JP7309245B1 - Spindle device and machine tool equipped with the spindle device - Google Patents

Abstract

[Problem] To provide a spindle device capable of clamping two points, inside and outside, of a multi-function holder with one driving means, and a machine tool equipped with the spindle device. [Solution] In a spindle device in which a holder having a first clamped portion and a second clamped portion arranged in a doubly arranged manner is attached to the tip of a spindle, a first draw bar 8 and a second draw bar 9 are arranged in series and overlapping each other within a spindle tube 8. A cylinder device 37 is disposed between the first draw bar 8 and the spindle tube 8, and the first draw bar 8 can be moved axially within the spindle tube 8 with a piston portion 10F as a piston by introducing hydraulic oil into the spindle tube 8. When the first draw bar 8 advances or retreats, a pressing force generated by the movement of the piston portion 10F is applied to the first draw bar 8. [Selected Figure] Figure 1

Description

In the present invention, a tool or work holder having a first clamped portion and a second clamped portion arranged doubly inside and outside on its base side is used by being attached to the tip of a spindle. The present invention relates to a main spindle device and a machine tool equipped with such a main 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. A holder holding mechanism used when 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, outer balls 92a, etc.) for clamping (holding) 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, disposing the two cylinder devices separately on the main spindle device as described above in order to clamp the two clamped parts results in an increase in the size and weight of the main shaft device, and also 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-described holder at two locations, the inner side and the outer side, using only one pushing means such as a cylinder device.
SUMMARY OF THE INVENTION In view of such problems, the main object of the present invention is to provide a spindle device capable of clamping two positions inside and outside a multifunctional holder by driving one pushing 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. 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 clamped portion of the holder. A second drawbar having a second clamping mechanism for clamping the clamping portion on the front end side, wherein the first drawbar and the second drawbar are arranged in series or partly overlapped in the series direction within the main shaft cylinder. The cylinder device is arranged in a state and arranged to be advanceable and retractable, and is configured such that the first drawbar on the piston side advances and retreats by means of the first drawbar and the main barrel using the main barrel as a cylinder. is provided, and the piston is allowed to move in the axial direction in the main shaft cylinder by introducing pressure fluid into the main shaft cylinder, and the first draw bar is pushed in the advance direction by a pushing means. , the second drawbar is pushed forward against the biasing force of the first biasing means, and the second drawbar is directly or indirectly pushed by the first drawbar as the first drawbar advances. The first drawbar is advanced against the biasing force of the second biasing means, and the first drawbar advanced by the pushing means releases the first clamping mechanism at a predetermined advanced position. At the same time, the second clamping mechanism of the second drawbar pushed by the first drawbar is also released, and the first drawbar is released from the main shaft cylinder as the pressing force of the pushing means is released. The first clamping mechanism of the first drawbar is actuated by being retracted in the direction of the base, and the second drawbar is retracted in the direction of the base of the spindle cylinder by the biasing force of the second biasing means. the second clamping mechanism is actuated to apply the pressing force of the pressure fluid introduced to the cylinder device to the first drawbar when the first drawbar advances or retreats. I made it
As a result, the first clamping mechanism and the second clamping mechanism can be released simply by pushing with the pushing means. Further, by retracting the pushing means, both the first clamping mechanism and the second clamping mechanism can be operated by the urging forces of the first and second urging means. This simplifies the structure for clamping and unclamping, which contributes to miniaturization and cost reduction of the spindle device.
Further, by adding the pressing force (pressing force of pressure fluid) generated by the movement of the piston of the cylinder device when the first drawbar advances and retreats, the urging force of the first urging means for the first drawbar is The pressing force of the cylinder device can be combined and the operating force of the first drawbar can be increased.

Further, as a second means, when the pressing force by the pushing means is released, the first drawbar is operated to combine the pressing force generated by the movement of the piston of the cylinder device with the urging force of the first urging means. The resultant force causes the first drawbar to be retracted toward the base of the main barrel to operate the first clamping mechanism of the first drawbar, and the second drawbar is moved toward the main barrel by the biasing force of the second biasing means. The second clamping mechanism was actuated by being retracted proximally.
This makes it possible to actuate the first clamp mechanism with a stronger force by the pressing force of the cylinder device. Specifically, when the first drawbar is retracted toward the base of the main barrel by the resultant force of the pressing force generated by the movement of the piston of the cylinder device and the urging force of the first urging means, these forces are simultaneously applied. Either of them may act first.
Further, as a third means, when the first clamping mechanism is released by the first drawbar advanced by the pushing means, the driving force in the forward direction of the first drawbar is applied to the A pressing force generated by the movement of the piston of the cylinder device is applied.
As a result, the pressing force of the cylinder device is added to the urging force of the first urging means, whereby the first drawbar can be advanced at a faster speed, and the first clamping mechanism can be released at a faster speed. It can be clamped. By unclamping the first clamping mechanism at a faster speed, the second clamping mechanism can also be unclamped at a faster speed.

