JP2012241782A - Linear motion guide device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motion guide device in which an attitude change of a slider is reduced without increasing the number of components.SOLUTION: A linear motion guide device includes a guide rail 10, a slider and a rolling element 30. In both sleeve parts 21A and 21A of a slider body 21, a plurality of slits 50 are formed along a rolling element trajectory path 41. The slits 50 are formed while being opened in inner side face parts 21a and outer side face parts 21c of the respective sleeve parts 21A, and terminal parts 21b in a moving direction. A buffering part 60 formed between the plurality of slits 50 and 50 is elastically deformed to absorb a force which is generated outside when the rolling element 30 enters/leaves the rolling element trajectory path 41 in the slider body 21.

Description

  The present invention relates to a linear motion guide device (linear guide) used in a machine tool or the like as a means for guiding a linearly moving object in its moving direction.

  In a conventional linear motion guide device in which a slider is straddled so as to be movable in the longitudinal direction of the guide rail via a rolling element, a rolling element passing vibration can be cited as a factor that reduces the motion performance. This is because the position of the slider slightly changes and the position of the slider slightly changes as the number of rolling elements that receive a load fluctuates periodically. This change is amplified at a machining point or measurement point away from the slider, resulting in a decrease in accuracy.

  In order to reduce such rolling element passing vibration, there is a case where crowning is applied to gently and gently incline the entrance and exit of the rolling element at the end of the slider track. As a crowning shape, a single arc shape, a single linear shape, an elliptical shape, and a shape in which a plurality of arcs are connected have been proposed. In Patent Document 1, the rigidity of the slider in at least one of the vertical direction, the horizontal direction, and the rolling direction is kept substantially constant even when the rolling element moves in the axial direction, and the pitching direction of the slider is A technique has been proposed in which the rigidity with respect to one or both of the yawing directions is set to a shape in which the rigidity is maintained substantially constant.

Patent Document 2 discloses a technique for eliminating the change in the attitude of the slider by aligning the phases of impacts when a plurality of tracks pass through the rolling elements and canceling out the influence of the rolling elements.
Further, in Patent Document 3, a free support that is not supported by the slider is formed at the end of the rolling element of the travel path element provided separately from the slider, and the free support is elastically deformed. A technique in which a relief is provided is disclosed.

JP 2003-35314 A JP 2008-115921 A JP 2004-232864 A

  However, in the linear motion guide device disclosed in Patent Document 1, it is necessary to process with high accuracy in order to obtain an optimal crowning shape, which requires a lot of labor and even if the phase of rolling element passage is aligned, It was sometimes difficult to make the crowning of each track the same. As a result, there is a case where the magnitudes of the forces acting due to the entry and exit of the rolling elements are not the same, and posture changes occur.

Further, in the linear motion guiding device disclosed in Patent Document 2, the force from the rolling elements acts on the elastic deformation of the legs when the track is above and below the legs of the slider. There is room for improvement because there is a difference in the size of the slider and the size of the slider that affects the change in posture of the slider is different.
Furthermore, since the invention described in Patent Document 3 has a large number of parts and requires joining to maintain assembly accuracy, the occurrence of posture change cannot be improved.
Accordingly, the present invention has been made paying attention to the above-mentioned problems, and an object thereof is to provide a linear motion guide device in which the change in the posture of the slider is reduced.

A linear motion guide apparatus according to claim 1 of the present invention includes a guide rail and a slider having a slider body having a substantially U-shaped cross section and straddling the guide rail. Has a rolling element rolling groove on the side surface, and the slider body has a load rolling element rolling groove on the inner side surface of the sleeve portion, and the rolling body rolling groove and the load rolling element rolling groove A linear motion guide device in which the slider moves relative to the guide rail by rolling of a large number of rolling elements loaded in a rolling element raceway formed between the rolling elements,
A plurality of slits are formed along the rolling element raceway so as to open at the inner side surface and the outer side surface of the sleeve portion of the slider body and at the end in the moving direction, and the slider body is moved to the rolling element raceway. A buffer portion for buffering a force generated outside when the rolling element enters and exits is formed between the plurality of slits.

  According to the first aspect of the present invention, the buffer portion 60 formed between the slits is directed outwardly as the rolling elements enter and exit the rolling element track at both axial ends of the slider body. It is elastically deformed with respect to the force. As a result, the rolling element smoothly enters and exits the rolling element raceway, so that the change in the posture of the slider can be reduced without increasing the number of parts.

A linear motion guide device according to a second aspect of the present invention is the linear motion guide device according to the first aspect, wherein a cage for holding the rolling element is disposed in the rolling element raceway. .
A linear motion guide device according to a third aspect of the present invention is the linear motion guide device according to the first aspect, wherein the end caps installed at both ends in the moving direction of the slider body lead to the plurality of rolling element raceways, A turning path for changing the moving direction of the rolling element is formed, and the rolling element circulates through the turning path and the plurality of rolling element track paths.

