JP2011245606A - Device for preventing attachmemt of cutting powder to holding surface of chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent degradation of chucking accuracy by attachment, to a holding surface, of cutting powder clinging to a jaw when applying air blow to a chuck in workpiece changeover or the like.SOLUTION: In a chuck including master jaws arranged on a body, equally distributed on a circumference and expanded/contracted in the radial direction, and soft jaws fixed to the master jaws through T nuts, and holding/releasing a workpiece, a large-diameter space relative to a holding surface of the soft jaw is formed on the back side of the soft jaw; a first cup is mounted to a center hole of the chuck; and a second cup sprung forward by a spring in the space, having a diameter without coming off even when the diameter of the soft jaw is increased, and abutting on the back face of the soft jaw is movably housed in the first cup.

Description

  The present invention relates to a chip adhesion preventing device for a gripping surface of a chuck attached to a lathe or the like.

  In a lathe or the like, a chuck is attached to the tip of the spindle, and the workpiece is gripped and turned by this chuck. When turning, chips are generated, but some of these chips are thin and continuous, and may be in a state where they are entangled across the back side of the jaw. If this happens, even if air blows, it is difficult to remove, and it must be removed by hand. In addition, it takes time and much time is required for changing the work. In particular, when turning is performed by gripping only with a chuck called a chuck work, this situation often occurs because a cutting tool is present in the vicinity of the chuck.

  By the way, in a recent NC lathe, a workpiece is gripped and released by an automatic chuck called a power chuck, and this is often performed by an autoloader and processed in an unattended state. In this case, between the unloading and loading, air blows to the chuck to remove chips, etc., but if there is chips that are entangled with the jaws, if air blows, the jaws will be rejected. Adhering to the gripping surface, the accuracy of chucking may be reduced, resulting in a defective product. However, when the operator is monitoring, the presence of this chip is noticed, but even in this case, an extra time is taken to remove the chip, and the work replacement time is lengthened to reduce the efficiency. The invitation is as described above.

  Thus, a chip accumulation preventing tool is proposed in Patent Document 1 below. This is a case of manual chucking, and is based on the premise that the operator is monitoring, but in short, a cylindrical body whose tip (outer end) is tapered is fitted into the center hole of the chuck. It is a thing. According to this, the chips certainly hit the taper surface and scatter in the large diameter direction, but on the other hand, the chips are guided between the face plate of the chuck and the jaws, Some remain.

JP 2003-019602 A

  The present invention prevents the situation where chips are entangled with the jaws, and as a result, the chips are prevented from adhering to the gripping surface of the jaws to increase the accuracy of chucking, so that defective products are not produced even in unmanned operation. It is what I did.

  Under the above problems, the present invention provides a master jaw that is provided on the body, is equally distributed on the circumference and is expanded and contracted in the radial direction, and is fixed to the master jaw via a T-nut. In a chuck consisting of a soft jaw that grips and releases a workpiece, a space larger in diameter than the gripping surface of the soft jaw is formed on the back side of the soft jaw, and a first cup is attached to the center hole of the chuck. A second cup that has a disc part that has a diameter that does not come off even when the soft jaw expands in diameter and is urged forward by a spring in the space, and is movably accommodated against the back of the soft jaw. An apparatus for preventing chips from adhering to a gripping surface of a chuck characterized by the above is provided.

  According to the present invention, in the above chip adhesion preventing device, the front boot according to claim 2 is provided with a front boot covered with a cover in the center hole on the front surface of the body, and the first cup removes the cover. The T-nut according to claim 3 is slidably fitted between the T-groove formed in the master jaw and the flat groove formed in the soft jaw. 5. A means in which the pressing position of the disc portion of the second cup to the soft jaw is located forward of the bottom of the flat groove, and the master jaw engaged with the serration at the rear position of the flat groove bottom according to claim 4 Means for adjusting the diameter of the gripping surface by changing the position of the serration mesh, and variously processing the gripping surface of the soft jaw according to the shape and diameter of the workpiece. , The means that the disc portion of the two cups is pressed against the back side of the appropriate gripping surface, the machine tool to which the chuck is attached is an NC lathe, and the work is gripped by the autoloader on the chuck And provides a means by which machining with an NC lathe is performed unattended.

