JP3609882B2 - Linear guide device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a linear guide device that includes a track rail and a bearing block that is slidably mounted along the track rail, and in particular, precisely measures how much the bearing block has moved relative to the track rail. The present invention relates to a linear guide device capable of performing the above.
[0002]
[Prior art]
The linear guide device is used in various industrial fields such as an NC lathe and an XY table, but there are many uses in which the movement position must be precisely controlled. For example, a coordinate measuring machine and a coordinate testing machine, an automatic assembly machine, a drilling machine for printed circuit boards, a photosetting machine, and a precision handling robot.
[0003]
In such a case, it is impossible to actually measure how much the bearing block has moved with respect to the track rail only by precisely controlling a driving motor such as a ball screw that drives the linear guide device. Therefore, conventionally, a metal tape with a scale is fixed to the track rail and the vicinity of the mounting reference plane (machine bed) of each device, and the scale attached to the metal tape is fixed by a scanning head fixed to a bearing block. The contact was read optically, thereby measuring the position of the bearing block.
[0004]
As such a metal tape for length measurement, for example, a LIDA linear bearing manufactured by HEIDENHAIN (Berlin, Germany) is commercially available. In this linear bearing, a metal tape having a scale interval of 100 μm is directly used as a scale main body or bonded to a steel base, and both ends thereof are fixed to a machine bed using screws or the like. On the other hand, the scanning head is fixed to the bearing block side, sine wave light having a signal period of 11 μm is irradiated, and the position of the bearing block is measured using the reflected light.
[0005]
[Problems to be solved by the invention]
In the above-described conventional method, both ends of the metal tape or the steel base to which the metal tape is bonded are fixed to the machine bed using screws or the like, so the metal tape or the steel tape is attached to the metal tape by warping or twisting of the steel base. The scale that was made did not adhere to the track rail while maintaining flatness, and accurate measurement was impossible.
[0006]
However, bonding the metal tape directly to the track rail with an adhesive has a problem that maintenance including replacement of the metal tape is complicated and difficult to employ.
[0007]
Furthermore, if chips or foreign objects get stuck in the mounting holes that house the bolts that fasten the track rail to the machine bed, they may enter the bearing block and hinder normal operation. A cover called a plate cover was installed. As a result, the cost has been increased.
[0008]
[Means for Solving the Problems]
The present invention has been made in view of the problems of the above-described conventional method, and a scale-like band-shaped body is brought into close contact with the upper surface of the track rail while maintaining flatness, thereby enabling accurate measurement. An object is to provide a linear guide device.
[0009]
It is another object of the present invention to provide a linear guide device that can attach a scale-like strip to a track rail by retrofitting, and thus facilitate maintenance such as replacement.
[0010]
Another object of the present invention is to provide a linear guide device that is configured so that it does not need to separately install such parts by serving as a plate cover.
[0011]
A linear guide device according to the present invention includes a track rail, a bearing block that is slidably mounted on the track rail, a scale-shaped strip disposed on an upper surface of the track rail, and one or both ends of the track rail. A tension applying mechanism that applies tension to the band with the scale by pulling at least one end of the band with the scale in the longitudinal direction, thereby maintaining flatness on the upper surface of the track rail. And is fixed to the outside of the bearing block and at a position facing the strip with the scale, and the scale attached to the strip with the scale is optically read in a non-contact manner, thereby accurately determining the position of the bearing block. And a scanning head capable of measuring.
[0012]
Embodiment
Hereinafter, the linear guide device of the present invention will be described in detail with reference to the drawings.
[0013]
As schematically shown in FIG. 3, the linear guide device 10 according to the present invention is disposed on a track rail 12, a bearing block 14 slidably mounted on the track rail 12, and an upper surface of the track rail 12. A scaled metal tape 16, a tensioner 20 fixed to one end of the track rail 12, and a scanning head 18 fixed outside the bearing block and at a position facing the metal tape 16. .
[0014]
Thus, since the scanning head 18 optically reads the scale attached to the metal tape 16 in a non-contact manner, the position of the bearing block 14 relative to the track rail 12 can be accurately measured.
[0015]
The track rail 12 and the bearing block 14 may take various conventionally known forms. Further, the metal tape 16 is provided with a scale 16a at a predetermined interval by etching or other means.
