JPS6248436A - Tool clamping device - Google Patents

Abstract

PURPOSE:To enable a tool to be clamped with a short stroke, by providing independently a sleeve having a plurality of steel balls arranged circumferentially and a sleeve having a circumferential groove for shunting the steel balls respectively. CONSTITUTION:A sleeve 11 is axially slidably inserted into a small diameter hole 8 provided with a groove 12 circumferentially. Also, a sleeve 14 is slidably axially inserted into a mounting hole in the sleeve 11. The large cylinder portion 21 of the sleeve 14 is provided on the same circumference near the left end and at equal intervals with a plurality of holes 20 at a right angle to the axis in which the same number of steel balls 15 can be inserted. In a gap between the right side large diameter hole 25 in the sleeve 14 and the outer diameter of a push rod 18 is interposed a spring 28 for normally urging right the push rod 18 relative to the sleeve 14. Also, in a circumferential gap formed of the right side small cylindrical portion 22 of the sleeve 14 and the right side hole 9 of a tool spindle 6 is interposed a counter-sunk spring group 30.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tool clamping device provided in and near a tool spindle for automatically attaching and removing a tool to and from the tool spindle of a machine tool with an ATC.

Conventional technology In the past, automatic attachment and detachment of tools to the tool spindle was common in machining centers, but in recent years FMS,
With the advancement of FMC, there has been a strong demand for automation of tool loading/unloading in lathes, grinding machines, etc. The tool clamping device used in machining centers, that is, the collet, is pulled by a number of disk springs and engages with the tool's blue star and retracts, fitting the tool into the taper hole of the tool spindle. Because a relatively large stroke is required, dozens of disc springs are required, and the installation length is long (although
Since the machining center has a relatively large spindle head, there was not much of a problem. However, it is very difficult to design it as is to be applied to lathes and grinders, and in particular, to apply it to the talent tool post in lathes, the taper of the spindle that grips the taper part of the tool shank is restricted by the shape of the talent. The rigidity of the tool system had to be sacrificed, such as by shortening the length of the hole.

Problems to be Solved by the Invention As mentioned above, it is extremely difficult to design a compact design by applying the pull stud method commonly used in machining centers to the main shaft of the turret turret of a lathe. Moreover, there was a major problem in that the rigidity of the tool system decreased. For this reason, the disadvantage of the conventional pull stud method is that it requires a long stroke, so dozens of disc springs are used, and the ramp system needs to be changed so that it can be clamped with a short stroke and a small number of disc springs.6 Problems Means to solve the problem A sleeve 14 has a plurality of steel balls 15 arranged in the circumferential direction instead of the conventional collet inserted into the tool spindle hole so that it can be gripped with a short stroke, and a collet when the conventional collet is open. This is a steel whose large diameter end of the pull stud 17 can pass through the arrangement part of the steel balls 15 when the pull stud 17 of the tool is inserted, while the recess groove of the convex part on the back of the top is provided directly inside the tool spindle hole. A sleeve 11, which is another member having a circumferential groove 12 for retracting the ball, is inserted between the sleeve 14 and the hole in the tool spindle 6, and the sleeves 11 and 14 are independently connected by a disc spring 32 and a spring 30, respectively. A thrust device (52, 56) that is biased in the direction of pulling the tool and pushes the sleeve 11 in the direction of the tool to unclamp the tool; and the sleeve 1;
4 in the direction of the tool.

Embodiment An embodiment of the present invention will be explained using a rotary tool shaft device and an unclamping thrust device attached to a talent tool rest of an NC lathe equipped with an ATC.

A turret 2 is attached to the turret tool rest main body 1 so as to be able to rotate and index, and one or more sets of rotary tool shaft devices 3 are attached to the outer periphery of the turret 2. At the index position, a clutch is activated by a drive shaft 35 on the tool rest side. It is rotated via the 3G intermediate shaft 37. Further, a tool unclamping thrust device 4 consisting of two cylinders arranged on the same axis is fixed on the talent tool rest main body 1.

