JP2006046570A - Ball circulation member and ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a side cap and a ball screw capable of improving high speed operation performance and durability. <P>SOLUTION: The side cap 17 is formed of two ball circulation member components 23 and 23 divided along a parting line PL extending in the advancing direction of balls 15 passed through the inside thereof. The side cap 17 comprises a ball pick-up part 24 picking up the balls 15 in a ball route 8 from one side and a ball circulation passage 27 returning the balls 15 picked up by the ball pick-up part 24 into the ball route 8 from the other side which are formed integrally with each other. Cutouts 25 are formed at a pick-up base end 24a where the integrated ball pick-up part 24 and the ball circulation passage 27 are joined to each other. The parting line PL is formed at a position where the cutout 25 on one side and the cutout 25 on the other side are parted from each other beforehand. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ball screw used in various industrial machines.

  This type of ball screw has, for example, a screw shaft 12 having a spiral ball rolling groove on its outer peripheral surface and extending in the axial direction, like a ball screw 100 shown in FIG. A nut 14 having a spiral ball rolling groove corresponding to the ball rolling groove of the screw shaft 12 on the inner peripheral surface is fitted to the screw shaft 12. Here, the ball rolling groove of the nut 14 and the ball rolling groove of the screw shaft 12 are opposed to each other to form a ball raceway 8 between them. A plurality of balls 15 are loaded so as to be able to roll.

  In recent years, in this kind of ball screw, as a ball circulation member for circulating the ball, in order to ensure a smooth circulation of the ball, that is, the ball rolling on the spiral ball raceway is smoothly guided into the ball circulation member, In addition, in order to smoothly return the ball moving in the ball circulation member to the ball track, the ball can be picked up in the tangential direction of the ball track and returned to the ball track from the tangential direction of the ball track. It has increased (see, for example, Patent Document 1).

For example, in this type of ball screw, as shown in FIG. 10, the nut 14 has a ball circulation member mounting surface 16 formed of a flat surface on the outer peripheral surface thereof. A pair of long holes 20 are formed in the ball circulation member mounting surface 16, and the long holes 20 are drilled in communication with the ball raceway 8. And the ball circulation member 170 is attached to this ball circulation member attachment surface 16 (for example, refer patent document 2).
Japanese Patent Laid-Open No. 2003-232421 Japanese Patent Application No. 2003-318123 (unpublished)

  Here, as shown in FIG. 10, the ball circulation member 170 is provided with a pair of leg portions 190 on both sides of the central portion of the ball circulation member 170. For example, as shown in FIG. 11, the pair of leg portions 190 are formed to be inclined at predetermined angles in different directions with respect to the central portion of the ball circulation member 170 so as to correspond to the lead angle of the screw shaft 12. . The pair of legs 190 can be fitted into the elongated hole 20 formed in the ball circulation member mounting surface 16 from the direction perpendicular to the screw shaft 12 with almost no gap.

  Here, this type of ball circulation member 170 is manufactured by resin molding, for example, and is configured by combining a pair of ball circulation member constituting members 230 and 230 as shown in FIG. That is, the ball circulation member 170 has two ball circulation passages formed along the dividing line extending in the traveling direction of the ball 15 passing through the inside of the ball circulation member 170. It is configured as a pair of divided side cap constituent members 230, 230. Here, the line indicated by the reference symbol PL ′ in the figure indicates a dividing line that divides the ball circulation member 170 into the side cap constituent members 230.

  By the way, it is conceivable that the position for setting the dividing line PL ′ is set in accordance with the locus of the center of the ball 15. That is, if the dividing line PL ′ is set at such a position and the ball circulating member 170 is divided into the pair of side cap constituent members 230 and 230, each of the ball circulating member constituent members 230 is This is because it is formed to surround the circumference of the ball 15 almost equally, so that it is considered a preferable division position in order to stabilize the performance of restraining the ball 15.

  However, the ball circulation member 170 normally has a ball scooping portion 240 at the tip of the ball scooping (returning) passage 210 of the ball circulation member 170, for example, as shown in FIG. Here, the ball scooping unit 240 rolls the ball of the screw shaft 12 in order to scoop up the ball 15 rolling in the ball raceway 8 from the ball raceway 8 to the ball scooping (returning) passage 210. It has a tongue-like shape that can be inserted into the groove, and is formed to protrude from the ball scooping (returning) passage 210 toward the ball rolling groove. Therefore, a notch 25 is formed as a V-shaped groove having an acute angle, for example, in the scooping base end 240a, which is a portion where the ball scooping section 240 and the ball scooping (return) passage 210 are connected. It will be.

