JP7075638B1 - Machine tools equipped with spindle devices and spindle devices - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle device capable of clamping two locations inside and outside a multifunction holder with one drive means, a machine tool equipped with the spindle device, and the like. SOLUTION: In a spindle device in which a holder having a first clamped portion and a second clamped portion arranged in a double manner is attached to a tip of a spindle and used, a first draw bar 6 and a second draw bar are used. 7 are overlapped and arranged in series in the spindle cylinder, and when the first draw bar 6 is pushed by the piston rod 21 and advances, the second draw bar 7 resists the urging force of the disc spring assembly 28. The second clamp mechanism is also released. As the first drawbar 6 retracts from the first advance position, the first clamp mechanism of the first drawbar 6 is activated, and the pushing operation to the second drawbar 7 is released to release the second. The second clamp mechanism is also activated by retracting the draw bar 7 by the urging force of the disc spring assembly 28. [Selection diagram] Fig. 1

Description

In the present invention, a holder for a tool or a work having a first clamped portion and a second clamped portion arranged on the inner side and the outer side on the base side thereof is attached to the tip of the spindle and used. It relates to a spindle device and a machine tool or the like equipped with the spindle device.

The applicant has developed a multifunctional holder that can be attached to the spindle of a machine tool to which both tools and workpieces can be attached as a holder. A holder holding mechanism for mounting such a holder on a spindle, a spindle device having such a holder holding mechanism, and the like have also been developed at the same time as the holder. Patent Document 1 is shown as the prior art in which these techniques are disclosed. The spindle device of Patent Document 1 is provided with a unique clamp structure for mounting such a multifunctional holder. Specifically, for example, as shown in FIG. 2, an outer grip mechanism (composed of an outer drawbar 85, an outer ball 92a, etc.) for clamping (grasping) the holder itself and a chuck mechanism of the holder are opened and closed. A configuration having an inner grip mechanism (composed of an inner drawbar 84, an inner ball 92b, etc.) for clamping the head of a movable pull stud for the purpose is adopted. That is, it is a mechanism for clamping a multifunctional holder having a double clamped portion on the inside and the outside. Then, the outer drawbar 85 and the inner drawbar 84 are moved back and forth separately by two cylinder devices (double push-pull mechanism 9a) arranged on the upper part of the main shaft so that the clamping operation is performed.

Japanese Unexamined Patent Publication No. 2010-284768

However, arranging the two cylinder devices separately on the spindle device as described above in order to clamp the two clamped portions makes the spindle device larger and heavier, and requires a plurality of cylinder devices. Therefore, the cost is increased. In addition, the operation of the two cylinder devices must be controlled, which is troublesome in terms of operation. It is also disadvantageous in terms of maintenance.
Therefore, there has been a demand for a mechanism for clamping two places inside and outside the holder as described above by using only one driving means such as a cylinder device.
In view of these problems, the main object of the present invention is to provide a spindle device capable of clamping two locations inside and outside the multifunction holder by driving one drive means, a machine tool equipped with the spindle device, and the like. It is to provide.

In order to solve the above-mentioned problems, in the first means, a holder for a tool or a work having a first clamped portion and a second clamped portion which are doubly arranged inside and outside on the base side thereof. In a spindle device used by mounting the above on the tip of the spindle, a first drawbar provided with a first clamping mechanism for clamping the first clamped portion of the holder on the front end side, and the second of the holder. A second draw bar provided with a second clamp mechanism for clamping the clamped portion on the front end side is provided, and the first draw bar and the second draw bar are in series so as to partially overlap in the spindle cylinder. The first draw bar is arranged so as to be driven by the driving means so as to be able to move forward and backward in the spindle cylinder, and the second draw bar is urged by the urging means toward the base of the spindle cylinder. As the first drawbar advances, the second drawbar is configured to be directly or indirectly pushed by the first drawbar to advance against the urging force of the urging means. The first draw bar is released from the first clamp mechanism at the first advance position and pushes the second draw bar, and the pushed second draw bar is the urging force of the urging means. The second clamp mechanism is also released by advancing against the above, and the first drawbar moves to the second advancing position retracted from the first advancing position. The first clamp mechanism of the draw bar is activated, the pushing operation to the second draw bar is released, and the second draw bar is retracted by the urging force of the urging means to retract the second clamp. The mechanism was activated.
As a result, the second drawbar can be moved back and forth according to the operation by simply moving the first drawbar forward and backward by one driving means, and as a result, the holder is held by the first clamp mechanism of the first drawbar. The first clamped portion of the holder can be clamped, and the second clamped portion of the holder can be clamped by the second clamping mechanism of the second drawbar. On the contrary, the clamping operation can be released (unclamped) by one driving means. That is, since the two clamped portions of the holder can be clamped and unclamped by one driving means, it contributes to the miniaturization and cost reduction of the spindle device.
Here, as the first drawbar moves to the second advance position, the first clamp mechanism is activated, and the second clamp mechanism is also activated accordingly. The clamp mechanism and the second clamp mechanism may be operated at the same time, or the second clamp mechanism may be operated before the first clamp mechanism.

