JP5245889B2 - Rolling guide device - Google Patents

Description

  The present invention relates to a rolling guide device having an endless track for infinite circulation of a cylindrical roller, and more particularly to a rolling guide device suitable for suppressing fretting between the rolling surface of the roller and the track surface. .

  Of the rolling guide devices used in a feed table device that supports the moving table so that it can move linearly with respect to the bed, in the linear motion rolling guide device having a finite track, the holding table is held by the reciprocating movement of the moving table. There is a known problem that the relative position of the cage is shifted little by little, and a phenomenon (micro slip phenomenon) in which the cage is finally detached from the guide rail occurs.

  Therefore, for example, in the techniques described in Patent Documents 1 and 2, the complexity and cost of the structure can be reduced without adding a special member based on the knowledge relating to the slip between the roller and the guide rail that is in rolling contact with the roller. The micro slip in the rolling guide device having a finite track is prevented without preventing the height and without causing a large-scale change in the structure of each member.

Japanese Patent No. 2808785 Japanese Patent No. 2897334

However, in the application of the rolling guide device, there is another problem that fretting occurs when the swing motion is repeatedly performed.
Here, as a countermeasure for suppressing fretting, in a rolling guide device having an endless track for infinite circulation of a cylindrical roller, when swinging with a set swing stroke amount, for example, it is set every predetermined cycle. By performing a maintenance operation in which the stroke is larger than the swing stroke, the lubricant is drawn between the roller rolling surface and the raceway surface to suppress fretting. However, such a countermeasure requires a maintenance operation of periodically performing an unnecessary stroke motion, so that there is still room for examination in order to improve the fretting resistance.

  Therefore, the present invention has been made paying attention to such a problem, and in the application of the rolling guide device, even when the swing motion is repeatedly performed, the above-described special maintenance operation is performed. It is an object of the present invention to provide a rolling guide device that can suppress the fretting wear and prolong the life of the device even when an inexpensive general grease is used for lubrication.

In order to solve the above-described problems, the present invention provides a rolling guide device having an endless track for infinite circulation of a cylindrical roller, the surface roughness in the circumferential direction of the rolling surface of the roller being the same. The surface roughness in the circumferential direction on the rolling surface of the roller is less than 0.05 μm in the center line average roughness, and the rolling surface of the roller is an elastic body. It is characterized in that it is a finished surface having a glossiness of 20 or more obtained by finish polishing in which abrasive particles comprising abrasive grains are made to collide with the rolling surface of the roller .
The rolling guide device according to the present invention can be applied to various rolling guide devices as long as it has an endless track for infinite circulation of a cylindrical roller. For example, this type of rolling guide device includes a guide rail and a linear guide device having a slider that is slid over a guide rail and is slidable through a cylindrical roller, a screw shaft, and a screw shaft thereof. For example, a ball screw having a nut externally fitted through a cylindrical roller and relatively movable in the axial direction can be exemplified.

  According to the rolling guide device of the present invention, since the circumferential surface roughness of the roller rolling surface is smaller than the axial surface roughness of the rolling surface, it is described in Patent Documents 1 and 2 above. The opposite effect of this technique occurs. That is, microslip occurs in the rolling roller. However, since the rolling guide device according to the present invention is limited to the one having an endless track that circulates the cylindrical roller infinitely, even if a micro slip occurs in the roller, the roller only revolves along the endless track. Thus, unlike the linear motion rolling guide device having a finite track, there is no problem that the cage is detached from the guide rail. And according to the rolling guide apparatus which concerns on this invention, a roller can be revolved little by little along an endless track by intentionally producing a micro slip in a roller. Therefore, the lubricant can be sequentially drawn between the rolling surface of the roller and the raceway surface. Therefore, the maintenance operation for replenishing the lubricant that causes the unnecessary stroke motion as shown in the above example is unnecessary, and fretting wear can be suppressed even if inexpensive general grease is used for lubrication. It has a particularly remarkable effect of being able to do it.

Further, in the rolling guide device according to the present invention, the surface roughness of the circumferential direction of the rolling surface of the roller is at 0.05μm or less in the center line average roughness, the rolling surface of the roller, the elastic body The finished surface having a glossiness of 20 or more obtained by finish polishing in which abrasive particles comprising abrasive grains are made to collide with the rolling surface of the roller. surface, i.e., without remaining foreign matter on the surface, more to a good surface roughness clean, seizure and wear, even more preferred in terms of improving the rolling performance and the sliding performance such as fatigue life extension It is.

