JP2003269450A - Linear motion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the influence of a certain manufacturing error at a connecting portion between ball paths constituting a ball circulation path in a linear motion device having a ball circulation path and to smoothly circulate the balls. Enable. SOLUTION: The ball rolling passage 3 is constituted by a guide groove 1a of a guide rail 1 and a guide groove 2a of a slider body 2, an end cap 6 attached to the slider body 1 and a return guide 10. The ball rolling passage 3 is connected to the ball return passage curved portion 8 at the connecting portion.
Inclined portion 1 whose diameter increases toward the curved portion 8 of the ball return passage
3a 'is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in industrial machines and the like, and is a linear motion device such as a linear guide device, a ball screw device, a ball spline device, a linear ball bush device, etc., which has a circulating function of rolling elements (for example, balls). Regarding

[0002]

2. Description of the Related Art Conventionally, in the structure of a linear motion device of this type, a step in the radial direction is formed at each connection portion of a ball circulation path formed by connecting a plurality of ball paths so as to guide the circulation of the ball. It has been a challenge to suppress the occurrence of the occurrence of the ball as much as possible and to circulate the ball smoothly, but for that purpose, chamfering and tapering are applied to the connecting part of both and a high processing accuracy is required. Therefore, the cost was inevitably increased. Therefore, as a structure of the ball circulation path capable of reducing the radial step in the connecting portion caused by some manufacturing error, for example, a structure described in Japanese Patent Laid-Open No. 2000-161354 has been proposed.

In the linear guide device having the ball circulation function described in this publication, the connecting portion between the straight portion of the ball circulation passage in the slider body and the curved portion of the ball circulation passage in the end cap has a tip end of the circulation passage curved portion. A cylindrical convex portion that is provided so as to extend with respect to the circulation path straight line portion,
It is configured such that a cylindrical concave portion provided on the side of the linear portion of the circulation path corresponding to the cylindrical convex portion is fitted in the cage, and the tip of the inner peripheral surface of the cylindrical convex portion is The taper surface is formed so as to spread toward the opening side.

[0004]

However, in the linear guide device of the above-mentioned conventional example, as shown in FIG. 4, even when there is an error in the relative position dimensions of the straight line portion of the circulation path and the curved portion of the circulation path. The cylindrical convex portion 31 absorbs an error in the position dimension by causing elastic deformation such as bending, and it is possible to improve the adhesion between the slider main body 32 and the end cap 33, and at the same time, in the ball passage. Since the inner peripheral edge 35 of the tip portion that projects is tapered,
Although it is possible to mitigate a step that significantly impedes the circulation of the ball, it cannot be denied that the smooth circulation of the ball may be impeded depending on the degree of protrusion with respect to the ball passage surface.

Further, it is premised that the ball passage surfaces of the circulation path straight portion 34 and the circulation path curved portion 36 are aligned.
When a manufacturing error occurs such that the inner diameter of the convex portion 31 is relatively small with respect to the straight line portion 34 of the circulation path, the step D formed on the bottom side of the concave portion 37 may hinder the smooth circulation of the ball. Will be. That is, in the above-described conventional linear guide device, when a certain degree of manufacturing error occurs in the structure of the ball circulation path, a factor that hinders the smooth circulation movement of the ball is reliably suppressed or mitigated at the joint portion of the ball passage. Since it is difficult to do so, there is an unsolved problem that the ball or the holding piece may be caught, which may cause deterioration of both or increase in vibration and noise.

In the linear guide device, the balls are generally hard spheres, whereas the end caps and the return guides are often made of synthetic resin, so that some steps may occur due to plastic deformation or wear over time. Although it can be expected to eliminate the problem, in a ball screw, since the return tube is generally made of metal, it cannot be expected to eliminate the step over time. Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and while aiming to improve productivity by further relaxing the allowable manufacturing accuracy, it is possible to improve the productivity of the ball passage that constitutes the ball circulation passage. It is an object of the present invention to provide a high-quality linear motion device that enables a ball to smoothly circulate in a connecting portion.

[0007]

In order to achieve the above object, a linear motion device according to claim 1 of the present invention comprises an inner member having a guide groove, and an inner member facing the guide groove of the inner member. An outer member that has a guide groove that forms a rolling member rolling passage and is movable relative to the inner member, and a plurality of rolling member passages that include the rolling member rolling passage communicate with each other. In a linear motion device including a rolling element circulation path and a large number of rolling elements that are rotatably loaded in the rolling element circulation path, in each connecting portion of the rolling element passages in the rolling element circulation path, It is characterized in that an inclined portion whose diameter increases from one side to the other side is formed.

