JP2009028864A - Chucking mechanism for tool holder, and tool holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chucking mechanism having high rigidity while ensuring a fastening force in a tool holder. <P>SOLUTION: This chucking mechanism for the tool holder includes: a chuck cylinder formed with a tapered surface formed on a peripheral surface and having a diameter reduced toward an end; a chuck cylinder screw formed with a first male screw provided on the peripheral surface formed integrally at the base end of the chuck cylinder; a cylindrical fastening ring which has an inner peripheral surface movably fitted in the axial direction of the chuck cylinder and tightly fitted to the tapered surface of the chuck cylinder, and is formed with a second male screw provided on a peripheral surface; and a lock ring as a cylindrical body fitted around the chuck cylinder screw and fastening ring, formed with a first female screw engaged with the first male screw and a second female screw engaged with the second male screw which are formed in the inner peripheral surface. Pitches of the first male screw and first female screw are set larger than pitches of the second male screw and second female screw, to thereby form a differential screw. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chuck mechanism in a tool holder for fixing a tool such as a drill to a spindle shaft of a machine tool such as a machining center.

In many cases, a chuck mechanism for fixing the tool is formed at the tip of a tool holder for fixing the tool to a spindle shaft such as a machining center. Typical examples of the chuck mechanism include a milling chuck and a collet chuck.
As shown in FIG. 7, the milling chuck has the same taper as that of the chuck cylinder 210 on the outer periphery of the chuck cylinder 210 having a taper formed on the outer peripheral surface, and is spirally arranged on the inner peripheral surface by a retainer 230a. A cylindrical clamping ring 220 that holds the needle roller 230 is fitted. With such a structure, when the tightening ring 220 is rotated and moved to the proximal end side of the chuck cylinder 210, the chuck cylinder 210 is tightened, whereby the tool inserted into the chuck cylinder 210 can be held.
As shown in FIG. 8, the collet chuck has a tapered collet 320 with a slotted inner surface that fits inside the collet chuck main body 310 having a taper formed on the inner circumferential surface, and a rear portion of the tapered collet 320. And a lock nut 330 that engages with a male screw formed on the outer periphery of the collet chuck main body 310. With such a structure, by tightening the lock nut 330 so as to push the tapered collet 320 into the collet chuck main body 310, the diameter of the tapered collet 320 is reduced, whereby the tool inside the tapered collet 320 can be held. When removing the taper collet 320, the lock nut 330 is rotated away from the collet chuck body 310, and a groove 320a provided in the outer periphery near the tip of the taper collet 320 and the lock nut 330 are provided inside. Since the flange portion 330a protruding inward is engaged, the taper collet 320 moves together with the lock nut 330, and the taper collet 320 can be removed.

By the way, the milling chuck clamps the chuck cylinder with a needle roller and has a strong clamping force, but the clamping ring and the chuck cylinder come into contact with each other by a line. For this reason, there exists a fault that it is easy to generate | occur | produce a vibration and is inferior to rigidity.
On the other hand, the collet chuck has a problem that the taper chuck and the collet chuck main body are in surface contact and pressed by a lock nut, so that the rigidity is high and the vibration is difficult, but the tightening force is weakened. That is, if the taper collet taper is reduced to increase the tightening force of the collet chuck, the force required to extract the taper collet increases, but the taper collet and the lock bolt are supported by a plate-like flange. As a result, it cannot withstand a certain level of force and will be damaged. Therefore, the taper of the collet chuck cannot be made smaller than a certain value, and as a result, it is difficult to increase the tightening force.
In view of such problems, an object of the present invention is to provide a chuck structure having high rigidity while securing a tightening force.