The "first drawbar" is provided with a first clamping mechanism for clamping the first clamped portion of the holder on the front end side. The front end side is the tip side of the main shaft. The first clamped portion of the holder is determined in relation to the second drawbar and may be inside or outside.
The "second drawbar" is provided with a 21st clamping mechanism for clamping the second clamped portion of the holder on the front end side.
The "driving means" may be, for example, a hydraulic cylinder device, an air cylinder device, a motor device, or the like. The motor device may be either an AC type or a DC type.
The "urging means" is a means for constantly urging the second drawbar toward the base of the spindle cylinder, and has a function of holding the second drawbar in a reference in-situ position. For example, in the case of a spring device, the urging means may be a coil spring, a disc spring, a leaf spring or the like. An air cylinder device or a hydraulic cylinder device may be used.
The "clamped portion" needs to have a shape that can be clamped (grasped) by the clamping mechanism. The clamped portion may have, for example, an overhanging portion or a shape into which a member on the clamp side is fitted. This is because the clamped portion interferes with the clamp mechanism and the movement of the holder in the taking-out direction is prevented.
The "clamp mechanism" may have a structure having, for example, an interfering body that advances and retreats in the radial direction of the main shaft with respect to the clamped portion. Then, it is preferable that the clamped portion appears and disappears in the passage through which the clamped portion is inserted to clamp the clamped portion. The shape of the interferer may be, for example, a ball shape, a cylindrical shape, or a barrel shape. Alternatively, the interfering body may be swung around an axis such as a collet so as to advance and retreat in the radial direction of the main axis.
Since "the second drawbar is pushed directly or indirectly by the first drawbar", the first drawbar may be pushed in contact with the second drawbar and pushed through another member. You may move it.

Further, as a second means, the first draw bar is provided with an outer peripheral surface in contact with the inner peripheral surface of the second draw bar, and is guided by the inner peripheral surface and the outer peripheral surface so as to slide back and forth. ..
As a result, when the first drawbar advances and retreats, or when the first drawbar pushes and the second drawbar advances, etc., the central axes do not rattle in the relative advance and retreat movements of the two. Can be moved to.
Further, as a third means, the second clamp mechanism is more than the first clamp mechanism arranged at a position where the first clamp mechanism and the second clamp mechanism are displaced in the front-rear direction. It was placed closer to the tip of the spindle.
As a result, it is easy to deal with the case where the positions of the first clamped portion and the second clamped portion of the holder are displaced back and forth, and since the first clamp mechanism and the second clamp mechanism are not in the same position, both are available. Does not interfere.

Further, as a fourth means, the first clamp mechanism has an interfering body that advances and retreats in the radial direction of the main shaft, and the first drawbar is arranged at the first advance position. The first clamping mechanism is released by arranging the interfering body that clamps the clamped portion of 1 at a position facing the accommodating portion formed on the inner peripheral surface of the second drawbar. did.
It is a configuration of a concrete release structure from the clamped state of the first clamp mechanism. As a result, the holder of the first clamping mechanism can be released (unclamped) from the clamped state to the first clamped portion.
Further, as a fifth means, the second clamp mechanism has an interfering body that advances and retreats in the radial direction of the main shaft, and the first drawbar is arranged at the first advance position. The second clamping mechanism is released by arranging the interfering body that clamps the clamped portion of No. 2 at a position facing the accommodating portion formed on the inner peripheral surface of the spindle cylinder.
It is a configuration of a concrete release structure from the clamped state of the second clamp mechanism. As a result, the holder of the second clamping mechanism can be released (unclamped) from the clamped state to the second clamped portion.
Here, the interfering body advances in the radial direction to clamp the clamped portion, and the clamped state is maintained, so that the holder is mounted. It is even better to have an engaging portion that prevents the holder from moving in the removing direction. As the interfering body that advances and retreats in the radial direction, for example, a ball or the like, a collet, or a split claw as described above may be arranged.

Further, as a sixth means, when the first drawbar retracts from the first advance position to the second advance position, after the second clamp mechanism of the second drawbar is activated. The first clamp mechanism of the first drawbar was activated.
By causing the first clamp mechanism to be operated after the second clamp mechanism is operated with a time lag in this way, it is possible to prevent erroneous mounting of the holder. For example, the holder is correctly mounted on the spindle device and clamped by the second clamping mechanism, and then the first clamping mechanism clamps the head of the movable pull stud, which enables a two-step clamping operation. , Problems such as clamping the pull stud in a tilted state before the holder is correctly mounted on the spindle device, or the first clamping mechanism not working properly are less likely to occur.
Further, as a seventh means, the first drawbar and the second drawbar are allowed to move forward and backward in the axial direction between the first drawbar and the second drawbar and the spindle cylinder, and the spindle is allowed to move forward and backward in the axial direction. A regulating means for regulating the relative rotation in the circumferential direction with respect to the cylinder is provided.
Thereby, when the spindle rotates, the first draw bar and the second draw bar can be rotated in synchronization with the rotation of the spindle cylinder. Further, although the first draw bar and the second draw bar have a structure capable of advancing and retreating in the axial direction of the main shaft, their operation is also allowed. Specifically, for example, a protrusion is arranged from the first draw bar (and the second draw bar) toward the main shaft, and a long hole formed with a width of the shaft diameter so that this member can move in the axial direction is formed as the main shaft. Realize to form. On the contrary, a protrusion may be arranged on the main shaft side to form a long hole on the first drawbar (and the second drawbar side).