Further, as a fourth 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 is attached to the tip . WHEREIN: The 1st draw bar which has a 1st clamp mechanism which clamps the said 1st clamped part of the said holder at the front-end side, and clamps the said 2nd clamped part of the said holder and a second drawbar having a second clamping mechanism on the front end side, wherein the first drawbar and the second drawbar are arranged in series or partially overlapped in the series direction within the main shaft cylinder. and a cylinder device arranged so as to be advanceable and retractable so that the first drawbar on the side of the piston advances and retreats by means of the first drawbar and the main shaft cylinder with the main shaft cylinder as a cylinder, The introduction of pressure fluid into the main shaft cylinder allows the piston to move axially in the main shaft cylinder, the first drawbar is advanced by pushing means, and the second drawbar moves the second drawbar. As one drawbar advances, it is directly or indirectly pushed by the first drawbar and advanced against the biasing force of the biasing means, and is advanced by the pushing means. When the first drawbar reaches a predetermined advanced position, the first clamping mechanism is released, and the second clamping mechanism of the second drawbar pushed by the first drawbar is also released. As the pressing force of the pressing means is released, the first drawbar at the predetermined advanced position is retracted by the cylinder device toward the base of the main shaft cylinder, and the first clamping mechanism is actuated. The second drawbar is retracted in the direction of the main barrel base portion by the biasing force of the biasing means so that the second clamping mechanism is actuated. This is the case where
As a result, the first clamping mechanism and the second clamping mechanism can be released simply by pushing with the pushing means. By retracting the pushing means, both the first clamping mechanism and the second clamping mechanism can be operated by the urging forces of the cylinder device and the urging means, thereby clamping the two clamped portions of the holder. Also, the unclamping structure is simplified, which contributes to the miniaturization and cost reduction of the spindle device. Further, the pressing force of the cylinder device can increase the operating force of the first drawbar.
Further, as a fifth means, when the first clamp mechanism is released at a predetermined advanced position by the first drawbar advanced by the pushing means , the first clamp mechanism is introduced into the cylinder device. The pressing force of the pressure fluid is applied .
As a result, the pressing force of the cylinder device is added to the urging force of the first urging means, whereby the first drawbar can be advanced at a faster speed, and the first clamping mechanism can be released at a faster speed. It can be clamped. By unclamping the first clamping mechanism at a faster speed, the second clamping mechanism can also be unclamped at a faster speed.

In the above description, the "first drawbar" has a first clamping mechanism for clamping the first clamped portion of the holder on the front end side. The front end side is the front end side of the spindle. The arrangement position of the first clamped portion of the holder is determined by the relationship with the second clamped portion, and may be inside or outside.
The "second drawbar" has a second clamping mechanism on the front end side for clamping the second clamped portion of the holder. The second drawbar is directly or indirectly pushed by the first drawbar as the first drawbar advances. The first drawbar and the second drawbar are arranged in series but may partially overlap.
Also, the "pressing means" may include a pressing member such as a ram (piston) driven by a hydraulic cylinder device, an air cylinder device, a motor device, or the like. The pushing means (pressing member) may or may not be connected to the first drawbar. If they are not connected, they are only in contact with each other for pushing, so they need not be a load when the main cylinder rotates.
When the pushing means presses the first drawbar to advance the first drawbar, the "first biasing means" is compressed as the first drawbar advances and has an internal biasing force. When the pressing force from the pushing means is released, the biasing force causes the first drawbar to retreat toward the base of the main barrel. The first urging means preferably already has a certain amount of urging force before it is pressed by the pushing means. There should be
The "second biasing means" is compressed by the second drawbar when the first drawbar advances by being pushed by the pushing means and the second drawbar advances accordingly, and has an inherent biasing force. It will happen. When the pressing force from the pushing means is released, the second drawbar is retracted toward the base of the main barrel by the biasing force. The second urging means preferably already has a certain amount of urging force before it is pressed by the pushing means. It's good.
The first and second urging means may be, for example, coil springs, disk springs, plate springs, etc., if they are spring devices. An air cylinder device or a hydraulic cylinder device may be used.
The "clamped portion" must 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.
A “cylinder device” is a type of actuator that is driven (advances and retreats) by sliding a piston within a cylinder by pressure fluid. In the present invention, the main cylinder is arranged around the first drawbar in order to move the first drawbar forward and backward (or to advance in only one direction) via the piston as a cylinder. For example, the first drawbar itself may constitute a cylinder device using the main cylinder as a piston. When supplying pressure fluid into the cylinder, it is preferable to provide a flow path inside the first draw bar. As the pressure fluid, hydraulic oil or coolant may be used, for example. The cylinder device may be of single-acting specification with only one channel or of double-acting specification with two channels.
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.