According to a second aspect of the present invention, in the linear motion device according to the first aspect, the rolling element circulation passage is formed in the rolling element rolling passage and the outer member connected to both ends thereof. It is characterized in that it is configured with a rolling element return passage that is formed. Further, in the linear motion device according to claim 3 of the present invention, in the invention of claim 2, the outer member is provided at a connecting portion of the rolling element return passage with the rolling element rolling passage, and at an end face to a tip. An engaging projection having an inclined outer peripheral surface with a smaller diameter and an inner cylindrical surface having a diameter larger than the inner diameter of the rolling element rolling passage is provided, and an engaging recess for engaging and holding the engaging projection is provided. An inclined inner peripheral surface portion is formed on the bottom side of the engagement recess so as to communicate with the guide groove and expand toward the rolling element return passage so as to engage with the inclined outer peripheral surface. The inclined portion is formed between the inner cylindrical surface of the engaging protrusion of the surface portion and the guide groove.

Further, in the linear motion device according to claim 4 of the present invention, in the invention of claim 2, the outer member is provided at a connecting portion of the rolling element return passage with the rolling element rolling passage,
The end face is provided with an engaging protrusion having an inclined outer peripheral surface whose diameter becomes smaller toward the tip and having an inner cylindrical surface having a diameter larger than the inner diameter of the rolling element rolling passage, and the engaging protrusion is engaged and held. An engaging recess and a cylindrical surface portion that is connected to the engaging recess and has a diameter smaller than the inner diameter of the engaging projection are provided. The bottom surface of the engaging recess communicates with the cylindrical surface portion and engages with the inclined outer peripheral surface. To form a slanted inner peripheral surface portion that expands in diameter toward the rolling element return passage, and to form the slanted portion between the inner cylindrical surface of the engaging protrusion and the cylindrical surface portion on the slanted inner peripheral surface portion. Is characterized by.

Still further, in the linear motion device according to a fifth aspect of the present invention, in the invention of the second aspect, the outer member has a main body forming a straight line portion of the rolling element return path, and both ends of the main body. And a cap having a curved portion having a diameter larger than the inner diameter of the linear portion of the rolling element return path disposed on the surface, and the inclined outer periphery having a smaller diameter toward the tip at a position facing the linear portion of the cap. An engaging protrusion having a surface formed on the tip side is formed, an engaging recess for engaging and holding the engaging protrusion is formed at a position facing the curved portion of the main body, and a bottom side of the engaging recess is formed. An inclined inner peripheral surface portion that communicates with the linear portion and expands in diameter toward the curved portion so as to engage with the inclined outer peripheral surface is formed, and the communication portion between the inclined inner peripheral surface portion and the inner surface of the engagement protrusion is formed. And the inclined portion is formed between the communicating portion with the straight portion and the communicating portion. There.

According to a sixth aspect of the present invention, in the linear motion device according to any one of the third to fifth aspects, the inclined outer peripheral surface of the engaging protrusion and the inclined inner peripheral surface of the engaging recess are conical. It is characterized in that it is formed in a planar shape. Further, in the linear motion device according to claim 7 of the present invention, in the invention according to any one of claims 3 to 5, the inclined outer peripheral surface of the engaging protrusion and the inclined inner peripheral surface of the engaging recess are formed into a trumpet shape. It is characterized by being formed.

Furthermore, the linear motion device according to claim 8 of the present invention is the linear motion device according to any one of claims 3 to 5, wherein the inclined outer peripheral surface of the engaging protrusion and the inclined inner peripheral surface of the engaging recess are ,
It is characterized by being shaped like a bowl. Further, in the linear motion device according to claim 9 of the present invention, in the invention according to any one of claims 1 to 8, a diameter difference between the rolling element passages of the inclined portion is 1% or more of an outer diameter of the rolling element 10 It is characterized by being set to a value of% or less.