In order to solve the above problems, the present invention has the following configuration.
According to the first aspect of the present invention, the chuck structure for the tool holder is integrally formed on the outer peripheral surface of the chuck cylinder having a tapered surface whose diameter decreases as it goes to the tip, and on the base end side of the chuck cylinder. A chuck cylinder screw portion, which is a cylinder having a first male screw formed on the outer peripheral surface, and an inner circumference that is fitted so as to be movable in the axial direction of the chuck cylinder and has a taper that is substantially the same as the taper surface of the chuck cylinder. A cylindrical fastening ring having a surface and a second male screw formed on the outer peripheral surface, and a cylindrical body externally fitted to the chuck cylindrical screw portion and the fastening ring, wherein A lock ring formed with a first female screw that engages with the second male screw and a second female screw that engages with the second male screw. The pitch of the first screw portion formed by the first male screw and the first female screw is larger than the pitch of the second screw portion formed by the second male screw and the second female screw. A differential screw is formed. When the lock ring is rotated in one direction by such a structure, the clamping ring is moved to the proximal end side with respect to the chuck cylinder by the differential screw, and the chuck cylinder is tightened.
According to a second aspect of the present invention, in the chuck structure for a tool holder, a tip side sealing ring is fixed near the tip of the outer peripheral surface of the chuck tube or the tip of the inner peripheral surface of the fastening ring, and the chuck tube A proximal-side sealing ring is fixed near the proximal end of the outer peripheral surface or near the proximal end of the inner peripheral surface of the tightening ring. Then, a recess in which lubricating oil is enclosed is formed on the outer peripheral surface of the chuck cylinder and / or the inner peripheral surface of the tightening ring between the distal end side sealing ring and the proximal end side sealing ring.
According to a third aspect of the present invention, there is provided a collet chuck main body in which a tapered hole whose diameter increases toward the tip is formed on the tip surface and a first male screw is formed on the outer peripheral surface as the chuck structure for the tool holder. A tapered collet having a substantially same tapered surface as the tapered hole is formed on the outer peripheral surface, and a second male screw is formed on the outer peripheral surface of the tip, and is fitted on the outer peripheral surface of the collet chuck body and the outer peripheral surface of the tapered collet tip. And a lock ring on the inner peripheral surface of which a first female screw that engages with the first male screw and a second female screw that engages with the second male screw are formed. The pitch of the first screw portion formed by the first male screw and the first female screw is larger than the pitch of the second screw portion formed by the second male screw and the second female screw. A differential screw is formed. With such a configuration, when the lock ring is rotated in one direction, the taper collet is moved toward the collet chuck body by the differential screw, and the taper collet is tightened. Conversely, when the lock ring is turned in the reverse direction, the tapered collet moves away from the collet chuck body.
A fourth aspect of the present invention is a tool holder having the chuck structure for a tool holder according to the first to third aspects.

In the first aspect of the invention, the clamping ring is moved with respect to the chuck cylinder by the differential screw, so that the force in the rotational force direction can be greatly enlarged and converted to the axial force. The force can be secured, and the contact portion of each member is formed by surface contact including contact by screws, so that rigidity can be increased.
According to the second aspect of the present invention, vibration can be suppressed by sealing lubricating oil between the outer peripheral surface of the chuck cylinder and the inner peripheral surface of the tightening ring.
In the invention according to claim 3, the taper collet can be moved in a direction away from the collet chuck main body by a differential screw without being damaged by a large force, so that the taper of the collet chuck can be made smaller than the conventional one. it can. As a result, the tightening force can be increased and the deflection accuracy can be improved. Further, the contact portion of each member is formed by surface contact including contact by screws, so that the rigidity can be maintained high.
According to the fourth aspect of the present invention, a tool holder having a chuck with high rigidity and strong clamping force can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a half sectional view of the tool holder X according to the first embodiment. The tool holder X has a shank portion 50 having an outer peripheral surface that fits into a tapered hole provided in the spindle shaft on the base end side, and a flange portion 60 that is integrally formed on the distal end side of the shank portion 50. A chuck mechanism A is formed on the further front end side of 60. FIG. 2 is an enlarged partial sectional view of the chuck mechanism A portion in FIG. The chuck mechanism A is integrally formed on the distal end side of the flange portion 60. A cylindrical chuck tube screw portion 40 having a first male screw 41 having a pitch of 1 mm formed on the outer periphery, and a tapered surface whose diameter decreases toward the tip on an outer peripheral surface formed integrally with the tip end side of the chuck tube screw portion 40. Are formed on the outer periphery of the chuck cylinder 10, the cylindrical clamping ring 20 having an inner peripheral surface closely fitted on the outer peripheral surface of the chuck cylinder 10, and the outer periphery of the clamping ring 20 and the outer periphery of the chuck cylinder screw portion 40. It is comprised from the cylindrical lock ring 30 to fit. From the shank part 50 to the collar part 60, it is the structure similar to a general tool holder, and description is abbreviate | omitted.

A step is formed on the outer peripheral surface of the tightening ring 20 so that the outer diameter increases toward the distal end side, and a second male screw having a pitch of 0.8 mm is formed on the outer peripheral surface having the smaller outer diameter on the proximal end side. 21 is formed. A proximal end side sealing groove 22 into which the proximal end side sealing ring 22a is fitted is formed in the vicinity of the inner peripheral surface proximal end side of the tightening ring 20.
In the vicinity of the tip of the outer peripheral surface of the chuck cylinder 10, a tip side sealing groove 11 into which the tip side sealing ring 11a is fitted is formed along the outer periphery. A groove 12 is formed along the outer periphery.
The space between the distal end side sealing ring 11a of the chuck cylinder 10 and the proximal end side sealing rig 22a of the clamping ring 20 is in a liquid-tight state, and the lubricating oil groove 12 is filled with lubricating oil. Part of the enclosed lubricating oil fills the space between the distal end side sealing ring 11a and the proximal end side sealing rig 22a.

