JP2022148049A - Main spindle device and machine tool equipped with main spindle device - Google Patents

Abstract

To provide a main spindle device capable of clamping two inside and outside positions in a multifunctional holder by one drive means, and a machine tool or the like equipped with the main spindle device.SOLUTION: A main spindle device is used in a state where a holder having a first clamped part and a second clamped part that are arranged in a double manner is mounted to a tip end of a main spindle. A first draw bar 6 and a second draw bar 7 are arranged in series so as to overlap each other in a main spindle cylinder. When the first draw bar 6 is pushed by a piston rod 21 to advance, the second draw bar 7 is caused to advance together with the first draw bar 6 against an energization force of a disc spring assembly 28, and a second clamp mechanism is released. When the first draw bar 6 retreats from a first advance position, a first clamp mechanism of the first draw bar 6 is actuated, a pushing action to the second draw bar 7 is released, the second draw bar 7 retreats by an energization force of the disc spring assembly 28, and as a result, the second clamp mechanism is actuated.SELECTED DRAWING: Figure 1

Description

In the present invention, a tool or workpiece holder having a first clamped portion and a second clamped portion that are doubly arranged inside and outside on its base side is used by being attached to the tip of the spindle. The present invention relates to a spindle device and a machine tool equipped with the spindle device.

The applicant has developed a multi-function holder for mounting on the spindle of a machine tool to which both tools and workpieces can be attached as holders. 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 been developed at the same time as the holder. Patent Document 1 is shown as a prior art disclosing these techniques. The spindle device of Patent Document 1 has a unique clamp structure for mounting such a multifunctional holder. Specifically, for example, as shown in FIG. 2, an outer gripping mechanism (consisting of an outer drawbar 85, an outer ball 92a, etc.) for clamping (gripping) the holder itself and a holder chuck mechanism are opened and closed. A structure including an inner gripping mechanism (consisting of an inner drawbar 84, an inner ball 92b, etc.) for clamping the head of a movable pull stud is adopted. That is, it is a mechanism for clamping a multifunctional holder having double clamped parts inside and outside. The outer drawbar 85 and the inner drawbar 84 are separately advanced and retracted by two cylinder devices (double push/pull mechanisms 9a) arranged above the spindle to perform the clamping operation.

JP 2010-284768 A

However, separately arranging the two cylinder devices on the main shaft device as described above in order to clamp the two clamped portions results in an increase in the size and weight of the main shaft device, and requires a plurality of cylinder devices. Therefore, the cost is increased. In addition, the operations of the two cylinder devices must be controlled, which is troublesome in terms of operation. Moreover, it is disadvantageous in terms of maintenance.
Therefore, there has been a demand for a mechanism that clamps the above holder at two locations, the inside and the outside, using only one driving means such as a cylinder device.
SUMMARY OF THE INVENTION In view of these problems, the main object of the present invention is to provide a spindle device capable of clamping two positions, the inside and the outside of a multifunctional holder, by driving one driving means, and a machine tool equipped with the spindle device. It provides.

In order to solve the above-mentioned problems, the first means is a holder for a tool or a work having, on its base side, a first clamped portion and a second clamped portion which are doubly arranged inside and outside. is attached to the distal end of the spindle and used, a first drawbar having a first clamping mechanism for clamping the first clamped portion of the holder on the front end side, and the second drawbar of the holder a second drawbar having a second clamping mechanism on the front end side for clamping the clamped portion, wherein the first drawbar and the second drawbar are arranged in series so as to partially overlap within the main shaft cylinder. The first drawbar is driven by a drive means to be able to move forward and backward in the main shaft cylinder, and the second drawbar is biased by a biasing means in the direction of the base of the main shaft cylinder, As the first drawbar advances, the second drawbar is directly or indirectly pushed by the first drawbar and is advanced against the biasing force of the biasing means, When the first drawbar is in the first advanced position, the first clamping mechanism is released and the second drawbar is pushed, and the pushed second drawbar is pushed by the urging force of the urging means. The second clamping mechanism is also released by advancing against the first drawbar, and the first drawbar moves to the second advanced position that is retreated from the first advanced position. When the first clamping mechanism for the drawbar is actuated, the push operation to the second drawbar is released, and the second drawbar is retracted by the biasing force of the biasing means, whereby the second clamp is I set the mechanism to work.
Accordingly, only by moving the first drawbar back and forth by a single driving means, the second drawbar can be moved back and forth along with the movement of the first drawbar. The first clamped part of the holder can be clamped by the second clamping mechanism of the second drawbar. Conversely, it is also possible to release the clamping operation (unclamp) by a single driving means. In other words, the two clamped portions of the holder can be clamped and unclamped by a single driving means, which contributes to miniaturization and cost reduction of the spindle device.
Here, the first clamping mechanism is actuated as the first drawbar moves to the second advanced position, and the second clamping mechanism is also actuated accordingly. The clamping mechanism and the second clamping mechanism may be activated simultaneously, or the second clamping mechanism may be activated before the first clamping mechanism.

