にのみ存在していて、第１ねじ軸軌道面１１側に存在していない。第２ボール５ｂには、第２ナット部３ｂに働く他方向（図１の矢印（２）方向）のみの荷重が負荷される。 A second ball 5b is interposed between the second screw shaft raceway surface 12 of the screw shaft 2 and the second nut raceway surface 22 of the nut 3. The second ball 5b exists only on the second screw shaft raceway surface 12 side of the screw thread 10 of the screw shaft 2, and does not exist on the first screw shaft raceway surface 11 side. A load is applied to the second ball 5b only in the other direction (direction of arrow (2) in FIG. 1) acting on the second nut portion 3b.
　図２に示すように、ねじ軸２のねじ山１０に形成される第１ねじ軸軌道面１１の形状は、単一円弧のサーキュラーアーク溝に形成される。このサーキュラーアーク溝の半径は、第１ボール５ａの半径よりも僅かに大きい。第１ねじ軸軌道面１１と第１ボール５ａとは、溝底の点Ｐ１で接触する。ねじ山１０はリード角を持つので、正確にいえば、ねじ山１０の直角断面視において、第１ねじ軸軌道面１１の形状がサーキュラーアーク溝に形成される。なお、第１ねじ軸軌道面１１の形状を第１ボール５ａと２点で接触するゴシックアーチ溝にしてもよい。 As shown in FIG. 2, the shape of the first screw shaft raceway surface 11 formed on the thread 10 of the screw shaft 2 is formed in a circular arc groove having a single arc. The radius of this circular arc groove is slightly larger than the radius of the first ball 5a. The first screw shaft raceway surface 11 and the first ball 5a come into contact with each other at a point P1 at the bottom of the groove. Since the screw thread 10 has a lead angle, to be precise, the shape of the first screw shaft raceway surface 11 is formed in the circular arc groove in the right-angled cross-sectional view of the screw thread 10. The shape of the first screw shaft raceway surface 11 may be a Gothic arch groove that contacts the first ball 5a at two points.
　ねじ軸２のねじ山１０の側面１０ｃ（図２のねじ山１０の根元部１０－１の側面と頂部１０－２の側面を結んだ線）は、ねじ軸２の軸線２ａ（図２には図１のねじ軸２の軸線２ａと平行な軸線２ａを示す）と直交する線２ｂに対して傾斜する。ねじ軸２のねじ山１０の根元部１０－１の幅は、頂部１０－２の幅よりも太い。側面１０ｃが傾斜していても、第１ねじ軸軌道面１１は、その溝底の点Ｐ１で第１ボール５ａと点接触する。すなわち、後述する接触角αは９０°近傍に保たれる。このため、第１ねじ軸軌道面１１の、点Ｐ１から根元部１０－１側（図２の下側）の溝端Ｎ１までの弧長が、第１ねじ軸軌道面１１の、点Ｐ１から頂部１０－２側（図２の上側）の溝端Ｎ２までの弧長よりも長い。 The side surface 10c of the screw thread 10 of the screw shaft 2 (the line connecting the side surface of the root portion 10-1 of the screw thread 10 in FIG. 2 and the side surface of the top portion 10-2) is the axis line 2a of the screw shaft 2 (in FIG. 2). It is inclined with respect to the line 2b orthogonal to the axis 2a parallel to the axis 2a of the screw shaft 2 in FIG. 1). The width of the root portion 10-1 of the thread 10 of the screw shaft 2 is wider than the width of the top portion 10-2. Even if the side surface 10c is inclined, the first screw shaft raceway surface 11 makes point contact with the first ball 5a at the point P1 at the bottom of the groove. That is, the contact angle α described later is maintained in the vicinity of 90 °. Therefore, the arc length of the first screw shaft raceway surface 11 from the point P1 to the groove end N1 on the root portion 10-1 side (lower side of FIG. 2) is the arc length from the point P1 to the top of the first screw shaft raceway surface 11. It is longer than the arc length up to the groove end N2 on the 10-2 side (upper side of FIG. 2).
　ねじ軸２の第１ねじ軸軌道面１１の溝幅（図２の中心角θ１で表される領域）は、第１ボール５ａと第１ねじ軸軌道面１１との接点Ｐ１に許容面圧４２００ＭＰａが働いたときに、当該溝幅から接触長軸半径（図２の中心角θ２で表される領域）が外れないように設定されるのが望ましい。 The groove width of the first screw shaft raceway surface 11 of the screw shaft 2 (the region represented by the central angle θ1 in FIG. 2) is an allowable surface pressure of 4200 MPa at the contact point P1 between the first ball 5a and the first screw shaft raceway surface 11. It is desirable that the contact long axis radius (the region represented by the central angle θ2 in FIG. 2) does not deviate from the groove width when