Therefore, when the dividing line PL ′ is set in accordance with the trajectory of the center of the ball over the entire ball circulation member 170 (a line indicated by the symbol BCD shown in FIG. 12) as shown in FIG. For example, as shown in FIG. 13, it is left as it is on the side of the scooping base end portion 240a (see the portion F ′ shown in FIG. 13).
That is, when the dividing line PL ′ at the scooping base end portion 240 is simply set at such a position, when a load is repeatedly applied to the ball scooping portion 240 during high-speed rotation of the ball screw 100 or the like. The notched portion 250 at the raised base end portion 240a becomes a base point of breakage due to stress concentration, which may cause a high speed.
The present invention has been made paying attention to such problems, and improves the high-speed driving performance and durability performance by improving the strength at the base end of the ball circulating member, which is weak in strength. It is an object of the present invention to provide a ball circulation member and a ball screw that can be made to exist.

  In order to solve the above problems, the invention according to claim 1 is a screw shaft having a ball rolling groove on an outer peripheral surface, and a nut having a ball rolling groove on an inner peripheral surface facing the outer peripheral surface of the screw shaft. And a plurality of balls disposed in a ball raceway formed between both ball rolling grooves of the nut and the screw shaft, and the ball in the ball raceway is moved from one side. A ball scooping part that scoops up the ball, and a ball circulation passage that returns the ball scooped up by the ball scooping part from the other side into the ball raceway, A ball circulation member having a notch at a scooping base end which is a portion connected to a ball circulation passage, wherein the ball circulation member is divided along a dividing line extending in a traveling direction of the ball passing through the inside. Two Bo The dividing line passes through the deepest portion of the notch portion on the one side and the deepest portion of the notch portion on the other side. It is characterized by that.

Here, “the deepest part of the notch” is, for example, the apex of the V-shape if the shape of the notch is V-shaped, and for example, the shape of the notch is U-shaped or If it is semicircular, it means the innermost part of the U or semicircle toward the inside of the ball circulation path.
According to the first aspect of the present invention, the dividing line that divides the ball circulation member into two ball circulation member constituting members has a notch portion generated at the base end portion of the scooping portion at the deepest portion of the notch portion, Each is divided in advance. Thereby, the notch part is not substantially formed in the scooping base end part which has conventionally been a problem of stress concentration. Therefore, even when an impact caused by a ball circulating in the ball circulation member acts on the ball scooping portion, the stress concentration at the scooping base end portion is alleviated. Therefore, the possibility of fatigue failure starting from the scooping base end portion is reduced. Therefore, if this ball circulating member is used for a ball screw, the high-speed operation performance and durability performance of the ball screw can be improved.

The dividing line is preferably formed with a gentle line. Thereby, the stress concentration in the scooping base end portion is further relaxed. Therefore, it is possible to more suitably reduce the risk of fatigue failure starting from the scooping base end.
Here, the ball circulating member according to the first aspect can suitably relieve stress concentration at the scooping base end portion, but the dividing line at the above position is based on the locus position of the ball center. In this case, it is formed at a position where the opposite side of the ball scooping part is shifted toward the scooping part side. That is, in the divided portion at the scooping base end portion, the peripheral wall of each ball circulation member constituting member does not uniformly hold the ball. Therefore, as a side effect, the ball restraining performance by the peripheral wall in the vicinity of the scooping base end may become unstable. Accordingly, the inventors of the present application have made extensive studies on a shape that relieves stress concentration at the scooping base end and stabilizes the ball restraining performance in the vicinity of the scooping base end. By setting the shape of the peripheral wall in the vicinity of the ball more effectively, the ball restraining performance aimed at was obtained.

That is, the invention according to claim 2 is the ball circulation member according to claim 1, wherein the two ball circulation member constituting members are outside the scooping base end portion of the other ball circulation member constituting member. It has the surrounding wall extension part which extended the surrounding wall so that it may cover.
According to the invention described in claim 2, the two ball circulation member constituting members are combined with each other so that one of them covers the other even if the ratio of the peripheral walls surrounding the balls is different. Become. Thereby, the ball | bowl restraint performance by the surrounding wall in the vicinity of the scooping base end part can be stabilized.

According to a third aspect of the present invention, a ball screw includes the ball circulation member according to the first or second aspect.
According to the invention described in claim 3, it is possible to provide a ball screw that exhibits the action and effect of the ball circulation member according to claim 1 or 2.