The "first drawbar" has a first clamping mechanism on the front end side for clamping the first clamped portion of the holder. The front end side is the front end side of the spindle. The first clamped portion of the holder is determined by the relationship with the second drawbar and may be the inner side or the outer side.
The "second drawbar" has a twenty-first clamping mechanism on the front end side for clamping the second clamped portion of the holder.
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 AC or DC.
The "biasing means" is means for normally biasing the second drawbar toward the base of the main barrel, and has the function of holding the second drawbar in the original position as a reference. For example, if the biasing means is a spring device, a coil spring, a disc spring, a leaf spring, or the like is preferable. An air cylinder device or a hydraulic cylinder device may be used.
The "clamped part" needs to have a shape that can be clamped (grabbed) by the clamping mechanism. It is preferable that the clamped portion has, for example, an overhang or a shape into which the member on the clamp side can be fitted. This is because the portion to be clamped interferes with the clamping mechanism to prevent the holder from moving in the take-out direction.
The "clamping mechanism" may be a structure having an interfering body that advances and retreats, for example, in the radial direction of the main shaft with respect to the clamped portion. Then, it is preferable to clamp the clamped portion by appearing and disappearing in the passage through which the clamped portion is inserted. The shape of the interfering body may be, for example, ball-shaped, cylindrical or barrel-shaped. Alternatively, the interfering body, such as a collet, may be oscillated around a shaft to advance and retreat in the radial direction of the main shaft.
Since "the second drawbar is directly or indirectly pushed by the first drawbar", the first drawbar may contact and push the second drawbar, and may be pushed through another member. may move.

As a second means, the first drawbar has an outer peripheral surface in contact with the inner peripheral surface of the second drawbar, 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 second drawbar is advanced by being pushed by the first drawbar, the central axes are aligned to prevent rattling. can be moved to
Further, as a third means, the first clamp mechanism and the second clamp mechanism are arranged at positions shifted in the front-rear direction, and the second clamp mechanism is arranged at a position shifted from the front-rear direction. It is arranged near the tip of the spindle.
As a result, it is easy to cope with the case where the positions of the first clamped portion and the second clamped portion of the holder are shifted back and forth. will not interfere.

As a fourth means, the first clamping mechanism has an interfering body that advances and retreats in the radial direction of the main shaft, and when the first drawbar is arranged at the first advanced position, the first clamping mechanism The first clamping mechanism is released by arranging the interference body for clamping one clamped portion at a position facing a housing portion formed on the inner peripheral surface of the second drawbar. did.
It is a configuration of a specific 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.
As a fifth means, the second clamping mechanism has an interference body that advances and retreats in the radial direction of the main shaft, and when the first drawbar is arranged at the first advanced position, the second clamping mechanism The second clamping mechanism is released by arranging the interference body for clamping the clamped portion 2 at a position facing a housing portion formed on the inner peripheral surface of the main shaft cylinder.
It is a configuration of a specific 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 holder is attached by maintaining the clamped state. It is even better if there is 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 as described above, a collet, or a split claw may be arranged.

Further, as a sixth means, when the first drawbar is retracted from the first advanced position to the second advanced position, after the second clamping mechanism of the second drawbar is operated, The first clamping mechanism of the first drawbar is operated.
Incorrect mounting of the holder can be prevented by activating the first clamping mechanism after the second clamping mechanism is actuated with a time lag. For example, a two-stage clamping operation is possible, in which the holder is properly attached to the spindle and clamped by the second clamping mechanism, and then the first clamping mechanism clamps the head of the movable pull stud. 2. Problems such as the pull stud being clamped in an inclined state before the holder is properly attached to the spindle device, or the first clamping mechanism not working well, are less likely to occur.
Further, as a seventh means, the first draw bar and the second draw bar are allowed to move forward and backward in the axial direction between the first draw bar and the second draw bar and the main shaft cylinder, and the main shaft A restricting means for restricting relative rotation in the circumferential direction with respect to the cylinder is provided.
As a result, when the spindle rotates, the first drawbar and the second drawbar can be rotated in synchronization with the rotation of the spindle tube. In addition, the first drawbar and the second drawbar are structured to move back and forth in the axial direction of the main shaft, and this movement is also permitted. Specifically, for example, a protruding body is arranged from the first drawbar (and the second drawbar) toward the main shaft, and an elongated hole is formed on the main shaft so that the member can move in the axial direction. realized to form Conversely, the protrusions may be arranged on the spindle side and the elongated holes may be formed on the first drawbar (and the second drawbar) side.