　ねじ軸２のねじ山１０の側面１０ｂは、側面１０ｃと反対方向に傾斜する。ねじ山１０の側面１０ｂには、第２ねじ軸軌道面１２が形成される。第２ねじ軸軌道面１２の形状は、第１ねじ軸軌道面１１と同様に、単一円弧のサーキュラーアーク溝に形成される。ねじ山１０の直角断面視において、ねじ山１０は左右対称に形成される。 The side surface 10b of the thread 10 of the screw shaft 2 is inclined in the direction opposite to the side surface 10c. A second screw shaft raceway surface 12 is formed on the side surface 10b of the screw thread 10. The shape of the second screw shaft raceway surface 12 is formed in a circular arc groove having a single arc, similarly to the first screw shaft raceway surface 11. In a right-angled cross-sectional view of the screw thread 10, the screw thread 10 is formed symmetrically.
　第１ナット部３ａのナットねじ山６ａに形成される第１ナット軌道面２１の形状も、単一円弧のサーキュラーアーク溝に形成される。このサーキュラーアーク溝の半径は、第１ねじ軸軌道面１１と同様に、第１ボール５ａの半径よりも僅かに大きい。第１ナット軌道面２１と第１ボール５ａとは、溝底の点Ｐ２で接触する。ナットねじ山６ａはリード角を持つので、正確にいえば、ナットねじ山６ａの直角断面視において、第１ナット軌道面２１の形状がサーキュラーアーク溝に形成される。なお、第１ナット軌道面２１の形状を第１ボール５ａと２点で接触するゴシックアーチ溝にしてもよい。 The shape of the first nut raceway surface 21 formed on the nut thread 6a of the first nut portion 3a is also formed in a circular arc groove having a single arc. The radius of the circular arc groove is slightly larger than the radius of the first ball 5a, like the first screw shaft raceway surface 11. The first nut raceway surface 21 and the first ball 5a come into contact with each other at a point P2 at the bottom of the groove. Since the nut thread 6a has a lead angle, to be precise, the shape of the first nut raceway surface 21 is formed in the circular arc groove in the right-angled cross-sectional view of the nut thread 6a. The shape of the first nut raceway surface 21 may be a Gothic arch groove that contacts the first ball 5a at two points.
　第１ナット部３ａの第１ナット軌道面２１の溝幅も、第１ねじ軸軌道面１１と同様に、第１ボール５ａと第１ナット軌道面２１との接点Ｐ２に許容面圧４２００ＭＰａが働いたときに、当該溝幅から接触長軸半径が外れないように設定されるのが望ましい。 As for the groove width of the first nut raceway surface 21 of the first nut portion 3a, an allowable surface pressure of 4200 MPa acts on the contact point P2 between the first ball 5a and the first nut raceway surface 21 as in the case of the first screw shaft raceway surface 11. At that time, it is desirable to set so that the contact semimajor axis does not deviate from the groove width.
　第１ナット部３ａのナットねじ山６ａの側面７ｂも、ねじ軸２の軸線２ａと直交する線２ｂに対して傾斜する。ナットねじ山６ａの根元部６－１の幅は、頂部６－２の幅よりも太い。側面７ｂが傾斜していても、第１ナット軌道面２１は、その溝底の点Ｐ２で第１ボール５ａと点接触する。すなわち、後述する接触角αは９０°近傍に保たれる。このため、第１ナット軌道面２１の、点Ｐ２から根元部６－１側（図２の上側）の溝端Ｍ１までの弧長が、第１ナット軌道面２１の、点Ｐ２から頂部６－２側（図２の下側）の溝端Ｍ２までの弧長よりも長い。 The side surface 7b of the nut thread 6a of the first nut portion 3a is also inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2. The width of the root portion 6-1 of the nut thread 6a is wider than the width of the top portion 6-2. Even if the side surface 7b is inclined, the first nut raceway surface 21 makes point contact with the first ball 5a at the point P2 at the bottom of the groove. That is, the contact angle α described later is maintained in the vicinity of 90 °. Therefore, the arc length of the first nut raceway surface 21 from the point P2 to the groove end M1 on the root portion 6-1 side (upper side in FIG. 2) is the arc length from the point P2 to the top portion 6-2 of the first nut raceway surface 21. It is longer than the arc length up to the groove end M2 on the side (lower side of FIG. 2).
　第１ナット部３ａのナットねじ山６ａの側面７ｃは、側面７ｂと反対方向に傾斜する。ナットねじ山６ａの側面７ｃには、第１ナット軌道面２１は形成されていない。 The side surface 7c of the nut thread 6a of the first nut portion 3a is inclined in the direction opposite to the side surface 7b. The first nut raceway surface 21 is not formed on the side surface 7c of the nut thread 6a.
　接点Ｐ１と接点Ｐ２を結んだ線とねじ軸２の軸線２ａに直交する線２ｂとのなす角度α、すなわち接触角αは、９０°±３０°の範囲、望ましくは９０°±２０°の範囲、さらに望ましくは９０°±１０°の範囲に設定される。なお、第１ねじ軸軌道面１１と第１ナット軌道面２１の形状をゴシックアーチ溝にした場合、接触角αを便宜的にゴシックアーチ溝の底を結んだ線とする。 The angle α formed by the line connecting the contact P1 and the contact P2 and the line 2b orthogonal to the axis 2a of the screw shaft 2, that is, the contact angle α is in the range of 90 ° ± 30 °, preferably in the range of 90 ° ± 20 °. , And more preferably set in the range of 90 ° ± 10 °. When the shape of the first screw shaft raceway surface 11 and the first nut raceway surface 21 is a Gothic arch groove, the contact angle α is a line connecting the bottoms of the Gothic arch groove for convenience.