  According to the first aspect of the present invention, a space larger in diameter than the gripping surface is formed on the back side of the soft jaw, and there is a second cup that does not come off even when the diameter of the soft jaw is expanded. By pressing it against the back with a spring (adhering it in close contact), the chips do not enter the back of the jaw. In particular, there is a case where chips such as lint enter the fine gap between the master jaw and the soft jaw, but it is not. Therefore, there is no situation where the chips adhere to the gripping surface of the soft jaw when air is blown. Thereby, the fall of a chucking precision can be prevented and the replacement | exchange time of a workpiece | work can be shortened. Further, according to the means of claim 2, the originally existing front boot can be used as it is, and the cost can be reduced.

  A flat groove where the T-nut can slide is formed in the rear part of the soft jaw in front of the mating surface with the master jaw. To tighten the soft jaw firmly to the T-nut, strictly speaking, the bottom of the flat groove There is a slight gap between the front end of the T-nut. Therefore, fine chips may enter into this. Therefore, according to the means of claim 3, such chips are also blocked by the second cup and do not enter the gap, and do not come out of the gap and adhere to the gripping surface when air blown. The soft jaw forms a gripping surface of various diameters according to the shape and diameter of the workpiece. At this time, according to the means of claim 5, a space having a large diameter is formed on the back side (back) of the corresponding gripping surface. By providing, the lid can be put on the back side of the gripping surface, and the lid can be placed at a position where the effect of preventing chip entry is high.

It is sectional drawing of the chuck | zipper concerning this invention. It is E arrow line view of FIG. It is a front view of the chuck concerning the present invention. It is principal part sectional drawing which shows the other example of the chuck | zipper which concerns on this invention. It is sectional drawing of the conventional chuck | zipper. It is a partial front view of the conventional chuck | zipper.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings by taking a power chuck as an example. First, the structure of a general power chuck will be described with reference to a sectional view of FIG. 5 and a partial front view of FIG. deep. In this case, the direction and position are sometimes referred to, but the back or rear refers to the left side (spindle side) when viewed from the operator, and the front or front refers to the right side (anti-spindle side). The power chuck is sewn to the tip of the main shaft 1 such as a lathe with a mounting bolt 2 or the like, and includes a body (main body portion) 3 and 3 or 4 jaws 4 arranged on the circumference. The jaw 4 in this case includes a master jaw 4a attached to the face plate 3 and a soft jaw 4b attached to the master jaw 4a via a T-nut 5. As the name implies, the soft jaw 4b is made of raw (not quenched) steel and can be freely processed.

  A T-groove 6 composed of a wide portion 6a and a width detail 6b is formed in the radial direction at the outer end of the master jaw 4a, and a T-nut 5 is slidably fitted in the T-groove 6. Further, the width detail 6b of the T groove 6 is continuous with the flat groove 7 formed in the radial direction at the rear portion of the soft jaw 4b. Thereby, a fixing bolt 8 composed of a hexagon socket head bolt is inserted from the front of the flat groove 7 and is screwed into a screw hole formed in the T groove 6 to be fixed. In this case, serrations 9 and 9 'are formed on the rear side of the bottom 7a of the flat groove 7 so that there is a mating surface between the master jaw 4a and the soft jaw 4b. To be adjusted. The inner end of the soft jaw 4b is a gripping surface for gripping the workpiece. In this example, the soft jaw 4b has two gripping surfaces A and B.

  There are various structures for expanding and contracting the master jaw 4a by sliding the master jaw 4a, and all of them are known, but in this example, both side surfaces on the outer end side of the master jaw 4a and the body 3 extend in the radial direction. The master jaw 4a can be moved (expanded / reduced) with respect to the body 3 by fitting the concavities and convexities. On the other hand, a slider 10 that can move in the front-rear direction is fitted to the center side of the body 3, and both side surfaces of the master jaw 4 a and the slider 10 are fitted with unevenness that is inclined upward. A draw pipe 11 is connected to the slider 10, and when the draw vip 11 is pulled rearward, the jaw 4 is reduced in diameter, and when pushed forward, the diameter is increased, thereby gripping or releasing the workpiece. To do. A through hole 12 is formed at the center of the slider 10 and the draw pipe 11.