  The present invention can provide a linear motion guide device in which a change in posture of the slider is reduced.

It is a perspective view which shows the structure in one Embodiment of the linear guide apparatus which concerns on this invention. It is a front view which shows the structure in one Embodiment of the linear motion guide apparatus which concerns on this invention. It is a side view which shows the structure in one Embodiment of the linear guide apparatus which concerns on this invention. It is a front view which shows the structure in other embodiment of the linear guide apparatus which concerns on this invention.

Embodiments of a linear guide apparatus according to the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing a configuration in an embodiment of a linear guide apparatus according to the present invention. FIG. 2 is a front view (however, the end cap is omitted) illustrating the configuration of the linear motion guide device according to the embodiment of the present invention. Moreover, FIG. 3 is a side view which shows the structure in one Embodiment of the linear guideway based on this invention.
As shown in FIG. 1, the linear motion guide device 1 of this embodiment includes a guide rail 10, a slider 20, and a rolling element 30.

<Guide rail>
The guide rail 10 extends in a square shape, and a rolling element rolling groove that is a concave groove having a substantially circular arc shape in cross section at the ridge line portion where the upper surface 11 and both side surfaces 12 and 12 intersect. 13 and 13 are formed in the axial direction (longitudinal direction).
Further, rolling element rolling grooves 14, 14 which are concave grooves having a substantially semicircular cross-sectional shape are formed on both side surfaces 12, 12 of the guide rail 10 in the axial direction.
That is, the guide rail 10 is formed with two rolling element rolling grooves 13 and 14 on both side surfaces 12 and 12 in the extending direction (longitudinal direction).

<Slider>
As shown in FIGS. 1 and 2, a slider 20 having a substantially U-shaped cross section is provided on the guide rail 10 so as to be relatively movable in the axial direction of the guide rail 10.
The slider 20 includes a slider main body 21 and end caps 25 attached to both ends along the moving direction of the slider main body 21.
Loaded rolling element rolling grooves 22, which face the rolling element rolling grooves 13 and 13 of the guide rail 10 and have a substantially semicircular cross section, are formed on the inner side surfaces 21 a and 21 a of both sleeve portions 21 A and 21 A of the slider body 21. , 22 are formed.

Further, the inner side surfaces 21a and 21a of both sleeve portions 21A and 21A are opposed to the rolling element rolling grooves 14 and 14 of the guide rail 10, and load rolling element rolling grooves 23 and 23 having a substantially semicircular cross-sectional shape. Each is formed.
That is, two load rolling element rolling grooves 22 and 23 facing the rolling element rolling grooves 13 and 14 are formed on the inner side surfaces 21a and 21a of both sleeve portions 21A and 21A of the slider body 21, respectively. .

Further, through holes 24, 24 parallel to the load rolling element rolling grooves 22, 23 are formed in both sleeve portions 21 A, 21 A of the slider body 21 in the axial direction of the guide rail 10 of the slider body 21.
The rolling element rolling grooves 13 and 14 of the guide rail 10 and the load rolling element rolling grooves 22 and 23 of the slider 20 constitute a rolling element raceway 41, and the rolling element return path 42 is defined by the through holes 24 and 24. Is configured. The rolling element raceway 41 and the rolling element return passage 42 together with the conversion path 43 described later constitute a rolling element circulation circuit 40.

<End cap>
The end cap 25 is an injection-molded product of a resin material, and is formed in a substantially U shape. The end cap 25 is installed at both ends of the slider body 21 in the axial direction with the direction of the opening of the shape being the same as the direction of the opening of the slider body 21.

  Here, the end cap 25 has a turning path for changing the moving direction of the rolling elements to a position facing the rolling element raceway 41 and the rolling element return passage 42 on the joint surface (the surface facing the slider body) (see FIG. (Not shown) is formed. This conversion path is formed so that the cross section along the moving direction of the slider 20 has a U-shape that opens to the joint surface of the end cap 25 and has both ends communicating with the rolling element raceway 41 and the rolling element return path 42. Is done. That is, the rolling element 30 that has rolled the rolling element raceway 41 to the end of the slider body 21 enters the rolling element return passage 42 while changing the moving direction in the reverse direction in the end cap 25, and enters the opposite side. The direction of the end cap is changed, and the inside of the slider body 21 rolls again. The rolling element raceway 41, the rolling element return path 42, and the two switching paths positioned on both ends of the slider body 21 constitute a rolling element circulation circuit 40 that is an infinite circulation path.