Further, a linear motion device according to a tenth aspect of the present invention is the rolling element space according to any one of the first to ninth aspects, in which a rolling element contact surface is provided with a recessed portion between the rolling elements. It is characterized in that the holding member is inserted.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram in which a part of a linear guide device having a ball circulation function is broken. In the figure, 1 is a guide rail as an inner member formed in a substantially square pole shape, and 2 is provided so as to be movable relative to the guide rail 1 and has a substantially U-shaped cross section. And a slider body as an outer member.

Ball grooves 1a, which serve as guide grooves and are axially ground, are formed on both side surfaces of the guide rail 1, and axially ground so as to face the ball grooves 1a inside both sleeves of the slider body 2. Ball grooves 2a as guide grooves are respectively formed, and the ball rolling as a rolling element rolling passage formed in a substantially cylindrical cross section by the ball groove 2a and the ball groove 1a at a portion facing the ball groove 2a. The passage 3 is configured. The ball grooves 1a and 2a are Gothic arch grooves, and the cross section thereof is formed in a substantially V shape in which two identical arcs having different centers of curvature are combined.

A large number of balls 4 as rolling elements made of a material such as steel or ceramics are rotatably loaded in the ball rolling passage 3 and the slider body 2 moves through rolling of the balls 4. A smooth relative movement along the guide rail 1 is possible. Since it is necessary to circulate the balls 4 in order to maintain the relative movement between the slider body 2 and the guide rail 1, another rolling element passage extending parallel to the ball groove 2a is provided on the inner edge side of both sleeve portions of the slider body 2. In order to form a certain ball return passage straight line portion 5 and to communicate the ball rolling passage 3 with the ball return passage straight line portion 5, further rolling elements described later are provided on both axial end faces of the slider body 2. The end caps 6 that form a part of the curved passage of the ball passage returning passage, which is a passage, are respectively fitted.

The communicating portion between the ball rolling passage 3 and the ball returning passage straight portion 5 will be described in detail with reference to FIG. 2 which is an enlarged view of a cross section passing through both passage axes. Note that FIG.
Although omitted in the schematic configuration of FIG. 3, spherical concave surfaces engageable with the balls 4 are formed back to back between the balls 4 in order to prevent the adjacent balls from interfering with each other's rolling motion. The holding piece 7 as the rolling element spacing holding member is inserted. At both ends (not shown on one side) of the ball rolling passage 3 and the ball returning passage linear portion 5, a semi-doughnut-shaped ball returning passage curved portion 8 is connected so as to connect them. The ball rolling passage 3, the ball returning passage straight portion 5, and the ball returning passage curved portion 8 constitute a ball circulating passage 9 as a rolling element circulating passage.

The ball return passage curved portion 8 is provided with an outer peripheral side guide groove 6a which is recessed to guide the outer peripheral side of the curved portion on the contact surface of the end cap 6 with the slider body 2, the ball groove 2a and the ball. On the outer surface of the return guide 10 attached to the slider body 2 so as to relate to the return passage straight line portion 5,
It is constituted by an outer peripheral side guide groove 6a and an inner peripheral side guide groove 10a which is provided so as to face the outer peripheral side guide groove 6a so as to guide the inner peripheral side of the curved portion.
One end of the ball return passage curved portion 8 which is connected to the ball rolling passage 3 has an inclined outer peripheral surface 11a on the end face whose diameter becomes smaller toward the tip and which is larger than the inner diameter of the ball groove 2a. The semi-cylindrical engagement protrusion 11 having the inner cylindrical surface 11b is provided in a protruding manner, and the other end of the ball return passage curved portion 8 connected to the ball return passage linear portion 5 has an end cap. 9 and the return guide 10 have inner peripheral surfaces 12Rb and 12E having inclined outer peripheral surfaces 12Ra and 12Ea whose diameter decreases toward the tip and having a diameter larger than the inner diameter of the ball return passage straight portion 5.
The semi-cylindrical engagement protrusions 12R and 12E having the shape b are provided in a protruding manner.

The engaging protrusions 11 are provided at both ends (not shown on one side) of the ball groove 2a forming the ball rolling passage 3.
2 and the engaging recess 13 ground to expand the diameter of the ball groove 2a along the ball rolling passage axis A _W shown by the alternate long and short dash line in FIG. An inclined inner peripheral surface portion 13a which is conically ground so as to engage with the inclined outer peripheral surface 11a and communicate with the ball groove 2a is formed on the bottom side of the. When the inner cylindrical surface 11b of the engaging protrusion 11 and the ball passage groove 2a are connected to each other, the inclined inner peripheral surface 13 is formed.
The slanted portion 13a 'is left on a and a smooth step D1 is secured.

