Patent Application
20090060645
The present invention relates to a structure for fixing a track rail to a base portion of a variety of machines, devices, and the like, the track rail relating to a guiding apparatus in which a slider moves along the track rail to convey and guide a variety of movable bodies in a freely reciprocating manner.
Heretofore, as a linear guiding apparatus for constructing a liner guide portion of machine tools and various industrial robots, there has been known one composed of a liner track rail on which a ball rotating/running surface is formed along a longitudinal direction, and a slider assembled to the track rail with a large number of balls interposed therebetween. The slider includes a load rotating/running surface opposite to the ball rotating/running surface of the track rail, and a circulation route that endlessly circulates therethrough the large number of balls rotating and running between the load rotating/running surface and the rotating/running surface of the track rail while applying a load therebetween. By circulating the balls in such an endless circulation route, it becomes possible for the slider to continuously move across an overall length of the track rail.
In general, the track rail is fixed to a base portion such as a bed or a column of the machine tool or the like by fastening a fixing bolt thereto. For this purpose, in the track rail, at a predetermined interval along a longitudinal direction thereof, rail attachment holes through which the fixing bolts are inserted are formed in a penetrating manner, or tap holes which are used for screwing the fixing bolts inserted through the base portion are formed (JP 2003-166531 A and the like).
Meanwhile, the range of use of such a guiding apparatus in which the track rail and the slider are combined is not only limited to the machine tools and the industrial robots, but also spread to fields of medical machines, various measuring instruments, and precision instruments. Following this, needs for a small guiding apparatus suitable for light-load use are increased. Further, in recent years, small-sized machines such as a milling machine, a lathe, and a press machine, each of which is miniaturized to a palm size, have also been studied, and needs for such an extremely miniaturized guiding apparatus have been increased also in this point.
Patent Document 1: JP 2003-166531 A
However, when such a small-sized guiding apparatus is put into practical use, the problem is how to fix the track rail to the base portion. As the guiding apparatus is further miniaturized, a width of the track rail is further narrowed as a matter of course, and a diameter of the fixing bolt for fixing the track rail to the base portion inevitably becomes smaller. Therefore, when the width of the track rail is excessively narrowed, the tap hole for the track rail or the base portion cannot be processed, and it becomes difficult to fix the track rail to the base portion by using the fixing bolts.
A guiding apparatus having a track rail whose width is 3 mm is actually available on the market (LM Guide RSR 3M/manufactured by THK Co., Ltd.). In this guiding apparatus, a tap hole with a nominal diameter of M1.6 is formed in the track rail, whereby the fixing of the track rail to the base portion is realized. However, for example, in a guiding apparatus having a track rail whose width is 1 mm, a hole having a diameter of 0.4 mm can be drilled at maximum, considering that the ball rotating/running surface is formed on each side surface of the track rail, and it is usually difficult to implement a tapping process for the hole. Hence, it is necessary to fix the track rail to the base station by another method than the fastening of the fixing bolts.
As a method of fixing the track rail without using the fixing bolts, there is considered a method of making the track rail adhere to the base station by using an adhesive. However, it is necessary to set a layer thickness of the adhesive to a certain extent or more in order to ensure adhesive strength, and there is a problem that a height of the track rail fixed to the base portion becomes large despite the small-sized guiding apparatus. Further, when the layer thickness of the adhesive is not constant, the track rail undesirably waves, thereby leading to such a fatal problem that running accuracy of the slider decreases.
Further, as still another fixing method, there is considered a method of providing a clamp member for sandwiching the track rail in a width direction thereof, and fixing the clamp member to the base station. However, the clamp member inevitably becomes larger than the width of the track rail, and there are problems that not only the miniaturization of the guiding apparatus is spoiled but also a cost thereof increases.
The present invention has been made in view of the above-mentioned problems. It is an object of the present invention to provide a fixing structure of a track rail, which is capable of fixing the track rail to a base portion without using a fixing bolt, in a case of fixing a guiding apparatus composed of the track rail and a slider to the base portion, and particularly suitable for an extremely small-sized guiding apparatus in which it is difficult to process a tap hole.
That is, the present invention relates to a structure for fixing a track rail of a guiding apparatus to a base portion including: a filling hole penetrating through the track rail toward the base portion; an anchor hole communicating with the filling hole and formed in the base portion; and a coupling anchor filled to the filling hole of the track rail and the anchor hole of the base portion, followed by curing.
In accordance with such a fixing structure, it is only necessary to form holes for filling thereto a die-molding material that becomes the coupling anchor in the track rail and the base portion. The die-molding material is filled to those holes formed so as to communicate with each other, followed by curing, whereby the coupling anchor is present so as to extend over the filling hole on the track rail side and the anchor hole on the base portion side. In this way, the track rail and the base portion are integrated together by the coupling anchor, thus making it possible to fix the track rail to the base portion.
