JP2007182907A - Ball screw device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball screw device which suppresses the production of vibration and noise due to floating-up of a return tube. <P>SOLUTION: In the ball screw device, a return tube 17 for returning to a ball load rolling passage 16 a ball 15 rolling on the load rolling passage 16, is fixed onto the plane part 12a formed on the outer peripheral surface of a ball screw nut 12 by a return tube presser 18 and a tube pressure fixing screw 19. A reinforcing rib 24 is provided to the surface part of the return tube presser 18 on an opposite side of the return tube 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ball screw device called a return tube type.

  A ball screw device called a return tube type generally has a ball screw shaft and a ball having a spiral ball rolling groove facing a spiral ball rolling groove formed on the outer peripheral surface of the ball screw shaft. A screw nut, and a ball load rolling path formed between the ball screw shaft and the ball rolling groove of the ball screw nut, and a number of balls that roll with the rotational movement of the ball screw shaft or the ball screw nut. The ball rolling on the ball load rolling path is returned to the ball load rolling path through a return tube attached to the ball screw nut.

When attaching the return tube of such a ball screw device to the ball screw nut, conventionally, a return tube presser as shown in FIG. 17 is used as a part for pressing the return tube to a flat portion formed on the outer peripheral surface of the ball screw nut. Used to attach the return tube to the ball screw nut. However, since the return tube press shown in FIG. 17 is formed by cutting a columnar body made of metal, there is a problem that a large processing cost is required for manufacturing the return tube press. Therefore, it has been studied to manufacture a return tube press by pressing a metal plate with a male die and a female die (see, for example, Patent Document 1).
JP 2004-69017 A

  However, when a return tube presser is manufactured by press-molding a metal plate with a male die and a female die, sufficient strength cannot be secured if the metal plate to be press-formed is thin. There was a possibility that deformation that would allow the return tube presser occurred, causing vibration and noise. On the other hand, when the metal plate is thick, there is a problem that it is difficult to accurately form the return tube presser.

  The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide a ball screw device capable of suppressing the generation of vibration and noise caused by the rising of the return tube. Another object of the present invention is to provide a method of manufacturing a return tube presser for a ball screw that can manufacture a return tube presser having sufficient strength even when the metal plate to be press-formed is thin. It is in.

  In order to solve the above-described problems, a ball screw device according to the first aspect of the present invention includes a ball screw shaft and a spiral facing a spiral ball rolling groove formed on an outer peripheral surface of the ball screw shaft. A ball screw nut having a ball-shaped ball rolling groove, and a ball load rolling path formed between the ball rolling groove of the ball screw shaft and the ball rolling groove of the ball screw nut. A number of balls that roll with the rotational movement of the ball screw nut, a return tube that returns the ball that has rolled on the ball load rolling path to the ball load rolling path, and the return tube that is the ball screw nut A return tube presser that is pressed against a flat surface formed on the outer peripheral surface of the tube, and a plurality of tube presser fixing screws that fix the return tube presser to the flat surface of the ball screw nut. The return tube presser is a ball screw device formed by press-molding a metal plate, and the return tube presser has a rib formed by press-molding on the surface portion opposite to the return tube. It is characterized by.

A ball screw device according to a second aspect of the present invention is the ball screw device according to the first aspect, wherein the pair of left and right plate portions fixed to the flat portion of the ball screw nut by the tube holding screw are provided. The return tube presser has a feature.
A ball screw device according to a third aspect of the present invention is the ball screw device according to the second aspect, wherein between the one plate portion of the pair of left and right plate portions and the flat portion of the ball screw nut. The return tube presser is formed by press-molding the metal plate so that a gap corresponding to the plate thickness of the return tube presser is formed.

A ball screw device according to a fourth aspect of the present invention is the ball screw device according to any one of the first to third aspects, wherein the height of the rib is 1/5 of the plate thickness of the return tube presser. It is characterized by being -2 times.
A ball screw device according to a fifth aspect of the present invention is the ball screw device according to any one of the first to fourth aspects, wherein the metal plate is a hardened metal plate. To do.

  A ball screw device according to a sixth aspect of the present invention is the ball screw device according to any one of the second to fifth aspects, wherein one of the pair of left and right plate portions includes a presser plate and a tube. It is fixed to the flat surface portion of the ball screw nut by the presser fixing screw, and the other plate portion is fixed to the upper surface portion of the seat plate arranged on the flat surface portion of the ball screw nut by the tube presser fixing screw. Features.