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 lathe 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.
These definitions also apply to the means below.

Further, as a sixth means, the cylinder device that operates when the pressing force by the pushing means is released is operated after the first urging means is operated.
By operating the first biasing means before the cylinder device in the first means, the second clamping mechanism of the second drawbar can be operated first. The first clamping mechanism of the first drawbar can then be actuated.
Further, as a seventh means, the cylinder device that operates when the pressing force by the pushing means is released is operated after the second biasing means is operated.
By activating the second biasing means before the cylinder device in the sixth means, the second clamping mechanism of the second drawbar can be actuated first. The first clamping mechanism of the first drawbar can then be actuated.
As an eighth means, the piston is integrally formed with the first drawbar.
This is the case, for example, when the piston of the cylinder device is constructed integrally with the outer wall of the first drawbar.
As a result, the first drawbar itself is integrated with the piston, and the main shaft cylinder is driven as a cylinder.
Further, as a ninth means, when the first drawbar is retracted from the predetermined advance position, after the second clamping mechanism of the second drawbar is actuated, the first drawbar is retracted. A first clamping mechanism was activated.
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.
Also, with this configuration, for example, the holder is correctly mounted on the spindle device and clamped by the second clamping mechanism, after which the first clamping mechanism clamps the head of the movable pull stud. Since the two-stage clamping operation is possible, it is possible to clamp the pull stud in an inclined state before the holder is properly attached to the spindle device, or the first clamping mechanism does not work well. Less likely to cause trouble.

As a tenth 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 of the two drawbars are aligned to prevent rattling. can be moved to
Further, as eleventh 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 in the above-described position relative to the first clamp mechanism. It is arranged near the tip of the spindle.
As a result, for example, when the positions of the first clamped portion and the second clamped portion of the holder are displaced forward and backward, the first clamping mechanism and the second clamping mechanism are not in the same position. The two do not interfere.

Further, as a twelfth means, the first 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 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. bottom.
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.
Further, as a thirteenth 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 fourteenth 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.
As a fifteenth means, the work holder has a structure in which the first clamped portion is formed on a lever member that can move back and forth, and the second clamp is attached to the holder attached to the tip end of the spindle. When the mechanism is actuated, the lever member is pulled out through the first clamped portion to clamp the work in an unclamped state, and the first draw bar advances to push back the lever member to clamp the work. The workpiece in the state is unclamped.
As a result, the lever member can be advanced and retracted by the first draw bar while the second clamp mechanism is operated to clamp the workpiece holder. Clamping and unclamping are possible. A lever member is, for example, a pull stud or a pull bolt.
As a sixteenth means, it is preferable to provide a machine tool equipped with the spindle device according to any one of the first to fifteenth means.
The inventions of the first to sixteenth means described above can be combined arbitrarily. In particular, it is preferable to have the configuration of the first means and to have at least one configuration and combination of each invention of the second to sixteenth means. Any component of each invention of the first to sixteenth means may be extracted and combined with other components.

In the above invention, the first clamping mechanism and the second clamping mechanism can be released only by pushing with the pushing means. In addition, by retracting the pushing means, both the first clamping mechanism and the second clamping mechanism can be operated, thereby simplifying the structure for clamping and unclamping the two clamped portions of the holder. , contributing to the miniaturization and cost reduction of spindle devices. Further, the operation of the first clamp mechanism can be assisted by the pressing force of the cylinder device.