Further, at both ends (not shown on one side) of the ball return passage straight line portion 5, the return passage straight line portion shown by the alternate long and short dash line in FIG. 2 can be fitted to the engaging protrusions 12R and 12E. An engaging recess 14 formed by performing a counterboring along the axis A _W ', and an inclined outer peripheral surface 12 on the bottom side of the engaging recess 14.
Ra and 12Ea engaging and ball return passage straight section 5
Inclined inner peripheral surface portion 14a ground in a conical shape so as to communicate with
And are formed. Also, the engaging protrusions 12R and 12
When the inner cylindrical surfaces 12Rb and 12Eb of E and the ball return passage straight line portion 5 are connected to each other, the inclined inner peripheral surface portion 14a is configured so that the inclined portion 14a 'remains, thereby ensuring a smooth step D2. .

Here, the engaging recess 14 is formed in the return passage straight line portion 5.
When forming, if the drill angle at the cutting edge of the drill used in the counterboring process is suitable for the inclination angle of the inclined inner peripheral surface portion 14a, the processing for forming the inclined inner peripheral surface portion 14a is omitted. be able to. The steps D1 and D2 have a value of 1% or more and 10% or less (preferably 1.5% or more and 3.0% or less) of the outer diameter of the ball 3 in order to ensure smooth rolling of the ball 3. ). With a step difference of less than 1%, it is possible to reliably suppress the occurrence of a step difference that may hinder the smooth circulation of the ball 3 if there is some manufacturing error or positional dimension error in the connecting portion between the ball passages. It is meaningless to intentionally provide a gentle step by narrowing the allowable range, and if a step exceeding 10% is provided, it would rather hinder the smooth circulation of the ball 4 and the holding piece 7. is there.

Further, the inclination angles of the inclined inner peripheral surface portions 13a and 14a are 10 ° to 55 ° (preferably 2 °) with respect to the ball rolling passage axis A _W and the ball returning passage straight portion axis A _W '.
It is set to a value opened at 0 ° to 45 °. It is 1
This is because if it is 0 ° or less, it is difficult to secure the rigidity of the engaging protrusions 11, 12R and 12E and it is difficult to secure the steps D1 and D2, and if it is 55 ° or more, the alignment property with the spigot is low. This is because the ball becomes weak and the circulation of the ball 4 and the holding piece 7 is hindered.

Next, the operation of the first embodiment will be described. Now, when the slider main body 2 is moved along the guide rail 1, the balls 4 existing in the ball rolling passage 3 receive the loads from the ball grooves 1a and 2a, and the slider main body 2 moves.
Rolls in the same direction with the linear motion of. Then, the balls 4 that have reached one end of the ball rolling passage 3 are sequentially ejected together with the holding piece 7 to the ball returning passage curving portion 8 in the unloaded state.

At the same time, the ball 4 and the holding piece 7 discharged from one end of the ball rolling passage 3 push the ball 4 and the holding piece 7 in the ball returning passage curved portion 8 and the ball returning passage straight portion 5 to move them. , Ball rolling passage 3
The ball 4 and the holding piece 7 reaching the other end side of
The balls are sequentially pushed into the ball rolling passage 3 to be restored. By circulating the balls 4 in this way, the slider body 2 can be continuously moved along the guide rail 1.

Here, when the ball 4 and the holding piece 7 move from the ball rolling passage 3 to the ball return passage curved portion 8, the passage diameter increases from the ball rolling passage 3 through the inclined portion 13a '. Since the ball-returning passage curved portion 8 is opened, the ball-returning passage is smoothly moved without being caught or clogged. Also, the ball return passage straight portion 8
When returning from the ball to the ball rolling passage 3, even if the ball 4 is moving along the inner peripheral surface of the engaging protrusion 11 in the return guide 10, the inclined portion 13a ′ does not move the ball 4 and the holding piece 7. Can be smoothly introduced into the ball rolling passage 3.

