JP2004169880A - Construction and method of for gap adjustment of ball screw containing spacer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide gap adjustment construction of a ball screw containing a spacer capable of adjusting gap between the spacer and the ball with minimum man-hour without extracting the ball and the spacer in rolling raceway. <P>SOLUTION: The construction forms screw grooves 7, 8 opposed to screw axis 2 and a nut 3, respectively and then forms the helical rolling raceway 9 between both of the screw grooves 7, 8. It provides a plurality of the balls 4 and the spacer 5 interposing between these balls 4 in the rolling raceway 9. It attaches to the nut 3 circulation parts, such as a tube 6 or the like on which a circulation pathway 10 is formed for circulating the balls 4 and the spacer 5 on the rolling raceway 9 with both ends of the tube being into communication with each other. It prepares a plurality of kinds distinct from each other in length of the circulation pathway 10 as the circulation parts, such as the tube 6 or the like. It makes it possible to adjust the gap between the ball 4 and the spacer 5 by selectively attaching to the nut 3 optional thing out of the circulation parts, such as a plurality of kinds of the tube 6 or the like. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a clearance adjusting structure for a ball screw having a spacer used in a machine tool, an electric injection molding machine, a semiconductor manufacturing apparatus, and various other devices.
[0002]
[Prior art]
Ball screws with spacers inserted between the balls are used to prevent torque fluctuations and wear by eliminating friction between the balls, and to prevent collision noise between the balls. In this case, the spacer is a substantially disk-shaped member having concave surfaces at both ends, and has an outer diameter smaller than a ball diameter so that the spacer can smoothly pass through a circulation path formed of a tube or the like. Here, when assembling the ball screw, if the ball and the spacer are alternately inserted into the rolling path between the screw shaft and the nut and the circulation path such as the tube, the spacer may fall down in some cases. Large gaps may remain. Conventionally, as a measure for adjusting the gap, there has been disclosed a technique of performing appropriate gap management by using, for example, several types of spacers having different widths and using them in combination (Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-120825
[Problems to be solved by the invention]
However, even if spacers having different widths are used as a measure for clearance adjustment as in the above-described conventional example, it is necessary to adjust the effective diameter of the rolling path formed by the screw grooves of the screw shaft and the nut or to adjust the preload. Due to factors such as a difference in the diameter of a ball that has been slightly changed in the order of microns with respect to the diameter, it was sometimes necessary to adjust the final gap by changing the combination of the spacers even if the model number was the same.
For example, if only the spacers in the circulation path made of tubes are changed, the number of steps for reassembly is reduced, but in some cases, all the balls and spacers in the rolling path are completely removed and reassembled. And the number of assembling steps is greatly increased.
[0005]
An object of the present invention is to provide a clearance adjustment structure and a clearance adjustment method for a ball screw with a spacer which can adjust the clearance between the spacer and the ball with minimum man-hour without extracting the ball and the spacer in the rolling path. It is.
[0006]
[Means for Solving the Problems]
In the gap adjusting structure for a ball screw with a spacer according to the present invention, opposed thread grooves are respectively formed on an outer diameter surface of a screw shaft and an inner diameter surface of a nut loosely fitted on an outer periphery of the screw shaft. A plurality of balls and a spacer interposed between the balls are provided on a spiral rolling path formed between the balls, and both ends of the ball and the spacer are communicated with the nut at both ends thereof. A ball screw with a spacer for mounting a circulating component having a circulating passage formed therein, the ball screw having the following configuration. That is, as the circulating component, a plurality of types of circulating paths having different lengths are provided, and an optional circulating component is selectively mounted on the nut from the plurality of types of circulating components, so that the ball and The gap between the spacers can be adjusted. In other words, as the circulating component, a plurality of types of components that are selectively attached to the nut are provided, and the plurality of types of circulating components include a ball in a circuit path formed by a circulating path and a rolling path. The lengths of the circulation paths are different from each other so that the gap between the spacers can be adjusted.
According to this configuration, when the gap between the spacer and the ball does not match at the time of assembling, the gap can be adjusted to be appropriate by replacing the circulating component with one having a different circulation path length. By adjusting the gap in this way, it is possible to obtain a ball screw in which the spacer does not fall in the circulation portion. The replacement of the circulating components does not require extracting the balls and spacers in the rolling path, and can be performed with the balls and spacers inserted in the rolling path. Therefore, gap adjustment can be performed with a minimum number of man-hours.