FIG. 2 is a partially broken vertical cross-sectional view of the spindle unit of the first embodiment; FIG. 4 is a vertical cross-sectional view of the main parts of the spindle device of the spindle unit according to the same embodiment 1, illustrating a state in which the first drawbar and the second drawbar are retracted to the maximum, in which the connecting pin does not press the first drawbar; FIG. 4 is a vertical cross-sectional view of main parts of the spindle device of the spindle unit according to the first embodiment, illustrating a state in which only the first drawbar is moved downward by pressing the first drawbar with the connecting pin; FIG. 4 is a vertical cross-sectional view of main parts of the spindle device of the spindle unit according to the first embodiment, illustrating a state in which the first draw bar is pushed by the connecting pin and the first draw bar and the second draw bar are moved to the lowest position; FIG. 2C is a vertical cross-sectional view of main parts of the device for explaining a state in which the holder is being attached to and detached from the spindle device of the spindle unit in the state of FIG. 2C; In the spindle device of the spindle unit of the same embodiment 1, the connecting pin in the pressed state is slightly raised, only the second draw bar is moved upward, and the flange portion of the holder is clamped (the second clamp mechanism is activated). FIG. 10 is a vertical cross-sectional view of main parts of the device for explaining the state). In the spindle device of the spindle unit of the same embodiment 1, the connecting pin in the pressed state rises greatly, both the first drawbar and the second drawbar move upward, and the bulging portion and the flange portion of the holder are clamped. Fig. 10 is a vertical cross-sectional view of main parts of the apparatus for explaining a state in which both the first clamping mechanism and the second clamping mechanism are actuated; In the spindle device of the spindle unit of the same embodiment 1, the connecting pin in the pressed state rises the most, and both the first drawbar and the second drawbar move upward, and the bulging portion and the flange portion of the holder are clamped. Fig. 10 is a vertical cross-sectional view of main parts of the device for explaining a clamped state (a state in which both the first clamping mechanism and the second clamping mechanism are actuated); In the vicinity of the clamping mechanism of the spindle device of the spindle unit of the same embodiment 1, the first drawbar is greatly retracted while the bulging portion and the flange portion of the holder are clamped, respectively, and the pull stud is pulled out from the holder. Enlarged explanatory view to explain. Enlarged explanation for explaining the state in which the first and second drawbars are advanced to a position where the balls inside and outside are locked and cannot be retracted in the vicinity of the clamping mechanism of the spindle device of the same spindle unit of the first embodiment. figure. An enlarged explanatory view for explaining 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 clamping mechanism of the spindle device of the spindle unit of the same embodiment 1. FIG. 4B is an enlarged explanatory view illustrating a state in which neither the protruding portion nor the flange portion of the holder are clamped during attachment or removal in the state of FIG. 4B around the clamping mechanism of the spindle device of the spindle unit of the same embodiment 1 . FIG. 4C is an enlarged explanatory view illustrating a state in which the second drawbar is retracted from the state of FIG. 4C and the flange portion of the holder is clamped around the clamping mechanism of the spindle device of the spindle unit of the same Embodiment 1; Enlarged description for explaining a state in which the first draw bar is retracted from the state of FIG. 4D and the bulging portion and the flange portion of the holder are clamped together around the clamping mechanism of the spindle device of the spindle unit of the same Embodiment 1. figure. 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. FIG. 6 is a partially broken vertical cross-sectional view of a spindle unit according to Embodiment 2; (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.
<Embodiment 1>
As shown in FIG. 1, a spindle unit 1 as an automatic tool changer includes a spindle device 2, a bearing unit 4 surrounded by a housing 3 disposed around the spindle device 2, and a bearing unit 4 disposed above the housing 3. Main components are a main shaft rotating mechanism 5, a rotary joint 6 disposed above the main shaft rotating mechanism 5, and a cylinder device 7 fixed to an upper position of the housing 3. As shown in FIG. First, an overview of the spindle unit 1 will be described. In the following description, it is assumed that the spindle unit 1 is arranged such that the axial direction of the spindle device 2 is in the vertical direction, and the tip side of the spindle device 2 is the lower side. The spindle unit 1 is supported by a spindle frame (not shown).
As shown in FIGS. 1 and 2A to 2F, the alloy spindle device 2 has a substantially cylindrical spindle tube 8 . The main shaft cylinder 8 has a passage that communicates in the vertical direction, and has a perfect circular outer peripheral shape. A first drawbar 10 and a second drawbar 11 are accommodated in the main shaft cylinder 8 . Between the first drawbar 10 and the main barrel 8, a first disk spring assembly 12 is arranged as a first urging means. Between the second drawbar 11 and the main barrel 8, a second disc spring assembly 13 is arranged as a second biasing means.