  As described above, according to the rolling guide device of the present invention, in the application of the rolling guide device, even when the swing motion is repeatedly performed, a special maintenance operation is not required, and an inexpensive general grease is used. Even when used for lubrication, fretting wear can be suppressed and the life of the apparatus can be extended.

It is a perspective view which shows the linear guide apparatus of one Embodiment of this invention. It is a right half sectional view in the ZZ section of FIG. It is a perspective view which shows the roller incorporated in the linear guide apparatus of FIG. 1, and the processing method of the rolling surface of this roller. It is a figure which shows the abrasive | polishing particle | grains which are projected on a roller when performing finish grinding | polishing to a roller. It is a figure explaining the projection angle of the abrasive particle projected on a roller, The figure (a) is the figure which looked at the roller from the end surface direction, The figure (b) is a top view of (a). It is a figure explaining the effect | action of the abrasive particle projected on the roller. It is sectional drawing (figure corresponding to ZZ section in Drawing 1 of an embodiment) of a roller guide device shown as other examples of a rolling guide device concerning the present invention.

Hereinafter, an embodiment of a rolling guide device according to the present invention will be described with reference to the drawings as appropriate. In this embodiment, as a rolling guide device having an endless track for infinite circulation of a cylindrical roller, a guide rail and a slider straddling the guide rail and being slidable via the cylindrical roller are provided. It is an example of the linear guide apparatus which has.
As shown in the perspective view of FIG. 1, the linear guide device 1 includes a guide rail 2 and a slider 3 straddling the guide rail 2.

  The guide rail 2 is a long rod-like member having a substantially I-shaped cross section, and a plurality of fixing bolt holes 2b are provided on the upper surface 2a at a predetermined pitch. Further, a substantially V-shaped recess 2c having a pair of track surfaces 4a and 4b on the upper and lower sides is formed on the left and right side surfaces of the guide rail 2, respectively. The track surfaces 4 a and 4 b on the left and right side portions are formed along the longitudinal direction of both side surfaces of the guide rail 2. The slider 3 includes a slider body 5 having a substantially U-shaped cross section, and a pair of substantially U-shaped end caps 6 attached to both sides of the slider body 5 in the sliding direction.

  2, the slider body 5 has a pair of raceway surfaces 9a and 9b facing the raceway surfaces 4a and 4b of the guide rail 2 on the inner surfaces of both sleeve portions 5b. . A total of four rows of load tracks 10a and 10b are constituted by the track surfaces 9a and 9b of the slider 3 and the track surfaces 4a and 4b of the guide rail 2 which are arranged to face each other. Each of the load tracks 10a and 10b is provided with a cylindrical steel roller (roller) 8 as a plurality of rolling elements while being held by a cage 20, and slides on the guide rail 2. The load of the slider 3 is supported. A holding piece (not shown) is interposed between the adjacent rollers 8.

  Also, the sleeves 5b of the slider body 5 are provided with through-holes along the sliding direction at a total of four positions on the left and right sides, and cylindrical holders 12 made of a resin material are fitted into the respective through-holes. Yes. The holder 12 has a through hole having a rectangular cross section in which a guide groove 13 for guiding the guide arm portion of the holding piece is formed. The through holes in the holder 12 serve as roller return paths 11a and 11b, and the roller return paths 11a and 11b smoothly guide the movement of the rolling roller 8 (and the holding piece) during infinite circulation. doing.

  Further, the pair of end caps 6 are provided with direction changing paths 14a and 14b, respectively. Each of the direction change paths 14a and 14b is a curved path having a substantially rectangular cross section, and in order to avoid the intersection between the upper and lower load tracks 10a and 10b and the roller return paths 11a and 11b, the direction change paths 14a and 14b are three-dimensionally crossed. At the same time, the load tracks 10a and 10b and the roller return paths 11a and 11b are communicated with each other so that the roller 8 (and the holding piece) is guided to change its circulation direction. As a result, the above-described load tracks 10a and 10b, the roller return paths 11a and 11b, and the direction change paths 14a and 14b are arranged in four rows of upper and lower rows for infinite circulation of the plurality of rollers 8 interposed in the load tracks 10a and 10b. The roller circulation path is configured as an endless track.