  The lathe work includes a bar work and a chuck work. In the chuck work, since the through hole 12 is not normally used, a lid is attached here to prevent chips and the like from entering. Specifically, a low step portion is formed at the tip of the body 3, a front boot 13 is fitted, and a cover 14 is attached to the tip. In this case, the rear surface of the flot boot 13 contacts the front surface 15 on the inner end side of the master jaw 4a behind the serration 9 and expands and contracts, and chips enter the inside (rear side) from here. There is no such thing.

  Further, the portion of the flot boot 13 where the jaw 4 exists is cut out, and the outer end thereof is inclined so that the front is lowered, so that the swarf that is caught here slides down. However, since there is a gap a between the cover 14 and the soft jaw 4b, it is impossible to prevent continuous chips from entering like the lint. Further, since there is a very small gap b between the tip of the T-nut 5 and the bottom 7a of the flat groove 7, it is not possible to prevent chips such as dust from entering here. As described above, these may adhere to the gripping surface when air blowing.

  Therefore, the present invention has been proposed, and the present invention will be described below based on the cross-sectional view of FIG. 1, the E-arrow view of FIG. 2, and the front view of FIG. 3. The reference numerals of the members are used as they are. In the present invention, first, the front boot 13 is removed, and the first cup 16 is attached thereto. The first cup 16 is different from the front boot 13 in that the first cup 16 has a surface portion 16a at the back and a screw is formed at the center thereof. In this regard, the first cup 16 may modify the front boot 13.

  A second cup 17 is slidably accommodated in the first cup 16. The second cup 17 has a body part 17a that is inscribed in the body part of the first cup 16, and a disk part 17b that is formed at the tip of the body part 17a. The above-mentioned space a is formed so that the inner diameter side of the serration 9 'on the backmost side of the soft jaw 4b is larger than the gripping surface A. There is also.) The front wall of the space a (the backmost surface of the soft jaw 4b) is set in front of the bottom 7a of the flat groove 7 of the soft jaw 4b. The second cup 17 is springed forward by the spring 18 with respect to the first cup 16.

  As a configuration, a spring holder 19 that holds the back end of the spring 18 is screwed into a screw hole of the surface portion 16 a of the first cup 16 with a set bolt 20. As a result, the tip of the spring 18 repels the disc portion 17b of the second cup 17 forward, and at this time, the disc portion 17b is allowed to move backward. This is for retracting the disc portion 17b which becomes an obstacle when the soft jaw 4b is replaced.

  Specifically, a screw hole is made in the front part of the set bolt 20 (the outer periphery is formed in a hexagonal shape for tightening), and the adjusting bolt 21 is inserted from the disk part 17b of the second cup 17 into this. And screw them together. In this case, the position of the adjusting bolt 21 can be adjusted by using a hexagon socket head bolt or the like, forming a counterbore hole in the disc portion 17b, inserting it from here, and screwing it into the screw hole. Thereby, the disc part 17b can be made to press with the required pressing force to the outermost back surface (it is also a front wall of the space a) of the soft jaw 4b. At this time, the diameter of the disc portion 17b must be such that it does not come off even when the soft jaw 4b is expanded, and it must not interfere with the upper wall of the space a when the diameter is reduced. is there.

  In this state, the workpiece is gripped and processed by the gripping surface A of the soft jaw 4b. At this time, it is suitable to remove the adjustment bolt 21 and cover the hole with a countersunk screw 22. The reason is that the adjustment bolt 21 may come out of the stop bolt 20 as the chuck rotates. For this reason, the inner surface where the head of the countersunk screw 22 enters the counterbore hole into which the adjustment bolt 21 is inserted is formed, and a screw is formed in the hole through which the adjustment bolt 21 of the disk portion 17b is inserted. According to this, the 2nd cup 17 can also incline to some extent, and there also exists an advantage pressed against the back surface of all the soft jaws 4b.

  FIG. 4 is a cross-sectional view of the main part of another example showing the configuration of the first cup 16 and the second cup 17, but in this example, the front boot 13 is used as it is, and the first cup 16 is inserted into this. (The structure below the second cup 17 is not changed). Although the size of the first cup 16 and related members is somewhat reduced, since the front boot 13 that is originally present is not removed, the cost can be reduced and the assembly can be simplified.