[0007]
In the present invention, the circulating component may be a tube. In the case of a tube, a plurality of types having different circulation path lengths can be easily prepared.
When the circulating component is a tube, the tube has, for example, a substantially U-shape including a pair of legs and a body connecting the legs. The tube has the pair of leg portions fitted into a pair of tube fitting holes formed in the nut so as to communicate with the rolling path.
[0008]
In such a substantially U-shaped tube, there are the following two configurations for varying the length of the circulation path. One is to make the various tubes different in length of the legs. Tubes selected from a plurality of types of tubes having different circulation path lengths are fitted with the legs on both sides into a pair of tube fitting holes of the nut as described above, but a tube with a long leg is used. When used, a gap is created between the outer surface of the nut and the body of the tube. Therefore, a spacer having a thickness corresponding to the length of the legs of the plurality of types of tubes is prepared, and the spacer having the corresponding thickness is interposed between the body of the tube and the outer surface of the nut. A tube holding member for holding the body of the tube is fixed to the nut from above the spacer.
When the spacer is used as described above, even if a tube having a long leg is used, the tube can be stably fixed without being unstable due to the body of the tube being lifted from the outer surface of the nut. Instead of using the spacer, the tube holding member may be prepared for each tube type having a different leg length. However, since the spacer has a simple shape such as a plate piece as compared with the tube holding member, a plurality of tube holding members are provided. It is easy to prepare.
[0009]
Another configuration in which the length of the circulation path of the substantially U-shaped tube is different is that the radius of curvature in the arc-shaped bent portion serving as a connection portion between the leg portion and the body portion is different from each other. . Since the radii of curvature at the bent portions are different from each other, a plurality of types of tubes having different lengths of the circulation path are prepared, and selectively mounted on the nut.
In the case of this configuration, even if tubes having different circulation path lengths are attached to the nut, the distance between the outer surface of the nut and the body of the tube does not change, and no gap is generated between the outer surface of the nut and the tube body. . Therefore, it is possible to stably fix each type of tube to the nut without interposing a spacer or preparing a plurality of types of tube pressing members. That is, it is sufficient to prepare a plurality of different types of tubes only.
[0010]
The ball screw with adjustable spacer according to the present invention is an invention in which the spacer using the spacer among the gap adjusting structures of the ball screw with spacer according to the present invention is grasped as a ball screw.
That is, in the ball screw with the adjustable spacer according to the present invention, opposed screw grooves are formed on the outer diameter surface of the screw shaft and the inner diameter surface of the nut loosely fitted on the outer periphery of the screw shaft. A plurality of balls and a spacer interposed between the balls are provided on a spiral rolling path formed between the grooves, and both ends of the ball and the spacer are communicated with the nut at both ends thereof. A ball screw with a spacer mounted with a circulating part having a circulating path formed therein for circulating, wherein the circulating part is a tube, and the tube is substantially composed of a pair of legs and a trunk connecting the legs. It is U-shaped, and the pair of leg portions respectively fits into a pair of tube fitting holes formed in the nut so as to communicate with the rolling path, between the outer surface of the nut and the body of the tube. A spacer with a thickness corresponding to the length of the tube leg Zaisa is one in which the tube is fixed to the nut be secured to the nut of the tube pressing member for pressing the body portion of the tube from the top of the spacer.
According to this configuration, since a spacer having a thickness corresponding to the length of the leg of the tube is interposed between the outer surface of the nut and the body of the tube, by using tubes having different leg lengths as appropriate, The clearance between the spacer and the ball can be adjusted with minimum man-hour without extracting the ball and the spacer in the rolling path, and in that case, the tube can be fixed to the nut stably.
[0011]
The gap adjusting method for a ball screw with a spacer according to the present invention is characterized in that opposing screw grooves are respectively formed on an outer diameter surface of a screw shaft and an inner diameter surface of a nut loosely fitted on an outer periphery of the screw shaft. A plurality of balls and a spacer interposed between the balls are provided on a spiral rolling path formed between the balls, and both ends of the ball and the spacer are communicated with the nut at both ends thereof. In a ball screw with a spacer for mounting a circulation part having a circulation path to be circulated, a plurality of types of circulation parts having different lengths of the circulation path are prepared as the circulation parts. The clearance between the ball and the spacer is adjusted by selectively mounting the circulating parts of the above on the nut.