  According to the present invention, it is possible to provide a ball circulating member capable of improving high-speed driving performance and durability performance, and a ball screw including the ball circulating member.

Embodiments of the present invention will be described below with reference to the drawings as appropriate. In addition, about the part similar to description with the ball screw mentioned above, the same code | symbol is attached | subjected and demonstrated also in description in each following embodiment.
First, a first embodiment of the present invention will be described.
FIG. 1 is an explanatory view for explaining a side cap type ball screw according to the present invention, and FIG. 2 is a radial sectional view in FIG. 1 for explaining an essential part thereof. 3 and 4 are views in the direction of arrow E in FIG. 2, respectively. FIG. 3 shows a nut before the side cap is attached, and FIG. 4 shows a state where the side cap according to the present invention is attached. Show.

As shown in FIGS. 1 and 2, the ball screw 10 includes a screw shaft 12 and a nut 14.
The screw shaft 12 has a spiral ball rolling groove 11 on the outer peripheral surface. The nut 14 has a spiral ball rolling groove 13 corresponding to the ball rolling groove 11 of the screw shaft 12 on the inner peripheral surface. The nut 14 is fitted to the screw shaft 12, and the ball rolling groove 13 of the nut 14 and the ball rolling groove 11 of the screw shaft 12 face each other, and the ball raceway 8 is configured between the two. Has been. The ball raceway 8 is loaded with a plurality of balls 15 as rolling elements so as to roll.

Further, as shown in FIG. 3, the nut 14 has a side cap attachment surface 16 formed of a rectangular flat surface on the outer peripheral surface thereof. A pair of long holes 20 are formed in the side cap mounting surface 16. The long hole 20 is drilled in communication with the ball raceway 8 formed between the ball rolling grooves 11 and 13.
As shown in FIG. 4, a side cap 17 as a ball circulation member is attached to the side cap attachment surface 16. Here, the side cap 17 has a pair of leg portions 19, and the pair of leg portions 19 is perpendicular to the screw shaft 12 in the long hole 20 formed in the side cap mounting surface 16. Therefore, it can be fitted with almost no gap (see FIG. 1). Then, as shown in FIG. 4, the entire side cap 17 is pressed toward the side cap mounting surface 16 by the lid-shaped side cap cover 26 covering the entire side cap 17, and is attached to the nut 14 by the set screw 18. .

  Here, a ball scooping (returning) passage 21 is formed in the side cap 17 inside the leg portion 19 (see FIG. 2). The ball scooping (returning) passage 21 is formed by inclining the continuous direction of the passage with respect to the outer peripheral wall surface of the leg portion 19. And it inclines in the direction along the circulation passage direction of a ball | bowl, and is formed. The ball scooping (returning) passage 21 communicates with the ball feeding passage 22, and the ball feeding passage 22 and the pair of ball scooping (returning) passages 21 constitute a ball circulation passage 27.

  That is, as shown in FIGS. 2 and 4, the side cap 17 has a ball circulation formed of an integral structure along the continuous direction of the ball circulation passage 27 by the ball scooping (returning) passage 21 and the ball feed passage 22. While forming the passage 27 and having a structure in which the leg 19 can be easily fitted into the long hole 20 formed in the side cap mounting surface 16, the ball scooping up (returning) formed in the leg 19 is made. ) A three-dimensional configuration in which the traveling direction of the ball 15 in the passage 21 can be scooped up in a direction substantially tangential to the screw shaft 12 and in a direction substantially coincident with the lead angle of both the ball rolling grooves 11 and 13. Yes. Therefore, the processing of the nut 14 is simple, and the design flexibility of the ball circulation passage 27 (that is, the ball scooping (returning) passage 21 and the ball feeding passage 22) can be improved.

The ball circulation passage 27 and the ball raceway 8 constitute an infinite circulation passage for the ball 15. Note that, for example, an output shaft of a motor (not shown) can be connected to one end of the screw shaft 12 via a coupling, whereby the nut 14 rotates the ball 15 by the rotation of the screw shaft 12. It is movable in the axial direction through movement.
Next, the divided structure of the side cap 17 will be described in detail. 5 and 6 are explanatory views showing the side cap according to the present invention, FIG. 5 is an explanatory perspective view of the side cap, and FIG. 6 is one side cap constituent member obtained by dividing the side cap. FIG.