Further, regarding the movement from the curved portion 5 of the ball returning passage to the straight portion 8 of the returning passage or from the straight portion 5 of the returning passage 5 to the curved portion 8 of the returning passage, the diameter is increased from one side to the other side. As in the case described above, the inclined portion 14a 'avoids the ball 4 and the holding piece 7 from being caught and realizes a smooth bidirectional passage thereof.
Then, even if the engaging protrusions 11, 12R and 12E and the engaging recesses 13 and 14 have some manufacturing errors, or even if the respective positional dimensions have some errors, the connecting portions of the two are connected. Steps D1 and D2, which are positively provided in advance, and the inclined portions 13a ′ and 14a ′
However, the balls 4 and the holding piece 7 are aligned while aligning the axes of both.
It is possible to suppress or avoid the occurrence of a step that hinders the smooth circulation of the ball, secure stable and smooth circulation of the ball 4 and the holding piece 7, and suppress an increase in vibration and noise.

Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is an application of the present invention to a ball screw device. That is, FIG. 3 is a schematic configuration diagram in which a part of the ball screw device having a tube type circulation function is broken.
Reference numeral 21 is a screw shaft as an inner member, and 22 is a ball nut as an outer member that is screwed into the screw shaft 21 so as to be relatively movable via a number of balls 4. A holding piece 7 (not shown) is interposed between the balls 4.

A ball screw groove 21a as a guide groove which is spirally ground is formed on the outer periphery of the ball screw shaft 21, and spirally ground on the inner periphery of the ball nut 2 so as to face the ball screw groove 21a. Ball screw groove 22a as a guide groove
Are formed respectively, and the ball screw groove 2a and the ball screw groove 2 at a portion facing the ball screw groove 22a are formed.
A ball rolling passage 23 as a rolling body rolling passage is configured with 1a. The ball screw grooves 21a and 22a are Gothic arch grooves, and the cross section thereof is formed into a substantially V shape in which two identical arcs having different centers of curvature are combined.

Ball nut 2 for ball screw shaft 21
Since it is necessary to circulate the ball 4 in order to maintain the linear movement of the ball nut 2 relative to the ball nut 2,
A part of the outer peripheral surface of 2 is formed into a flat surface, and a pair of through holes 24 communicating with the ball rolling passage 23 are formed at right angles to the flat surface. Both ends of the return tube 25, which is a substantially U-shaped bent tube, are inserted. These ball rolling passages 2
The return tube 25 which is the third rolling element passage and the other rolling element passage constitutes a ball circulation passage 26 as a rolling element circulation passage.

The connecting portion between the ball rolling passage 23 and the return tube 25 will be described in detail with reference to FIG. 4, which is an enlarged view of a cross section perpendicular to the axis of the ball screw 21 and passing through the axis of the return tube 25. To do. Both ends of the return tube 25 (not shown on one side) have engaging projections that partially have an inclined outer peripheral surface 27a that becomes smaller in diameter toward the tip end and that has an inner cylindrical surface 27b that is larger in diameter than a cylindrical surface portion 28b described later. And a tongue portion 27c that is formed by further extending a part of the circumferential edge of the projection to scoop up the ball 4 and the ball 27.
And are formed.

The through hole 24 communicating with the ball rolling passage 23 is first formed with a through hole having substantially the same diameter as the ball rolling passage 23 as shown by the chain double-dashed line in FIG. Engagement concave portion 28 formed by deep-drilling along the penetrating axis A _T to enable fitting with the portion 27, and the inclined outer peripheral surface 27 a on the bottom side of the engagement concave portion 28. An inclined inner peripheral surface portion 28a ground in a conical shape is formed. Further, the first through hole is connected to the inclined inner peripheral surface portion 28a and has a diameter smaller than the inner diameter of the engaging recess 28, and the ball rolling passage 2
A cylindrical surface portion 28b is formed so as to be connected to the inner surface of No. 3.

Furthermore, when the inner cylindrical surface 27b and the cylindrical surface portion 28b of the engagement protrusion 27 of the return tube 25 are connected to each other, the inclined inner peripheral surface portion 28a is inclined to the inclined portion 28a '.
Is configured to remain, and a smooth step D is secured. Next, the operation of the above second embodiment will be described. Therefore, when the ball screw shaft 21 is rotated with respect to the ball nut 22, the balls 4 existing in the ball rolling passage 23 are rotated by the ball screw shaft 21 while receiving the load from the ball screw grooves 21a and 22a. Roll in the same direction as. Then, the balls 4 that have reached one end of the ball rolling passage 23, together with the holding pieces, are sequentially discharged to the unloaded return tube 25.