Further, as an eighth means, the holder is mounted in a holder mounting hole formed at the tip of the spindle cylinder.
That is, the holder is mounted in the holder mounting hole of the spindle device, and its own first clamped portion and second clamped portion are clamped to the first clamp mechanism and the second clamp mechanism.
The "holder" has a first clamped portion and a second clamped portion which are doubly arranged inside and outside on the base side thereof. It is preferable that it is a highly versatile multifunctional holder that can be used for both tools and workpieces. It may have a first clamped portion and a second clamped portion, or may be a holder specialized for, for example, a tool. If there are two clamping portions, a first clamped portion and a second clamped portion, the pulling force of the holder is improved, which is particularly suitable for high-load cutting. In this case, it functions as a tool holder instead of a multifunction holder.
In the case of a multifunction holder, for tools, for example, various machining tools such as milling cutters, drills, end mills, cutting tools, reamers, etc. prepared in ATC (Automatic Tool Change) of machining centers are used at the tip. It can be used by chucking it on the side with a chuck mechanism. In the case of a work, the work can be directly or indirectly chucked and attached to the tip side by a chuck mechanism, and the work can be machined by, for example, an NC processing machine. The chuck mechanism also includes a clamp mechanism. For example, the first clamped portion is formed on a lever member such as a pull stud, and the chuck mechanism is opened and closed by pushing and pulling the first clamped portion. The second clamped portion may be formed in a mounting portion to be mounted in the holder mounting hole, and the holder may be mounted on the tip of the spindle cylinder by the second clamped portion.

Further, as a ninth means, the holder is formed with a movable lever member that protrudes rearward from the mounting portion mounted in the holder mounting hole, and the lever member has the first clamped portion. The second clamped portion is formed at a position surrounding the lever member in the mounting portion.
For such a holder, the first clamp mechanism is clamped to the first clamped portion of the lever member, and the second clamp mechanism is clamped to the second clamped portion on the mounting portion side. It will be.
Further, as a tenth means, the first drawbar operates the first clamping mechanism at the second advance position to clamp the first clamped portion formed on the lever member, and the first clamped portion is clamped. The lever member is moved to a third advance position that is retracted from the advance position of 2.
By moving the lever member to the third advance position, the mechanism interlocking with the lever member can be operated. That is, by clamping the first clamped portion, the lever member can be operated by the first draw bar.

Further, as an eleventh means, a first engaging portion that engages with the first clamping mechanism in a clamped state is formed in the first clamped portion.
By providing a first engaging portion that engages with the first clamping mechanism in the first clamped portion, rather than simply clamping, the first drawbar can be advanced and retreated even if it is not clamped firmly with a strong force. The lever member can be pushed and pulled through the first engaging portion.
Further, as a twelfth means, the second clamped portion is formed with a second engaging portion that engages with the second clamp mechanism in a clamped state.
By providing a first engaging portion that engages with the second clamping mechanism in the first clamped portion, rather than simply clamping, the holder body can be placed in a predetermined position even if it is not firmly clamped with a strong force. It will be possible to hold it in.
The first engaging portion or the second engaging portion has an overhanging shape so that the holder cannot be retracted by being engaged with the first clamp mechanism or the second clamp mechanism in a clamped state, for example. It should be. For example, it may be a protrusion, have an outwardly bulging body, have a flange shape, or have a shape in which a first clamp mechanism and a second clamp mechanism are fitted together. That's good.
Further, as the thirteenth means, it is preferable to use a machine tool equipped with the spindle device according to any one of the first to thirteenth means.
As a machine tool, an NC machine tool or a machining center is preferable. In a machining center, it is particularly preferable to use it as a spindle device of an ATC (automatic tool changer).
The inventions of the first to thirteenth means described above can be arbitrarily combined. In particular, the configuration of the first means may be provided, and the configuration and combination of at least one of the inventions of the second to thirteenth means may be provided. Any component of each invention of the first to thirteenth means may be extracted and combined with other components.

In the above invention, since the two clamped portions of the holder can be clamped and unclamped by one driving means, it contributes to the miniaturization and cost reduction of the spindle device.

FIG. 3 is a partially broken vertical sectional view of the automatic tool changer according to the embodiment. FIG. 6 is a vertical cross-sectional view of a main part of an apparatus for explaining a state immediately before mounting and immediately after removing a holder in a spindle device of an automatic tool changing device of the same embodiment. FIG. 6 is a vertical cross-sectional view of a main part of an apparatus for explaining a state in which a first drawbar is retracted and a mounting portion is clamped in a spindle device of an automatic tool changer according to the same embodiment. FIG. 6 is a vertical cross-sectional view of a main part of an apparatus for explaining a state in which a first drawbar is retracted and a mounting portion and a pull stud are clamped in a spindle device of an automatic tool changer according to the same embodiment. FIG. 6 is a vertical cross-sectional view of a main part of an apparatus for explaining a state in which a first draw bar is further retracted from the clamped state of FIG. 2C and a pull stud is pulled out from a holder in a spindle device of an automatic tool changing device of the same embodiment. The side view of the main part of the spindle device of the automatic tool changer of the same embodiment. An enlarged explanatory view illustrating a state in which a first draw bar and a second draw bar advance to a position where the inner and outer balls can freely appear and disappear around the clamp mechanism of the spindle device of the automatic tool changer of the same embodiment. An enlarged explanatory view illustrating a state in which neither the mounting portion and the pull stud during mounting or removal are clamped in the state of FIG. 4A around the clamping mechanism of the spindle device of the automatic tool changing device of the same embodiment. An enlarged explanatory view illustrating a state in which the first draw bar and the second draw bar are retracted from the state of FIG. 4B and the mounting portion is clamped around the clamp mechanism of the spindle device of the automatic tool changer of the same embodiment. .. An enlarged explanatory view illustrating a state in which the first drawbar is retracted from the state of FIG. 4C and the pull stud is clamped in addition to the mounting portion around the clamping mechanism of the spindle device of the automatic tool changer of the same embodiment. .. An enlarged explanatory view illustrating a state in which the first draw bar is further retracted from the state of FIG. 4D and the pull stud is pulled out from the holder around the clamp mechanism of the spindle device of the automatic tool changer of the same embodiment. A partially enlarged perspective view of the tip of the first drawbar. (A) is a front view and (b) is a bottom view of the chuck holder in the chuck open state. (A) is a front view and (b) is a bottom view of the chuck holder in the chuck closed state. (A) of the tool chuck holder is a front view, and (b) is a vertical sectional view.