A spindle device 2 is surrounded by a bearing unit 4 . The bearing unit 4 is a part of the spindle unit 1 that rotatably supports the spindle device 2 . The inner cylindrical portion 4A of the bearing unit 4 is fixed to the main shaft device 2 and becomes a portion that rotates together with the main shaft device 2. As shown in FIG. The outer cylindrical portion 4B of the bearing unit 4 is fixed to the housing 3 side and does not rotate. The housing 3 is supported by a spindle frame (not shown).
A first pulley 14 that constitutes the spindle rotating mechanism 5 is fixed to the outer circumference of the first draw bar 10 exposed upward from the spindle cylinder 8 . A first pulley 14 is secured to the first drawbar 10 by a lock nut 19 . The main shaft tube 8 rotates as the first pulley 14 rotates. A second pulley 15 is supported at a lateral position spaced from the first pulley 14 by a bearing fixed to the main shaft frame (not shown). A drive transmission belt 16 is wound around the outer circumferences of the first pulley 14 and the second pulley 15 . An output shaft 17 a of a motor device 17 is coaxially connected to the second pulley 15 . The motor device 17 is supported on the spindle frame side (not shown).
A rotary joint 6 is arranged at the upper end position of the first drawbar 10 . The rotary joint 6 supplies hydraulic fluid from a hydraulic pump device (not shown) as a pressure source into the spindle device 2 through a fixed pipe. The rotary joint 6 is divided into a shaft portion 18A that rotates together with the spindle device 2 and a non-rotating housing portion 18B to which a joint from an external fixed pipe (not shown) is connected. Hydraulic oil introduced through the housing portion 18B is supplied to the interior of the first drawbar 10 through the shaft portion 18A, circulated, and discharged from the first drawbar 10 through the shaft portion 18A.

A cylinder device 7 is arranged at an upper position of the housing 3 . The cylinder device 7 as a pushing means has a function of pushing the first drawbar 10 downward (in the advancing direction). The cylinder device 7 includes a cylindrical cylinder body 20 attached to the upper portion of the housing 3 and a piston 21 arranged in the cylinder body 20 so as to be vertically movable. The cylinder body 20 is a non-rotating part fixed to the housing 3 . The cylinder body 20 has a first port 23 and a second port 24 serving as inlets and outlets for hydraulic oil. The piston 21 is arranged so as to surround the outer periphery of the first drawbar 10, and has a very small gap between itself and the first drawbar 10, so that the piston 21 does not rotate itself and allows the rotation of the first drawbar 10. do. The piston 21 is held within the cylinder body 20 without rotating with the rotation of the first drawbar 10 .
A ring-shaped slider 25 is arranged below the piston 21 and outside the main shaft tube 8 . The slider 25 is held by connecting pins 26 . The connecting pin 26 is inserted in a direction perpendicular to the axial direction of the first drawbar 10 and fixed to the first drawbar 10 . Both ends of the connecting pin 26 protrude outward from a through hole 22 formed in the main barrel 8 and are connected to the slider 25 . The slider 25 and the connecting pin 26 rotate in synchronism with the first drawbar 10 as the first drawbar 10 (or the main shaft tube 8) rotates. As a result, the downward pressing force of the piston 21 is transmitted to the connecting pin 26 via the slider 25, and the first drawbar 10 is pushed by the connecting pin 26 to be able to move downward.
The cylinder device 7 receives hydraulic oil supplied into the cylinder body 20 from a hydraulic pump device as a pressure source (not shown), and the piston 21 slides vertically. As the piston 21 moves, the slider 25 is pushed by the piston 21 and moves vertically. As the piston 21 moves downward, the first drawbar 10 is pressed downward through the connecting pin 26 while compressing the first disc spring assembly 12 .

Next, the spindle device 2 will be described in more detail.
As shown in FIGS. 1 and 2A to 2F, a main shaft cap 28 is connected to the front end side of the main shaft cylinder 8. As shown in FIG. The spindle cap 28 is a tubular body having a circular cross section and communicating in the vertical direction. The main shaft cap 28 is fitted and fixed to the front end of the main shaft cylinder 8 . The main shaft cylinder 8 has two regions with different inner diameter dimensions. The tubular portion 8B contacts the outer periphery of the second drawbar 11 and the second disk spring assembly 13. As shown in FIG. A tapered holder mounting hole 29 is formed in the inner peripheral surface of the spindle cap 28 so that the diameter increases downward. The spindle cap 28 constitutes a housing 30 of the spindle device 2 together with the spindle tube 8 .
A partition wall 31 partitions the first cylindrical portion 8A and the second cylindrical portion 8B of the main shaft cylinder 8 . A fixing ring 32 is fixed at a position spaced slightly downward from the partition wall 31 .