　図１に示すように、第２ナット部３ｂのナットねじ山６ｂは、第１ナット部３ａのナットねじ山６ａと左右対称に形成される。 As shown in FIG. 1, the nut thread 6b of the second nut portion 3b is formed symmetrically with the nut thread 6a of the first nut portion 3a.
　第１ナット部３ａと第２ナット部３ｂとの間には、第１ボール５ａと第２ボール５ｂに予圧を付与するための予圧付与手段としての間座４が存在する。間座４は、第１ナット部３ａを一方向（図１の矢印（１）方向）に押し、第１ナット部３ａとねじ軸２との間で第１転動体を圧縮させる。また、間座４は、第２ナット部３ｂを他方向（図１の矢印（２）方向）に押し、第２ナット部３ｂとねじ軸２との間で第２転動体を圧縮させる。なお、予圧付与手段として、間座４の替わりにばねを用いてもよい。 Between the first nut portion 3a and the second nut portion 3b, there is a spacer 4 as a preload applying means for applying the preload to the first ball 5a and the second ball 5b. The spacer 4 pushes the first nut portion 3a in one direction (direction of the arrow (1) in FIG. 1), and compresses the first rolling element between the first nut portion 3a and the screw shaft 2. Further, the spacer 4 pushes the second nut portion 3b in the other direction (direction of the arrow (2) in FIG. 1), and compresses the second rolling element between the second nut portion 3b and the screw shaft 2. As the preload applying means, a spring may be used instead of the spacer 4.
　ナット３を第１ナット部３ａ、第２ナット部３ｂを一体にしたシングルナットにしてもよい。シングルナットの中央部で第１ナット部３ａのナットねじ山６ａと第２ナット部３ｂのナットねじ山６ｂをシフトさせれば、第１ボール５ａと第２ボール５ｂに予圧を付与することができる。 The nut 3 may be a single nut in which the first nut portion 3a and the second nut portion 3b are integrated. By shifting the nut thread 6a of the first nut portion 3a and the nut thread 6b of the second nut portion 3b at the central portion of the single nut, preload can be applied to the first ball 5a and the second ball 5b. ..
　また、第１ナット部３ａと第２ナット部３ｂを図１に示す状態から左右反対に配置し、すなわち、第１ナット部３ａを右側に、第２ナット部３ｂを左側に配置し、第１ナット部３ａと第２ナット部３ｂとが互いに引っ張り合うように、第１ボール５ａと第２ボール５ｂに予圧を付与してもよい。 Further, the first nut portion 3a and the second nut portion 3b are arranged in opposite directions from the state shown in FIG. 1, that is, the first nut portion 3a is arranged on the right side and the second nut portion 3b is arranged on the left side. Preload may be applied to the first ball 5a and the second ball 5b so that the nut portion 3a and the second nut portion 3b pull each other.
　図３は、本実施形態のボールねじ１の循環構造を示す。図３（ａ）はボールねじ１の平面図、図３（ｂ）はナット３の上側半分のみを示すボールねじ１の側面図、図３（ｃ）は図３（ｂ）のｃ矢視図である。 FIG. 3 shows the circulation structure of the ball screw 1 of the present embodiment. 3 (a) is a plan view of the ball screw 1, FIG. 3 (b) is a side view of the ball screw 1 showing only the upper half of the nut 3, and FIG. 3 (c) is a view taken along the line c of FIG. 3 (b). Is.
　第１ナット部３ａには、例えば２．５巻きの循環路が２列設けられる。第１ナット部３ａには、循環路の一端と他端に接続される２つのリターンパイプ２３が設けられる。リターンパイプ２３は、循環路の一端まで転がる第１ボール５ａを掬い上げ、循環路の他端に戻す。第２ナット部３ｂには、例えば２．５巻きの循環路が２列設けられる。第２ナット部３ｂにも、循環路の一端と他端に接続される２つのリターンパイプ２５が設けられる。２４は、第１ナット部３ａと第２ナット部３ｂを回り止めするためのキーである。 For example, two rows of 2.5 winding circulation paths are provided in the first nut portion 3a. The first nut portion 3a is provided with two return pipes 23 connected to one end and the other end of the circulation path. The return pipe 23 scoops up the first ball 5a that rolls to one end of the circulation path and returns it to the other end of the circulation path. The second nut portion 3b is provided with, for example, two rows of 2.5 winding circulation paths. The second nut portion 3b is also provided with two return pipes 25 connected to one end and the other end of the circulation path. Reference numeral 24 denotes a key for stopping the rotation of the first nut portion 3a and the second nut portion 3b.