Hereinafter, embodiments will be described with reference to the drawings.
As shown in FIG. 1, the spindle unit 1 mainly includes a spindle device 2, a bearing unit 3 arranged around the spindle device 2, and a motor device 4. First, the outline of the spindle unit 1 will be described. In the following description, the spindle unit 1 is assumed to have the spindle device 2 arranged in the vertical direction, and the tip end side of the spindle device 2 is the lower side.
As shown in FIGS. 1 and 2A to 2D, the alloy spindle device 2 includes a substantially cylindrical spindle cylinder 5. The spindle cylinder 5 is provided with a passage that communicates in the vertical direction, and the outer peripheral shape is a perfect circle shape. A first draw bar 6 and a second draw bar 7 are housed in the spindle cylinder 5. A rotary cylinder device 8 is arranged at an upper position of the spindle cylinder 5.
The bearing unit 3 is composed of a bearing 10, a bearing retainer 11, and a bearing case 12. The spindle device 2 is supported by the bearing 10 of the bearing unit 3 and the bearing retainer 11 so that the spindle cylinder 5 can rotate around the central axis O. The bearing case 12 supports the spindle device 2 as a non-rotating portion.
The motor device 4 is arranged at an upper position of the bearing unit 3. The spindle device 2 is rotated around the central axis O by the rotational force of the motor device 4. The motor device 4 includes a stator 14 and a rotor 15 housed in a housing 13. In this embodiment, a 6-phase AC servomotor is used as the motor device 4. The housing 13 fixed to the bearing case 12 and the stator 14 fixed to the housing 13 are non-rotating parts of the spindle device 2, and the rotor 15 fixed to the spindle cylinder 5 rotates together with the spindle device 2. A holding plate 17 surrounding the spindle cylinder 5 is arranged at an upper position of the housing 13 of the motor device 4. A bearing 16 is arranged on the inner circumference of the through hole 17a of the holding plate 17 to rotatably support the upper position spindle cylinder 5 of the spindle cylinder 5.

Next, the spindle device 2 will be described in more detail.
The spindle device 2 is roughly divided into a spindle cylinder 5 side and a rotary cylinder device 8 side. The rotary cylinder device 8 includes a lower housing 19 that is connected to the spindle cylinder 5 and rotates integrally, and an upper housing 20 that is a non-rotating portion. A cylinder and a piston (not shown) are arranged in the lower housing 19. The tip (lower end) of the piston rod 21 hanging from the piston is advanced into the spindle cylinder 5 and connected to the upper end of the first draw bar 6. A holder mounting hole 18 having a tapered inner peripheral surface for mounting a chuck holder 51, which will be described later, is formed at the tip of the spindle cylinder 5.
As shown in FIGS. 1 and 2A to 2D, the first drawbar 6 and the second drawbar 7 housed in the spindle cylinder 5 are arranged in series so as to partially overlap each other. The first drawbar 6 is configured to have a circular outer shape in a cross section, and is slidable along the inner peripheral surface of the headstock cylinder 5 in the headstock cylinder 5.

The first drawbar 6 is composed of three parts having different diameters. That is, the first drawbar 6 has a first large-diameter portion 6A having the largest diameter in contact with the upper inner peripheral surface 5a of the spindle cylinder 5, and a small-diameter portion 6B having the smallest diameter in front of the first large-diameter portion 6A. It has a second large diameter portion 6C having a diameter of an intermediate size connected to the tip of the small diameter portion 6B. The small diameter portion 6B and the second large diameter portion 6C are housed in the second drawbar 7.
The front end of the second large diameter portion 6C is a cylindrical portion 6D formed in a cylindrical shape having the same outer shape as the second large diameter portion 6C. The internal space of the cylindrical portion 6D is a position for accommodating and clamping the rear end of the pull stud 55 of the chuck holder 51, which will be described later. A coolant passage 24 that communicates vertically is formed at the axial center position of the first draw bar 6.
A first large-diameter portion 6A of the first drawbar 6 is fitted with a first cylindrical connecting pin 22 as a regulating means so as to project on both sides. As shown in FIG. 3, a pair of first elongated holes 23 are formed in the spindle cylinder 5 so as to face each other at a position facing the inner peripheral surface 5a on the upper side. The major hole 23 is arranged on the major axis side so as to be parallel to the axial direction of the spindle cylinder 5. The width of the first elongated hole 23 on the minor axis side matches the diameter of the first connecting pin 22 (actually, the minor axis width is slightly wider so that it can slide). The first connecting pin 22 is slidably inserted into the first elongated hole 23. The tip surface of the first large diameter portion 6A to which the base of the small diameter portion 6B of the first draw bar 6 is connected is a pushing surface 29 that pushes the second draw bar 7.