<Rolling elements>
A plurality of rolling elements 30 are arranged in parallel between the rolling element rolling grooves 13 and 14 formed on the both side surfaces 12 and 12 of the guide rail 10 and the rolling element rolling grooves 22 and 23. The rolling element 30 is disposed in the rolling element track 41 and the rolling element return passages 42 and 43 that constitute the rolling element circulation circuit 40.
The plurality of rolling elements 30 that are arranged to roll in the rolling element circulation circuit 40 roll while rotating between the guide rail 10 and the slider 20 as the slider 20 moves relative to the guide rail 10. .
Examples of the rolling elements 30 include balls (balls) and rollers. In the present embodiment, balls (balls) are used.
In addition, there is no restriction | limiting in particular as the kind of rolling element 30 of this embodiment, a magnitude | size (diameter), and the number of incorporation, According to the magnitude | size, shape, use purpose, and use environment of the guide rail 10, the slider 20, etc. It is selected as appropriate.

<Slit>
A plurality of slits 50 are formed in the sleeve portions 21A and 21A of the slider main body 21 so as to open to the inner side surface portion 21a and the outer side surface portion 21c of the slider main body 21 and the end portion 21b in the axial direction.
These slits 50 are formed in the slider body 21 in parallel with the upper and lower sides of the rolling element raceway 41.

These slits 50 may be formed so as to open to at least one of the end portions 21b and 21b in the axial direction of the slider body 21. It is preferably formed so as to open at both ends 21b and 21b. Specifically, as shown in FIGS. 1 to 3, four slits 50 are cut from both ends 21 b and 21 b in the axial direction of the slider body 21 along the upper and lower sides of the rolling element raceway 41. Formed. And the buffer part 60 is formed between the two slits 50 and 50 formed in the height direction of the slider main body 21 across the rolling element track 41. The shock absorber 60 is directed outwardly when the rolling element 30 enters and exits the rolling element raceway 41 in the slider main body 21 at both axial ends 21b and 21b of the slider main body 21 (from the inner side surface 21a to the outer side surface). It is elastically deformed against the force in the direction toward 21c). As a result, the rolling element 30 smoothly enters and exits the rolling element raceway 41, and as a result, the influence of the posture change is reduced. Moreover, since the slit 50 is formed in the slider main body 21, the machining is easier than the conventional crowning formed on the rolling element raceway.
Here, the width of the slit 50, the depth of the slit 50, and the interval between the pair of slits 50, 50 are determined as follows.

[Slit width]
In this embodiment, the width | variety of the slit 50 refers to the opening dimension of the height direction in the end surface 21b and the inner surface part 21a and the outer surface part 21c.
In this embodiment, as shown in FIG. 2, when two or more rolling element rolling grooves are provided on one inner side surface portion 21a, two through holes provided in parallel to the rolling element rolling grooves 22 and 23 are provided. Even if the slit 50 is provided in the thick part between 24 and 24, the thickness between the through hole 24 and the slit 50 and the thickness between the slits 50 and 50 does not deform during the process, and the through hole 24 and the slider body What is necessary is just to satisfy | fill that the thickness of the lower surface of 21 is the thickness which does not deform | transform during a process.

[Slit depth]
In the present embodiment, the depth of the slit 50 refers to the dimension in the axial direction of the slider body 21 with respect to the end face 21b.
The depth L of the slit 50 is defined by the following formula (a). In equation (a), δ is the amount of preload, E is the longitudinal elastic modulus of the material of the slider main body 21, I is the moment of inertia of the cross section of the buffer portion 60, and P is the preload.
L ≧ (3δEI / P) ^1/3 ... Formula (a)

[Slit spacing]
In this embodiment, the space | interval between the slits 50 and 50 which make a pair refers to the dimension of the height direction of the buffer part 60 in the end surface 21b and the inner surface part 21a and the outer surface part 21c.
In the present embodiment, when the through hole 24 is formed in the slider main body 21, the slit 50 is provided so as to sandwich the through hole 24. Therefore, the space | interval of a slit should just be a dimension which the thickness between the through-hole 24 and the slit 50 does not deform | transform in a process. Further, when the through hole 24 is not formed in the slider main body 21, the slit 50 is provided so as to sandwich the rolling element rolling grooves 22 and 23. Also in this case, the thickness between the rolling grooves 22 and 23 and the slit 50 may be a thickness that does not deform during the process.

  When rollers are employed as the rolling element 30, the rolling element 30 is often disposed with its axial direction inclined around the axial direction of the slider body 21 (for example, 45 °), so a pair of slits is formed. It is preferable that the interval between 50 and 50 is longer than the length projected on the orthogonal plane of the slit 50 so that the rolling element 30 is disposed between the pair of slits 50 and 50.

[Slit formation method]
Examples of the method of forming the slit 50 include electric discharge machining using a wire. That is, the slit 50 is formed by performing wire-cut electric discharge machining on both sleeve portions 21 </ b> A of the slider body 21.

