JP2004084822A - Ball spline device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball spline device which prevents the generation of noise and vibration due to a position displacement of end caps. <P>SOLUTION: The end caps 20 and 21 are respectively provided with a cylindrical inlay part 26 communicated with a ball deflector passage 23, and a ball return hole 24 provided in a spline nut 12 is provided with a fitting part 27 to be fitted to the inlay part 26. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ball spline device, and more particularly to an end cap type ball spline device.
[0002]
[Prior art]
Conventionally, as an end cap type ball spline device, for example, those disclosed in Japanese Patent Application Laid-Open No. 63-152718 and Japanese Utility Model Application Laid-Open No. 2-29317 have been known. As shown in FIGS. 8 and 9, this type of ball spline device includes a spline shaft 11 and a cylindrical spline nut 12, and the outer peripheral surface of the spline shaft 11 has ball spline grooves 13, 14,. 15 (see FIG. 9 for the ball spline groove 15) is formed along the axial direction of the spline shaft 11.
[0003]
These ball spline grooves 13 to 15 are opposed to the ball spline grooves 16, 17, 18 (see FIG. 9) formed on the inner peripheral surface of the spline nut 12, respectively, and are provided between these opposed ball spline grooves. Is provided with a number of balls 19 forming a ball row.
The ball spline device shown in FIG. 8 is provided with annular end caps 20 and 21 at both ends of the spline nut 12, and these end caps 20 and 21 are provided with balls as shown in FIGS. A tongue portion 22 for scooping up the ball 19 is provided corresponding to the ball spline grooves 16 to 18, and a ball deflecting path 23 for deflecting the rolling direction of the ball 19 scooped up by the tongue portion 22 in a predetermined direction is provided. It is formed corresponding to the spline grooves 16-18.
[0004]
The ball deflecting path 23 communicates with a ball return hole 24 opening at the end face of the spline nut 12, and the ball 19 scooped up by the tongue portion 22 passes through the ball deflecting path 23 of the end cap 20, for example. It is designed to be introduced into 12 ball return holes 24. After the ball 19 introduced into the ball return hole 24 rolls in the ball return hole 24, the ball 19 is returned to the original position via the ball deflection path 23 of the end cap 21, for example. The end caps 20 and 21 are provided with mounting holes 25 (see FIG. 10) for mounting the end caps 20 and 21 to the end faces of the spline nut 12 by bolts (not shown).
[0005]
FIG. 12 shows an end face of the spline nut 12. As shown in FIG. 12, the return guide 32 of the end caps 20 and 21 is pressed against the end face of the spline nut 12. The return guide 32 is formed in a semi-cylindrical shape.
[0006]
[Problems to be solved by the invention]
In such a ball spline device, a circulation path for the ball 19 can be formed by the ball deflection path 23 formed in the end caps 20 and 21 and the ball return hole 24 penetrated through the spline nut 12. Had such a problem. That is, in the ball spline device described above, for example, if the center of the end cap 20 is slightly displaced from the center of the spline nut 12 when the end cap 20 is attached to the end face of the spline nut 12, the ball deflection In some cases, the ball 19 passing through the path 23 collides with the opening of the ball return hole 24, generating noise, vibration, and the like.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a ball spline device that can prevent generation of noise, vibration, and the like due to misalignment of an end cap. It is in.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a spline shaft having a ball spline groove on an outer peripheral surface, a spline nut having an inner peripheral surface with a ball spline groove opposed to the ball spline groove of the spline shaft, and the spline shaft. Alternatively, the spline nut includes a plurality of balls rolling in the ball spline groove by linear motion, and end caps disposed at both ends of the spline nut, and a circulation path of the ball is provided through the spline nut. In a ball spline device formed by a ball return hole and a ball deflection path formed in the end cap, a cylindrical spigot portion that communicates with the ball deflection path is provided in the end cap, and the spigot hole is formed in the ball return hole. A fitting portion for fitting with the portion is provided.
[0009]
According to such a configuration, since the ball that has passed through the ball deflection path of the end cap is introduced into the ball return hole via the spigot portion, the end cap can be prevented from being displaced, and the ball that has passed through the ball deflection path can be removed. Collision with the opening of the ball return hole can be avoided. Therefore, it is possible to prevent noise, vibration, and the like due to the displacement of the end cap.