Also, 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 attached to the holder attachment hole of the spindle device, and the first clamped portion and the second clamped portion of itself are clamped by the first clamping mechanism and the second clamping mechanism.
The "holder" has a first clamped portion and a second clamped portion that are doubly arranged inside and outside on its base side. It should be a highly versatile multifunctional holder that can be used for either tools or workpieces. The holder may have a first clamped portion and a second clamped portion, or may be a holder specialized for tools, for example. Having two clamping portions, the first clamped portion and the second clamped portion, improves the tensile force of the holder and is particularly suitable for high-load cutting. In this case, it functions as a tool holder rather than a multifunctional holder.
In the case of a multi-function holder, for tools, for example, various processing tools such as milling cutters, drills, end mills, cutting tools, reamers, etc. prepared in the ATC (Automatic Tool Change) of the machining center are attached to 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 on the tip side by a chuck mechanism and processed 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. It is preferable that the second clamped portion is formed in a mounting portion that is mounted in the holder mounting hole, and the holder is mounted to the tip of the spindle barrel by the second clamped portion.

As a ninth means, the holder is provided with a movable lever member projecting rearward from a mounting portion mounted in the holder mounting hole, and the first clamped portion is formed on the lever member. and the second clamped portion is formed in the mounting portion at a position surrounding the lever member.
For such a holder, the first clamping mechanism clamps the first clamped portion of the lever member, and the second clamping mechanism clamps the second clamped portion of the mounting portion. It will be.
Further, as tenth means, the first drawbar operates the first clamping mechanism at the second advanced position to clamp the first clamped portion formed on the lever member, and The lever member is moved to a third advanced position retreated from the second advanced position.
By moving the lever member to the third advanced position, a 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 drawbar.

Further, as eleventh means, the first clamped portion is formed with a first engaging portion that engages with the first clamping mechanism in a clamped state.
In addition to simply clamping, by providing the first engaging portion that engages with the first clamping mechanism on the first clamped portion, the first drawbar can be advanced and retracted without being firmly clamped with a strong force. The lever member can be pushed/pulled through the first engagement portion when the lever member is engaged.
As a twelfth means, the second clamped portion is formed with a second engaging portion that engages with the second clamping mechanism in a clamped state.
In addition to simply clamping, by providing the first engaging portion that engages with the second clamping mechanism on the first clamped portion, the holder body can be held in a predetermined position without being firmly clamped with a strong force. can be held at
For example, the first engaging portion or the second engaging portion has an overhanging shape that prevents the holder from retreating when it is engaged with the first clamping mechanism or the second clamping mechanism in a clamped state. should be For example, it may be a projection, have a bulging body that bulges outward, have a flange shape, or have a shape in which the first clamping mechanism and the second clamping mechanism are fitted. It's good.
As a thirteenth means, it is preferable to provide 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 suitable for use as a spindle device for an ATC (automatic tool changer).
The inventions of the first to thirteenth means described above can be combined arbitrarily. In particular, it is preferable to have the configuration of the first means and at least any one configuration and combination of each invention of the second to thirteenth means. Any component of each invention of the first to thirteenth means may be extracted and combined with other components.

In the above invention, the two clamped portions of the holder can be clamped and unclamped by a single drive means, which contributes to miniaturization and cost reduction of the spindle device.

FIG. 2 is a partially broken longitudinal sectional view of the automatic tool changer according to the embodiment; FIG. 4 is a vertical cross-sectional view of main parts of the device, illustrating states immediately before mounting and immediately after removing the holder in the spindle device of the automatic tool changer according to the same embodiment; FIG. 10 is a vertical cross-sectional view of main parts of the device for explaining a state in which the first draw bar is retracted and the mounting portion is clamped in the spindle device of the automatic tool changer of the same embodiment; FIG. 10 is a vertical cross-sectional view of main parts of the device for explaining a state in which the first drawbar is retracted and the mounting portion and the pull stud are clamped in the spindle device of the automatic tool changer of the same embodiment; FIG. 2C is a vertical cross-sectional view of the main part of the device for explaining the state in which the pull stud is pulled out from the holder by retracting the first drawbar further from the clamped state of FIG. 2C in the spindle device of the automatic tool changer of the same embodiment. The side view of the principal part 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 and the second draw bar are advanced to a position where the inner and outer balls can freely move in and out around the clamp mechanism of the spindle device of the automatic tool changer of the same embodiment. FIG. 4B is an enlarged explanatory view illustrating a state in which neither the mounting portion nor the pull stud are clamped during mounting or removal in the state of FIG. 4A in the vicinity of the clamp mechanism of the spindle device of the automatic tool changer of the same embodiment. FIG. 4C is an enlarged explanatory view illustrating a state in which the first drawbar and the second drawbar are retracted from the state in FIG. . FIG. 4B is an enlarged explanatory view for explaining 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; . 4D is an enlarged explanatory view illustrating a state in which the first drawbar 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. FIG. FIG. 4 is 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 released state. (a) is a front view and (b) is a bottom view of the chuck holder in the chuck closed state. (a) is a front view of the tool chuck holder, and (b) is a vertical sectional view.