The second draw bar 7 is also configured so that the outer shape in the cross section has a circular shape, and can be slidably moved along the inner peripheral surface of the spindle cylinder 5 in the spindle cylinder 5. The second drawbar 7 is composed of two portions having different diameters. The second draw bar 7 is composed of a small diameter portion 7A accommodating the small diameter portion 6B of the first draw bar, and a large diameter portion 7B formed on the front side of the small diameter portion 7A and in contact with the lower inner peripheral surface 5b of the spindle cylinder 5. There is. The inner peripheral surface 7a in the small diameter portion 7A is in close contact with the small diameter portion 6B of the first drawbar 6, and the inner peripheral surface 7b in the large diameter portion 7B is in close contact with the second large diameter portion 6C of the first drawbar.
That is, the second draw bar 7 is a member that allows the slide movement of the first draw bar 6 and guides the slide operation of the first draw bar 6.
A slide collar 25 in contact with the upper inner peripheral surface 5a of the spindle cylinder 5 is fixed to the base end of the second draw bar 7. The slide collar 25 serves as a guide when the second draw bar 7 slides in the vertical direction with respect to the upper inner peripheral surface 5a of the spindle cylinder 5.
A cylindrical second connecting pin 26 as a regulating means is attached to the small diameter portion 7A of the second draw bar 7 at a position adjacent to the slide collar 25 so as to project on both sides. As shown in FIG. 3, a pair of second elongated holes 27 are formed in the spindle cylinder 5 so as to face each other at a position facing the inner peripheral surface 5a on the upper side. The major axis side of the second elongated hole 27 is arranged parallel to the axial direction of the spindle cylinder 5. The width of the second elongated hole 27 on the minor axis side matches the diameter of the second connecting pin 26 (actually, the minor axis width is slightly wider so that it can slide). The second connecting pin 26 is slidably inserted into the second elongated hole 27.
A disc spring assembly 28 as an urging means is disposed between the small diameter portion 7A of the second draw bar 7 and the spindle cylinder 5. The disc spring assembly 28 is a member in which a plurality of disc springs are arranged in a column and fitted into the small diameter portion 7A, and the second connecting pin 26 on the second drawbar 7 side is always upward in the arranged state. It is pressed to generate an urging force. The second drawbar 7 is constantly pushed upward by this urging force.
The tips of the first drawbar 6 and the second drawbar 7 are not in the same advance position, and the second drawbar 7 is always arranged so as to protrude forward from the first drawbar 6.

Next, the clamping mechanisms of the first drawbar 6 and the second drawbar 7 will be described with reference to FIGS. 2A to 2D, FIGS. 4A to 4E, and FIGS.
The first draw bar 6 clamps the pull stud 55 side of the chuck holder 51 described later, and the second draw bar 7 clamps the mounting portion 53 side of the chuck holder 51 described later.
As shown in FIG. 5, a plurality of first through holes 31 are formed in the cylindrical portion 6D of the first draw bar 6 at predetermined intervals in the circumferential direction. Each first through hole 31 has a circular opening that communicates with the inside and outside of the cylindrical portion 6D of the first drawbar 6 in the radial direction. Each first through hole 31 is configured such that the inner opening diameter is smaller than the outer opening diameter and the inner wall is tapered. A first ball 32 is housed in each first through hole 31. The diameter of the first ball 32 is larger than the diameter of the inner opening of the first through hole 31 and smaller than the diameter of the outer opening.
A plurality of second through holes 33 are also formed at predetermined intervals in the circumferential direction at positions near the tip of the second draw bar 7. Since the configuration of the second through hole 33 is the same as that of the first through hole 31, it is omitted. Further, a second ball 34 is housed in each of the second through holes 33. Since the configuration / operation of the second ball 34 is the same as that of the first ball 32, it is omitted.

The first recesses 35 are formed at predetermined intervals in the circumferential direction on the inside of the large diameter portion 7B of the second draw bar 7 and above the second through hole 33.
The first recess 35 has a circular opening shape and is configured to have the same diameter as the outer opening diameter of the first through hole 31. The first recess 35 has a concave shape slightly deeper than the protrusion amount of the first ball 32 in the state where the first ball 32 is most inwardly advanced in the first through hole 31 (state of FIG. 4A). It is configured as follows. That is, the first ball 32 retracts outward in a state where the first recess 35 is collated with the first through hole 31, and the first ball 32 is in a state where it is submerged in the first recess 35. It does not protrude from the surface of the drawbar 6 of 1. The wall surface of the first recess 35 is formed in a tapered shape so as to easily appear and disappear in the first through hole 31.
The first recess 35 is collated with the first through hole 31 by the relative positional relationship between the first draw bar 6 and the second draw bar 7. When the first recess 35 and the first through hole 31 are collated, the first ball 32 is in a loosely fitted state, so that it can be retracted to the outside and is in an unclamped state. On the other hand, if they are not collated, the first ball 32 is held in a state where the tip side is slightly protruding inside the first through hole 31 and cannot be moved in or out, so that it is in a clamped state. In the present embodiment, the clamp is to press the pull stud 55 of the chuck holder 51 and the axial portion of the mounting portion 53 from the periphery thereof with a plurality of first balls 32.