[0010]
In this case, when the ball deflection path is formed by the end cap and a return guide that forms return guide grooves at both ends of the spline nut, a mold such as injection molding is formed. Since the used molding can be performed, the end cap can be manufactured at low cost. Further, when the cross-sectional shape of the return guide groove is at least the same as the cross-sectional shape of the ball spline groove at a connection portion with the ball spline groove as in the invention according to claim 3, when the ball changes direction, Since the collision with the end face of the spline nut is suppressed, generation of noise, vibration, and the like can be prevented, and operability can be improved.
[0011]
Further, as in the invention according to claim 4, the spigot portion may have an inner diameter surface having the same diameter as the hole diameter of the ball return hole. A step can be prevented from being formed between the return hole and the hole. Further, a spacer may be arranged between the balls as in the invention according to claim 5, and by adopting such a configuration, it is possible to prevent the occurrence of noise, malfunction and the like due to the competition between the balls. And the spacer can be prevented from being caught.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same parts as those shown in FIGS. 8 to 12 are denoted by the same reference numerals, and detailed description of those parts will be omitted because they are duplicated.
1 to 6 show a first embodiment of the present invention, and FIG. 1 is a schematic cross-sectional view along the axial direction of a ball spline device according to the first embodiment of the present invention. As shown in the figure, the ball spline device according to the first embodiment of the present invention has end caps 20 and 21 at both ends of a spline nut 12, and the end caps 20 and 21 have end cap side end faces. As shown in FIGS. 2 and 3, a cylindrical spigot portion 26 is provided corresponding to the tongue portion 22. The spigot portion 26 communicates with a ball deflecting path 23 formed in the end caps 20, 21 and has an inner diameter surface 26a having the same diameter as the diameter of the ball return hole 24 formed through the spline nut 12 (see FIG. 3). have.
[0013]
FIG. 4 is a perspective view showing an end surface portion of the spline nut 12. As shown in FIG. 4, a fitting portion 27 that fits with the outer diameter surface of the spigot portion 26 is provided in the ball return hole 24. It is provided at both ends. The end caps 20 and 21 are composed of an annular end cap body 28 and a number of return guides 29 corresponding to the ball return holes 24 of the spline nut 12 as shown in FIG. Each return guide 29 is formed with a return guide groove 29 a for guiding the ball 19 picked up from the ball spline groove of the spline nut 12 to the ball return hole 24 of the spline nut 12. Further, in the present embodiment, as shown in FIG. 3, the spigot portion 26 is divided into two semi-cylindrical shapes.
[0014]
FIG. 5 is a perspective view showing a part of the spline shaft 11 located in the spline nut 12. As shown in FIG. 5, a spacer 30 made of a buffer material such as resin is provided between the balls 19. I have. The spacer 30 is formed in a disk shape with a diameter smaller than the diameter of the ball 19, and rolling element contact surfaces 30a and 30b are formed on both end surfaces thereof as shown in FIG. These rolling element contact surfaces 30a and 30b have a radius of curvature R larger than the radius r of the ball 19, and the cross section along the axial direction of the spacer 30 is formed in a gothic arch or arc shape.
[0015]
As described above, if the end caps 20 and 21 are provided with the cylindrical spigot portion 26 communicating with the ball deflection path 23 and the ball return hole 24 is provided with the fitting portion 27 that fits the spigot portion 26, Since the ball scooped up by the tongue portion 22 of the cap 20 passes through the ball deflection path 23 and is introduced into the ball return hole 24 via the spigot portion 26, it is possible to prevent the end cap 20 from being misaligned, The collision of the ball 19 passing through the deflection path 23 with the opening of the ball return hole 24 can be avoided. Therefore, it is possible to prevent the occurrence of noise, vibration, and the like due to the displacement of the end cap, and it is possible to reduce the noise and vibration of the ball spline device.
[0016]
In the above-described embodiment, since the spigot portion 26 has the inner diameter surface 26a having the same diameter as the hole diameter of the ball return hole 24, a step is generated between the inner diameter surface 26a of the spigot portion 26 and the ball return hole 24. It is also possible to prevent noise and vibration of the ball spline device from being reduced more effectively.
