JP2008303954A - Linear motion device - Google Patents

Abstract

A means for accurately determining the presence or absence of an abnormality in a linear guide device without being affected by an operating environment is provided.
A rail having a rail track groove, a nut track groove facing the rail track groove, a slider that moves linearly on the rail, a rail track groove, and a nut track groove are provided. The slider 9 of the linear guide device 1 is provided with a detection unit 28 that directly detects the unevenness of the rail track groove 5, and the detection unit 28 is made of an elastic material. The beam member 15 is formed, a strain gauge 24 attached to the beam member 15, and a stylus 19 attached to the distal end portion 15 a of the beam member 15 and slidably contacting the rail track groove 5.
[Selection] Figure 1

Description

  The present invention relates to a linear motion device such as a linear guide device or a ball screw device used for a feed mechanism of a mechanical device such as a manufacturing device, a machine tool, or a measuring device.

  A linear guide device as a conventional linear motion device has a return path provided on a slider, a direction change path provided on an end cap, a rail track groove provided on a rail, and a slider track groove provided on a slider facing each other. A ball as a linear motion device is configured by loading a plurality of balls in a circulation path communicating with the formed load path and supporting a slider that linearly moves the rail by a ball rolling on the load path of the circulation path. The screw device includes a shaft raceway groove formed in a spiral shape on the outer peripheral surface of the screw shaft, a nut raceway groove facing the shaft raceway groove formed on the inner peripheral surface of the nut, and a nut raceway groove and a shaft raceway groove arranged to face each other. The ball can be linearly moved to the screw shaft by a ball that rolls along the load path of the circulation path. The slider and nut as a moving body, or the rail and screw shaft as a fixed body, contact or collision with the moving body or the fixed body when the rolling element circulates in the linear motion device, and the raceway groove. An AE sensor that detects elastically generated waves (AE: acoustic emission) due to contact between the rolling element and the contact between the rolling elements, and processing of the digital envelope of the output signal of the AE sensor The maximum value of the data, the event rate, and the like are compared with a preset threshold value to determine the presence / absence of abnormality and the type of abnormality, and the determination result is displayed on the display unit (for example, see Patent Document 1).

  Also, in linear motion devices such as the linear guide device and ball screw device similar to the above, a color sensor for monitoring the raceway groove of the rolling element provided on the fixed body is provided, and the color of the lubricant coated on the raceway groove is changed. In some cases, the life of the parts of the linear motion device is determined by comparing the color of the lubricant detected by the color sensor with data such as the type of lubricant inputted in advance (for example, Patent Document 2). reference.).

Furthermore, in linear motion devices such as the linear guide device and ball screw device similar to the above, the peak point of the envelope created by the envelope detector by detecting the vibration of the linear motion device by providing an acceleration sensor on the moving body The frequency level corresponding to the frequency of the frequency is compared with a predetermined threshold, and when the frequency level falls below the threshold, it is determined that an abnormality has occurred in the circulation of the linear motion device (for example, , See Patent Document 3).
JP 2004-263775 A (mainly page 10 paragraph 0043-page 12 paragraph 0058, page 13 paragraph 0072-page 14 paragraph 0080, FIG. 4, FIG. 6, FIG. 7) JP 2002-106785 A (mainly page 3, paragraphs 0015-0030, FIG. 1, FIG. 6, FIG. 7) Japanese Patent Laid-Open No. 5-281094 (2nd page, paragraphs 0008-0009, FIGS. 1 and 2)

  However, in the technologies of the conventional patent documents described above, sensors such as an AE sensor, a color sensor, and an acceleration sensor that indirectly detect the operating state of the rolling element are provided on the moving body or fixed body of the linear motion device. Since the abnormality of the linear motion device is indirectly detected, it is difficult to determine the abnormality depending on the operating environment of the linear motion device. For example, in the case of an AE sensor or an acceleration sensor, the wave or vibration from the installed mechanical device It is difficult to remove the influence of the color sensor, and in the case of a color sensor, it is difficult to remove the influence of contamination caused by the entry of dust etc. into the lubricant from the installed external environment, making it difficult to cope with various operating environments. There is a problem that there is a risk of becoming.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide means for accurately determining the presence or absence of an abnormality in a linear motion device without being affected by the operating environment.