Embodiments will be described below with reference to the drawings.
As shown in FIG. 1, the spindle unit 1 mainly includes a spindle device 2 and a bearing unit 3 and a motor device 4 arranged around the spindle device 2 . First, an overview of the spindle unit 1 will be described. In the following description, it is assumed that the spindle unit 1 has the spindle device 2 arranged in the vertical direction, and the tip side of the spindle device 2 is the lower side.
As shown in FIGS. 1 and 2A to 2D, the alloy spindle device 2 has a substantially cylindrical spindle tube 5 . The main shaft tube 5 has a passage communicating in the vertical direction, and has a perfect circular outer peripheral shape. A first drawbar 6 and a second drawbar 7 are accommodated in the main shaft cylinder 5 . A rotary cylinder device 8 is arranged above the main shaft tube 5 .
The bearing unit 3 is composed of a bearing 10, a bearing retainer 11, and a bearing case 12. The main shaft device 2 is rotatable around the central axis O with the main shaft tube 5 supported by the bearing 10 and the bearing retainer 11 of the bearing unit 3 . The bearing case 12 supports the spindle device 2 as a non-rotating portion.
The motor device 4 is arranged above 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 comprises a stator 14 and a rotor 15 housed within a housing 13 . In this embodiment, a six-phase AC servomotor is used as the motor device 4 . A housing 13 fixed to the bearing case 12 and a stator 14 fixed to the housing 13 are non-rotating parts of the main shaft device 2, and a rotor 15 fixed to the main shaft tube 5 rotates together with the main shaft device 2. A retainer plate 17 surrounding the main shaft tube 5 is provided at an upper portion of the housing 13 of the motor device 4 . A bearing 16 is arranged on the inner periphery of the through hole 17a of the pressing plate 17, and supports the upper portion of the main shaft tube 5 so as to be rotatable.

Next, the spindle device 2 will be described in more detail.
The main shaft device 2 is divided into a main shaft tube 5 side and a rotating cylinder device 8 side. The rotary cylinder device 8 includes a lower housing 19 that is connected to the main shaft cylinder 5 and rotates integrally, and an upper housing 20 that does not rotate. A cylinder and a piston (not shown) are arranged in the lower housing 19 . A tip (lower end) of a piston rod 21 suspended from the piston is advanced into the main barrel 5 and connected to the upper end of the first drawbar 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 main shaft cylinder 5. As shown in FIG.
As shown in FIGS. 1 and 2A to 2D, the first drawbar 6 and the second drawbar 7 accommodated in the main barrel 5 are arranged in series so as to partially overlap. The first draw bar 6 is configured to have a circular outer shape in cross section, and is slidable within the main shaft tube 5 along the inner peripheral surface of the main shaft tube 5 .

The first drawbar 6 is composed of three parts with 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 main barrel 5, and a small-diameter portion 6B having the smallest diameter in front of the first large-diameter portion 6A. , and a second large-diameter portion 6C having an intermediate diameter connected to the tip of the small-diameter portion 6B. The small diameter portion 6B and the second large diameter portion 6C are accommodated in the second drawbar 7. As shown in FIG.
The front end of the second large-diameter portion 6C is a cylindrical portion 6D having the same outer shape as the second large-diameter portion 6C. The internal space of the cylindrical portion 6D serves as 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 communicating vertically is formed at the axial center position of the first draw bar 6 .
The first large-diameter portion 6A of the first drawbar 6 is provided with a cylindrical first connecting pin 22 as a restricting means so as to protrude on both sides. As shown in FIG. 3, a pair of first elongated holes 23 are formed in the main shaft tube 5 so as to face the upper inner peripheral surface 5a. The first long hole 23 is arranged so that the long diameter side is parallel to the axial direction of the main shaft tube 5 . The width of the short diameter side of the first long hole 23 matches the diameter of the first connecting pin 22 (actually, the width of the short diameter is slightly wider so that it can slide). The first connecting pin 22 is slidably inserted into the first elongated hole 23 . The front end surface of the first large diameter portion 6A to which the base of the small diameter portion 6B of the first drawbar 6 is connected serves as a pushing surface 29 for pushing the second drawbar 7. As shown in FIG.