  The inner peripheral surface of the lock ring 30 is formed with a portion having an inner diameter that can be loosely fitted to the outer peripheral surface on the distal end side of the tightening ring 20 on the distal end side. A second female screw 32 that engages with the second male screw 21 is formed, and a first female screw 31 that engages with the first male screw 41 of the chuck tube screw portion 40 is formed on the proximal end side. A groove is formed in a ring shape between the second female screw 32 and the first female screw 32. On the outer peripheral surface of the lock ring 30, a step is formed in the vicinity of the proximal end, and an engagement hole 33 for engaging a tightening tool is formed in the vicinity of the center. The first screw portion formed from the first male screw 41 and the first female screw 31 has a pitch of 1 mm, and the second screw portion formed from the second male screw 21 and the second female screw 32 has a pitch. Since it is 0.8 mm, when the lock ring 30 is rotated once, the tightening ring 20 advances and retreats by 0.2 mm which is a difference with respect to the chuck cylinder 10. That is, the first screw portion and the second screw portion constitute a differential screw having a pitch of 0.2 mm.

  When the chuck structure A having the above configuration is used, a tool is inserted into the chuck cylinder 10 with the tightening ring 20 loosened, and the lock ring 30 is rotated so as to move to the base end side. As a result, the differential screw operates and the clamping ring 20 moves to the proximal end side with respect to the chuck cylinder 10 to tighten the chuck cylinder 10, thereby fixing the tool. FIG. 3 is a half sectional view of the tool holder X in a state where the tool is fixed. In this state, the machining is performed while being fixed to a spindle shaft such as a machining center. In the chuck structure A, since the lubricating oil is sealed between the clamping ring 20 and the chuck cylinder 10, vibration is suppressed, and the chuck cylinder screw part formed integrally with the clamping ring 20 and the chuck cylinder 10 is also provided. 40 is fixed integrally by the lock ring 30 and thus has high rigidity.

(Embodiment 2)
FIG. 4 is a half sectional view of the tool holder Y according to the second embodiment. The tool holder Y includes a shank portion 110 having an outer peripheral surface that fits into a tapered hole provided in the spindle shaft on the base end side, and a ring-shaped flange portion 120 that fits slidably on the distal end side of the shank portion 110. And a chuck mechanism B is formed on the distal end side of the flange 120. FIG. 5 is an enlarged partial sectional view showing the chuck mechanism B in FIG. The chuck mechanism B includes a collet chuck main body 80, a tapered collet 90, and a lock ring 100 that are integrally formed on the distal end side of the shank portion 110. Since the shank part 110 and the collar part 120 are a well-known structure, description is abbreviate | omitted.

The collet chuck body 80 is a cylindrical body in which a tapered hole whose diameter increases toward the tip is formed on the tip side. Here, the taper angle is set to 2 degrees. A step is formed on the outer peripheral surface of the collet chuck main body 80 so that the diameter becomes smaller in the vicinity of the tip, and a first male screw 81 having a pitch of 1 mm is formed on the outer peripheral surface on the tip side where the diameter is reduced.
The taper collet 90 is a cylindrical body having an outer periphery that fits tightly into the taper hole of the collet chuck main body 80, and a slit 91 is formed on the taper surface toward the proximal end side. A second male screw 92 having a pitch of 0.8 mm is formed on the outer peripheral surface of the tip of the taper collet 90.

  The lock ring 100 is a cylindrical body that is externally fitted to the outer peripheral tip of the collet chuck main body 80 and the outer peripheral tip of the tapered collet 90, and engages with a first male screw 81 formed at the tip of the collet chuck main body on the base end side. The first female screw 101 is formed, and the second female screw 102 that engages with the second male screw 92 formed at the tip of the tapered collet 90 is formed on the tip side. The first screw portion formed from the first male screw 81 and the first female screw 101 has a pitch of 1 mm, and the second screw portion formed from the second male screw 92 and the second female screw 102 has a pitch. Since it is 0.8 mm, when the lock ring 100 is rotated once, the taper collet 90 advances and retreats with respect to the collet chuck main body 80 by a difference of 0.2 mm. That is, a differential screw having a pitch of 0.2 mm is constituted by the first screw portion and the second screw portion.