A ball screw device according to a seventh aspect of the present invention is the ball screw device according to the sixth aspect, wherein the upper and lower surfaces of the pair of left and right plate portions are finished to a rough surface, The lower surface portion of the presser plate is finished to have a rough surface.
The ball screw device according to an eighth aspect of the present invention is the ball screw device according to the sixth aspect, wherein a rotation-preventing concave portion is provided on a lower surface portion of one plate portion of the pair of left and right plate portions, An anti-rotation convex portion that fits into the anti-rotation concave portion is provided on the upper surface of the seat plate.

A ball screw device according to a ninth aspect of the present invention is the ball screw device according to any one of the first to eighth aspects, wherein the return tube presser moves the central portion of the return tube to the ball screw nut. It has a tube pressing surface to be pressed on the flat portion, and the tube pressing surface is formed in an arc shape, a Gothic arch shape or a non-curved surface shape.
The ball screw return tube retainer manufacturing method according to claim 10 of the present invention is a method of manufacturing a ball screw return tube retainer by press-molding a metal plate with a male mold and a female mold, When the metal plate is press-molded, a convex portion for forming reinforcing and reinforcing ribs is formed in the central portion of the male mold, and a concave portion that fits the convex portion is formed in the central portion of the female mold. It is characterized by leaving.

According to the ball screw device of the present invention, deformation that allows the return tube to lift is less likely to occur in the return tube presser, so that it is possible to suppress the occurrence of vibration and noise due to the lift of the return tube.
According to the ball screw return tube press manufacturing method according to the present invention, the reinforcing rib is formed at the time of press molding the metal plate, and deformation that allows the return tube to lift is less likely to occur in the return tube press. Even when the metal plate to be press-formed is thin, a return tube presser having sufficient strength can be manufactured.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, reference numeral 10 denotes a ball screw device according to a first embodiment of the present invention, and this ball screw device 10 includes a ball screw shaft 11 and a ball screw nut 12. On the outer peripheral surface of the ball screw shaft 11, a spiral ball rolling groove 13 is continuously formed from one end portion to the other end portion of the ball screw shaft 11. The ball rolling groove 13 is opposed to a spiral ball rolling groove 14 formed on the inner peripheral surface of the ball screw nut 12, and a large number of balls are formed between the ball rolling groove 13 and the ball rolling groove 14. Ball 15 is provided.

The ball 15 rolls on a ball load rolling path 16 formed between the ball rolling grooves 13 and 14 as the ball screw shaft 11 or the ball screw nut 12 rotates. The ball 15 rolling on the path 16 is returned to the ball load rolling path 16 through a return tube 17 attached to the ball screw nut 12.
The return tube 17 is formed by bending a tubular body made of metal into a U-shape, and the return tube 17 has a central portion at a flat portion 12 a formed on the outer peripheral surface of the ball screw nut 12 and a return tube presser 18. It is pressed by. Note that two tube insertion holes (not shown) into which end portions of the return tubes 17 are inserted are formed at predetermined positions on the flat surface portion 12a of the ball screw nut 12, respectively.

The return tube presser 18 has a pair of left and right plate portions 181 and 181 (see FIGS. 2 and 3). Each of these plate portions 181 and 181 is fixed to the flat surface portion 12a of the ball screw nut 12 by means of a tube retainer fixing screw 19, and the upper surface portion and the lower surface portion of each plate portion 181 are finished to a rough surface. .
Further, the return tube retainer 18 is carburized so that a gap corresponding to the plate thickness of the return tube retainer 18 is formed between the plate portion 181 on the right side in FIG. 2 and the flat portion 12a of the ball screw nut 12. As shown in FIG. 3, the first reinforcing member is formed on the surface portion of the return tube presser 18 on the opposite side of the return tube 17 by press molding a metal plate that has been subjected to a hardening process such as nitriding. The ribs 24 and the second reinforcing ribs 25 are provided at predetermined positions. Further, the return tube presser 18 has a tube presser surface 182 that presses the center portion of the return tube 17 onto the flat surface portion 12 of the ball screw nut 12, and this presser surface 182 is formed in an arc shape with a single radius of curvature. Has been.

  Of the pair of left and right plate portions 181 and 181 of the return tube retainer 18, the right plate portion 181 in FIG. 2 is placed on the upper surface of the seat plate 21 (see FIG. 2) disposed on the flat surface portion 12a of the ball screw nut 12. It is fixed by a fixing screw 19, and a detent recess 22 (see FIG. 4) is formed on the lower surface of the right plate 181 in FIG. On the other hand, the left plate portion 181 in FIG. 2 is pressed against the flat surface portion 12 a of the ball screw nut 12 by the presser plate 20. The presser plate 20 is made of a metal such as steel, and the lower surface portion of the presser plate 20 has a rough surface.