According to this method, the clearance can be adjusted with a minimum number of man-hours without extracting the ball and the spacer in the rolling path.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a ball screw having a spacer having a gap adjusting structure according to this embodiment, and FIGS. 2A and 2B are a plan view and a side view of a main part of the ball screw. The ball screw 1 includes a screw shaft 2, a nut 3 loosely fitted on the outer periphery of the screw shaft 2, a plurality of balls 4 and a spacer 5, and a tube 6 as a circulating component is attached to the nut 3. . The screw shaft 2 has a spiral screw groove 7 on its outer diameter surface. The nut 3 has a helical thread groove 8 on the inner diameter surface thereof that faces the thread groove 7 of the screw shaft 2. As shown in a sectional view in FIG. 3, a plurality of the balls 4 and a plurality of balls 4 are interposed in a spiral rolling path 9 formed between the screw shafts 7 and 8 of the screw shaft 2 and the nut 3. The spacer 5 is accommodated in a row. The spacer 5 is a substantially disk-shaped member having concave ends at both ends. The spacer 5 may be a ring-shaped member or a ball-shaped member.
[0013]
The tube 6 is a component having a circulation path 10 formed at both ends thereof to communicate with the rolling path 9 to circulate the ball 4 and the spacer 5, and in this case, a pair of legs 6a, 6a and these legs 6a , 6a and a trunk portion 6b. The portion following the leg portion 6a to the trunk portion 6b is a bent portion 6c having a curvature that does not hinder circulation of the ball 4 and the spacer 5. The ball 4 and the spacer 5 are alternately accommodated in the circulation path 10 following the rolling path 9. The circulating path 10 and the rolling path 9 constitute a circulating path 11 around which the ball 4 and the spacer 5 circulate.
[0014]
A plurality of types of tubes 6 having different lengths of the circulation path 10, for example, several types of tubes are prepared. In order to make the length of the circulation path 10 different, here, the various tubes 6 have their legs 6a having different lengths. The degree of the difference in the length of the leg portions 6a is set to an extent that can cope with the variation in the total gap between the ball 4 and the spacer 5 accommodated in the orbiting path 11.
[0015]
The tube 6 has a pair of leg portions 6a, 6a fitted in a pair of tube fitting holes 12, 12 formed in the nut 3 in communication with the rolling path 9, and a tube retainer 6b. The member 13 is fixed to the nut 3 as shown in FIG. 3 by pressing the nut 3 toward the flat surface 3 a formed on the outer periphery of the nut 3. The tube holding member 13 is fixed to the outer flat surface 3a of the nut 3 with a bolt 15 (FIG. 2). The flat surface 3a is a flat portion, that is, a notched surface in which a circular nut is notched flat. As shown in FIG. 4, spacers 14 having a thickness corresponding to the lengths of the legs 6a of the plurality of types of tubes 6 are selectively interposed between the nut flat surface 3a and the body 6b of the tube 6. That is, FIG. 3 shows a case where the tube 6 having the shortest leg 6a is attached, and in this case, the spacer 14 is omitted. FIG. 4 shows a case in which another tube 6 having a longer leg 6a than in the case of FIG. 3 is attached, and a spacer 14 having a thickness β corresponding to the increase in the length of the leg 6a is selected.
[0016]
In this ball screw with a spacer, the gap between the ball 4 and the spacer 5 can be adjusted as follows. First, the tube 6 is fixed to the nut 3 without interposing the spacer 14 as shown in FIG. In this case, the length of the leg 6 a of the tube 6 is equal to the length H of the tube fitting hole 12 of the nut 3. In this assembled state, if it is found that the total gap, which is the sum of the gaps between the balls 4 and the spacers 5 accommodated in the orbiting path 11, is smaller than a predetermined value or becomes a negative gap, Replace 6 with a longer leg. That is, the tube 6 is removed from the nut 3, and another tube 6 whose leg portion 6a is longer than the tube 6 by a predetermined length β is selected, and the tube 6 is fixed to the nut 3 as shown in FIG. In this case, the spacer 14 having the thickness β of the increased length of the tube leg 6a is selected, and the spacer 14 is interposed between the nut flat surface 3a and the body 6b of the tube 6. The tube pressing member 13 is attached to the nut 3 from above the spacer 14 with the bolt 15 (FIG. 15), and presses the body 6b of the tube 6 against the nut flat surface 3a. As a result, the length of the orbital path 11 is increased by 2β, so that by selecting a tube 6 having an appropriate leg length from a plurality of types of tubes 6 having different lengths of the leg portion 6a, The gap between the spacers 5 can be adjusted.