The side cap 17 is manufactured by resin molding, and as shown in FIG. 5, for example, a side cap constituent member 23, 23 which is a pair of ball circulation member constituent members formed by molding a resin material is combined. Has been. Here, the line indicated by the symbol PL in the figure indicates a dividing line that divides the ball circulation member 17 into the side cap constituent members 23.
As shown in FIG. 6, the side cap 17 is formed with a ball circulation passage 27 including a ball scooping (returning) passage 21 and a ball feeding passage 22 inside thereof, and is point-symmetric along the traveling direction of the ball 15. The side cap component member 23 is divided into two parts. Therefore, as shown in the figure, a split surface 23d (also a mutual mating surface) is generated at a portion where the side cap constituent members 23 are mutually divided by the dividing line PL.

Next, the dividing line PL (or dividing surface 23d) between the side cap constituent members 23 will be described in more detail. FIG. 7 is an explanatory view showing, in an enlarged manner, the main part of the dividing line of the side cap (the periphery of the F part in FIG. 6). In this figure, the scooping base end of the ball scooping part according to the present invention is shown. The example of the division | segmentation in the part is shown. 8 and 9 are explanatory views for explaining the combined state of the peripheral walls in the vicinity of the scooping base end portion by the pair of side cap constituent members according to the present invention.
As described above, since the side cap 17 is divided into the two side cap constituent members 23 from the dividing line PL, the pair of side cap constituent members 23 and 23 each have a split surface (mating surface) 23d. (See FIG. 6).

  Incidentally, as shown in FIG. 7, the side cap 17 has a ball scooping portion 24 at the tip of the ball scooping (returning) passage 21 of the side cap 17. The ball scooping section 24 smoothly scoops up the ball 15 rolling in the ball raceway 8 from the ball raceway 8 to the ball scooping (returning) passage 21, and the ball rolling groove 11 of the screw shaft 12. Is formed so as to protrude from the ball scooping (returning) passage 21 toward the ball rolling groove 11. Therefore, the scooping base end portion 24a, which is a portion connecting the ball scooping (returning) passage 21 formed in the leg 19 and the ball scooping portion 24, has, for example, a V-shaped groove portion having an acute angle. The notch 25 is formed.

  Here, in the side cap 17 according to the present invention, as shown in FIG. 7, the dividing line PL is formed at a position passing through the deepest portion of each notch portion 25 of the pair of leg portions 19. That is, the position of the dividing line PL that divides the side cap 17 into the two side cap constituent members 23, 23 is set so that each notch 25 generated at the scooping base end 24a, that is, the notch 25 on one side. And the notch 25 on the other side are preliminarily divided at the V-shaped vertices to form the respective divided surfaces 23d.

  Further, the dividing line PL passing through each notch 25 has an arc in the vicinity of the scooping base end 24a, as shown by reference numeral 23f in FIG. The peripheral wall extension is set to connect gently. In other words, as shown in FIG. 6, the split surface 23d of the ball circulation member constituting member 23 is in the vicinity of the scooping base end portion 24a (the F portion shown in FIG. 6) at the scooping base end portion 24a. The parting line PL is shifted to the ball scooping portion 24 side with respect to the trajectory BCD of the center of the ball 15 in the ball raceway 8 on the side opposite to the ball scooping portion 24 (the leg 19 side in the figure). A peripheral wall extending portion 23f. For this reason, the split surface 23d at the scooping base end portion 24a is divided by the gentle ridge line by the peripheral wall extending portion 23f, so that the stress concentration at the scooping base end portion 24a can be more suitably mitigated. It has become. In addition, the code | symbol Z in the figure has shown the scooping point which scoops up the ball | bowl 15. FIG. In addition, in the division performed over the entire side cap 17, the dividing line PL in a portion other than the vicinity of the scooping base end portion 24a surrounds the circumference of the ball almost equally according to the locus of the ball center. Are set evenly.

Next, functions and effects of the ball screw 10 and the side cap 17 in the first embodiment of the present invention will be described.
As described above, in the ball screw 10, when the side cap 17 is attached to the side cap attachment surface 16 of the nut 14, the ball 15 rolling between the ball rolling grooves 11, 13 is lifted up by the side cap 17. The portion 24 is lifted up in the lead angle direction of the ball rolling grooves 11 and 13 and smoothly introduced into the ball feed passage 22. Therefore, in this ball screw 10, unlike the tube circulation type ball screw, even if the lead of the ball rolling groove increases, the traveling direction of the ball 15 hardly changes suddenly in the circulating portion of the ball 15. Therefore, when the ball 15 is scooped up, it is possible to suppress the damage of the ball 15 and the generation of noise and the like, and the number of circulation circuits of the ball is limited to the number of threads of the thread groove, for example, like an end cap type ball screw. Since there are no restrictions, the load capacity can be increased without increasing the number of balls (number of turns) per circuit.