The second draw bar 7 is also configured to have a circular outer shape in cross section, and is slidable within the main shaft tube 5 along the inner peripheral surface of the main shaft tube 5 . The second drawbar 7 consists of two diametrically different portions. The second drawbar 7 is composed of a small diameter portion 7A that accommodates the small diameter portion 6B of the first drawbar, and a large diameter portion 7B formed in front of the small diameter portion 7A and in contact with the lower inner peripheral surface 5b of the main shaft cylinder 5. there is The inner peripheral surface 7a in the small diameter portion 7A contacts the small diameter portion 6B of the first drawbar 6, and the inner peripheral surface 7b in the large diameter portion 7B contacts the second large diameter portion 6C of the first drawbar.
In other words, the second drawbar 7 serves as a member that allows the first drawbar 6 to slide and guides the sliding movement of the first drawbar 6 .
A slide collar 25 is fixed to the base end of the second drawbar 7 so as to be in contact with the upper inner peripheral surface 5a of the main shaft cylinder 5. As shown in FIG. The slide collar 25 serves as a guide when the second draw bar 7 slides vertically with respect to the upper inner peripheral surface 5 a of the main shaft cylinder 5 .
A cylindrical second connecting pin 26 serving as a restricting means is attached to the small diameter portion 7A of the second drawbar 7 at a position adjacent to the slide collar 25 so as to protrude on both sides. As shown in FIG. 3, a pair of second elongated holes 27 are formed in the main shaft tube 5 so as to face the upper inner peripheral surface 5a. The long diameter side of the second long hole 27 is arranged parallel to the axial direction of the main shaft tube 5 . The width of the minor axis side of the second long hole 27 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 .
Between the small diameter portion 7A of the second drawbar 7 and the main barrel 5, a disk spring assembly 28 is arranged as a biasing means. The coned disc spring assembly 28 is a member in which a plurality of coned disc springs are arranged in tandem and inserted into the small diameter portion 7A. A biasing force is generated by pressing. The second drawbar 7 as a whole is always pushed upward by this urging force.
The tips of the first drawbar 6 and the second drawbar 7 are not at the same advanced position, and the second drawbar 7 is always arranged in a state of protruding forward from the first drawbar 6.例文帳に追加

Next, the clamping mechanism for the first drawbar 6 and the second drawbar 7 will be described with reference to FIGS. 2A to 2D, 4A to 4E and 5. FIG.
, the first drawbar 6 clamps the pull stud 55 side of the chuck holder 51 to be described later, and the second drawbar 7 clamps the mounting portion 53 side of the chuck holder 51 to be described later.
As shown in FIG. 5, a plurality of first through holes 31 are formed in the cylindrical portion 6D of the first drawbar 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 6</b>D of the first drawbar 6 in the radial direction. Each first through-hole 31 is configured such that the diameter of the inner opening is smaller than the diameter of the outer opening and the inner wall is tapered. A first ball 32 is accommodated 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 a position near the tip of the second drawbar 7 . Since the configuration of the second through hole 33 is the same as that of the first through hole 31, it will be omitted. A second ball 34 is accommodated in each second through hole 33 . Since the configuration and operation of the second ball 34 are the same as those of the first ball 32, a description thereof will be omitted.

Inside the large-diameter portion 7B of the second drawbar 7 and above the second through hole 33, first recesses 35 are formed at predetermined intervals in the circumferential direction.
The first concave portion 35 has a circular opening shape and has the same diameter as the diameter of the outer opening portion of the first through hole 31 . The first concave portion 35 has a concave shape that is slightly deeper than the projection amount of the first ball 32 when the first ball 32 is in the innermost state in the first through hole 31 (the state of FIG. 4A). is configured as In other words, the first ball 32 retreats outward when the first recess 35 is aligned with the first through hole 31, and when it is submerged in the first recess 35, the first ball 32 moves backward. It does not protrude from the face (icicle) of the drawbar 6 of 1. The wall surface of the first recess 35 is tapered so that it can easily enter and retract into the first through hole 31 .
The first recess 35 is matched with the first through hole 31 according to the relative positional relationship between the first drawbar 6 and the second drawbar 7 . When the first recessed portion 35 and the first through hole 31 are matched, the first ball 32 is loosely fitted, so that it can be retracted outward and is unclamped. On the other hand, if the first ball 32 is not collated, the first ball 32 is held in a state in which the tip side protrudes slightly inside the first through hole 31 and cannot be moved in and out, so that a clamped state is established. In this embodiment, clamping means pressing the pull stud 55 of the chuck holder 51 and the shaft-like portion of the mounting portion 53 with the plurality of first balls 32 from the periphery thereof.