When the tube 6 is replaced, the ball 4 and the spacer 5 in a portion of the rolling path 9 can be replaced while the ball 4 and the spacer 5 in the circuit path 11 are left. Therefore, the gap between the spacer 5 and the ball 4 can be adjusted with a minimum number of man-hours. In addition, depending on the type of the tube 6, the trunk portion 6b rises from the nut flat surface 3a, but since the spacer 14 having a thickness corresponding to the length of the leg is interposed, the tube 6 can be stably connected to the nut 3 regardless of the tube type. Can be fixed.
[0017]
5 and 6 show another embodiment. In this embodiment, when the lengths of the circulation paths 10 of the various tubes 6 are made different, the curvature radii of the arc-shaped bent portions 6c serving as connecting portions between the leg portions 6a and the body portions 6b are made different from each other. . In the case of this configuration, the lengths H of the leg portions 6b of the various tubes 6 are the same, and the spacer 14 as in the case of the first embodiment is unnecessary regardless of which tube 6 is selected. FIG. 5 shows a half portion of one type of tube 6 in which the radius of curvature of the bent portion 6c is R1, and FIG. 6 shows a half portion of another type of tube 6 in which the radius of curvature of the bent portion 6c is R2 (> R1). Is shown. The length of the circulation path 10 differs between the tube 6 in FIG. 5 and the tube 6 in FIG. 6 due to the difference in the radius of curvature of one bent portion 6c, and as a whole, the circulation of the tube 6 in FIG. The path length is longer by 2α than the circulation path length of the tube 6 in FIG. Other configurations in this embodiment are the same as those in the first embodiment, and the description of the overall structure and drawings are omitted here.
[0018]
In this embodiment, as shown in FIG. 3, when the tube 6 having the curvature radius R1 of the bent portion 6c is selected and a ball screw is assembled, for example, a gap is formed between the ball 4 and the spacer 5 in the orbiting path 11. If 2α occurs, a ball screw is assembled by replacing the tube 6 with the tube 6 of FIG. As a result, the length of the circulation path 10 is increased by 2α, so that the gap between the ball 4 and the spacer 5 in the orbiting path 11 can be adjusted to an appropriate value. Also in this case, the tube 6 can be replaced without removing the ball 4 and the spacer 5 in the rolling path 9 and the gap can be adjusted with a minimum number of man-hours.
[0019]
In each of the above embodiments, the case where the circulating component is the tube 6 has been described. However, it is possible to adjust the gap by replacing the circulating component with a different circulating path length. It can also be applied to ball screws of the formula. The guide plate type ball screw is obtained by attaching a guide plate which is a circulating component having a ball circulating groove to a flat surface on the outer periphery of a nut. The end cap type ball screw is a type in which an end cap having a ball circulation groove is attached to both end surfaces of a nut, and a ball circulation hole formed in the nut communicates with the ball circulation groove. Even with these guide plate type and end cap type ball screws, height can be adjusted by inserting a space between the guide plate or end cap and the nut, or by changing the radius of curvature of the bent portion of the ball circulation groove. Adjustment similar to that of the tube type is possible.
[0020]
【The invention's effect】
In the gap adjusting structure for a ball screw with a spacer according to the present invention, a plurality of types of circulating parts having different lengths of circulating paths are provided as circulating parts, and an arbitrary circulating part is selectively selected from the plurality of types of circulating parts. The gap between the spacer and the ball can be adjusted with minimum man-hour without removing the ball and the spacer in the rolling path by mounting the nut on the nut. Adjustments can be made.
In the ball screw with adjustable gap spacer according to the present invention, the circulating component is a substantially U-shaped tube, a pair of legs of which are fitted into the tube fitting hole of the nut, and the body of the tube and the nut of the nut. A spacer with a thickness corresponding to the length of the tube leg is interposed between the outer surface and the gap between the spacer and the ball with minimum man-hours without removing the ball and spacer from the rolling path. It is possible to stably fix tubes of different lengths.
In the gap adjusting method for a ball screw with a spacer according to the present invention, a plurality of types of circulation parts having different lengths of circulation paths are prepared as circulation parts, and an arbitrary circulation part is selectively selected from the plurality of types of circulation parts. The gap between the ball and the spacer is adjusted by mounting it on the nut, and the gap between the spacer and the ball is adjusted with minimum man-hours without extracting the ball and the spacer in the rolling path. be able to.