The first drawbar 10 is constructed to have a circular outer shape in cross section and is composed of six diameter portions of different sizes. That is, the first drawbar 10 includes a disc-shaped table portion 10A arranged at the top, an upper slide portion 10B extending downward (forward) of the table portion 10A and having a diameter smaller than that of the table portion 10A, and an upper slide portion 10B. A central slide portion 10C having a smaller diameter than the upper slide portion 10B extending downward (forward) from the central slide portion 10C, a lower slide portion 10D having a smaller diameter than the central slide portion 10C extending downward (forward) from the central slide portion 10C, and a lower slide and a tip slide portion 10E attached to the tip side of the portion 10D. A piston portion 10F projecting like a flange is formed on the central slide portion 10C.
A cylindrical portion 31 formed in a cylindrical shape is formed at the front end of the tip slide portion 10E. The internal space of the cylindrical portion 31 accommodates the rear end side of the pull stud 55 of the chuck holder 51, which will be described later, and serves as a position for clamping the bulging portion 56, which will be described later.
A first flow path 35 and a second flow path 36 are formed in the interior of the first drawbar 10 through which hydraulic fluid flows. The first flow path 35 and the second flow path 36 are connected to the shaft portion 18A of the rotary joint 6 at the upper end position of the first drawbar 10. As shown in FIG. The first flow path 35 is arranged in the center of the first drawbar 10 and opens to the rear surface of the piston portion 10F of the first drawbar 10 . The second flow path 36 is arranged so as to surround the first flow path 35, extends from the middle of the upper slide portion 10, shifts toward the main shaft tube 8 indicated by the dashed line, and extends from the second cylindrical portion 8B. The inside is suspended and opened on the rear surface of the partition wall 31 .
A first coned disc spring assembly 12 is arranged around the outer periphery of the first draw bar 10 . The first disk spring assembly 12 is housed in a space 33 formed between the connecting pin 26 and the partition wall 31 on the outer periphery of the first drawbar 10 (the outer periphery of the central slide portion 10C) while being biased.

Next, the structure of the cylinder device 37 formed near the center of the first drawbar 10 in the vertical direction will be described. The cylinder device 37 has the main shaft tube 8 as a cylinder tube and a piston portion 10F formed integrally with the first draw bar 10 as a piston. An upper chamber 34A is provided above the piston portion 10F, and a lower chamber 34B is provided below the piston portion 10F. The upper chamber 34A communicates with the second flow path 36, the lower chamber 34B communicates with the first flow path 35, and is filled with hydraulic oil.
The piston portion 10F of the first draw bar 10 moves upward and the upper chamber 34A disappears, thereby restricting further upward movement. Downward movement is restricted. That is, the piston portion 10F advances and retreats by pushing and pulling hydraulic oil from the two passages of the first flow path 35 and the second flow path 36 to the upper chamber 34A and the lower chamber 34B to the upper chamber 34A and the lower chamber 34B. It is a double-acting cylinder device. As a result, the first drawbar 10 is moved vertically by controlling the hydraulic fluid through the piston portion 10F.
Further upward movement of the second draw bar 11 is restricted when the upper surface of the flange portion 11B comes into contact with the lower surface of the fixing ring 32 . The tip of the cylindrical portion 8D of the first drawbar 10 is always arranged at a position retreating from the tip of the second drawbar 11. As shown in FIG.

The second drawbar 11 is also configured to have a circular outer shape in cross section. The second drawbar 11 has a cylindrical main body 11A, a flange portion 11B projecting from the outer periphery near the upper portion of the main body 11A, a partition wall 11C between the main body 11A and the flange portion 11B, and a ring-shaped upper portion. It is composed of a projecting ring portion 11D. A passage 11Ca is formed in the partition wall 11C.
The lower part of the main body 11A of the second drawbar 11 is accommodated in the spindle cap 28 and brought into close contact with the inner peripheral surface 28a, and the outer periphery of the flange portion 11B contacts the inner peripheral surface of the second cylindrical portion 8C of the main shaft tube 8. are kept in close contact. Such a close contact structure guides the second drawbar 11 when it slides linearly in the vertical direction. An internal space near the tip of the main body 11A accommodates a flange portion 57 of a chuck holder 51, which will be described later, and serves as a position for clamping a constricted portion 58. As shown in FIG.
A second disc spring assembly 13 is arranged around the main body 11A of the second drawbar 11. As shown in FIG. The second coned disc spring assembly 13 is arranged between the main body 11A and the main shaft cylinder 8, and arranged so as to be sandwiched between the flange portion 11B and the main shaft cap 28 in the vertical direction while being biased. It is A pin 38 is arranged between the second drawbar 11 and the fixing ring 32 to prevent the second drawbar 11 from rotating in the circumferential direction. A key 39 is attached to the tip of the holder mounting hole 29 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.