Second recesses 37 are formed at predetermined intervals in the circumferential direction at positions near the base side of the holder mounting hole 18 on the lower inner peripheral surface 5b of the spindle cylinder 5.
The second recess 37 has a diameter larger than that of the second through hole 33 in order to prevent the second draw bar 7 from interfering with the spindle cylinder 5. Further, the second ball 34 is most retracted when the second recess 37 is collated with the second through hole 33, and the second ball 34 is the second drawbar when the second recess 37 is submerged in the second recess 37. It is the same as the first drawbar 6 side that it does not protrude from the surface of No. 7. The wall surface of the second recess 37 is formed in a tapered shape so as to easily appear in the second through hole 33.
The second recess 37 is collated with the second through hole 33 by arranging the second draw bar 7 at a predetermined advance position. Similar to the above, in the collation state, the second ball 34 is in the loosely fitted state, so that it can be retracted to the outside and is in the unclamped state. On the other hand, if they are not collated, the second ball 34 is held in a state where the tip side is slightly protruding and cannot move inward or outward, so that it is in a clamped state.
A first clamp mechanism is formed between the first draw bar 6 and the second draw bar 7 by the first through hole 31, the first ball 32, the first recess 35, and the like.
A second clamp mechanism is formed between the spindle cylinder 5 and the second drawbar 7 by the second through hole 33, the second ball 34, the second recess 37, and the like.

At the tip of the holder mounting hole 18, a key 39 is mounted to prevent the chuck holder 51 from rotating in the circumferential direction by engaging with the chuck holder 51 side when the chuck holder 51 is mounted on the spindle device 2. The upper housing 20 of the rotary cylinder device 8 is connected between the upper housing 20 and the holding plate 17 with a detent stay 40 for preventing the upper housing 20 from rotating with the rotation of the spindle device 2. The rotary cylinder device 8 is provided with a dog 41 for detecting the advance position of the piston (piston rod 21) and a proximity sensor 42 (advancement amount detecting means). A rotation amount detection sensor 44 is installed on the holding plate 17. The speed of the ring 43 rotating together with the spindle device 2 is detected and output to a computer device (not shown) to control the rotation speed of the motor device 4.
The spindle unit 1 configured in this way is mounted on a saddle (not shown) in a machining center, and a workpiece is machined under the control of a computer device (not shown).

In the present embodiment, the three-claw chuck holder 51 shown in FIGS. 6 and 7 is mounted in the holder mounting hole 18 of the spindle device 2. The chuck holder 51 includes a holder main body 52 in which a chuck mechanism (not shown) is housed, and a mounting portion 53 for mounting on the spindle device 2. The mounting portion 53 is a conical protrusion formed integrally with the holder main body 52. The outer peripheral shape of the mounting portion 53 corresponds to the inner peripheral shape of the holder mounting hole 18. Three claws 54 are movably attached to the holder body 52. The state of FIGS. 6 (a) and 6 (b) is the state in which the claw portion 54 is most open, and the state of FIGS. 7 (a) and 7 (b) is the state in which the claw portion 54 is the most closed (chucked state). A pull stud 55 is projected from the rear end of the mounting portion 53. The pull stud 55 is connected to the chuck mechanism in the holder body 52 as a lever member, and when the pull stud 55 advances (pulls) rearward, the claw portion 54 is in a closed state from an open state.
At the tip of the pull stud 55, a substantially ellipsoidal bulging portion 56 as an engaging portion is integrally formed. The tip of the mounting portion 53 is integrally formed with a flange portion 57 as an engaging portion that projects outward in a disk shape. A constricted portion 58 as an engaging portion is formed between the mounting portion 53 adjacent to the flange portion 57 and the flange portion 57. The constricted portion 58 is a portion in which a recess discontinuous with respect to the continuous tapered shape of the mounting portion 53 is formed in a collar shape over the entire circumference. The flange portion 57 is arranged behind the holder mounting hole 18 when the chuck holder 51 is mounted in the holder mounting hole 18 (the tapered surfaces are in close contact with each other).
Next, the clamping and unclamping operations of the chuck holder 51 on the spindle device 2 in the spindle unit 1 will be described with reference to FIGS. 2A to 2D and FIGS. 4A to 4E. The default state of the chuck holder 51 when the chuck holder 51 is mounted on the spindle device 2 is the state in which the claw portion 54 of FIGS. 6A and 6B is most open.

A. 2A and 4A are the positions where the piston rod 21 is moved downward and the first draw bar 6 is most advanced (lowered), and both the first clamp mechanism and the second clamp mechanism are released. .. This advance position corresponds to the first advance position. This position is determined by the proximity sensor 42.
The first advance position is S1 in FIG. 2A, and the position of the first connecting pin 22 is used as a reference. At this S1 position, the first drawbar 6 pushes the second drawbar 7 from behind together with the slide collar 25 by the pushing surface 29, and the pushing pressure causes the disc to resist the urging force of the disc spring assembly 28. The spring assembly 28 is compressed (pushed back) and the second draw bar 7 is moved downward. At this time, the first ball 32 in the first through hole 31 is allowed to move in the direction of the first recess 35, and the second ball 34 in the second through hole 33 is also allowed to move in the direction of the second recess 37. As shown in FIG. 4A, both the first and second clamping mechanisms are in the unclamped state because the movement to the clamp mechanism is allowed.
In this state, the chuck holder 51 is mounted in the holder mounting hole 18 of the spindle device 2. Even if the mounting portion 53 and the pull stud 55 advance to the back side of the holder mounting hole 18, the bulging portion 56 of the pull stud 55 and the flange portion 57 of the mounting portion 53 are the first balls 32 (as shown in FIG. 4B). The second ball 34) is not interfered with and the advance is not hindered.
B. Next, the piston rod 21 retracts (raises) the first draw bar 6 from the first advance position by a predetermined control operation. When the first draw bar 6 reaches S1 to S2 as shown in FIG. 2B, the pressing force on the disc spring assembly 28 is released, so that the second draw bar 7 retracts due to the urging force of the disc spring assembly 28. I will do it. When the second draw bar 7 retracts, the constricted portion 58 at the tip of the mounting portion 53 of the chuck holder 51 is first clamped by the second clamping mechanism. However, at this time, the first clamp mechanism still does not operate. Since the second draw bar 7 retreats together with the retreat of the first draw bar 6, the first recess 35 of the first clamp mechanism faces the first through hole 31 and the first ball 32 can retreat. This is because the state is maintained (the state shown in FIG. 4C).