Specifically, according to the present invention, even in such a case where the tap hole for fastening the fixing bolts to the track rail and the base portion cannot be processed, it becomes possible to fix the track rail to the base portion.
Fixing strength of the track rail with respect to the base portion depends on an area where the coupling anchor is brought into contact with the filling hole on the track rail side and the anchor hole on the base portion side. If such a contact area becomes larger, the fixing strength of the track rail is enhanced by an increased amount. Further, from a viewpoint of enhancing the fixing strength, it is preferable to form an engagement protrusion on the coupling anchor for the purpose of preventing the coupling anchor from coming off from the filling hole of the track rail or the anchor hole of the base portion. In order to make the coupling anchor include such an engagement protrusion, it is necessary to form a stopper groove on an inner wall of any one of the filling hole and the anchor hole or the inner walls of both of them. If such a stopper groove is formed before filling the die-molding material, the engagement protrusion is formed naturally as the die-molding material is being filled to the filling hole and the anchor hole, and the coupling anchor can be prevented from coming off from the track rail and the base portion. Such a shape change of the filling hole and the anchor hole is appropriately performed according to the required fixing strength of the track rail. If the requirement for the fixing strength of the track rail is not strict, the filling hole and the anchor hole may be holes with an even inner diameter.
Further, the present invention is an effective one when the track rail of the extremely small-sized guiding apparatus in which it is difficult to process the tap hole is fixed to the base portion of the guiding apparatus. As described above, the shape of the filling hole on the track rail side and the shape of the anchor hole on the base portion side are appropriately changed, thus making it possible to sufficiently ensure the fixing strength of the track rail to the base portion. Accordingly, the present invention enables to fix, to the base portion, even a track rail having a size at which the process for the tap hole can be performed. The fixing structure of the track rail according to the present invention does not require the fixing bolt. Accordingly, it is not necessary to perform the tapping process for the track rail side or the base portion side. In addition, the fixing of the track rail is completed only by injecting the die-molding material to the filling hole and the anchor hole. Accordingly, it is possible to embody the fixing structure at low cost in comparison with the conventional fixing structure in which the fixing bolt is fastened. Hence, the fixing structure according to the present invention is a fixing structure effective in track rails with all sizes.
Further, in the fixing structure of the track rail according to the present invention, it is not necessary to perform the tapping process for the base portion side, and accordingly, the fixing structure according to the present invention is an extremely effective one also in a case where it is difficult to perform machining with respect to the base portion.
Still further, it is satisfactory if the die-molding material filled to the filling hole and the anchor hole can be filled as a fluid or a semi-fluid to the filling hole and the anchor hole, is cured after being filled, and maintains a shape thereof. For example, a resin material such as an adhesive, gypsum, cement, paper clay, solder, and the like are considered.
1 . . . track rail,
2 . . . slider,
6 . . . base portion,
7 . . . coupling anchor,
11 . . . filling hole,
61 . . . anchor hole
A description of a fixing structure of a track rail according to the present invention will be made below in detail referring to the accompanying drawings.
In the track rail 1, a cross section perpendicular to a longitudinal direction thereof is formed to be substantially rectangular, and a ball rotating/running groove 10 on which balls 3 rotate and run is formed on each of side surfaces thereof. Further, in the track rail 1, filling holes 11 are formed at an appropriate interval in the longitudinal direction, and the filling holes are formed so as to penetrate from a top surface 12 of the track rail to a bottom surface 13 thereof.
Meanwhile, the slider 2 is composed of a stainless steel-made moving block 4 having tap holes 42 to which an attachment surface 41 of a movable body such as a table and fixing bolts of the movable body are screwed, and a pair of synthetic resin-made cap bodies 5 and 5 fixed to both front and rear end surfaces of the moving block 4. The cap bodies 5 are fixed to the moving block 4 by using an attachment bolt 50, whereby each endless circulation route of the balls 3 is provided in the slider.
The moving block 4 is formed into a substantial saddle shape in cross section, and is disposed so as to straddle the track rail 1. The balls 3 rotate and run between the moving block 4 and the ball rotating/running grooves 10 formed on both side surfaces of the track rail 1 while applying loads therebetween. In this way, the slider 2 that mounts the movable body thereon is freely movable along the track rail 1 while applying a load thereto. Further, the balls 3 circulate in each endless circulation route, whereby the slider 2 becomes freely movable along the track rail 1 without imposing limitations on a stroke.