Second recesses 37 are formed at predetermined intervals in the circumferential direction on the lower inner peripheral surface 5b of the spindle tube 5 and at positions near the base of the holder mounting hole 18. As shown in FIG.
The second recess 37 has a larger diameter than the second through hole 33 in order to prevent the second drawbar 7 from interfering with the main barrel 5 . When the second recess 37 is in contact with the second through hole 33, the second ball 34 is retracted most. It is the same as the first drawbar 6 side that it does not protrude from the face (icicle) of 7 . The wall surface of the second concave portion 37 is formed in a tapered shape so that it can easily protrude into the second through hole 33 .
The second recess 37 is matched with the second through hole 33 when the second drawbar 7 is arranged at a predetermined advanced position. Since the second ball 34 is loosely fitted in the matching state as described above, it can be retracted to the outside and is in an unclamped state. On the other hand, if the second ball 34 is not collated, the second ball 34 is held in a state in which the tip side protrudes slightly and cannot be moved inward or outward, resulting in a clamped state.
A first clamping mechanism is formed between the first drawbar 6 and the second drawbar 7 by the first through hole 31, the first ball 32, the first recess 35, and the like.
A second clamping mechanism is formed between the main shaft tube 5 and the second drawbar 7 by the second through hole 33, the second ball 34, the second recess 37, and the like.

A key 39 is attached to the tip of the holder mounting hole 18 to engage with the chuck holder 51 side when the chuck holder 51 is attached to the spindle device 2 to prevent the chuck holder 51 from rotating in the circumferential direction. A detent stay 40 is connected between the upper housing 20 and the pressing plate 17 to prevent the upper housing 20 of the rotating cylinder device 8 from rotating together with the rotation of the main shaft device 2 . The rotary cylinder device 8 is provided with a dog 41 for detecting the advanced position of the piston (piston rod 21) and a proximity sensor 42 (progress detection means). A rotation amount detection sensor 44 is installed on the pressing 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 constructed in this way is mounted on a saddle (not shown) in a machining center and machines a workpiece under the control of a computer device (not shown).

In this embodiment, the three-jaw chuck holder 51 shown in FIGS. The chuck holder 51 is composed of a holder body 52 containing a chuck mechanism (not shown) and a mounting portion 53 for mounting on the spindle device 2 . The mounting portion 53 is a cone-shaped protrusion integrally formed 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 claw portions 54 are movably attached to the holder body 52 . The state of FIGS. 6A and 6B is the most open state of the claw portion 54, and the state of FIGS. 7A and 7B is the most closed state of the claw portion 54 (chucked state). A pull stud 55 protrudes from the rear end of the mounting portion 53 . The pull stud 55 is connected as a lever member to a chuck mechanism in the holder main body 52, and the pull stud 55 advances (pulls) rearward to change the claw portion 54 from the open state to the closed state.
At the tip of the pull stud 55, a substantially elliptical bulging portion 56 projecting outward is integrally formed as an engaging portion. A disk-shaped flange portion 57 as an engaging portion projecting outward is integrally formed at the tip of the mounting portion 53 . Between the mounting portion 53 adjacent to the flange portion 57 and the flange portion 57, a constricted portion 58 is formed as an engaging portion. The constricted portion 58 is a portion in which discontinuous recesses are formed in the shape of a collar over the entire periphery of the continuous tapered shape of the mounting portion 53 . The flange portion 57 is arranged deeper than 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, clamping and unclamping operations of the chuck holder 51 to 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 attached to the spindle device 2 is the state in which the claws 54 are most opened as shown in FIGS. 6(a) and 6(b).

A. 2A and 4A show the position where the piston rod 21 is moved downward and the first drawbar 6 is most advanced (lowered), and the first clamp mechanism and the second clamp mechanism are released. . This advanced position corresponds to the first advanced position. This position is determined by the proximity sensor 42 .
The first advanced position is S1 in FIG. 2A, and the position of the first connecting pin 22 is used as a reference. At the S1 position, the first drawbar 6 pushes the second drawbar 7 together with the slide collar 25 from the rear by the pushing surface 29, and this pushing force resists the urging force of the coned disc spring assembly 28, causing the coned disc to move. This is a state in which the spring assembly 28 is compressed (pushed back) and the second drawbar 7 is moved downward. At this time, the first ball 32 inside the first through hole 31 is allowed to move toward the first recess 35, and the second ball 34 inside the second through hole 33 is also allowed to move toward the second recess 37. , both the first and second clamping mechanisms are in an unclamped state as shown in FIG. 4A.
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 extend beyond the holder mounting hole 18, as shown in FIG. Advancement is not hindered by interference with the second ball 34).
B. Next, the piston rod 21 retracts (raises) the first drawbar 6 from the first advanced position by a predetermined control operation. When the first drawbar 6 moves from S1 to S2 as shown in FIG. 2B, the pressing force on the coned disc spring assembly 28 is released, so that the biasing force of the coned disc spring assembly 28 moves the second drawbar 7 backward. continue. As the second draw bar 7 retreats, first, the constricted portion 58 at the tip of the mounting portion 53 of the chuck holder 51 is clamped by the second clamping mechanism. However, at this time, the first clamping mechanism still does not work. Since the second drawbar 7 is retracted together with the retraction of the first drawbar 6, the first concave portion 35 of the first clamping mechanism faces the first through hole 31 and the first ball 32 can be retracted. This is because the state is maintained (the state in FIG. 4C).