The center through hole of the tool spindle 6, which is supported on the main body 5 of the rotary tool spindle device 3, is a tapered hole 7° and a small diameter hole 8 from the left in FIG. A flange 33 projecting inward is formed at the boundary between the large diameter hole 9, the small diameter hole 8, and the large diameter hole 9. A taper shank 10a of a tool 1G having an ATC grip guide is attached to the taper hole 7, and its pull stud 17 faces the small diameter hole 8. A sleeve 11 is inserted into the small diameter hole 8 so as to be slidable in the axial direction, and a groove 12 is cut in the circumferential direction on the inner diameter near the end face on the tool side, and a groove 12 is cut in the circumferential direction on the inner diameter near the end face on the opposite side to the tool. Holes 27 are drilled 180 degrees apart on a right-angled diameter line, and the amount of movement in the right direction in FIG. 1 is restricted by a collar 33. A sleeve 14 is inserted into the stepped hole of the sleeve 11 so as to be slidable in the axial direction,
In FIG. 1, the sleeve 14 has a cylindrical portion 21 with a large diameter and a short length on the left side that is connected to the large diameter hole on the tool side of the L-bub 11, and a small cylindrical portion 22 with a small diameter and a long length on the right side of the sleeve 11. It passes through a small diameter hole and protrudes outside the main body 5, and the left side of the hole is a large diameter hole 23. The center part has a small diameter hole 24. The right side forms a stepped cylinder consisting of a hole 25 with a large diameter, and the large cylindrical part 21
The same number of holes 20 are drilled at equal intervals on the same circumference near the left end, perpendicular to the axis, into which a plurality of steel balls 15 can be inserted, and these holes 20 are filled with steel balls! 5 is shaped so that it cannot pass through into the large diameter hole 23. A push piece 16 is press-fitted into the left end of the small diameter hole 24 of the sleeve 11-b 14, and its left end has a slight gap with the end surface of the pull stud 17 of the tool 10 in the large diameter hole 23.

Furthermore, a hole 24 is formed at approximately the center of the small diameter hole 24 in the center of the sleeve 14.
- An elongated hole 29.29 whose length is parallel to the axis and is 180' apart is carved at a position corresponding to the hole 27 of the tube 11.

A push rod 18 is inserted into the small-diameter hole 24 of the sleeve 14 so as to be able to slide in the axial direction at a distance from the push piece 16, and a hole 26 is bored near the left end at right angles to the axis.
The push rod 18 passes through the sleeve 14 through the long diameter 29, 29 and fits into the hole 27 of the sleeve 11.
1 is connected.

The push rod 18 extends into the large diameter hole 25 of the sleeve 14 and has a large diameter portion 19 formed at its right end. A spring 28 is interposed in the gap between the large diameter hole 25 on the right side of the sleeve 14 and the outer diameter of the push rod 18, and constantly urges the push rod 18 to the right with respect to the sleeve 14. Also, the small cylindrical portion 2 on the right side of the sleeve 14
A disc spring group 30 is interposed in the circumferential gap formed by the hole 9 at the right end of the tool spindle 6 and the small cylindrical portion 22 of the sleeve 14.
The ring 31 adjacent to the napht 32 screwed into the right end of the
The sleeve 14 is compressed between the sleeve 14 and the collar 33 through the sleeve 14, so that the sleeve 14 is always urged to the right with respect to the tool main shaft 6.

Although FIG. 1 shows a state in which the tool 10 is clamped to the tool spindle 6, the unclamping mechanism will be explained.

A tool unclamping thrust device 4 is attached to a position corresponding to the tool exchange position on the turret tool rest main body 1,
There are independent large cylinders 51 on the left and right sides of the main body 50 in FIG. A small cylinder 52 is cut concentrically with the sleeve 14. A piston 53 is fitted in the cylinder 51, and a small diameter portion 54 continuous to the left side of the piston 53 is connected to the cylinder 51.
It penetrates the center hole of the lid 55 of No. 1 and protrudes to the outside, and faces the right end of the sleeve 14 with a gap therebetween. On the other hand, a piston 56 is fitted in the cylinder 52, and a left piston rod 57 fixed to the center hole of the cylinder 52 is connected to both cylinders 51 and 52.
The hole 58 in the partition wall and the piston 53. It slidably penetrates the center hole of the small diameter portion 54 of the piston and protrudes to the outside, and connects the l-b 14 and the small diameter portion 54 of the piston to the right end of the push rod 18.
They face each other with a smaller gap than the gap with the edge. Further, the right piston rod 59 passes through the center hole of the lid 60 of the cylinder 52 and protrudes to the outside, and a dog 61 is fixed to the right end of the rod, which acts on a limit switch (not shown) to take signals for tool clamping and unclamping. There is. Furthermore, the piston 53
．． Pressure fluid is sent to 56 so that it is located on the right side within each cylinder when the tool is clamped.

Operation FIG. 1 shows a state in which the tool 10 is clamped to the tool spindle 6, so the explanation will start from tool unclamping.

When machining with the currently installed tool 10 is completed, the talent tool post 1 moves to a predetermined tool exchange position and stops. The turret 2 rotates and indexes the rotary tool shaft device 3 to the tool exchange position. At this time, the center lines of both the rotary tool shaft device 3 and the tool unclamping thrust device 4 on the turret tool post 1 coincide with each other. Upon receiving the indexing completion signal, the ATC (not shown) grips the tool 10 and moves the large cylinder 51.
The same pressure oil is sent to the right chambers of the small cylinders 52, the pistons 53 and 56 move to the left, and the left end of the small diameter portion 54 of the piston 53 touches the right end of the sleeve 14, and the piston 56 moves to the left.
The piston rods 57 push the right ends of the push rods 18, respectively.