The seat plate 21 is made of a metal such as steel like the press plate 20, and an anti-rotation convex portion 23 (FIG. 5) fitted on the upper surface portion of the seat plate 21 with the anti-rotation concave portion 22 of the return tube presser 18. Reference) is formed.
The first reinforcing rib 24 and the second reinforcing rib 25 are formed by press molding, and the height thereof is about 1/5 to 2 times the thickness of the return tube presser 18. Further, the first reinforcing rib 24 is formed at the center of the return tube presser 18, and the second reinforcing rib 25 is an upper surface portion of the right plate portion 181 in FIG. 3 of the pair of left and right plate portions 181 and 181. Is formed.

  When the height of the reinforcing ribs 24 and 25 is less than 1/5 of the plate thickness of the return tube presser 18, a sufficient strength improvement effect can be obtained when the strength increase rate by providing the reinforcing rib is 10% or less. If the height of the reinforcing ribs 24, 25 exceeds twice the plate thickness of the return tube presser 18, the rise of the reinforcing ribs becomes abrupt, and the bottom surface of the reinforcing rib and the return tube presser In this embodiment, the height of the reinforcing ribs 24 and 25 is set to 1/5 to 2 of the plate thickness of the return tube presser 18 because the stress at the time of the press work becomes excessive at the intersection of the planes and cracks may occur. About double.

  As described above, when the reinforcing ribs 24 and 25 are provided on the surface portion of the return tube presser 18 opposite to the return tube 17, the return tube presser 18 is reinforced by the reinforcing ribs 24 and 25. Therefore, in the first embodiment described above, deformation that allows the return tube 17 to lift is less likely to occur in the return tube presser 18, so that vibration and noise caused by the lift of the return tube 17 are suppressed. Can do.

  In addition, the upper and lower surfaces of the pair of left and right plate portions 181 and 181 of the return tube presser 18 have a rough surface, and the lower surface of the press plate 20 has a rough surface. Since the presser plate 20 does not rotate around the axis perpendicular to the plate portion 181 of the return tube presser 18 even when the rotation moment is applied, the tube presser fixing screw 19 is loosened by the rotation of the presser plate 20. Can be prevented.

  Further, a rotation-preventing concave portion 22 is provided on the lower surface portion of one plate portion 181 of the pair of left and right plate portions 181 and 181 of the return tube presser 18, and the rotation-preventing convex portion 23 is fitted to the rotation-preventing concave portion 22. Is provided on the upper surface of the seat plate 21 so that the plate portion 181 of the return tube retainer 18 can rotate about an axis perpendicular to the seat plate 21 even if a rotational moment acts on the return tube retainer 18. Therefore, loosening of the tube retainer fixing screw 19 due to the rotation of the return tube retainer 18 can be prevented.

  In the first embodiment described above, the tube pressing surface 182 of the return tube pressing member 18 is formed in an arc shape with a single radius of curvature. However, the present invention is not limited to this. For example, as shown in FIG. The tube retainer surface 182 of the tube retainer 18 may be formed in a Gothic arch shape (a shape in which two arc surfaces are combined in a Gothic arch shape), or the tube retainer surface of the return tube retainer 18 as shown in FIG. 182 may be formed into a non-curved surface.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In FIG. 8, reference numeral 30 denotes a ball screw device according to a second embodiment of the present invention, and this ball screw device 30 includes a ball screw shaft 11 and a ball screw nut 12. On the outer peripheral surface of the ball screw shaft 11, three spiral ball rolling grooves 13 are formed continuously from one end to the other end of the ball screw shaft 11. These ball rolling grooves 13 are respectively opposed to spiral ball rolling grooves 14 formed on the inner peripheral surface of the ball screw nut 12, and between the ball rolling grooves 13 and the ball rolling grooves 14. A number of balls 15 are provided.

  The ball 15 rolls on a ball load rolling path 16 formed between the ball rolling grooves 13 and 14 as the ball screw shaft 11 or the ball screw nut 12 rotates. The ball 15 that has rolled on the path 16 passes through one of the three return tubes 17 (see FIGS. 8 and 9) attached to the ball screw nut 12 (see FIGS. 8 and 9). It is supposed to be returned to.