　なお、循環路の巻き数、列数は一例であり、定格荷重に合わせて適宜設定される。また、循環方式として、リターンパイプ方式の替わりに、こま式、エンドキャップ式、エンドデフレクタ式、リターンプレート式等の循環方式を採用してもよい。 The number of turns and the number of rows of the circulation path are examples, and are set appropriately according to the rated load. Further, as the circulation method, instead of the return pipe method, a circulation method such as a spinning top type, an end cap type, an end deflector type, or a return plate type may be adopted.
　以上に本実施形態のボールねじ１の構成を説明した。本実施形態のボールねじ１によれば、以下の効果を奏する。 The configuration of the ball screw 1 of the present embodiment has been described above. According to the ball screw 1 of the present embodiment, the following effects are obtained.
　接触角αを軸方向の荷重を受けるのに有利な角度に設定できるし、ボール５ａ，５ｂとねじ軸２との接触面積が大きいので、軸方向の定格荷重を大きくすることができる。従来のボールねじでは、ねじ軸とボールの接触面積が小さい代わりに、ナットとボールの接触面積が大きい。そのため、定格荷重は小さい方のねじ軸側で決まる。一方、本実施形態状では、両者の接触面積の差が減少・消失するため、定格荷重が大きくなる。 The contact angle α can be set to an angle advantageous for receiving the load in the axial direction, and since the contact area between the balls 5a and 5b and the screw shaft 2 is large, the rated load in the axial direction can be increased. In the conventional ball screw, the contact area between the screw shaft and the ball is small, but the contact area between the nut and the ball is large. Therefore, the rated load is determined on the smaller screw shaft side. On the other hand, in the present embodiment, the difference in contact area between the two is reduced or eliminated, so that the rated load becomes large.
　ねじ軸２とボール５ａ，５ｂの接点位置の半径（ねじ軸を中心とする半径）とナット３とボール５ａ，５ｂの接点位置の半径とが略一致するので、ボール５ａ，５ｂが転動しても、ゴシックアーチ溝の場合には第３の接触点を生じず、本実施形態のサーキュラーアーク溝においても２つの接触点Ｐ１，Ｐ２とボール中心Ｏを結ぶ２つの線の成す角度がほぼ１８０度となる。このため、滑り（摩擦）を少なくすることができ、摩擦に起因するボールねじの発熱を抑制することができる。 Since the radius of the contact position between the screw shaft 2 and the balls 5a and 5b (the radius centered on the screw shaft) and the radius of the contact position between the nut 3 and the balls 5a and 5b are substantially the same, the balls 5a and 5b roll. However, in the case of the Gothic arch groove, a third contact point is not generated, and even in the circular arc groove of the present embodiment, the angle formed by the two lines connecting the two contact points P1 and P2 and the ball center O is approximately 180. It becomes a degree. Therefore, slippage (friction) can be reduced, and heat generation of the ball screw due to friction can be suppressed.
　転がり方向反転時にボール５ａ，５ｂの接触状態が２点接触状態のままなので、フリーゾーンによる摩擦トルクの変動を抑制できる。 Since the contact state of the balls 5a and 5b remains in the two-point contact state when the rolling direction is reversed, the fluctuation of the friction torque due to the free zone can be suppressed.
　ねじ軸２のねじ山１０の一対の側面１０ｂ，１０ｃそれぞれに第１ねじ軸軌道面１１と第２ねじ軸軌道面１２それぞれを形成し、第１ナット部３ａの第１ボール５ａをねじ軸２の第１ねじ軸軌道面１１側にのみ設け、第２ナット部３ｂの第２ボール５ｂをねじ軸２の第２ねじ軸軌道面１２側にのみ設けるので、ねじ軸２のリード角を小さくすることができる。また、第１ボール５ａ、第２ボール５ｂに予圧を付与することができる。 A first screw shaft raceway surface 11 and a second screw shaft raceway surface 12 are formed on each of the pair of side surfaces 10b and 10c of the screw thread 10 of the screw shaft 2, and the first ball 5a of the first nut portion 3a is attached to the screw shaft 2 Since the second ball 5b of the second nut portion 3b is provided only on the second screw shaft raceway surface 12 side of the screw shaft 2, the lead angle of the screw shaft 2 is reduced. be able to. Further, a preload can be applied to the first ball 5a and the second ball 5b.
　第１ナット部３ａと第２ナット部３ｂとの間に間座４を設けるので、第１ナット部３ａと第２ナット部３ｂに予圧を付与することができる。 Since the spacer 4 is provided between the first nut portion 3a and the second nut portion 3b, preload can be applied to the first nut portion 3a and the second nut portion 3b.