Here, as shown in a perspective view in FIG. 3, the roller 8 has a surface roughness in the circumferential direction A on the rolling surface 8a smaller than a surface roughness in the axial direction B on the rolling surface 8a. ing. In particular, in this embodiment, the surface roughness in the circumferential direction A on the rolling surface 8a of the roller 8 is set to 0.05 μm or less in the center line average roughness.
Hereinafter, a method for polishing the rolling surface 8a of the roller 8 will be described in detail.

  On the rolling surface 8a of the roller 8, after grinding the rolling surface 8a with a grindstone (not shown), the method shown in FIG. 3, that is, abrasive particles 22 having an average particle diameter of about 0.02 to 3 mm are shot blasted. The desired finish polishing, that is, the rolling surface 8a of the roller 8 is roughened in the circumferential direction A on the rolling surface 8a by a method of projecting and polishing from the nozzle 23 to the rolling surface 8a of the roller 8. Finish polishing is performed so that the surface roughness is smaller than the surface roughness in the axial direction B of the rolling surface 8a.

  Here, the abrasive particles 22 projected from the roller 8 are abrasive particles 22 made of an elastic body (elastic material) such as rubber or thermoplastic elastomer and containing abrasive grains 24 (see FIG. 4) of # 2000 or more. The material of the abrasive grains 24 used and contained in the abrasive particles 22 includes alumina (Al 2 O 3), diamond, or silicon carbide (SiC). The proportion of the abrasive grains 24 contained in the abrasive particles 22 is 0.5 to 90% by mass, preferably 0.5 to 50% by mass, and more preferably 0.5 to 8% by mass. Most preferably, it is 0.5-5 mass%. In the example of the present embodiment, as the abrasive grains contained in the abrasive particles 22, abrasive grains having a smaller particle diameter than the abrasive grains of the grindstone used in the previous step of the final polishing are used.

Further, when the abrasive particles 22 are projected onto the roller 8, as shown in FIG. 5, the abrasive particles are angled from 0 ° to 90 ° with respect to the grinding direction (axial direction of the roller 8) in the previous step ( The angle of projection of the abrasive particles θ1 toward the plane 5 perpendicular to the central axis 8b of the roller 8 was projected.
Furthermore, the incident angle θ2 of the abrasive particles with respect to the direction perpendicular to the plane formed by the grinding surface (rolling surface 8a of the roller 8) in the pre-finishing process, that is, horizontal to the central axis 8b of the roller 8 The angle θ <b> 2 at which the abrasive particles 22 are projected onto the rolling surface 8 a of the roller 8 toward the flat surface 26 is projected to exceed 0 ° and less than 90 °. In FIG. 5, reference numeral 27 denotes a grinding eye generated on the rolling surface 8 a of the roller 8 in the previous grinding process.

Next, operations and effects of the linear guide device 1 will be described.
As described above, according to the linear guide device 1, the surface roughness in the circumferential direction A on the rolling surface 8a of the roller 8 is smaller than the surface roughness in the axial direction B on the rolling surface 8a. The effect opposite to the technique described in Patent Documents 1 and 2 occurs. That is, micro slip occurs in the rollers 8 that roll on the upper and lower four rows of roller circulation paths.

  However, in this linear guide device 1, the upper and lower four rows of roller circulation paths cause the cylindrical rollers 8 to circulate infinitely, so that even if microslip occurs in the rollers 8, the rollers 8 revolve along the roller circulation paths. Only. And according to this linear guide apparatus 1, the roller 8 can be revolved little by little along a roller circulation path by intentionally producing the micro slip in the roller 8.

  Therefore, in the application of the linear guide device 1, even when the swing motion is repeatedly performed, the lubricant can be sequentially drawn between the rolling surface 8a of the roller 8 and the load tracks 10a and 10b. it can. Therefore, the maintenance operation for replenishing the lubricant that causes the unnecessary stroke motion as shown in the above example is unnecessary, and fretting wear can be suppressed even if inexpensive general grease is used for lubrication. It has a particularly remarkable effect of being able to do it.

  Further, the linear guide device 1 is configured such that when the abrasive particles 22 are projected onto the rolling surface 8a of the roller 8 to perform the desired finish polishing, the abrasive particles 22 projected on the roller 8 are made of rubber, heat, and the like. Since the abrasive particles 22 made of an elastic material such as a plastic elastomer and containing # 2000 or more abrasive grains 24 are used, the rolling of the roller 8 is caused by the abrasive particles 22 projected onto the roller 8 as shown in FIG. The desired finish polishing is performed on the surface 8a, and there is an effect that the abrasive grains 28 of the grindstone remaining on the surface of the rolling surface 8a in the previous grinding step are removed. Also, the rolling surface 8a of the roller 8 can be finish-polished to a glossiness of 20 (JIS Z 8741) or higher.