  In order to solve the above problems, the present invention has a fixed body having a rolling element guide surface and a rolling element guide surface facing the rolling element guide surface of the fixed body, and linearly moves the fixed body. A linear motion device comprising: a moving body; and a rolling element that rolls on a load path formed by the rolling element guide surface of the fixed body and the rolling element guide surface of the movable body. The present invention is characterized in that a detection unit for directly detecting irregularities on the rolling element guide surface of the body is provided.

  As a result, the present invention eliminates the influence of vibration from the mechanical device and the influence of contamination from the external environment without the moving body and the fixed body being separated from each other by vibration from the mechanical device in which the linear motion device is installed. Thus, there is an effect that the presence or absence of abnormality of the linear motion device can be accurately determined without being affected by the driving environment.

  Embodiments of a linear motion device according to the present invention will be described below with reference to the drawings.

1 is a perspective view showing a linear guide device of an embodiment, FIG. 2 is an explanatory view showing an installation state viewed from the front of the detection portion of the embodiment, and FIG. 3 is an explanatory view showing a side surface of the detection portion of the embodiment. 4 is an explanatory view showing the upper surface of the beam member of the embodiment.
In FIG. 1, 1 is a linear guide device as a linear motion device.
Reference numeral 2 denotes a rail as a fixed body of the linear motion device, which is a long columnar member made of a steel material such as alloy steel, and has an upper surface for fixing the rail 2 to a base of a mechanical device or the like. A plurality of rail installation holes 3 which are stepped bolt holes are provided at a predetermined pitch.

Reference numeral 4 denotes a plug, which is a resin-made disk-like member that fits into the large-diameter portion of the rail mounting hole 3, and after the rail 2 is fixed to the base or the like with bolts, The rail 2 is press-fitted so as to be flush with the upper surface of the rail 2.
Reference numeral 5 denotes a rail track groove as a rolling element guide surface of the fixed body, which is a groove having an arcuate cross section formed along the longitudinal direction of both side surfaces of the rail 2.

Reference numeral 6 denotes a slider as a moving body of the linear motion device, which is a bowl-shaped member having a substantially U-shaped cross section made of a steel material such as an alloy steel, and a screw hole 7 is provided on the upper surface thereof. The moving table or the like of the mechanical device is fastened with a bolt or the like using the screw hole 7.
Reference numeral 8 denotes a slider raceway groove as a rolling element guide surface of the moving body, which is a groove having an arcuate cross section provided inside the sleeve walls 6 a of the slider 6 so as to face the rail raceway groove 5.

Reference numeral 9 denotes a ball as a rolling element of the linear motion device, which is a sphere made of a steel material such as alloy steel.
A return path 10 has a diameter larger than the diameter of the ball 9 for circulating the ball 9 formed on the sleeve wall 6 a of the slider 6, and the slider 6 moves in the moving direction of the slider 6 (referred to as the slider moving direction). Is provided corresponding to each slider raceway groove 7.

  Reference numeral 11 denotes an end cap, which is made of a metal material, a resin material, or the like, and is disposed at the front and rear end portions of the slider 6 in the slider moving direction. The direction change path 12 which is a U-shaped curved path connecting the load path formed by the above and the return path 10 of the slider 6 is provided corresponding to each load path.

  A side seal 13 is made of a core material made of a plate material such as alloy steel, and a rubber material having elasticity such as natural rubber or synthetic rubber joined to the core metal by a joining means such as baking or bonding. The end cap 11 is arranged on the outer end surface of the end cap 11 in the slider moving direction, and the lip portion at the tip of the seal body slides on the outer surface of the rail 2 to function as a contact seal.

  Both ends of the load path are connected to each other by a communication path formed by the direction change path 12 of the end cap 11 and the return path 10 of the slider 6 to form a circulation path of the linear guide device 1. As the ball 9 moves, the ball 9 circulates in the circulation path, the ball 9 rolling on the load path supports the load applied to the slider 6 so as to reciprocate, and the slider 6 linearly reciprocates along the longitudinal direction of the rail 2. It is supported movably. Thereby, the linear guide apparatus 1 functions as a linear motion apparatus.

In the linear guide device 1 of the present embodiment, two circulation paths are formed on one side and four on both sides.
In FIG. 2, reference numeral 15 denotes a beam member, which is a film member formed of an elastic material such as a resin material having a relatively soft elasticity but a large resistance against tension, and has one end thereof in an L shape. A fixing bolt 15 (see FIG. 1) is inserted into the fixing screw hole 16 provided in the end surface of the slider 6 in the slider moving direction through the end cap 11 and the side seal 13 through the fixed end 15a formed by bending. Accordingly, the slider 6 is fastened to the end face of the side seal 13 in a cantilever manner.