C. Furthermore, when the first drawbar 6 moves backward from S2 to S3 as shown in FIG. The concave portion 35 is moved, and the pull stud 55 of the chuck holder 51 (the constricted corner portion at the base of the bulging portion 56 thereof) is also clamped by the first clamping mechanism. The advanced position of the first drawbar 6 in this state is the second advanced position. In this state, the chuck holder 51 is firmly fixed to the spindle device 2 at the clamped portions at the two front and rear portions (state shown in FIG. 4D).
D. Further, when the first drawbar 6 is retracted from S3 to S4 as shown in FIGS. 2D and 4E, the first ball 32 engages the bulge 56 of the pull stud 55, thereby causing the pull stud 55 to move. is pulled out rearward (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. to D. A tool or the like is 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 in which the chuck holder 51 is attached to the spindle device 2 in this way, the piston rod 21 in the raised state is advanced (lowered) in the opposite manner to the above. in order from A. control to reach

By configuring as described above, 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 double clamped portions of inside and outside (and front and rear). Since only one cylinder device 8 is used, the spindle unit 1 and the spindle device 2 can be reduced in size and weight.
(2) A mechanism that operates the second drawbar 7 via the first drawbar 6 only by advancing and retracting the piston rod 21. The second drawbar 7 is the first drawbar 6 and the disc spring assembly 28. Since it advances and retreats, it has a simple configuration and is less prone to failure.
(3) Since the first drawbar 6 and the second drawbar 7 are arranged in series and partly overlapped, the overall length and width of the spindle device 2 can be reduced.
(4) In the clamping operation, first, the second clamping mechanism by the second drawbar 7 actuates the mounting portion 53 of the chuck holder 51 , and then the pull stud 55 of the chuck holder 51 is clamped by the first drawbar 6 . Since the clamping operation is performed with a time difference so that the clamping mechanism 1 is operated and clamped, the chuck holder 51 can be reliably fixed to the holder mounting hole 18 first, and malfunction of the clamping of the pull stud 55, for example, pull Clamping errors such as the second ball 34 being unable to be firmly clamped at a predetermined position due to the movement or vibration of the stud 55 are less likely to occur.
(5) Since the first drawbar 6 advances and retreats using the inner peripheral surfaces of the main barrel 5 and the second drawbar 7 as guides, it is difficult for vibration to occur during the advance and retreat. Further, since the second drawbar 7 is also guided by the main barrel 5 and the first drawbar 6, the second drawbar 7 is also less likely to vibrate when moving forward and backward.

The above embodiments are merely illustrative of the principles and concepts of the present invention. That is, the present invention is not limited to the above embodiments. The present invention can also be embodied, for example, in the following modified aspects.
- In the above-described embodiment, the chuck holder 51 having a chuck function is clamped. For example, a tool holder 60 as shown in FIGS. 8(a) and 8(b) may be used. The tool holder 60 has a holder body 61 and a mounting portion 62 . A base of a tool (not shown) is fixed to the mounting hole 61a in the holder body 61. As shown in FIG. A stud 63 protrudes from the rear end of the mounting portion 62 . The stud 63 is configured not to advance or retreat. A substantially ellipsoidal bulging portion 64 projecting outward is integrally formed at the tip of the stud 63 as an engaging portion. A disk-shaped flange portion 65 as an engaging portion projecting outward is integrally formed at the tip of the mounting portion 62 . Between the mounting portion 62 adjacent to the flange portion 65 and the flange portion 65, a constricted portion 69 is formed as an engaging portion. In this tool holder 60, the mounting portion 62 and the stud 63 are configured to have the same shape as the mounting portion 53 of the chuck holder 51 and the pull stud 55 which is not extended.
Since such a tool holder 60 can also be attached to the spindle device 2 at two positions to be clamped as described above, the tool holder 60 can be firmly attached to the spindle device 2 inside, outside, and front and rear.