　ねじ軸２のねじ山１０の側面１０ｂ，１０ｃが、ねじ軸２の軸線２ａと直交する線２ｂに対して傾斜しているので、ねじ山１０の側面１０ｂ，１０ｃにねじ軸軌道面１１，１２を加工するのが容易である。図４に示すように、ねじ軸２のねじ山１０の側面１０ｂ，１０ｃを図中実線から破線に示すように傾斜させることで、第１ねじ軸軌道面１１を研削する砥石Ｔを実線から破線に示すように傾斜させることができ、砥石Ｔの周面Ｔ１で第１ねじ軸軌道面１１を研削できるようになる。 Since the side surfaces 10b and 10c of the thread 10 of the screw shaft 2 are inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2, the screw shaft raceway surfaces 11 and 12 are on the side surfaces 10b and 10c of the screw thread 10. Is easy to process. As shown in FIG. 4, the grindstone T for grinding the first screw shaft raceway surface 11 is broken down from the solid line by inclining the side surfaces 10b and 10c of the thread 10 of the screw shaft 2 from the solid line in the figure as shown by the broken line. As shown in the above, the first screw shaft raceway surface 11 can be ground on the peripheral surface T1 of the grindstone T.
　ねじ軸２のねじ山１０の根元部１０－１が頂部１０－２よりも太いので、ねじ軸２のねじ山１０の強度を向上させることができる。同様に、ナット３のナットねじ山６ａ，６ｂの強度を向上させることができる。
　（第２の実施形態） Since the root portion 10-1 of the thread 10 of the screw shaft 2 is thicker than the top portion 10-2, the strength of the thread 10 of the screw shaft 2 can be improved. Similarly, the strength of the nut threads 6a and 6b of the nut 3 can be improved.
(Second Embodiment)
　図５は、本発明の第２の実施形態の転動体ねじ装置としてのボールねじ３１の断面図である。２はねじ軸、２ａはねじ軸の軸線、３はナット、３ａは第１ナット部、３ｂは第２ナット部、５ａは第１ボール、５ｂは第２ボール、４は間座である。第２の実施形態のボールねじ３１の基本構成は、第１の実施形態のボールねじ１と同様なので、同一の符号を附してその説明を省略する。 FIG. 5 is a cross-sectional view of a ball screw 31 as a rolling element screw device according to a second embodiment of the present invention. 2 is a screw shaft, 2a is a screw shaft axis, 3 is a nut, 3a is a first nut portion, 3b is a second nut portion, 5a is a first ball, 5b is a second ball, and 4 is a spacer. Since the basic configuration of the ball screw 31 of the second embodiment is the same as that of the ball screw 1 of the first embodiment, the same reference numerals are given and the description thereof will be omitted.
　第１の実施形態のボールねじ１では、ねじ軸２のねじ山１０の側面１０ｂ，１０ｃがねじ軸２の軸線２ａと直交する線２ｂに対して傾斜しているのに対し、第２の実施形態のボールねじ３１では、ねじ軸２のねじ山１０の側面１０ｂ，１０ｃがねじ軸２の軸線２ａと直交する線２ｂに対して平行である。同様に、第１の実施形態のボールねじ１では、ナット３のナットねじ山６ａ，６ｂの側面７ｂ，７ｃがねじ軸２の軸線２ａと直交する線２ｂに対して傾斜しているのに対し、第２の実施形態のボールねじ３１では、ナット３のナットねじ山６ａ，６ｂの側面７ｂ，７ｃがねじ軸２の軸線２ａと直交する線２ｂに対して平行である。 In the ball screw 1 of the first embodiment, the side surfaces 10b and 10c of the screw thread 10 of the screw shaft 2 are inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2, whereas the second embodiment In the ball screw 31 of the form, the side surfaces 10b and 10c of the thread 10 of the screw shaft 2 are parallel to the line 2b orthogonal to the axis 2a of the screw shaft 2. Similarly, in the ball screw 1 of the first embodiment, the side surfaces 7b and 7c of the nut threads 6a and 6b of the nut 3 are inclined with respect to the line 2b orthogonal to the axis 2a of the screw shaft 2. In the ball screw 31 of the second embodiment, the side surfaces 7b and 7c of the nut threads 6a and 6b of the nut 3 are parallel to the line 2b orthogonal to the axis 2a of the screw shaft 2.
　第２の実施形態のボールねじ３１においては、ねじ山１０の側面１０ｂ，１０ｃとナットねじ山６ａ，６ｂの側面７ｂ，７ｃが傾斜していないので、ねじ軸軌道面１１，１２とナット軌道面２１，２２を加工しにくいという欠点があるが、この点を除いて、第１の実施形態のボールねじ１と同様な効果を奏する。
　（第３の実施形態） In the ball screw 31 of the second embodiment, since the side surfaces 10b and 10c of the screw thread 10 and the side surfaces 7b and 7c of the nut threads 6a and 6b are not inclined, the screw shaft raceway surfaces 11 and 12 and the nut raceway surface Although there is a drawback that 21 and 22 are difficult to process, the same effect as that of the ball screw 1 of the first embodiment is obtained except for this point.
(Third Embodiment)
　図６は、本発明の第３の実施形態の転動体ねじ装置としてのボールねじ４０の断面図である。４１はねじ軸、４１ａはねじ軸の軸線、４２はナット、４３はボールである。第１の実施形態のボールねじ１と第２の実施形態のボールねじ３１では、ボールねじ１，３１が往路と復路の二方向の荷重を受けられるように構成されているが、第３の実施形態のボールねじ４０では、ボールねじ４０が一方向（図６の矢印（３）で示すＺ軸下方向）の荷重を受けられるように構成される。 FIG. 6 is a cross-sectional view of a ball screw 40 as a rolling element screw device according to a third embodiment of the present invention. 41 is a screw shaft, 41a is a screw shaft axis, 42 is a nut, and 43 is a ball. The ball screw 1 of the first embodiment and the ball screw 31 of the second embodiment are configured so that the ball screws 1 and 31 can receive loads in two directions of the outward path and the return path, but the third embodiment. The ball screw 40 of the form is configured so that the ball screw 40 can receive a load in one direction (downward on the Z axis indicated by the arrow (3) in FIG. 6).