Specifically, in a roller used in a rolling guide device such as the linear guide device 1, various surface properties represented by the surface roughness of the rolling surface 8a are important factors as well as the dimensional accuracy of the roller. It is known that the fatigue life of the roller is affected by these surface properties. Conventionally, various surface polishing methods have been proposed in order to optimize the surface properties.
For example, in the finish polishing of a roller (cylindrical roller) used in the linear guide device 1, conventionally, so-called lapping or superfinishing has been performed in order to improve surface roughness and dimensional accuracy. However, in the lapping process, it is inevitable that the abrasive grains dropped from the grindstone pierce and remain on the rolling surface 8a (surface to be polished) of the roller 8.

  That is, in the lapping process or the superfinishing process, the grindstone is pressed against the rolling surface 8a of the roller 8 for processing, so that the abrasive grains dropped from the grindstone are pressed against the rolling surface 8a and pierced. The abrasive grains remaining after being pierced into the rolling surface 8a cannot be easily removed in the subsequent cleaning process or the like, and remain until the final product is obtained. If the use conditions are high load conditions or rolling or sliding at high speed while the abrasive grains are pierced, surface damage or surface wear occurs due to the pierced abrasive grains.

The number of abrasive grains remaining after piercing the rolling surface 8a can be reduced by improving the supply and discharge of the grinding liquid, the composition of the grinding liquid filter, the grindstone, etc., but the number of remaining abrasive grains is smaller. This contributes to a longer life of the linear guide device 1.
Further, in the above-described conventional processing method, a streak peculiar to grinding called so-called “grinding eyes” remains in a certain direction or a specific direction on the surface of the rolling surface 8a, and a so-called “mirror surface” that is brilliant is obtained. Hateful. Moreover, in order to obtain the surface roughness below 0.03 μmRa, the processing cost is usually large. Further, it is possible to obtain a surface roughness of less than 0.03 μm Ra while maintaining the dimensional accuracy, but the processing cost is increased.

  With respect to such a problem, according to the polishing method employed for the rolling surface 8a of the roller 8 of the above embodiment, the abrasive particles 22 made of an elastic material and containing the abrasive grains 24 are removed from the roller 8 (object to be polished). By performing finish polishing by colliding with the rolling surface 8a, the rolling surface 8a of the roller 8 can be a finished surface having a glossiness of 20 or more. By making the rolling surface 8a of the roller 8 a finished surface having a glossiness of 20 or more, that is, a surface having no foreign matter remaining on the surface and having a good cleanness and roughness, the rolling performance and sliding performance such as extending the seizure life can be achieved. There is a performance improvement effect.

  Furthermore, according to the polishing method employed for the rolling surface 8a of the roller 8 of the above embodiment, when the final polishing is performed by causing the abrasive particles 22 to collide with the rolling surface 8a of the roller 8, the preceding step of the final polishing is performed. Since the abrasive particles 22 collided with the rolling surface 8a of the roller 8 at an angle of 0 ° or more and 90 ° or less with respect to the grinding direction in FIG. Therefore, the abrasive grains sticking to the rolling surface 8a of the roller 8 can be efficiently removed by setting the collision direction of the abrasive particles to a state having a horizontal angle from the grinding direction. . This is because the piercing direction of the abrasive grains remaining after being pierced into the workpiece by the processing by grinding is along the grinding direction.

  And according to the grinding | polishing method employ | adopted as the rolling surface 8a of the roller 8 of the said embodiment, it removes the abrasive grain which stabbed into the rolling surface 8a of the roller 8, and is removed at the same time as the grinding mark and grinding of a previous process. The streaks are also removed well, and a clean and rough surface can be obtained. Further, since the abrasive grains remaining after the piercing are removed, the rolling performance such as the seizure life and the sliding performance can be improved on the rolling surface 8a of the roller 8 and the raceway surface facing the rolling surface 8a. Here, the angle of the abrasive particles 22 that collide with the rolling surface 8a is preferably 45 ° or more and 90 ° or less, and more preferably 70 ° or more and less than 90 ° with respect to the grinding direction in the previous step.