At the same time, the ball 4 and the holding piece 7 discharged from one end of the ball rolling passage 23 push the ball 4 and the holding piece 7 in the return tube 25 to move the ball 4 and the holding piece 7 to the other end side of the ball rolling passage 23. The ball 4 and the holding piece 7 that have reached the ball rolling path 23 in order.
Push it back in to restore. In this way, the ball 4 circulates, so that the ball nut 2 is moved along the ball screw shaft 21.
2 can be continuously linearly moved.

Here, when the ball 4 and the holding piece 7 move from the ball rolling passage 23 to the return tube, the return diameter from the ball rolling passage 23 is increased through the inclined portion 28a '. Since the tube 25 is opened, it moves smoothly without being caught or clogged. Further, when returning from the return tube 25 to the ball rolling passage 23, even if the ball 4 is moving along the inner peripheral surface of the engagement protrusion 27, the inclined portion 28
a ′ connects the ball 4 and the holding piece 7 to the ball rolling passage 2
It can be smoothly introduced into 3.

Even if the engaging protrusion 27 and the engaging recess 28 have some manufacturing errors, or even if the respective positional dimensions have some errors, the connecting portions of the two are positively active in advance. Step D and slope 2 provided on the
8a ′ suppresses or avoids the occurrence of a step that hinders the smooth circulation of the ball 4 and the holding piece 7 while aligning the axes of the both, and stabilizes and smoothly circulates the ball 4 and the holding piece 7. It is possible to secure the above, and to suppress an increase in vibration and noise.

In the above second embodiment, the ball screw device having the tube type circulation function has been described, but the present invention is not limited to this, and the top type and the end cap type and other types are also used. It can be applied to a ball screw device having a circulation function of. Further, in the above-described first embodiment, the inclined outer peripheral surface portion of the engaging protrusion and the inclined inner peripheral surface of the engaging concave portion are conical at the connecting portion between the ball return passage straight line portion 5 and the ball return passage curved portion 8. Although the structure formed in FIG. 5 has been described, the structure is not limited to this, and may be formed in a trumpet shape as shown in FIG. 5A or a bowl shape as shown in FIG. 5B. The point is that the ball passages can be formed in any shape as long as a smooth step can be formed between the ball passages. In addition, the ball rolling passage 3 and the ball return passage curved portion 8
Also in the connecting portion between the ball rolling passage 23 and the return tube 25 in the second embodiment,
The inclined outer peripheral surface portion and the inclined portion, which are formed in a substantially semi-conical shape, may be similarly formed in a substantially half-trumpet shape or a substantially half-bowl shape.

Furthermore, in the first and second embodiments described above, the structure in which the holding piece 4 is interposed between the balls 3 has been described, but the present invention is not limited to this.
The holding piece 4 may be omitted.

[0038]

As described above, according to the linear motion device of the present invention, the connecting portion of the ball passages forming the ball circulation passage is provided with the inclined portion whose diameter increases from one to the other. As a result, even if there is a manufacturing error or a positional dimensional error, a step may be created at the joint between the ball passages and the ball passages so as to prevent smooth circulation of the balls and the holding piece while aligning the axial cores of the passages. Can be avoided or suppressed, and the deterioration of the ball or the holding piece and the increase of vibration and noise can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a linear guide device that is a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing respective connecting portions of the ball rolling passage, the ball returning passage curved portion, and the ball returning passage straight portion in the linear guide device according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a ball screw device that is a second embodiment of the present invention.

FIG. 4 is an enlarged sectional view showing a connecting portion of a ball rolling passage and a return tube in the ball screw device according to the second embodiment of the present invention.

FIG. 5 is an embodiment in which the inclined outer peripheral surface and the inclined inner peripheral surface of the present invention are formed in a trumpet shape and a bowl shape.

FIG. 6 is an explanatory diagram showing that in the conventional example, it is difficult to reliably ensure smooth circulation of the ball when a manufacturing error or a position dimension error occurs.