C. Further, as shown in FIG. 2C, when the first drawbar 6 recedes from S2 to S3, the first drawbar 6 recedes relative to the second drawbar 7, so that the first drawbar 6 retreats. The recess 35 moves, and the pull stud 55 of the chuck holder 51 (the constricted corner portion at the base of the bulging portion 56) is also clamped by the first clamping mechanism. The advance position of the first drawbar 6 in this state becomes the second advance position. In this state, the chuck holder 51 is firmly fixed to the spindle device 2 at the two clamped portions in the front and rear (state in FIG. 4D).
D. Further, as shown in FIGS. 2D and 4E, when the first draw bar 6 recedes from S3 to S4, the first ball 32 engages with the bulging portion 56 of the pull stud 55, so that the pull stud 55 Is pulled out backward (upward), and the chuck holder 51 is displaced from the state shown in FIG. 6 to the state shown in FIG. 7 (the claw portion 54 is closed). For control of the entire machine tool, C.I. From D. A tool or the like will be attached to the claw portion 54 of the chuck holder 51 during the transition to.
When the chuck holder 51 is removed from the state where the chuck holder 51 is mounted on the spindle device 2 in this way, the piston rod 21 in the ascending state is advanced (descended) in the opposite direction to the above, and the D. In order from A. Control to reach.

With the above configuration, the spindle unit 1 of the embodiment has the following effects.
(1) Only one cylinder device 8 can be driven and clamped in order to clamp the chuck holder 51 having a double clamped portion on the inside and outside (and front and back). Since it is realized by only one cylinder device 8, the spindle unit 1 and the spindle device 2 can be made smaller and lighter.
(2) It is a mechanism that operates the second draw bar 7 via the first draw bar 6 only by advancing and retreating the piston rod 21, and the second draw bar 7 is a first draw bar 6 and a disc spring assembly 28. Since it moves forward and backward, it has a simple structure and is unlikely to break down.
(3) Since the first draw bar 6 and the second draw bar 7 are arranged in series and partially overlap each other, the overall length and width of the spindle device 2 can be reduced.
(4) In the clamping operation, the second clamping mechanism by the second draw bar 7 operates first on the mounting portion 53 of the chuck holder 51, and then the pull stud 55 of the chuck holder 51 is moved by the first draw bar 6. Since the clamping operation is performed with a time lag so that the clamping mechanism of 1 operates and clamps, the chuck holder 51 can be reliably fixed to the holder mounting hole 18 first, and the clamp malfunction of the pull stud 55, for example, pulling. Clamping mistakes such that the second ball 34 cannot be firmly clamped at a predetermined position due to the stud 55 moving or vibrating are unlikely to occur.
(5) Since the first drawbar 6 advances and retreats using the inner peripheral surfaces of the spindle cylinder 5 and the second drawbar 7 as guides, vibration due to advancing and retreating is unlikely to occur. Further, since the second draw bar 7 also uses the spindle cylinder 5 and the first draw bar 6 as guides, the second draw bar 7 is also unlikely to generate vibration due to advancing and retreating.

The above-described embodiment is merely described as a specific embodiment for exemplifying the principle of the present invention and its concept. That is, the present invention is not limited to the above embodiment. The present invention can also be embodied in a modified manner as follows, for example.
-In the above embodiment, an example in which the chuck holder 51 having a chuck function is to be clamped has been described, but another holder may be mounted on the spindle device 2. For example, the tool holder 60 as shown in FIGS. 8A and 8B may be used. The tool holder 60 includes a holder body 61 and a mounting portion 62. The base of a tool (not shown) is fixed to the mounting hole 61a in the holder body 61. A stud 63 is projected from the rear end of the mounting portion 62. The stud 63 has a structure that does not advance or retreat. A substantially ellipsoidal bulging portion 64 as an engaging portion is integrally formed at the tip of the stud 63. At the tip of the mounting portion 62, a flange portion 65 as an engaging portion protruding outward like a disk is integrally formed. A constricted portion 69 as an engaging portion is formed between the mounting portion 62 adjacent to the flange portion 65 and the flange portion 65. In this tool holder 60, the shapes of the mounting portion 62 and the stud 63 are configured to be the same as the mounting portion 53 of the chuck holder 51 and the pull stud 55 in a non-advanced state.
Since such a tool holder 60 can also be attached to the spindle device 2 at two clamped positions as described above, the tool holder 60 can be firmly attached to the spindle device 2 both inside and outside and in the front-rear direction.