In the above embodiment, the cylinder device 8 is used as the drive means, but other drive means such as a motor device can be used to move the first drawbar 6 back and forth. Either hydraulic type or pneumatic type can be used for the cylinder device 8 as well.
- Other spring devices may be used as means or devices for urging the second draw bar 7 . Also, a cylinder device may be used as the urging device.
- As the motor device 4, a motor other than a six-phase AC servomotor, or a DC motor device instead of an AC motor device may be used.
・In the above example, the first and second balls 32 and 34 were used as interference bodies that advance and retreat in the radial direction of the clamp mechanism. It may be a clamping mechanism that advances and retreats so as to do so.
The present invention is not limited to the configurations described in the above-described embodiments. The constituent elements of the above-described embodiments and modifications may be arbitrarily selected and combined. In addition, arbitrary constituent elements of each embodiment and modifications, arbitrary constituent elements described in Means for Solving the Invention, or constituent elements embodying arbitrary constituent elements described in Means for Solving the Invention and may be configured in any combination. We intend to acquire the rights for these as well in the amendment of the present application or in a divisional application.
In addition, the applicant intends to acquire rights to the entire design or partial design by converting the design application. Although the entire device is drawn in solid lines in the drawing, the drawing includes not only the overall design but also the partial design claimed for a part of the device. For example, it is a drawing that includes a part of the device as a partial design regardless of the member, as well as a partial design of a part of the member of the device. The part of the device may be a part of the device or a part of the member.

2 Main shaft device 6 First drawbar 7 Second drawbar 8 Rotary cylinder device as driving means 28 Coned disc spring assembly as biasing means 51 Chuck holder as holder 55 ... pull stud as first clamped portion, 58, 69 ... constricted portion of mounting portion as second clamped portion, 60 ... tool holder as holder, 63 ... stud as first clamped portion.

2 Main shaft device 6 First drawbar 7 Second drawbar 8 Rotary cylinder device as driving means 28 Coned disc spring assembly as biasing means 51 Chuck holder as holder 55 Pull stud as a lever member 58, 69 Constricted portion of the mounting portion as a second clamped portion 60 Tool holder as a holder 63 Stud as a lever member .

Claims (13)

1. A spindle device in which a holder for a tool or a workpiece having a first clamped part and a second clamped part arranged doubly inside and outside on the base side thereof is attached to the tip of the spindle and used,
A first drawbar having 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 on the front end side. a second drawbar provided on the side, wherein the first drawbar and the second drawbar are arranged in series so as to partially overlap within the main shaft cylinder;
The first drawbar is driven by a drive means to be able to move forward and backward in the main shaft cylinder, and the second drawbar is biased toward the base of the main shaft cylinder by a biasing means. the second drawbar is directly or indirectly pushed by the first drawbar as the drawbar advances, and is advanced against the biasing force of the biasing means;
When the first drawbar is in the first advanced position, the first clamping mechanism is released and the second drawbar is pushed, and the pushed second drawbar is pushed by the urging force of the urging means. The second clamping mechanism is also released by advancing against
As the first drawbar moves to the second advanced position, which is more retracted than the first advanced position, the first clamping mechanism of the first drawbar is actuated, and the second The spindle device is characterized in that the second clamping mechanism is actuated when the second drawbar is retracted by the biasing force of the biasing means after the drawbar is released from being pushed. 2. The apparatus according to claim 1, wherein said first drawbar has an outer peripheral surface in contact with an inner peripheral surface of said second drawbar, and is guided by said inner peripheral surface and said outer peripheral surface to slide back and forth. Spindle device. 3. The spindle device according to claim 1, wherein said first clamping mechanism and said second clamping mechanism are arranged at positions shifted in the longitudinal 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 in which the first drawbar is arranged at the first advanced position. 3. The first clamping mechanism is released by arranging the interference body at a position facing an accommodating portion formed on the inner peripheral surface of the second drawbar. The spindle device according to any one of 1. The second clamping mechanism has an interference body that advances and retreats in the radial direction of the main shaft, and clamps the second clamped portion in a state in which the first drawbar is arranged at the first advanced position. 5. The second clamping mechanism is released by arranging the interference body at a position facing an accommodating portion formed on the inner peripheral surface of the main cylinder. The spindle device according to 1. When the first drawbar is retracted from the first advanced position to the second advanced position, the second clamping mechanism of the first drawbar is operated after the second clamping mechanism of the second drawbar is operated. 6. The spindle device according to claim 1, wherein one clamping mechanism operates. Between the first drawbar and the second drawbar and the main barrel, the first drawbar and the second drawbar are allowed to advance and retreat in the axial direction, and rotate relative to the main barrel in the circumferential direction. The spindle device according to any one of claims 1 to 6, characterized in that regulating means for regulating is provided. 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 that protrudes rearward from a mounting portion that is mounted in the holder mounting hole, and the lever member is formed with the first clamped portion. 9. The spindle device according to claim 8, wherein said second clamped portion is formed at a position surrounding said lever member. The first drawbar operates the first clamping mechanism at the second advanced position to clamp the first clamped portion formed on the lever member, and retreats from the second advanced position. 10. The spindle device according to claim 9, wherein said lever member is moved to a third advanced position. 11. 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 clamping mechanism in a clamped state. Device. The spindle according to any one of claims 8 to 11, wherein the second clamped portion is formed with a second engaging portion that engages with the second clamping mechanism 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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