  Reference numeral 19 denotes a stylus, which is formed in a conical shape from a highly rigid material such as a highly rigid metal or ceramics, and is attached to the tip 15b opposite to the fixed end 15a of the beam member 15 by bonding or the like. 15 is pressed in the vertical direction against the rolling surface of the ball 9 of the rail track groove 5 formed on the rail 2 by the elasticity (see FIG. 4), and the rail track groove 5 rolls as the slider 6 moves. The sliding contact follows the unevenness of the moving surface.

Reference numeral 20 denotes a suction plate, which is a thin plate made of a magnetic metal material, and is attached to the surface of the distal end portion 15b of the beam member 15 on the opposite side of the stylus 19 by adhesion or the like, as shown in FIG. ing.
Reference numeral 21 denotes a mounting bracket, which is an L-shaped member formed of a steel material or the like having a relatively high rigidity. A flange portion 21a which is a short side of the mounting bracket is fastened to the slider 6 together with the beam member 15 by a mounting bolt 17. An electromagnet 22 that attracts the suction plate 20 by magnetic force is attached to a fitting hole that is fixed in a holding shape and is provided at a position facing the suction plate 20 of the tip 21b opposite to the flange portion 21a.

A lead wire 23 has a function of supplying electric power to the electromagnet 22.
In FIG. 3, reference numeral 24 denotes a strain gauge, which is attached to the surface opposite to the surface on which the stylus 19 of the beam member 15 is attached by bonding or the like, and signals constituting the wiring 26 by bonding at both ends thereof. Lines 26a and 26b are connected to each other, and have a function of changing an electrical signal by a stress generated in the strain gauge 24 as the beam member 15 is deformed.

The detection unit 28 of this embodiment is formed by the cantilevered beam member 15 provided with the stylus 19 and the strain gauge 24 and the electromagnet 22 that attracts the beam member 15 attached to the mounting bracket. As shown in FIG. 4, the operation of the above-described configuration in which a total of four rail rail grooves 5 are arranged one by one will be described.
A slider 6 having a detection unit 28 having an electromagnet 22 and a cantilevered beam member 15 attached to one end of the slider moving direction is attached to the rail 2, and the electromagnet 22 is de-energized so that each detection unit 28 is touched. The needle 19 is pressed against each rail track groove 5 by utilizing the elasticity of the beam member 15.

Then, a predetermined voltage is applied between the signal lines 26a and 26b of the wiring 26 connected to the strain gauge 24 on the beam member 15, and the slider 6 is moved at a relatively low speed, as shown in FIG. The stylus 19 is brought into sliding contact with the rolling surface of the rail track groove 5.
At this time, as shown in FIG. 5B, when the rail raceway groove 5 has irregularities formed by peeling or flaking, the stylus 19 slidably contacted and curved along the irregularities. The curvature of the beam member 15 changes due to its elasticity, the stress state of the strain gauge 24 changes, and the electrical signal output changes according to the amount of change in the stress.

This electrical signal is guided to the wiring 26 and input to an abnormality detection device (not shown), the effective value of the change amount of the input electrical signal is obtained, and when the effective value exceeds a preset threshold value, An abnormality has been detected.
After the slider 6 is moved beyond the length corresponding to the stroke range set in the mechanical device, the electromagnet 22 is energized to cause the suction plate 20 of the beam member 15 to resist the elasticity of the beam member 15. As shown in FIG. 6, the beam member 15 is attracted by a magnetic force so that the stylus 19 is separated from the rail track groove 5.

In this way, abnormality detection of the linear guide device 1 using the detection unit 28 of the present embodiment is performed.
As described above, in the linear guide device 1 according to the present embodiment, the contact point 19 of the detection unit 28 fixed to the slider 6 is brought into sliding contact with the rail track groove 5 to directly detect the unevenness of the rail track groove 5. The slider 6 and the rail 2 are not vibrated at the same time due to the vibration from the mechanical device in which the linear guide device 1 is installed, and the two are not separated from each other. It is possible to accurately determine the presence or absence of abnormality of the linear motion device without being affected by the operating environment by eliminating the influence, and to easily cope with various operating environments.