In a state where the track rail 1 is disposed at a predetermined position on the base portion 6, each filling hole 11 on the track rail 1 side and each anchor hole 61 on the base portion 6 side communicate with each other. Into insides of the filling hole 11 and the anchor hole 61, one coupling anchor 7 is inserted so as to extend over, both thereof. The coupling anchor 7 is one formed in such a manner that a die-molding material in a fluid state is filled to the filling hole 11 of the track rail 1 from an upper opening thereof, and is kept being filled to the anchor hole 61 of the base portion 6 and the filling hole 11 of the track rail 1, followed by curing. Hence, the coupling anchor 7 is formed into just the same shape as those of the anchor hole 61 of the base portion 6 and the filling hole 11 of the track rail 1, and is brought into close contact with inner walls of the anchor hole 61 and the filling hole 11.
As the die-molding material that forms the coupling anchor 7, for example, a resin material, gypsum, cement, paper clay, solder, and the like are considered, and in this example, an adhesive of a biliquid room-temperature curing type is used. As shown in
Then, when the poured adhesive is cured, the coupling anchor 7 brought into close contact with the filling hole 11 on the track rail 1 side and the anchor hole 61 on the base portion 6 side is formed. Although differing depending on types, shear strength of a general adhesive is approximately 10 to 40 MPa, and as a surface area of the hole to which the coupling anchor 7 is filled is further increased, drag against force to pull out the anchor 7 becomes larger. For example, in the case of using, as the coupling anchor 7, an adhesive with shear strength of 30 Mpa, when the adhesive is filled to the anchor hole 61 having an inner diameter of 0.4 mm and a depth of 1.4 mm, followed by the curing, and the adhesive is formed as the coupling anchor 7, the drag against the pulling out of the coupling anchor 7 becomes approximately 52.8 N. This value is one regarding one filling hole 11 and one anchor hole 61. When the plurality of filling holes 11 are provided on one track rail 1, and the anchor holes 61 whose number corresponds to that of those are provided in the base portion 6, the drag becomes much larger. Hence, if the number of filling holes 11 formed in the track rail 1 is selected in response to a range of use of the liner guiding apparatus, it becomes possible to fix the track rail 1 onto the fixed base 6 with sufficient strength.
Note that, in
In an example shown in
As shown in
In order to make the integration of the die-molding material that forms the coupling anchor and the reinforcement pin stable, irregularities may be provided on a surface of the reinforcement pin. In particular, in the case of using gypsum, cement, or the like as the die-molding material, in order to make it possible to sufficiently apply a reverse radial load applied by the coupling anchor to the track rail, it is preferable that, as in this embodiment, the reinforcement pin be provided in the coupling anchor, and the irregularities be formed on the surface of the reinforcement pin in order to stably integrate the reinforcement pin and the die-molding material.
In an example shown in
Specifically, in each filling hole 11 of the track rail 1, the stopper groove 9a larger in inner diameter than the filling hole 11 is formed in the opening edge in the top surface 12. Meanwhile, in each anchor hole 61 of the base portion 6, the stopper groove 9b is formed in the inside thereof apart from the attachment surface 60. The stopper groove 9b of the anchor hole 61 can be formed in such a manner that, after the anchor hole 61 is drilled, as shown in
Then, after the stopper grooves 9a and 9b are formed as described above, in a similar way to the method shown in
Note that it is not always necessary that each stopper groove 9b in the inside of the anchor hole 61 be formed by the chipping using the end mill 70, and for example, the stopper groove 9b may be formed by forming a spiral groove on the inner wall of the anchor hole 61 as in the tapping process.
The fourth embodiment illustrates an example of the fixing structure in the case where the base portion 6 is a plate member such as an iron plate. When the base portion 6 is the plate member, the depth of each anchor hole 61 cannot be ensured sufficiently. If only through holes are formed in the base portion 6, the adhesive is filled to the through holes, and the coupling anchors 7 are thereby formed, the coupling anchors 7 easily come off from the base portion 6 when the load in the direction of lifting up the track rail 1 is applied to the track rail 1.
Accordingly, in the example shown in
As a method of making the coupling anchor 7 include the engagement head portion 71, as shown in
In accordance with the fixing structure shown in the fourth embodiment, even if the base portion 6 is the plate-like member, the fixing structure of the present invention is embodied, and it is possible to stably fix the track rail 1 to the base portion 6 without using fixing bolts.
Note that, the description has been made of the case of fixing the track rail of the linear guiding apparatus to the base portion thereof in each of the above-described embodiments, but the track rail is not limited to the linear one, and may be a curved one that is curved with a fixed curvature.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-103688 | Mar 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2006/304982 | 3/14/2006 | WO | 00 | 9/28/2007 |