Further, in this ball screw 10, the side cap 17 is composed of a pair of ball circulation member constituting members 23, 23 divided into two along the traveling direction of the ball 15. It is possible to easily form the ball circulation passage 27 in the side cap 17 by resin molding or the like by scooping up the ball 15 in the direction coinciding with the lead angle and returning it to the initial position.
Further, the ball screw 10 is formed by combining the side cap 17 with a pair of side cap constituent members 23 and 23 having the same outer shape, so that the side cap constituent members 23 and 23 are molded with a single mold. Thus, the side cap 17 can be more easily manufactured.

  Furthermore, in this ball screw 10, the split surfaces 23 d of the side cap constituent members 23, 23 have the notch portions 25 at the scooping base end portion 24 a of the ball scooping portion 24 at the deepest of the notch portions. Each part is formed by a dividing line PL that is divided in advance. That is, the side cap 17 is formed at a position where the dividing line PL dividing the two side cap constituent members 23, 23 divides the notch 25 generated at the scooping-up base end 24 a in advance. Thereby, the notch 25 is not substantially formed in the scooping base end 24a, which has conventionally been a problem of stress concentration. Therefore, even when an impact caused by the ball 15 circulating in the side cap 17 acts on the side cap constituting member 23, fatigue starting from the scooping base end portion 24a or the vicinity of the scooping base end portion 24a. There is almost no risk of destruction. Therefore, the high-speed operation performance and durability performance of the ball screw 10 can be improved.

  Here, as described above, if the dividing line PL is divided from the deepest portion of each notch 25 at a position where the dividing line PL starts (and ends), that is, the notch 25 is formed at the scooping base end 24a. If it is divided so that it is not substantially formed, the stress concentration at the scooping base end portion 24a can be suitably mitigated. However, as a side effect, the split surface of the ball circulation member constituting member 23 is located at the center of the ball 15. Since the opposite side of the ball scooping portion 24 is shifted toward the ball scooping portion 24 with respect to the drawn ball trajectory, the performance of restraining the ball 15 by the peripheral wall in the vicinity of the scooping base end portion 24a May become unstable.

Then, next, as a second embodiment of the present invention, a shape that can relieve stress concentration at the scooping base end and stabilize ball restraining performance in the vicinity of the scooping base end will be described. .
Note that the second embodiment differs from the side cap 17 in the first embodiment described above only in the shape of the peripheral wall extension 23f, and otherwise the first described above. The configuration is the same as that of the embodiment. Therefore, only the shape of the peripheral wall extending portion 23f will be described here, and the other description will be omitted.

  In the side cap 17 of the second embodiment, as shown in FIGS. 8 to 9, the two side cap components 23 and 23 are different from the side cap 17 of the first embodiment described above. A peripheral wall extending portion 23f, which is a peripheral wall formed by shifting the dividing line PL, is extended so as to cover the outside of the scooping base end portion 24a of the other ball circulation member constituting member 23.

As a result, even if the two ball circulation member constituting members 23 and 23 are in the divided positions where the ratio of the peripheral wall surrounding the ball by the scooping base end portion 24a is different, one covers the other as shown in FIG. In this way, they are combined with each other. Therefore, the ball restraining performance by the peripheral wall in the vicinity of the scooping base end portion 24a can be stabilized. Note that the symbol O in the figure indicates the center position of the ball 15.
Thus, in the side cap 17 of the second embodiment, the peripheral wall extending portion 23f can be combined so as to cover the outside in the vicinity of the scooping base end portion 24a. Therefore, the ball restraining performance by the peripheral wall in the vicinity of the scooping base end portion 24a can also be stabilized.

  As described above, according to the ball screw 10 of the present invention, in the side cap 17 which is a ball circulation member, the strength of the scooping base end portion 24a having a low strength is improved at the ball scooping portion 24. The side cap 17 capable of improving the high-speed driving performance and the durability performance and the ball screw 10 including the side cap 17 can be provided.