  In use, the chuck structure B having the above-described configuration inserts a tool into the tapered collet 90 with the tapered collet 90 loosened, and rotates the lock ring 30 to move to the proximal end side. As a result, the differential screw operates, and the tapered collet 90 moves to the proximal end side with respect to the collet chuck main body 80, whereby the tapered collet 90 is tightened, thereby fixing the tool. FIG. 5 shows a half sectional view of the tool holder Y in a state where the tool is fixed. In this state, the machining is performed while being fixed to a spindle shaft such as a machining center. In the chuck structure B, the taper angle of the taper collet 90 is as small as 2 degrees, and the taper collet 90 can be pushed toward the base end side with a strong force by the differential screw, so that the clamping force of the tool is high. In addition, the deflection system can be improved by reducing the taper angle. When removing the tool, when the tool holder Y is removed from the spindle shaft and the lock ring 30 is rotated so as to move to the tip side, the taper collet 90 moves to the tip side due to the action of the differential screw. The tool is loosened and the tool can be removed. At this time, the tapered collet 90 that is strongly pushed in is also moved by the differential screw, and the screw portion is not easily damaged mechanically, so that damage to the lock ring 30 or the tip of the tapered collet 90 is suppressed. Conversely, the taper angle can be reduced by having such a structure.

FIG. 3 is a half sectional view of the tool holder according to the first embodiment. FIG. 3 is a partial enlarged cross-sectional view illustrating the chuck mechanism according to the first embodiment. It is a half section view in the state where a tool of a tool holder concerning Embodiment 1 was fastened. 6 is a half sectional view of a tool holder according to Embodiment 2. FIG. FIG. 6 is a partial enlarged cross-sectional view illustrating a chuck mechanism according to a second embodiment. It is a half sectional view in the state where a tool of a tool holder concerning Embodiment 2 was fastened. It is sectional drawing of the tool holder which has a milling chuck. It is sectional drawing of the tool holder which has a collet chuck.

Explanation of symbols

X, Y Tool holder A, B Chuck structure 10 Chuck cylinder 11a Tip side sealing ring 12 Lubricating oil groove 20 Tightening ring 21 Second male screw 22a Base end side sealing ring 30 Lock ring 31 First female screw 32 Second Female screw 40 Chuck cylinder screw portion 41 First male screw 80 Collet chuck body 81 First male screw 90 Taper collet 92 Second male screw 100 Lock ring 101 First female screw 102 Second female screw

Claims (4)

A chuck cylinder formed with a tapered surface whose diameter decreases toward the tip on the outer peripheral surface;
A chuck cylinder screw portion which is a cylinder body in which a first male screw is formed on the outer peripheral surface integrally formed on the proximal end side of the chuck cylinder;
Cylindrical tightening having an inner peripheral surface that is fitted so as to be movable in the axial direction of the chuck cylinder and has a taper surface substantially the same as the taper surface of the chuck cylinder, and a second male screw is formed on the outer peripheral surface Ring,
A cylindrical body externally fitted to the chuck cylindrical screw portion and the tightening ring, the first female screw engaging the first male screw on the inner peripheral surface and the second female screw engaging the second male screw. In a chuck structure for a tool holder having a lock ring formed with an internal thread,
The pitch of the first screw portion formed by the first male screw and the first female screw is larger than the pitch of the second screw portion formed by the second male screw and the second female screw. A chuck structure for tool holders where screws are formed. A tip side sealing ring is fixed near the tip of the outer peripheral surface of the chuck cylinder or near the tip of the inner peripheral surface of the clamping ring,
A proximal-side sealing ring is fixed in the vicinity of the proximal end of the outer peripheral surface of the chuck cylinder or in the vicinity of the proximal end of the inner peripheral surface of the clamping ring,
2. The chuck for a tool holder according to claim 1, wherein the chuck cylinder outer peripheral surface and / or the tightening ring inner peripheral surface between the distal end side sealing ring and the proximal end side sealing ring is formed with a recess in which lubricating oil is sealed. Construction. A collet chuck body in which a tapered hole whose diameter increases toward the tip is formed on the tip surface, and a first male screw is formed on the outer peripheral surface;
A tapered collet in which a tapered surface substantially the same as the tapered hole is formed on the outer periphery, and a second male screw is formed on the outer peripheral surface tip,
A cylindrical body externally fitted to the outer peripheral surface of the collet chuck main body and the distal end of the tapered collet outer peripheral surface, the inner peripheral surface engaging the first male screw and the second male screw. In a chuck structure for a tool holder having a lock ring on which a second female thread is formed,
The pitch of the first screw portion formed by the first male screw and the first female screw is larger than the pitch of the second screw portion formed by the second male screw and the second female screw. A chuck structure for tool holders where screws are formed.   A tool holder having the chuck structure for a tool holder according to claim 1.

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