  In addition, according to the polishing method employed for the rolling surface 8a of the roller 8 of the above embodiment, the abrasive particles 22 are set at 0 ° or more with respect to the grinding direction in the pre-finishing process of the rolling surface 8a of the roller 8. Since the incident angle of the abrasive particles with respect to the direction perpendicular to the plane formed by the grinding surface in the pre-finishing polishing process is more than 0 ° and less than 90 ° because it collides with the rolling surface 8a at an angle of 90 ° or less. That is, since the abrasive particles collide at an angle in the direction perpendicular to the rolling surface 8a, the abrasive particles 22 collide with the rolling surface 8a at a so-called incident angle with respect to the rolling surface 8a. It is possible to polish the rolling surface 8a efficiently.

  Further, by causing the abrasive particles to collide with the rolling surface 8a with the incident angle, a clean and rough surface can be more effectively obtained simultaneously with the removal of the abrasive grains which have been stuck. Further, since the abrasive grains remaining after being stuck into the rolling surface 8a are removed, the rolling performance and sliding performance such as seizure life can be improved on the rolling surface and raceway surface. Here, the incident angle of the abrasive particles 22 is preferably 45 ° or less, and more preferably 20 ° or less.

  Further, according to the polishing method employed for the rolling surface 8a of the roller 8 of the above embodiment, the abrasive particles 24 included in the polishing particle 22 are used when the final polishing is performed by causing the abrasive particles 22 to collide with the rolling surface 8a. As the abrasive grains having a particle diameter smaller than the abrasive grains of the grindstone used in the previous step of the finish polishing are used, the contact area between the rolling surface 8a and the abrasive particles 22 when colliding with the rolling surface 8a is: It becomes a thing larger than the particle size of the abrasive grain used at the previous process. Therefore, even if the grain size of the abrasive grains 24 contained in the abrasive grains 22 is smaller than the grain size of the abrasive grains used in the previous step, the abrasive grains that stick into the rolling surface 8a are elasticized. It can be effectively removed by the body part. Moreover, since the particle size of the abrasive grains 24, which is a component having a polishing effect, contained in the abrasive particles 22 is smaller than the particle size of the abrasive particles in the previous step, a surface having a better roughness than the surface obtained in the previous step is obtained. It is done.

The rolling guide device according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, as the rolling guide device according to the present invention, the linear guide device having the guide rail 2 and the slider 3 straddling the guide rail 2 and slidably movable via the cylindrical roller 8. However, the present invention is not limited to this, and the rolling guide device according to the present invention can be applied to various rolling guide devices as long as it has an endless track for infinite circulation of a cylindrical roller. . For example, this type of rolling guide device is applicable even to a ball screw having a screw shaft and a nut that is externally fitted to the screw shaft via a cylindrical roller and is relatively movable in the axial direction. Is possible. Further, as this type of rolling guide device, a roller guide device having a U-shaped guide rail 2 and a slider 3 slidably movable in a U-shaped recess of the guide rail 2 as illustrated in FIG. 1 may be adopted for the roller 8.

1 Linear guide device (rolling guide device)
2 Guide rail 3 Slider 5 Slider body 6 End cap 8 Roller (roller)
DESCRIPTION OF SYMBOLS 12 Holder 20 Cage 22 Abrasive particle 23 Nozzle for shot blast 24 Abrasive grain 27 Grinding eye 28 Abrasive grain of grindstone remaining stuck in roller rolling surface

Claims (4)

A rolling guide device having an endless track for infinite circulation of a cylindrical roller,
Circumferential surface roughness of the rolling surface of the roller is smaller than the axial surface roughness in the same rolling surface,
Surface roughness in the circumferential direction of the rolling surface of the roller state, and are 0.05μm or less in the center line average roughness,
The rolling surface of the roller is made of an elastic body and is a finished surface having a glossiness of 20 or more obtained by finish polishing in which abrasive particles containing abrasive grains collide with the rolling surface of the roller. A rolling guide device. 2. The rolling guide device according to claim 1, wherein a surface roughness in a circumferential direction on a rolling surface of the roller is 0.03 μm or less in a center line average roughness . The surface roughness in the circumferential direction of the rolling surface of the roller is smaller than the surface roughness in the axial direction of the rolling surface so as to intentionally generate microslip in the roller. The rolling guide apparatus according to claim 1 or 2.   The rolling surface of the roller is the finish in which, after the rolling surface is ground with a grindstone, polishing particles having an average particle diameter of 0.02 to 3 mm are projected from the shot blast nozzle onto the rolling surface and polished. The rolling guide apparatus according to any one of claims 1 to 3, wherein the rolling guide apparatus is obtained by polishing.

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