-In the above embodiment, the cylinder device 8 is exemplified as the drive means, but in order to advance and retreat the first draw bar 6, other drive means, for example, a motor device can be used. Both the hydraulic type and the pneumatic type can be used for the cylinder device 8.
-Other spring devices may be used as means and devices for urging the second draw bar 7. Further, a cylinder device may be used as the urging device.
-As the motor device 4, a motor other than the 6-phase AC servomotor or a DC type motor device instead of the AC type may be used.
-The first and second balls 32 and 34 were used as an example in the above as an interfering body that advances and retreats in the radial direction of the clamp mechanism, but in addition to this, collets and split claws are arranged to swing in the radial direction. It may be a clamp mechanism that moves forward and backward.
The invention of the present application is not limited to the configuration described in the above-described embodiment. The components of each of the above-described embodiments and modifications may be arbitrarily selected and combined. Further, any component of each embodiment or modification, and any component described in the means for solving the invention or any component described in the means for solving the invention are embodied. It may be configured in any combination with. We also intend to acquire the rights to these in the amendment or divisional application of the present application.
In addition, he intends to acquire the rights to the whole design or the partial design by filing a change application to a design application. Although the entire drawing of the device is drawn with a solid line, it is a drawing including not only the whole design but also the partial design requested for a part of the device. For example, it is a drawing which includes a part of the device as a partial design regardless of the member as well as a part of the member of the device as a partial design. The part of the device may be a part of the device or a part of the member.

2 ... spindle device, 6 ... first draw bar, 7 ... second draw bar, 8 ... rotary cylinder device as drive means, 28 ... disc spring assembly as urging means, 51 ... chuck holder as holder, 55. ... Pull studs as lever members , 58, 69 ... Constricted portion of mounting portion as second clamped portion, 60 ... Tool holder as holder, 63 ... Studs as lever member .

Claims (13)

In a spindle device used by attaching a holder for a tool or a work having a first clamped portion and a second clamped portion arranged doubly on the inside and the outside on the base side thereof to the tip of the spindle.
The front end is a first draw bar provided with a first clamping mechanism for clamping the first clamped portion of the holder on the front end side, and a second clamping mechanism for clamping the second clamped portion of the holder. A second drawbar provided on the side is provided, and the first drawbar and the second drawbar are arranged in series so as to partially overlap in the spindle cylinder.
The first drawbar is driven by a driving means so that it can move forward and backward in the spindle cylinder, and the second drawbar is urged by an urging means toward the base of the spindle cylinder, and the first drawbar is used. The second drawbar is configured to be directly or indirectly pushed by the first drawbar to advance against the urging force of the urging means.
When the first draw bar is released at the first advance position, the first clamp mechanism is released and the second draw bar is pushed, and the pushed second draw bar is the urging force of the urging means. The second clamp mechanism is also released by advancing against
As the first drawbar moves to a second advance position retracted from the first advance position, the first clamp mechanism of the first drawbar is activated and the second advance position is activated. A spindle device characterized in that the second clamp mechanism is operated by releasing the push operation to the draw bar and retracting the second draw bar by the urging force of the urging means. The first drawbar according to claim 1, wherein the first draw bar has an outer peripheral surface in contact with the inner peripheral surface of the second draw bar, and is guided by the inner peripheral surface and the outer peripheral surface to slide back and forth. Main shaft device. The spindle device according to claim 1 or 2, wherein the first clamp mechanism and the second clamp mechanism are arranged at positions displaced in the front-rear direction. The first clamping mechanism has an interfering body that advances and retreats in the radial direction of the main shaft, and clamps the first clamped portion in a state where the first draw bar is arranged at the first advance position. Claims 1 to 3 are characterized in that the first clamping mechanism is released by arranging the interfering body at a position facing the accommodating portion formed on the inner peripheral surface of the second draw bar. The spindle device according to any one of. The second clamping mechanism has an interfering body that advances and retreats in the radial direction of the main shaft, and clamps the second clamped portion in a state where the first draw bar is arranged at the first advancing position. Any of claims 1 to 4, wherein the second clamp mechanism is released by arranging the interfering body at a position facing the accommodating portion formed on the inner peripheral surface of the spindle cylinder. The spindle device described in Clamp. When the first drawbar retracts from the first advance position to the second advance position, the second clamp mechanism of the second drawbar is activated and then the first of the first drawbar. The spindle device according to any one of claims 1 to 5, wherein the clamp mechanism of No. 1 is operated. The first drawbar and the second drawbar are allowed to move forward and backward in the axial direction between the first drawbar and the second drawbar, and the relative rotation in the circumferential direction with respect to the main shaft cylinder. The spindle device according to any one of claims 1 to 6, wherein a regulating means for regulating the above is disposed. The spindle device according to any one of claims 1 to 7, wherein the holder is mounted in a holder mounting hole formed at the tip of the spindle cylinder. The holder is formed with a movable lever member protruding rearward from the mounting portion mounted in the holder mounting hole, the lever member is formed with the first clamped portion, and the mounting portion is formed with the first clamped portion. The spindle device according to claim 8, wherein the second clamped portion is formed at a position surrounding the lever member. The first drawbar operates the first clamping mechanism at the second advancing position to clamp the first clamped portion formed on the lever member, and retracts from the second advancing position. The spindle device according to claim 9, wherein the lever member is moved to a third advance position. The spindle according to any one of claims 8 to 10, wherein the first clamped portion is formed with a first engaging portion that engages with the first clamp mechanism in a clamped state. Device. The spindle according to any one of claims 8 to 11, wherein a second engaging portion that engages with the second clamping mechanism is formed in the second clamped portion in a clamped state. Device. A machine tool equipped with the spindle device according to any one of claims 1 to 12.

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