　ねじ軸４１はＺ軸方向に配置される。そして、ナット４２に取り付けられる図示しない可動体の重力によって、がたつきが発生するのを防止する。 The screw shaft 41 is arranged in the Z-axis direction. Then, rattling is prevented from occurring due to the gravity of a movable body (not shown) attached to the nut 42.
　第３の実施形態のボールねじ４０においても、ねじ軸４１の螺旋状のねじ山４４の側面には、ねじ軸軌道面４５が形成される。ナット４２の螺旋状のナットねじ山４６の側面には、ねじ軸軌道面４５に対向するナット軌道面４７が形成される。ねじ軸軌道面４５とナット軌道面４７との間には、転がり可能に複数のボール４３が介在する。ねじ軸４１のねじ山４４の外径は、ナット４２のナットねじ山４６の内径よりも大きく、接触角は９０°±３０°の範囲に設定される。 Also in the ball screw 40 of the third embodiment, the screw shaft raceway surface 45 is formed on the side surface of the spiral thread 44 of the screw shaft 41. A nut raceway surface 47 facing the screw shaft raceway surface 45 is formed on the side surface of the spiral nut thread 46 of the nut 42. A plurality of balls 43 are interposed between the screw shaft raceway surface 45 and the nut raceway surface 47 so as to be rollable. The outer diameter of the thread 44 of the screw shaft 41 is larger than the inner diameter of the nut thread 46 of the nut 42, and the contact angle is set in the range of 90 ° ± 30 °.
　第３の実施形態のボールねじ４０によれば、第１の実施形態のボールねじ１と第２の実施形態のボールねじ３１と同様に、軸方向の定格荷重が大きく、発熱が少なく、転がり方向反転時のフリーゾーンによる摩擦トルクの変動も抑制できる。 According to the ball screw 40 of the third embodiment, similarly to the ball screw 1 of the first embodiment and the ball screw 31 of the second embodiment, the rated load in the axial direction is large, the heat generation is small, and the rolling direction. Fluctuations in friction torque due to the free zone during reversal can also be suppressed.
　なお、本発明は、上記実施形態に具現化されるのに限られることはなく、本発明の要旨を変更しない範囲で他の実施形態に具現化できる。 Note that the present invention is not limited to being embodied in the above embodiment, and can be embodied in other embodiments without changing the gist of the present invention.
　例えば上記実施形態では、転動体としてボールを使用しているが、転動体としてローラを使用してもよい。 For example, in the above embodiment, the ball is used as the rolling element, but a roller may be used as the rolling element.
　本明細書は、２０１９年８月１日出願の特願２０１９－１４１９８６に基づく。この内容はすべてここに含めておく。 This specification is based on Japanese Patent Application No. 2019-141986 filed on August 1, 2019. All this content is included here.
１，３１，４０…ボールねじ（転動体ねじ装置）、２…ねじ軸、３ａ…第１ナット部（ナット）、３ｂ…第２ナット部（ナット）、４…間座、５ａ…第１ボール（転動体）、５ｂ…第２ボール（転動体）、６ａ，６ｂ…ナットねじ山、６－１…ナットねじ山の根元部、６－２…ナットねじ山の頂部、７ｂ，７ｃ…ナットねじ山の側面、１０…ねじ山、１０－１…ねじ山の根元部、１０－２…ねじ山の頂部、１０ｂ，１０ｃ…ねじ山の側面、１１…第１ねじ軸軌道面（ねじ軸軌道面）、１２…第２ねじ軸軌道面（ねじ軸軌道面）、２１…第１ナット軌道面（ナット軌道面）、２２…第２ナット軌道面（ナット軌道面）、４１…ねじ軸、４３…ボール（転動体）、４４…ねじ山、４５…ねじ軸軌道面、４６…ナットねじ山、４７…ナット軌道面、Ｄ１…ねじ山の外径、Ｄ２…ナットねじ山の内径、α…接触角 1,31,40 ... ball screw (rolling element screw device), 2 ... screw shaft, 3a ... first nut part (nut), 3b ... second nut part (nut), 4 ... spacer, 5a ... first ball (Rolling body), 5b ... 2nd ball (rolling body), 6a, 6b ... Nut thread, 6-1 ... Nut thread root, 6-2 ... Nut thread top, 7b, 7c ... Nut thread 10 ... Thread, 10-1 ... Root of screw thread, 10-2 ... Top of thread, 10b, 10c ... Side of thread, 11 ... 1st screw shaft raceway surface (thread shaft raceway surface), 12 ... 2nd screw shaft raceway surface (screw shaft raceway surface), 21 ... 1st nut raceway surface (nut raceway surface), 22 ... 2nd nut raceway surface (nut raceway surface), 41 ... screw shaft, 43 ... ball ( Rolling element), 44 ... Thread, 45 ... Screw shaft raceway surface, 46 ... Nut thread, 47 ... Nut raceway surface, D1 ... Thread outer diameter, D2 ... Nut thread inner diameter, α ... Contact angle