[Brief description of the drawings]
FIG. 1 is a perspective view of a ball screw with a spacer having a gap adjusting structure according to a first embodiment of the present invention.
FIG. 2A is a plan view of a main part of the ball screw, and FIG. 2B is a side view of the same.
FIG. 3 is a cross-sectional view showing an assembled state in which a circulating component is mounted without interposing a spacer in the ball screw.
FIG. 4 is a sectional view showing an assembled state in which a circulating component is mounted with a spacer interposed in the ball screw.
FIG. 5 is a sectional view showing an assembled state of a half part of one type of circulating component according to another embodiment of the present invention.
FIG. 6 is a sectional view showing an assembled state of a half part of another type of circulating component in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ball screw 2 ... Screw shaft 3 ... Nut 4 ... Ball 5 ... Spacer 6 ... Tube (circulation part)
7 Thread groove of screw shaft 8 Thread groove 9 of nut 9 Rolling path 10 Circulating path 12 Tube fitting hole 13 Tube holding member 14 Spacer

Claims (6)

Opposite screw grooves are formed on the outer diameter surface of the screw shaft and the inner diameter surface of the nut loosely fitted on the outer periphery of the screw shaft, and a plurality of spiral rolling paths formed between the two screw grooves are formed. A ball and a spacer interposed between the balls, and a nut for mounting a circulating component having a circulating path for circulating the ball and the spacer with both ends communicating with the rolling path on the nut. For ball screws containing
A plurality of types of circulating parts having different lengths of circulating paths are provided as the circulating parts, and an arbitrary circulating part is selectively mounted on the nut from among the plurality of types of circulating parts, so that a space between the ball and the ball is provided. A gap adjusting structure for a ball screw with a spacer, wherein the gap between the seats can be adjusted. 2. The gap adjusting structure according to claim 1, wherein the circulation component is a tube. 3. The tube according to claim 2, wherein the tube has a substantially U-shape including a pair of legs and a body connecting the legs, and each of the plurality of types of circulating parts has a length of the legs. Are different from each other, and a tube selected from the plurality of types of tubes has the pair of leg portions fitted into a pair of tube fitting holes formed in the nut so as to communicate with the rolling path, respectively. A spacer having a thickness corresponding to the length of the legs of the plurality of types of tubes is interposed between the outer surface of the tube and the body of the tube, and a tube pressing member for pressing the body of the tube is formed from above the spacer. A clearance adjustment structure for a ball screw with a spacer that fixes the tube to the nut by fixing it to the nut. 3. The tube according to claim 2, wherein the tube has a substantially U-shape including a pair of legs and a body connecting the legs, and the various tubes as the plurality of types of circulating parts include the legs and the body. A gap adjusting structure for a ball screw with a spacer, wherein the lengths of the circulation paths are different due to different curvature radii in the arc-shaped bent portions serving as connection portions with the ball screw. Opposite screw grooves are formed on the outer diameter surface of the screw shaft and the inner diameter surface of the nut loosely fitted on the outer periphery of the screw shaft, and a plurality of spiral rolling paths formed between the two screw grooves are formed. And a spacer interposed between the balls, and a nut mounted on the nut with a circulating component having a circulation path for circulating the ball and the spacer with both ends communicating with the rolling path. A ball screw containing
The circulating component is a tube, and the tube has a substantially U-shape including a pair of legs and a body connecting the legs, and a pair of tubes formed in the nut so as to communicate with the rolling path. The pair of legs are fitted into the fitting holes, and a spacer having a thickness corresponding to the length of the tube leg is interposed between the outer surface of the nut and the body of the tube. A ball screw with an adjustable spacer that fixes the tube to the nut by fixing the tube holding member that holds the nut to the nut from above the spacer. Opposite screw grooves are formed on the outer diameter surface of the screw shaft and the inner diameter surface of the nut loosely fitted on the outer periphery of the screw shaft, and a plurality of spiral rolling paths formed between the two screw grooves are formed. A ball and a spacer interposed between the balls, and a nut for mounting a circulating component having a circulating path for circulating the ball and the spacer with both ends communicating with the rolling path on the nut. For ball screws containing
A plurality of types of circulation parts having different lengths of circulation paths are prepared as the circulation parts, and an arbitrary circulation part is selectively mounted on the nut from among the plurality of types of circulation parts, so that the distance between the ball and the spacer is increased. A method for adjusting the clearance of a ball screw with a spacer, wherein the clearance is adjusted.

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