The return tube 17 is formed by bending a tubular body made of metal into a U shape,
The center portion of each return tube 17 is pressed against a flat surface portion 12 a formed on the outer peripheral surface of the ball screw nut 12 by a return tube presser 18. Note that six tube insertion holes (not shown) into which the end portions of the return tubes 17 are inserted are formed at predetermined positions on the flat surface portion 12a of the ball screw nut 12, respectively.
The return tube presser 18 has a pair of left and right plate portions 181 and 181 (see FIGS. 10 and 11). Each of these plate portions 181 and 181 is fixed to the flat surface portion 12a of the ball screw nut 12 by means of a tube retainer fixing screw 19, and the upper surface portion and the lower surface portion of each plate portion 181 are finished to a rough surface. .

  In addition, the return tube presser 18 is carburized so that a gap corresponding to the plate thickness of the return tube presser 18 is formed between the plate portion 181 on the right side in FIG. 11 and the flat portion 12a of the ball screw nut 12. As shown in FIG. 10, the first reinforcing member is formed on the surface portion of the return tube presser 18 on the opposite side of the return tube 17 by press molding a metal plate that has been subjected to a hardening process such as nitriding. The ribs 24 and the second reinforcing ribs 25 are provided at predetermined positions. Further, the return tube presser 18 has a tube presser surface 182 that presses the center portion of the return tube 17 onto the flat surface portion 12 of the ball screw nut 12, and this presser surface 182 is formed in an arc shape with a single radius of curvature. Has been.

  The retainer plate 20 (see FIG. 9) for retaining the plate portion 181 of the return tube retainer 18 against the flat surface portion 12a of the ball screw nut 12 is made of metal such as steel, and the lower surface portion of the retainer plate 20 is finished to a rough surface. ing. The seat plate 21 (see FIG. 9) interposed between the flat portion 12a of the ball screw nut 12 and the plate portion 181 of the return tube retainer 18 is made of a metal such as steel, like the retainer plate 20. On the upper surface portion of the seat plate 21, a rotation prevention convex portion that fits with a rotation prevention concave portion 22 (see FIG. 12) of the return tube presser 18 is formed.

The first reinforcing rib 24 and the second reinforcing rib 25 are formed by press molding. The first reinforcing rib 24 is formed at the center of the return tube presser 18, and the second reinforcing rib 25 is formed. Is formed on the right plate portion 181 in FIG. 10 of the pair of left and right plate portions 181 and 181.
In the ball screw device according to the second embodiment of the present invention configured as described above, by providing the reinforcing ribs 24 and 25 on the surface portion of the return tube presser 18 on the side opposite to the return tube 17, the return tube is provided. The presser foot 18 is reinforced by the reinforcing ribs 24 and 25. Accordingly, deformation that allows the return tube 17 to lift is less likely to occur in the return tube presser 18, so that generation of vibration and noise due to the lift of the return tube 17 can be suppressed.

Next, with reference to FIGS. 13-16, the manufacturing method of the return tube holder for ball screws which concerns on this invention is demonstrated.
FIG. 13 is a view showing an example of a return tube presser manufactured by the ball screw return tube presser manufacturing method according to the present invention. When the return tube presser 18 shown in FIG. A rectangular metal plate 31 (see FIG. 14) that has been subjected to a curing process such as a process or a nitriding process is prepared. Next, as shown in FIG. 15, after setting the metal plate 31 between the male mold 32 and the female mold 32 of the press molding machine, the press molding machine is operated to press-mold the metal plate 31. At the time, a wide protrusion 34 (see FIGS. 15 and 16) for forming a reinforcing rib is formed at the center of the male mold 32 so as to be orthogonal to the longitudinal direction of the metal plate 31, and fitted with the protrusion 34. A wide concave portion 35 (see FIG. 15) to be joined is formed in the central portion of the female mold 33. The height of the convex portion 34 and the depth of the concave portion 35 are not particularly limited, but are desirably about 1/5 to 2 times the thickness of the metal plate 31.

In this way, when the metal plate 31 is press-molded with the male mold 32 and the female mold 33 to produce a ball screw return tube presser, a wide convex portion 34 is formed at the center of the male mold 32. If the wide concave portion 35 that fits the convex portion 34 is formed in the central portion of the female die 33, the reinforcing rib 24 as shown in FIG. 13 is formed during the press molding of the metal plate 31. As a result, deformation that allows the return tube 17 to lift is less likely to occur in the return tube retainer 18, so that a return tube retainer having sufficient strength can be manufactured even when the thickness of the press-formed metal plate is thin. Can do.
In the above-described embodiment, a rectangular metal plate is exemplified as the metal plate used when manufacturing the return tube presser. However, the present invention is not limited to this, and for example, a square metal plate is used. Also good.