  As described above, since the space 17 is closed between the disc portion 17b of the second cup 17 and the soft jaw 4b, that is, the space a is blocked, there is a thin and continuous chip straddling the soft jaw 4b. However, the air blow does not adhere to the gripping surface A. Similarly, since the innermost back surface of the soft jaw 4b is in front of the bottom 7a of the flat groove 7, fine chips do not enter the gap b described above and adhere to the gripping surface A even if air blows. Never do. In this way, it is possible to expect the effect of preventing the deterioration of chucking accuracy and not producing defective products.

  The back surface of the soft jaw 4b pressed by the disc portion 17b of the second cup 17 may be the front wall of the space a described above, but if the gripping surface is different, a similar space is formed immediately behind the space a. By placing it, the back surface of the gripping surface can be closed. Specifically, when processing a workpiece using the gripping surface B, if a space a ′ is formed behind the gripping surface a, the back surface of the gripping surface A is pressed against the front wall of the space a ′. Can be (as is the chain line). Although it is preferable to cover the rear side from the viewpoint of preventing the invasion of chips, it is preferable that the front part is suitable when the chips are likely to collect in the gaps a ′ and b depending on the material of the work. In this case, the shapes of the spring 18 and the second cup 17 are changed.

  By the way, the jaw 4 expands and contracts as the workpiece is gripped and released. As described above, the disc portion 17b of the second cup 17 should not interfere with or be disengaged in this expansion / contraction range. However, since the expansion / contraction range of the power chuck, that is, the stroke of the jaw 4 is small (about 8 mm in diameter), the length of the space a does not need to be so large. Although the above is a case of a power chuck, the present invention can also be applied to a manual chuck.

DESCRIPTION OF SYMBOLS 1 Main axis | shafts, such as a lathe 2 Mounting bolt 3 Body 4 Jaw 4a Master jaw 4b Soft jaw 5 T nut 6 T groove 6a Wide part of ridge 6b Narrow part of ridge 7 Flat groove 7a Bottom of ridge 8 Fixing bolt 9 Serration 9 'Serration DESCRIPTION OF SYMBOLS 10 Slider 11 Draw pipe 12 Through-hole 13 Front boot 14 Cover 15 Front surface of inner surface of master jaw 16 First cup
16a 面 face portion 17 second cup 17a 胴 body portion 17b 円 disc portion 18 spring 19 spring holder 20 set bolt 21 adjusting bolt 22 countersunk screw AB holding space ab space and gap

Claims (6)

  In a chuck comprising a master jaw that is provided on the body and that is equally distributed on the circumference and is expanded and contracted in the radial direction, and a soft jaw that is fixed to the master jaw via a T-nut and that grips and releases the workpiece. A space larger than the gripping surface of the soft jaw is formed on the back side, and the first cup is attached to the center hole of the chuck. An apparatus for preventing chips from adhering to a gripping surface of a chuck, characterized in that a second cup that has a disc portion having a diameter that does not come off and is pressed against the back surface of a soft jaw is movably accommodated.   The gripping surface of the chuck according to claim 1, wherein a front boot covered with a cover is provided in a central hole on the front surface of the body, and the first cup is inserted into the inner periphery of the front boot with the cover removed. Chip adhesion prevention device.   The T nut is slidably fitted over the T groove formed on the master jaw and the flat groove formed on the soft jaw, and the pressing position of the disc part of the second cup to the soft jaw is the flat groove. The apparatus for preventing chips from adhering to the gripping surface of the chuck according to claim 1, which is located in front of the bottom of the chuck.   4. The chip of the gripping surface of the chuck according to claim 3, wherein there is a mating surface of the master jaw and the soft jaw meshing by serration at a position behind the bottom of the flat groove, and the diameter of the gripping surface is adjusted by changing the position of serration meshing. apparatus.   The chuck according to any one of claims 1 to 4, wherein the gripping surface of the soft jaw is variously processed according to the shape and diameter of the workpiece, and the disc portion of the second cup is pressed against the back surface of the appropriate gripping surface. For preventing chip adhesion to the gripping surface of   The machine tool to which the chuck is attached is an NC lathe, the workpiece is held by the chuck by an autoloader, and machining by the NC lathe is performed unattended. apparatus.