[Explanation of symbols]

1 Guide rail 2 Slider body Four balls 5 Ball return passage straight section 6 End cap 7 holding piece 8 Ball return passage curved part 10 Return guide 11a, 12Ra and 12Ea inclined outer peripheral surface 11b, 12Rb and 12Eb inner cylindrical surface 11, 12R and 12E engagement protrusion 13 Engagement recess 13a inclined inner peripheral surface 13a 'inclined portion 14 Engagement recess 14a inclined inner peripheral surface 14a 'inclined portion 21 Ball screw shaft 22 Ball nut 24 through holes 25 Return tube 27a inclined outer peripheral surface 27b inner cylinder surface 27 Engagement protrusion 28 Engagement recess 28a inclined inner peripheral surface portion 28a 'inclined portion

Claims (10)

[Claims] 1. An inner member having a guide groove, and a guide groove that forms a rolling element rolling passage facing the guide groove of the inner member, and is relatively movable with respect to the inner member. Outer member, the rolling element circulation path formed by communicating a plurality of rolling element passages including the rolling element rolling passage, and a large number of rolling elements rotatably loaded in the rolling element circulation path. In the linear motion device including the linear motion device, a linear motion device in which each of the connecting parts of the rolling element passages in the rolling element circulation path is formed with an inclined portion whose diameter increases from one to the other. 2. The rolling element circulation path is constituted by a rolling element rolling passage and rolling element returning passages formed in the outer member and connected to both ends thereof. The linear motion device described. 3. The rolling member rolling passage, wherein the outer member has an inclined outer peripheral surface whose end surface has a smaller diameter toward the tip, at a connecting portion of the rolling body returning passage with the rolling body rolling passage. An engaging protrusion having an inner cylindrical surface with a diameter larger than the inner diameter of the engaging protrusion, and an engaging recess for engaging and holding the engaging protrusion, the bottom of the engaging recess communicating with the guide groove. An inclined inner peripheral surface portion that expands in diameter toward the rolling element return passage is formed so as to engage with the inclined outer peripheral surface, and the inclination is formed between the inner cylindrical surface of the engaging protrusion and the guide groove in the inclined inner peripheral surface portion. The linear motion device according to claim 2, wherein a portion is formed. 4. The rolling member rolling passage, wherein the outer member has an inclined outer peripheral surface whose end surface has a smaller diameter toward the tip, at a connecting portion of the rolling body returning passage with the rolling body rolling passage. An engaging projection having an inner cylindrical surface with a diameter larger than the inner diameter of the engaging projection, an engaging recess for engaging and holding the engaging projection, and a diameter smaller than the inner diameter of the engaging projection connected to the engaging recess. And a slanted inner peripheral surface portion that is in communication with the cylindrical surface portion and that expands in diameter toward the rolling element return passage so as to engage with the slanted outer peripheral surface. 3. The linear motion device according to claim 2, wherein the inclined portion is formed between the inner cylindrical surface of the engaging protrusion and the cylindrical surface portion of the inclined inner peripheral surface portion. 5. The outer member includes a main body forming a straight line portion of the rolling element return passage, and a curve having a diameter larger than an inner diameter of the straight line portion of the rolling element return passage arranged on both end surfaces of the main body. A cap formed with a portion, and at the position facing the linear portion of the cap, an engaging protrusion having an inclined outer peripheral surface having a smaller diameter toward the tip is formed on the tip side. An engaging recess for engaging and holding the engaging protrusion is formed at a position facing the curved portion, the bottom of the engaging recess is communicated with the linear portion and engaged with the inclined outer peripheral surface. Forming an inclined inner peripheral surface portion that expands in diameter toward the curved portion,
3. The linear motion device according to claim 2, wherein the inclined portion is formed between a communication portion of the inclined inner peripheral surface portion with the inner surface of the engagement protrusion and a communication portion of the straight portion. 6. The linear motion according to claim 3, wherein the inclined outer peripheral surface of the engagement protrusion and the inclined inner peripheral surface of the engagement recess are formed in a conical surface shape. apparatus. 7. The linear motion according to claim 3, wherein the inclined outer peripheral surface of the engaging protrusion and the inclined inner peripheral surface of the engaging recess are formed in a trumpet shape. apparatus. 8. The linear motion according to claim 3, wherein the inclined outer peripheral surface of the engagement protrusion and the inclined inner peripheral surface of the engagement recess are formed in a bowl shape. apparatus. 9. The inclined portion is set such that the diameter difference between the rolling element passages is set to a value of 1% or more and 10% or less of the outer diameter of the rolling element. Direct acting device described in. 10. The rolling element spacing holding member having a recess on the rolling element contact surface is interposed between each of the rolling elements, as set forth in claim 1. Moving device.