[0016]
In the preferred embodiment shown, one end of the metal tape 16 is tensioned by a tensioner 20 secured to one end of the track rail 12 and the other end is a plate secured to the other end of the track rail 12. 19 is fixed. Of course, tension can be applied to both ends of the metal tape 16 by the tensioner 20.
[0017]
As shown in detail in FIG. 1, the tensioner 20 is a case fixed to its end by a pair of case fixing bolts 22 a that engage with female screws 12 a and 12 b formed on the end surface of the track rail 12. 22, a slide member 24 slidably mounted inside the case 22, a tension applying screw 26 for moving the slide member 24 in a direction toward and away from the end face of the track rail 12, It is comprised from the fixing plate 28 for fixing the one end part of the metal tape 16 to the upper surface using the screw 28a.
[0018]
Although not shown, a V-shaped projection can be formed on the lower surface of the fixed plate 28, and a V-shaped groove can be formed on the upper surface of the corresponding slide member 24. As a result, when one end of the metal tape 16 is sandwiched between the slide member 24 and the fixed plate 28 and firmly tightened with the screw 28a, the metal tape 16 is bent into a V shape and tension is applied to the metal tape 16. It can be prevented from coming out.
[0019]
The tension applying screw 26 has a male screw 26a screwed with a female screw 12b formed on the end surface of the track rail 12, and a hexagonal hole 26b into which a hexagon wrench is fitted on the head side end surface. Is formed. When the hexagon wrench is fitted into the hexagon hole 26 b and the tension applying screw 26 is rotated, the slide member 24 slides in the perspective direction with respect to the track rail 12. When the slide member 24 approaches the track rail 12, the metal tape 16 is folded in a U shape along the curved surface 22 b of the case 22, and thus is pulled in the longitudinal direction and tension is applied to the metal tape 16. . As a result, the metal tape 16 is brought into close contact with the upper surface of the track rail 12.
[0020]
Referring to FIG. 1, the track rail 12 is formed with mounting holes 12c for receiving bolts 32 for fixing the track rail 12 to the machine bed 30 at predetermined intervals. In the linear guide device 10 of the present invention, since the metal tape 16 covers the mounting holes 12c, it is not necessary to separately provide a plate cover, which contributes to cost reduction.
[0021]
In the preferred embodiment shown in the figure, the case 22 is formed with a groove 22c corresponding to the ball rolling groove of the track rail 12. However, if a protrusion (not shown ) is provided in this portion, a linear guide is provided. It can also be used as a retaining member for the bearing block 14 when carrying the device 10.
[0022]
The illustrated tensioner 20 is an example, and it is needless to say that any configuration may be adopted as long as the metal tape 16 can be tensioned.
[0023]
【The invention's effect】
In the linear guide device of the present invention, at least one end of the scaled strip is pulled in the longitudinal direction by the tension applying mechanism, whereby tension is applied to the scaled strip to correct warping and twisting. Thus, the flat surface is kept in close contact with the upper surface of the track rail. As a result, the scanning head can accurately read the scale of the band with the scale, and thereby the position of the bearing block with respect to the track rail can be accurately measured optically.
[0024]
Further, since the tension is applied to the band with the scale by a tension applying mechanism fixed to the end of the track rail, the band with the scale can be retrofitted, and therefore, maintenance such as replacement is facilitated. Have advantages.
[0025]
Furthermore, since the band with a scale completely covers the mounting hole of the track rail, there is no need to separately install a cover called a plate cover, which contributes to cost reduction.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an essential part of an embodiment of a linear guide device according to the present invention.
2 is a perspective view of an assembled state of the linear guide device of FIG. 1. FIG.
FIG. 3 is a perspective view of an embodiment of a linear guide device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Linear guide device 12 Track rail 14 Bearing block 16 Scaled metal tape 18 Scan head 20 Tensioner 22 Case 24 Slide member 26 Tension applying screw 28 Fixing plate

Claims (1)

Track rails,
A bearing block slidably mounted on the track rail;
A band with scales arranged on the upper surface of the track rail;
The track rail is fixed to one or both ends of the track rail, and tension is applied to the scale strip by pulling at least one end of the scale strip in the longitudinal direction. A tension-applying mechanism that keeps the flatness in close contact, and
Fixed to the outside of the bearing block and facing the scaled strip, the scale attached to the scaled strip is optically read without contact, thereby accurately measuring the position of the bearing block A scanning head that can
A linear guide device configured to include:

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