Since the gap between the piston rod 57 is small and the diameter of the small cylinder 52 is smaller than that of the large cylinder 51, the push shaft 18 is pushed faster against the spring 2, and the circumferential groove 12 of the sleeve 11 is Close to the position of steel ball 15 in 14<
, - The end of the small diameter portion 54 of the piston of the universal cylinder 51 abuts the end of the sleeve 14 and moves the sleeve 14 to the left against the disk spring 30, causing the top 1 to be press-fitted into the small diameter hole 24 of the sleeve 14.
6 touches the right end of the pull stud 17 of the tool to loosen the fit between the taper shank 10a and the taper hole 7.

Steel ball 15 and circumferential groove 2 at the left-hand end of the piston 53, 56
The positions of match. At this point, the dog 61 at the right end of the piston rod 58 issues a tool loosening signal.
When the ATC (not shown) that previously gripped the tool 10 moves to the left, a portion of the steel ball 15 sinks into the circumferential groove 12 due to the action of the slope 340 at the right end of the pull stud, and the tool 10 is shifted to the left along with the ATC and removed from the tool spindle 6. You can make a withdrawal. Tool I
When O is completely removed from the tool spindle 6, the ATC rotates 180 degrees and stops the tool IO for the next process on the center line of the spindle 6.
Move to the right and insert the tool 10 into the tapered hole 7 of the tool spindle 6. Since the a ball 15 is at the same position as the circumferential groove 12, the tool 1
The large diameter part on the right end of the pull stud 17 of 0 can easily be attached to the steel ball 15.
The slope 34 comes into contact with the steel ball 15. Therefore, the large cylinder 51. Pressure oil is sent to the left chamber of the small cylinder 52, and the piston rod 57 first moves to the right, so the action of the spring 28 causes the push rod 18. As the sleeve 11 moves to the right, the steel ball 15 is pushed out of the circumferential groove 12 and comes into engagement with the slope 34 of the pull stud 17. Eventually, when the piston 53 of the large cylinder 51 begins to move to the right, the disc spring 30 The sleeve 14 moves to the right, the steel ball 15 pushes the slope 34 of the pull stud 17, and the tool 10 moves to the right, finally connecting the taper hole 7 of the main shaft 6 and the taper shank 10a of the tool 10.
is in close contact. At that time, due to the action of the dog 61, a clamp completion signal is issued from the limit switch, and the ATC
is released, moves to the retracted position, and completes the tool exchange operation.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the tool clamping device of the present invention during tool clamping, FIG. 2 is an enlarged explanatory view of the clamping action, and FIG. 3 is a sectional view of the connecting portion between the sleeve 11 and the push rod 18. l...Turret tool post 2...Turret 3...Rotary tool shaft device 4...Thrust device for tool unclamping 6
...Tool spindle 10...Tool 11.14...Sleeve 15...Steel ball 30...Disc spring 12...Circumferential groove 51, 52...
・Cylinder 53.56...Piston

Claims (1)

[Claims] (1) In a tool clamping device for a tool spindle of a machine tool, a plurality of steel balls are movably inserted into a hole adjacent to a tapered hole of the tool spindle and grip the pull stud of a mounted tool. a first sleeve member that is movably held in a direction perpendicular to an axis on the same circumference near an end face and has a push piece that faces the end face of the pull stud of the tool; and the first sleeve member is always biased toward a side opposite to the tool. a first spring slidably interposed in the axial direction between the first sleeve member and a hole adjacent to the tapered hole of the tool spindle, the steel ball retracting outward when the tool is unclamped; a second sleeve member having a possible circumferential groove therein;
a second spring that always biases the sleeve member toward the opposite tool side; a first thrust device that acts on the end surface of the first sleeve member opposite the tool toward the tool side when the tool is unclamped; A second thrust device is provided on the end surface of the second sleeve member on the side opposite to the tool, and the second thrust device acts on the tool side at a faster speed than the first thrust device, and when the tool is clamped, the first sleeve member is pulled and the stud is retracted by the steel ball. Pull the second sleeve member to shift the circumferential groove from the steel ball position to fix the steel ball, and when unclamping the tool, the first sleeve member, the second
A tool clamping device characterized in that the sleeve member is advanced toward the tool side, a pull stud is driven until it is pushed in, and the circumferential groove is moved to the steel ball position so that the steel ball can be retracted.