Claims (8)

  1. 　外面に螺旋状のねじ山を有し、前記ねじ山の側面にねじ軸軌道面が形成されるねじ軸と、
    　内面に螺旋状のナットねじ山を有し、前記ナットねじ山の側面に前記ねじ軸軌道面に対向するナット軌道面が形成されるナットと、
    　前記ねじ軸軌道面と前記ナット軌道面との間に転がり可能に介在する複数の転動体と、を備え、
    　前記ねじ軸の前記ねじ山の外径が前記ナットの前記ナットねじ山の内径よりも大きい転動体ねじ装置。     A screw shaft having a spiral thread on the outer surface and a screw shaft raceway surface formed on the side surface of the thread,
    A nut having a spiral nut thread on the inner surface and a nut raceway surface facing the screw shaft raceway surface formed on the side surface of the nut screw thread.
    A plurality of rolling elements that are rollably interposed between the screw shaft raceway surface and the nut raceway surface are provided.
    A rolling element screw device in which the outer diameter of the thread of the screw shaft is larger than the inner diameter of the nut thread of the nut.
  2. 　前記ねじ軸の前記ねじ山の一対の側面それぞれに第１ねじ軸軌道面と第２ねじ軸軌道面それぞれが形成され、
    　前記ナットは、前記ねじ軸の前記第１ねじ軸軌道面に対向する第１ナット軌道面が形成される第１ナット部と、前記ねじ軸の前記第２ねじ軸軌道面に対向する第２ナット軌道面が形成される第２ナット部と、を備え、
    　前記第１ナット部における第１転動体が前記ねじ軸の前記第１ねじ軸軌道面側にのみ存在し、
    　前記第２ナット部における第２転動体が前記ねじ軸の前記第２ねじ軸軌道面側にのみ存在することを特徴とする請求項１に記載の転動体ねじ装置。     A first screw shaft raceway surface and a second screw shaft raceway surface are formed on each of the pair of side surfaces of the thread of the screw shaft.
    The nuts are a first nut portion on which a first nut raceway surface facing the first screw shaft raceway surface of the screw shaft is formed, and a second nut facing the second screw shaft raceway surface of the screw shaft. A second nut portion on which a raceway surface is formed is provided.
    The first rolling element in the first nut portion exists only on the raceway surface side of the first screw shaft of the screw shaft.
    The rolling element screw device according to claim 1, wherein the second rolling element in the second nut portion exists only on the raceway surface side of the second screw shaft of the screw shaft.
  3. 　前記第１ナット部と前記第２ナット部との間には、前記第１転動体と前記第２転動体に予圧を付与するための間座が存在することを特徴とする請求項２に記載の転動体ねじ装置。 The second aspect of the present invention, wherein a spacer for applying a preload to the first rolling element and the second rolling element is present between the first nut portion and the second nut portion. Rolling body screwing device.
  4. 　前記ナットは、前記第１ナット部と前記第２ナット部を有するシングルナットであることを特徴とする請求項２又は３に記載の転動体ねじ装置。 The rolling element screwing device according to claim 2 or 3, wherein the nut is a single nut having the first nut portion and the second nut portion.
  5. 　前記ねじ軸の前記ねじ山の前記側面及び／又は前記ナットの前記ナットねじ山の前記側面が前記ねじ軸の軸線と直交する線に対して傾斜することを特徴とする請求項１ないし４のいずれか一項に記載の転動体ねじ装置。 Any of claims 1 to 4, wherein the side surface of the thread of the screw shaft and / or the side surface of the nut thread of the nut is inclined with respect to a line orthogonal to the axis of the screw shaft. The rolling element screwing device according to item 1.
  6. 　前記ねじ軸の前記ねじ山及び／又は前記ナットの前記ナットねじ山の根元部が頂部よりも太いことを特徴とする請求項５に記載の転動体ねじ装置。 The rolling element screw device according to claim 5, wherein the root portion of the nut screw thread of the screw shaft and / or the nut screw thread is thicker than the top portion.
  7. 　前記ねじ軸軌道面と前記ナット軌道面の形状がサーキュラーアーク溝であることを特徴とする請求項１ないし６のいずれか一項に記載の転動体ねじ装置。 The rolling element screw device according to any one of claims 1 to 6, wherein the shape of the screw shaft raceway surface and the nut raceway surface is a circular arc groove.
  8. 　接触角が９０°±３０°の範囲に設定されることを特徴とする請求項１ないし７のいずれか一項に記載の転動体ねじ装置。 The rolling element screwing device according to any one of claims 1 to 7, wherein the contact angle is set in the range of 90 ° ± 30 °.
PCT/JP2020/028380 2019-08-01 2020-07-22 Roller screw unit WO2021020263A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2021536991A JPWO2021020263A1 (en) 2019-08-01 2020-07-22