An arrangement state of the first draw bar 10 and the second draw bar 11 having such a structure with respect to the housing 30 (the main shaft tube 8 and the main shaft cap 28) will be described.
The first drawbar 10 and the second drawbar 11 are arranged in series so as to partially overlap inside the housing 30 .
The second draw bar 11 is slidably arranged in a cylindrical housing 30, and is also configured in a cylindrical shape to accommodate the first draw bar 10 and allow the first draw bar 10 to slide. . The first drawbar 10 is slidably accommodated in the second drawbar 11 near the bottom. In other words, the housing 30, the first drawbar 10, and the second drawbar 11 form a double sliding mechanism that overlaps inside and outside.
In the first drawbar 10, the upper slide portion 10B is housed in close contact with the first cylindrical portion 8A of the main shaft tube 8, and the central slide portion 10C is suspended in close contact with the passage 31a of the partition wall 31 and fixed. The passage 32a of the ring 32 is communicated. The lower slide portion 10D extending below the central slide portion 10C communicates with the passage 11Ca of the partition wall 11C on the side of the second drawbar 11, and the tip slide portion 10E is arranged in the main body 11A on the side of the second drawbar 11. be done. Each member is arranged in close contact with each other and guides the first draw bar 10 when it slides linearly in the vertical direction.

Next, the clamping mechanism for the first drawbar 10 and the second drawbar 11 will be described with reference to FIGS. 2A to 2F, 4A to 4E and 5. FIG.
The first drawbar 10 clamps the pull stud 55 side of the chuck holder 51 to be described later, and the second drawbar 11 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 41 are formed in the cylindrical portion 8D of the first drawbar 10 at predetermined intervals in the circumferential direction. Each first through hole 41 has a circular opening that communicates with the inside and outside of the cylindrical portion 8D of the first drawbar 10 in the radial direction. The wall surface 41a of each first through-hole 41 is formed so 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 42 is accommodated in each first through hole 41 . The diameter of the first ball 42 is larger than the diameter of the inner opening of the first through hole 41 and smaller than the diameter of the outer opening.
A plurality of second through-holes 43 are also formed at predetermined intervals in the circumferential direction near the tip of the second drawbar 11 . Since the configuration of the second through hole 43 is the same as that of the first through hole 41, detailed description thereof will be omitted. A second ball 44 is accommodated in each second through hole 43 . Since the configuration and operation of the second ball 44 are the same as those of the first ball 42, detailed description thereof will be omitted.

Inside the main body 11A of the second drawbar 11 and above the second through hole 43, first recesses 45 are formed at predetermined intervals in the circumferential direction.
The first concave portion 45 has a circular opening shape and has the same diameter as the diameter of the outer opening portion of the first through hole 41 . The first recess 45 is slightly deeper than the protrusion of the first ball 42 when the first ball 42 is in the innermost position in the first through hole 41 (the state shown in FIGS. 4A and 4E). configured to take shape. In other words, the first ball 42 retreats outward when the first recess 45 is aligned with the first through hole 41, and when it is submerged in the first recess 45, the first ball 42 moves backward. It does not protrude from the face (icicle) of the drawbar 10 of 1. The wall surface of the first recess 45 is tapered so that it can easily enter and retract into the first through hole 41 .
The first recess 45 is matched with the first through hole 41 according to the relative positional relationship between the first drawbar 10 and the second drawbar 11 . When the first recessed portion 45 and the first through hole 41 are matched, the first ball 42 is loosely fitted, so that it can be retracted to the outside and is in an unclamped state. On the other hand, if the first ball 42 is not collated, the first ball 42 is held in a state in which the tip side protrudes slightly inside the first through hole 41 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 axial portion of the mounting portion 53 with the plurality of first balls 42 from the periphery thereof.