It is a figure showing a schematic structure of a ball screw device concerning a 1st embodiment of the present invention. It is sectional drawing which follows the II-II line of FIG. It is a top view of the return tube presser shown in FIG. FIG. 4 is a bottom view of the return tube presser shown in FIG. 3. FIG. 3 is a plan view and a side view of the seat plate shown in FIG. 2. It is a figure showing the 1st modification of a return tube presser. It is a figure which shows the 2nd modification of a return tube presser. It is a figure which shows schematic structure of the ball screw apparatus which concerns on the 2nd Embodiment of this invention. It is a perspective view of the return tube presser shown in FIG. It is a top view of the return tube presser shown in FIG. It is sectional drawing of the return tube clamp shown in FIG. It is a bottom view of the return tube presser shown in FIG. It is a figure which shows an example of the return tube press manufactured by the manufacturing method of the return tube press for ball screws which concerns on this invention. It is a figure which shows an example of the metal plate used for the manufacturing method of the return tube presser for ball screws which concerns on this invention. It is explanatory drawing for demonstrating the manufacturing method of the return tube presser for ball screws which concerns on this invention. It is a perspective view of the male type | mold shown in FIG. It is a perspective view which shows the prior art example of the return tube presser used when fixing the return tube of a ball screw apparatus to a ball screw nut.

Explanation of symbols

11 Ball screw shaft 12 Ball screw nut 13, 14 Ball rolling groove 15 Ball 16 Ball load rolling path 17 Return tube 18 Return tube presser 181 Plate part 19 Tube presser fixing screw 20 Presser plate 21 Seat plate 22 Recessed recess 23 Convex part for rotation prevention 31 Metal plate 32 Male mold 33 Female mold 34 Convex part 35 Concave part

Claims (10)

A ball screw shaft, a ball screw nut having a spiral ball rolling groove facing a spiral ball rolling groove formed on the outer peripheral surface of the ball screw shaft, and a ball rolling groove of the ball screw shaft; A number of balls that roll along a ball load rolling path formed between the ball screw nut and the ball rolling groove of the ball screw nut as the ball screw shaft or the ball screw nut rotates, and the ball load rolling A return tube for returning the ball that has rolled on the path to the ball load rolling path, a return tube presser that presses the return tube against a flat surface formed on the outer peripheral surface of the ball screw nut, and the return tube presser A plurality of tube presser fixing screws that are fixed to the flat surface of the screw nut, and the return tube presser is formed by press-molding a metal plate. Flip a device,
The ball screw device, wherein the return tube presser has a rib formed by press molding on a surface portion opposite to the return tube.   2. The ball screw device according to claim 1, wherein the return tube press has a pair of left and right plates fixed to the flat portion of the ball screw nut by the tube press fixing screw.   3. The ball screw device according to claim 2, wherein a gap corresponding to a plate thickness of the return tube presser is formed between one plate portion of the pair of left and right plate portions and a flat portion of the ball screw nut. In addition, the return tube presser is formed by press-molding the metal plate.   The ball screw device according to any one of claims 1 to 3, wherein a height of the rib is 1/5 to 2 times a plate thickness of the return tube presser.   The ball screw device according to any one of claims 1 to 4, wherein the metal plate is a hardened metal plate.   The ball screw device according to any one of claims 2 to 5, wherein one plate portion of the pair of left and right plate portions is fixed to a flat portion of the ball screw nut by a presser plate and a tube presser fixing screw. 2. The ball screw device according to claim 1, wherein the other plate portion is fixed to the upper surface portion of the seat plate disposed on the flat portion of the ball screw nut by the tube pressing fixing screw.   7. The ball screw device according to claim 6, wherein the upper and lower surfaces of the pair of left and right plates are finished on a rough surface, and the lower surface of the presser plate is finished on a rough surface. A ball screw device characterized by that.   The ball screw device according to claim 6, wherein a rotation-preventing concave portion is provided on a lower surface portion of one plate portion of the pair of left and right plate portions, and the rotation-preventing convex portion that is fitted to the rotation-preventing concave portion A ball screw device provided on an upper surface of a seat plate.   The ball screw device according to any one of claims 1 to 8, wherein the return tube presser has a tube presser surface that presses a central portion of the return tube against a flat portion of the ball screw nut, and the tube presser surface is A ball screw device characterized by being formed in an arc shape, a Gothic arch shape, or a non-curved surface shape.   A method of manufacturing a return screw for a ball screw by press-molding a metal plate with a male die and a female die, wherein when the metal plate is press-molded, a protrusion for forming a reinforcing rib is formed at the center of the male die. A method of manufacturing a return screw for a ball screw, wherein a recess is formed in a central portion of the female mold while a portion is formed.

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