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019-141986 2019-08-01
JP2019141986 2019-08-01

Publications (2)

Publication Number Publication Date
WO2021020263A1 true WO2021020263A1 (en) 2021-02-04
WO2021020263A9 WO2021020263A9 (en) 2021-03-25

Family

ID=74230288

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/028380 WO2021020263A1 (en) 2019-08-01 2020-07-22 Roller screw unit

Country Status (3)

Country Link
JP (1) JPWO2021020263A1 (en)
TW (1) TW202113253A (en)
WO (1) WO2021020263A1 (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6154541U (en) * 1984-09-14 1986-04-12
US5535638A (en) * 1994-11-10 1996-07-16 Cincinnati Milacron Inc. Antifriction screw drive
JP2003194177A (en) * 2001-12-26 2003-07-09 Nsk Ltd Ball screw
JP2004138214A (en) * 2002-10-21 2004-05-13 Nsk Ltd Ball screw equipment and manufacturing method of the same
WO2017010553A1 (en) * 2015-07-15 2017-01-19 Ntn株式会社 Ball-screw and electrically driven actuator with same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6154541U (en) * 1984-09-14 1986-04-12
US5535638A (en) * 1994-11-10 1996-07-16 Cincinnati Milacron Inc. Antifriction screw drive
JP2003194177A (en) * 2001-12-26 2003-07-09 Nsk Ltd Ball screw
JP2004138214A (en) * 2002-10-21 2004-05-13 Nsk Ltd Ball screw equipment and manufacturing method of the same
WO2017010553A1 (en) * 2015-07-15 2017-01-19 Ntn株式会社 Ball-screw and electrically driven actuator with same

Also Published As

Publication number Publication date
WO2021020263A9 (en) 2021-03-25
JPWO2021020263A1 (en) 2021-02-04
TW202113253A (en) 2021-04-01

Similar Documents

Publication Publication Date Title
US7536928B2 (en) Ball screw
US8141448B2 (en) Ball spline
US8371760B2 (en) Rolling bearing
WO2012144371A1 (en) Linear motion guide mechanism
US4253342A (en) Arrangement for transforming a rotary movement of a smooth shaft into a thrust movement of a rolling nut
JP7162608B2 (en) Backlash prevention device and method
JPH0154570B2 (en)
TWI435986B (en) Roller screw and roller circulating method for roller screw
US11047459B2 (en) Ball screw device
WO2021020263A1 (en) Roller screw unit
KR101152786B1 (en) Improved loaded ball screw having thread profile showing in a cross section a multiple pointed gothic arch shape
JP5951873B2 (en) Ball screw
JP5182145B2 (en) Ball screw
JP4292779B2 (en) Rolling screw device
JP6540266B2 (en) Ball screw preload recovery device
JPWO2005038301A1 (en) Roller screw
JP2018048687A (en) Multipoint contact ball bearing
JP6903761B2 (en) Double row ball bearings and their manufacturing methods
JP2017009052A (en) Preload recovery device for ball screw
JP4829436B2 (en) Ball screw with alternately inserted steel balls and ceramic balls
JP2004316660A (en) Ball screw fitment
JP6604145B2 (en) Ball screw preload recovery device
WO2024041113A1 (en) Universal swinging-type recirculating ball nut mechanism of electric power steering machine
JP2004138214A (en) Ball screw equipment and manufacturing method of the same
JPS6338584B2 (en)

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20847521

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021536991

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20847521

Country of ref document: EP

Kind code of ref document: A1