In addition, the ball screw which concerns on this invention is not limited to said each embodiment, A various deformation | transformation is possible unless it deviates from the meaning of this invention.
For example, each of the above embodiments may further include a protrusion and a hole provided as positioning portions for mutual alignment with respect to the split surface (mating surface) 23d. Further, the side cap 17 may have a structure in which a side cap attachment hole for directly passing the set screw 18 is formed.

  Further, in each of the above embodiments, in the division performed over the entire side cap 17, the dividing line PL at a portion other than the vicinity at the scooping base end portion 24a is set equally according to the locus of the ball center. However, the present invention is not limited to this, and the positions of the dividing lines may not be equally divided. However, in order to stabilize the performance of restraining the ball by encircling the circumference of the ball substantially equally with respect to the ball, each of the ball circulation member constituent members is divided at a portion other than the vicinity of the scooping base end portion. The line PL is preferably set evenly according to the trajectory of the ball center.

Further, for example, in each of the above-described embodiments, the description has been given of the example in which the shape of the notch portion 25 formed in the scooping base end portion 24a is a V-shaped groove portion having an acute angle. The shape is not limited to a V-shaped groove. That is, the notch includes a “dent” such as a recess or a groove. For example, the shape of the notch may be U-shaped or semicircular.
Further, for example, in each of the above embodiments, the ball screw 10 has been described with an example in which the side cap 17 (side cap constituent members 23, 23) is formed of a resin. It may be formed of a sintered material such as, or may be molded by metal injection molding (MIM), and by using such a configuration, it can be used even under high temperature conditions that are not suitable for resin use.

It is explanatory drawing explaining the side cap type ball screw which concerns on this invention. It is radial direction sectional drawing in FIG. FIG. 3 is a view taken in the direction of arrow E in FIG. 2, and shows the nut before the side cap is mounted. FIG. 3 is a view taken in the direction of arrow E in FIG. 2, in which the side cap according to the present invention is attached. It is explanatory drawing which shows the side cap which concerns on this invention. It is explanatory drawing which shows the side cap structural member which concerns on this invention. It is explanatory drawing which expands and shows the principal part (F part in FIG. 6) of the dividing line of the side cap which concerns on this invention. It is explanatory drawing sectional drawing of the combined state of the surrounding walls in a scooping base end part. It is an explanatory perspective view of the combined state of the peripheral walls at the scooping base end. It is explanatory sectional drawing which looked at the side cap type ball screw from the radial direction. It is explanatory explanatory drawing which shows the side cap of a comparative example. It is explanatory drawing which expands and shows the principal part of the comparative example which matched the dividing line with the locus | trajectory of a ball center. It is explanatory explanatory drawing which shows the comparative example which divided | segmented the side cap according to the locus | trajectory of a ball | bowl center.

Explanation of symbols

8 Ball track 10, 100 Ball screw 11 Ball rolling groove 12 Screw shaft 13 Ball rolling groove 14 Nut 15 Ball 16 Side cap mounting surface (Ball circulating member mounting surface)
17, 170 Side cap (ball circulation member)
18 Set screw 19, 190 Leg 20 Long hole 21, 210 Ball scooping (returning) passage 22 Ball feed passage 23, 230 Side cap component (ball circulation member component)
23d Dividing surface 23f Peripheral wall extending part 24, 240 Ball scooping part 24a, 240a Scooping base end part 25 Notch part 26 Side cap cover 27 Ball circulation path PL, PL 'Dividing line

Claims (3)

A screw shaft having a ball rolling groove on the outer peripheral surface, a nut having a ball rolling groove on the inner peripheral surface facing the outer peripheral surface of the screw shaft, and both the ball rolling grooves of the nut and the screw shaft are configured. A ball scooping part that scoops up the ball in the ball raceway from one side, and scooped up by the ball scooping part A ball circulation passage for returning the ball from the other side into the ball raceway, and a notch in a scooping base end portion, which is a portion where the integrally formed ball scooping portion and the ball circulation passage are connected A ball circulation member having a portion,
The ball circulation member is configured to include two ball circulation member constituent members divided along a parting line extending in the traveling direction of the ball passing through the inside,
The ball circulation member, wherein the dividing line passes through a deepest portion of the cutout portion on the one side and a deepest portion of the cutout portion on the other side.   2. The two ball circulation member constituting members include a peripheral wall extending portion that extends a peripheral wall so as to cover an outside of the scooping base end portion of the other ball circulation member constituting member. The ball circulation member according to 1.   A ball screw comprising the ball circulation member according to claim 1.

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