Further, in the above-described embodiment, since the spacers 34 are provided between the balls 19, it is possible to prevent the occurrence of noise, malfunction and the like due to the competition between the balls, and to prevent the spacers from being caught. can do.
[0017]
Note that the present invention is not limited to the embodiment described above. For example, in the first embodiment, the end caps 20 and 21 are each constituted by an annular end cap body 28 and a number of end caps 29 corresponding to the ball return holes 24 of the spline nut 12, as shown in FIG. As in the second embodiment, each of the end caps 20 and 21 may be constituted by an annular end cap body 28 and an annular end cap 31. Further, as a spacer arranged between the balls 19, a connection type spacer may be used.
[0018]
【The invention's effect】
As described above, according to the first aspect of the present invention, it is possible to prevent the occurrence of noise, vibration, and the like due to the displacement of the end cap, and to reduce the noise and vibration of the ball spline device. Can be.
According to the second aspect of the present invention, since molding using a mold such as injection molding becomes possible, in addition to the above-described effects, the end cap can be manufactured at low cost.
[0019]
According to the invention of claim 3, since the collision of the ball with the end face of the spline nut when the direction is changed is suppressed, it is possible to prevent the generation of noise, vibration and the like, and to improve the operability. Can be.
According to the fourth aspect of the present invention, it is possible to prevent a step from being formed between the inner diameter surface of the spigot portion and the ball return hole, and it is possible to more effectively reduce the noise and vibration of the ball spline device. .
According to the fifth aspect of the present invention, in addition to the effects of the first aspect of the present invention, it is possible to prevent the occurrence of noise, malfunction and the like due to the competition between the balls, and to prevent the spacer from being caught. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view along an axial direction of a ball spline device according to a first embodiment of the present invention.
FIG. 2 is a front view of the end cap shown in FIG.
FIG. 3 is a perspective view showing a part of the end cap shown in FIG. 2;
FIG. 4 is a perspective view showing an end face portion of the spline nut shown in FIG. 1;
FIG. 5 is a perspective view showing a part of a spline shaft located in a spline nut.
FIG. 6 is a sectional view of the spacer shown in FIG. 5;
FIG. 7 is a sectional view along a radial direction of a ball spline device according to a second embodiment of the present invention.
FIG. 8 is a schematic sectional view along the axial direction of a conventional ball spline device.
9 is a schematic sectional view along a radial direction of the ball spline device shown in FIG.
FIG. 10 is a front view of the end cap shown in FIG. 8;
FIG. 11 is a perspective view showing a part of the end cap shown in FIG. 10;
FIG. 12 is a perspective view showing an end face of a spline nut in a conventional ball spline device.
[Explanation of symbols]
Reference Signs List 11 spline shaft 12 spline nut 13-18 ball spline groove 19 ball 20, 21 end cap 22 tongue 23 ball deflection path 24 ball return hole 25 mounting hole 26 spigot 27 fitting portion 28 end cap main body 29, 31 return guide 29a Return guide groove 30 Spacer

Claims (5)

A spline shaft having a ball spline groove on the outer peripheral surface; a spline nut having a ball spline groove on the inner peripheral surface facing the ball spline groove of the spline shaft; and the ball spline groove by linear motion of the spline shaft or the spline nut. A plurality of balls for rolling the ball, and end caps disposed at both ends of the spline nut, and a ball return hole formed in the spline nut through a circulation path of the ball and a ball formed in the end cap. In the ball spline device formed with the deflection path,
A ball spline device, wherein the end cap is provided with a cylindrical spigot portion communicating with the ball deflection path, and the ball return hole is provided with a fitting portion that fits with the spigot portion. The ball spline device according to claim 1, wherein the ball deflection path is formed by the end cap and a return guide that forms return guide grooves at both ends of the spline nut. 3. The ball spline device according to claim 2, wherein the cross-sectional shape of the return guide groove is the same as the cross-sectional shape of the ball spline groove at least at a connection portion with the ball spline groove. 4. The ball spline device according to claim 1, wherein the spigot portion has an inner diameter surface having the same diameter as a diameter of the ball return hole. 5. The ball spline device according to any one of claims 1 to 4, wherein a spacer or a connected body thereof is arranged between the balls.

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