Moreover, since the beam member 15 is attracted by the electromagnet 22 and the stylus 19 is separated from the rail track groove 5 except when an abnormality is detected, the occurrence of scratches on the rail track groove 5 can be suppressed.
As described above, in this embodiment, the rail having the rail raceway groove, the slider having the nut raceway groove facing the rail raceway groove and moving linearly on the rail, the rail raceway groove and the nut raceway groove, The slider of the linear guide device is provided with a detecting unit that directly detects the unevenness of the rail track groove, and has a fixed end that fixes the detecting unit to the slider. By comprising a beam member formed of an elastic material, a strain gauge attached to the beam member, and a stylus attached to the tip of the beam member on the side opposite to the fixed end and slidingly contacting the rail track groove, The slider and rail are not separated by the vibration from the machine that the linear guide device is installed, and the influence of the vibration from the machine and the influence of contamination from the external environment are eliminated, and the influence of the operating environment. Rukoto without the presence of an abnormality of the linear guide apparatus can be accurately determined.

In addition, by providing an electromagnet for attracting the beam member by magnetic force in the detection unit, the stylus can be separated from the rail track groove by attracting the beam member with the electromagnet except when an abnormality is detected. The occurrence of scratches can be suppressed.
In the above embodiment, the beam member is provided with the suction plate and the beam member is attracted by the electromagnet. However, the stylus itself may be formed of a magnetic material and the beam member may be attracted by the electromagnet. . In this way, the suction plate can be omitted, the tip end portion of the beam member can be reduced in weight, and the influence of the inertial force can be suppressed, and the sensitivity of detecting irregularities by the stylus can be further increased.

Moreover, in the said Example, although the stylus was demonstrated as a cone shape, a pyramid shape, an elliptical cone shape, etc. may be sufficient. In short, it suffices if the tip slidably contacting the rail track groove is formed at an acute angle.
Further, in the above embodiment, the detection unit is described as being provided at one end of the slider, but may be provided at both ends. In this way, it is possible to easily detect an abnormality when the slider stroke is long.

Furthermore, in the said Example, although the linear guide apparatus using a ball | bowl as a rolling element was demonstrated to the example, the same effect can be acquired also in the linear guide apparatus using a roller as a rolling element. In this case, the rolling element guide surface of the rail and the rolling element guide surface of the slider forming the load path are constituted by a rail raceway surface on which the roller rolls and a slider raceway surface.
Further, in the above-described embodiment, the linear motion device is described as a linear guide device. However, the linear motion device is linearly connected to the screw shaft as the fixed body having the shaft raceway groove as the rolling element guide surface via the ball as the rolling element. A ball screw device having a nut as a movable body having a nut raceway groove as a rolling element guide surface supported in a movable manner may be used as the linear motion device. In this case, the load path is formed by arranging the shaft raceway groove and the nut raceway groove to face each other.

The perspective view which shows the linear guide apparatus of an Example. Explanatory drawing which shows the installation state seen from the front of the detection part of an Example Explanatory drawing which shows the side of the detection part of an Example Explanatory drawing which shows the upper surface of the beam member of an Example Explanatory drawing which shows the sliding contact state of the stylus of an Example Explanatory drawing which shows the suction state of the beam member of an Example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Linear guide apparatus 2 Rail 3 Rail mounting hole 5 Rail track groove 6 Slider 6a Sleeve wall 7 Screw hole 8 Slider track groove 9 Ball 10 Return path 11 End cap 12 Direction change path 13 Side seal 15 Beam member 15a Fixed end 15b, 21b Tip 16 Mounting screw hole 17 Mounting bolt 19 Stitch 20 Suction plate 21 Mounting bracket 21b Flange 22 Electromagnet 23 Lead wire 24 Strain gauge 26 Wiring 26a, 26b Signal wire 28 Detector

Claims (3)

A fixed body having a rolling element guide surface, a rolling element guide surface facing the rolling element guide surface of the fixed body, and a moving body that linearly moves the fixed body, and the rolling element guide surface of the fixed body And a rolling element that rolls on a load path formed by the rolling element guide surface of the movable body,
A linear motion device, wherein the moving body is provided with a detection unit that directly detects irregularities of the rolling element guide surface of the fixed body. In claim 1,
The detection unit has a fixed end fixed to the moving body, a beam member formed of an elastic material, a strain gauge attached to the beam member, and a tip end opposite to the fixed end of the beam member And a stylus which is slidably in contact with the rolling element guide surface of the fixed body. In claim 2,
A linear motion device characterized in that an electromagnet for attracting the beam member by magnetic force is provided in the detection unit.