  Specifically, in the electric discharge machining using the wire, the slider body 21 before being assembled is immersed in the machining liquid, and the slider body 21 and a machining electrode (wire) (not shown) are connected to a high-frequency pulse power source. . Then, the processing electrode is operated along the positions where the slits 50 are formed on both sleeve portions 21A of the slider main body 21, and a spark is generated by the potential difference between the processing electrode and the slider main body 21, thereby forming a plurality of slits. 50 is formed on the sleeve portion 21 </ b> A of the slider body 21. During the electric discharge machining, by repeating the spark for removing the surface of the slider main body 21, the distance between the surface of the slider main body 21 and the processing electrode is increased, so that the distance between the surface of the slider main body 21 and the processing electrode is increased. The machining electrode is moved by a servo mechanism or the like so as to be constant. Then, based on the processing groove width, the wire correction amount, the discharge gap, and the wire diameter, the processing electrode is moved while being sparked, so that the sleeve portion 21 </ b> A of the slider body 21 has a plurality of positions set in desired positions and dimensions. The slit 50 is formed.

In this embodiment, the electric discharge machining using a wire is adopted as a method of forming the slit 50, but other cutting methods such as laser machining and ultrasonic machining are used in addition to this machining method. Also good.
As described above, in the present embodiment, the end of the rolling element raceway 41 is elastically formed by the buffer portion 60 formed between the two slits 50 and 50 that form a pair above and below the end of each rolling element raceway 41. The structure is easy to deform. By adopting such a configuration, the force acting when the rolling element 30 enters and exits the slider main body 21 is used for elastic deformation of the end of the rolling element raceway 41 and does not affect the posture change of the slider 20. Further, it is possible to provide a linear motion guide device that reduces the change in the posture of the slider. Moreover, since the buffer part 60 is comprised only by forming the two slits 50 and 50 which make a pair by electrical discharge machining using a wire, the number of parts is not increased. In addition to the configuration of the present embodiment, a crowning shape may be processed in each rolling element rolling groove 22, 23.

(Other embodiments)
FIG. 4 is a front view showing a configuration in another embodiment of the linear guide device according to the present invention. As shown in FIG. 4, in the present embodiment, a plurality of rolling elements 30 that are arranged to roll on the rolling element raceway 41 are loaded into a holder 35 that holds them, and are integrated with the holder 35. As the slider 20 moves relative to the guide rail 10, it rolls while rotating between the guide rail 10 and the slider 20.

[Cage]
As shown in FIG. 4, the retainer 35 has a shape extending along the outer contour of the guide rail 10. That is, the retainer 35 has a shape along the side surface portions 35 a and 35 a along the side surface portions 12 and 12 of the guide rail 10 and the upper surface portion 11 of the guide rail 10, and the side surface portions 35 a and 35 a are arranged above the guide rail 10. And an upper surface portion 35b connected to each other. The side surface portions 35a and 35a and the upper surface portion 35b may be integrally molded.

Further, a plurality of pockets (not shown) are provided on the side surface portions 35a and 35a, respectively, for rotatably holding the plurality of rolling elements 30 one by one at positions facing the rolling element rolling grooves 13 and the rolling element rolling grooves 14. Are integrally provided. The pockets are arranged in parallel with each other along the extending direction of the guide rail 10 and in the same phase at equal intervals.
As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.

DESCRIPTION OF SYMBOLS 1 Linear motion guide apparatus 10 Guide rail 20 Slider 21 Slider main body 21A Sleeve part 21a Inner side surface part 21b End part 21c Outer side surface part 30 Rolling body 35 Cage 50 Slit 60 Buffer part

Claims (3)

A guide rail and a slider having a slider body having a substantially U-shaped cross-section and straddling the guide rail, the guide rail having rolling element rolling grooves on a side surface, The slider body has a load rolling element rolling groove on the inner side surface of the sleeve, and is loaded into a rolling element raceway formed between the rolling element rolling groove and the load rolling element rolling groove. A linear motion guide device in which the slider moves relative to the guide rail by rolling of a large number of rolling elements,
A plurality of slits are formed along the rolling element raceway so as to open at the inner side surface and the outer side surface of the sleeve portion of the slider body and at the end in the moving direction, and the slider body is moved to the rolling element raceway. A linear motion guide device characterized in that a buffer portion for buffering a force generated outside when the rolling element enters and exits is formed between a plurality of slits.   The linear motion guide device according to claim 1, wherein a cage for holding the rolling element is disposed in the rolling element raceway.   A plurality of rolling element raceways are formed in the end caps installed at both ends of the slider body in the moving direction, and a turning path for changing the moving direction of the rolling elements is formed. The turning path and the plurality of rolling element raceways The linear motion guide device according to claim 1, wherein the rolling elements circulate in a path.

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