Second recesses 47 are formed at predetermined intervals in the circumferential direction on the lower inner peripheral surface 7a of the main shaft tube 8 and in the vicinity of the base side of the holder mounting hole 29 .
The second recess 47 has a larger diameter than the second through hole 43 in order to prevent the second drawbar 11 from interfering with the main barrel 8 . When the second recess 47 is in contact with the second through hole 43, the second ball 44 is retracted the most. It is the same as the first drawbar 10 side that it does not protrude from the 11 face (icicle). The wall surface of the second recess 47 is tapered so that it can easily move into and out of the second through hole 43 .
The second recess 47 is matched with the second through-hole 43 by placing the second drawbar 11 at a predetermined advanced position. Since the second ball 44 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 44 is not collated, the second ball 44 is held in a state in which the tip side protrudes slightly and cannot be moved in and out, so that a clamped state is established.
A first clamping mechanism is formed between the first drawbar 10 and the second drawbar 11 by the first through hole 41, the first ball 42, the first recess 45, and the like.
The second through hole 43, the second ball 44, the second recess 47 and the like form a second clamping mechanism between the main shaft tube 8 and the second drawbar 11. As shown in FIG.

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 Embodiment 1, the chuck holder 51 with three claws 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 29 . Three claw portions 54 are movably attached to the holder body 52 . 6(a) and 6(b), the claw portion 54 is most opened, and the claw portion 54 is most closed (chucked state) in the state of FIGS. 7(a) and 7(b). 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 29 when the chuck holder 51 is mounted in the holder mounting hole 29 (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 2F 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 claws 54 are most opened as shown in FIGS. 6(a) and 6(b).
In the following, first, A. ~C. , the movement of the first drawbar 10 and the second drawbar 11 and the movement of the first and second clamping mechanisms near the tips of the first drawbar 10 and the second drawbar 11 will be mainly described.
A. 2A and 4A, the first drawbar 10 is pushed upwards by the biasing force of the first disc spring assembly 12, and the second drawbar 11 is pushed upwards by the biasing force of the second disc spring assembly 13. is being pushed up by Both the first clamping mechanism and the second clamping mechanism are released. In addition, in a state in which hydraulic oil is supplied to the cylinder device 37 from the first flow path 35, the piston portion 10F is arranged at the most upwardly moved position. A port of an electromagnetic valve of a hydraulic pump device (not shown) that supplies hydraulic oil to the cylinder device 37 is in a neutral position. Since the solenoid valve has an open center at its neutral position, the piston portion 10F moves freely up and down within the cylinder device 37. Since the drawbar 10 is pushed up, the piston portion 10F is arranged at the highest position.
Such an advanced position of the first drawbar 10 is the initial advanced position of the first drawbar 10 . The initial advance position is S1 in FIG. 2A, and the end position of the first drawbar 10 is used as a reference. The end position of the first drawbar 10 described below is determined by a proximity sensor (not shown).

The biasing state of the first disc spring assembly 12 to the first drawbar 10 and the biasing state of the first disc spring assembly 12 to the first drawbar 10 will be described in more detail. The first disc spring assembly 12 presses the upper slide portion 10B with the partition wall 31 as a reference. Then, the entire first drawbar 10 is pushed upward via the upper slide portion 10B. Further, the second disc spring assembly 13 presses the flange portion 11B with the main shaft cap 28 as a reference. Then, the entire second drawbar 11 is pushed upward via the flange portion 11B. Since the flange portion 11B comes into contact with the lower surface of the fixing ring 32, further upward movement is restricted.
At this time, as shown in FIG. 4A, the first ball 42 in the first through hole 41 is locked in a clamping position where movement toward the first recess 45 is not permitted. The second ball 44 in the second through hole 43 is also locked in a clamping position where movement toward the second recess 47 is not permitted. In other words, in this state, the chuck holder 51 interferes with the first ball 42 and the second ball 44, so the connection is still impossible.

B. Next, the cylinder device 7 is actuated by a predetermined control operation, and the first drawbar 10 is also pressed and moved downward in synchronism with the downward movement of the connecting pin 26 by being pushed by the piston 21 . At this time, the first drawbar 10 is moved downward against the urging force of the first disc spring assembly 12 pushing the first drawbar 10 upward. First, the first drawbar 10 moves from position S1 in FIG. 2A to position S2 in FIG. 2B. The piston portion 10F also moves downward by a distance of S1 to S2. At this time, since the spring force of the second disc spring assembly 13 is stronger than that of the first disc spring assembly 12, the connecting pin 26 of the first disc spring assembly 12 is pressed by the piston 21, thereby lowering the first disc spring assembly 12. The second disk spring assembly 13 is not compressed during the stage of being compressed by movement. That is, only the first drawbar 10 moves downward, and the second drawbar 11 does not move downward and remains at that position.
In the state shown in FIG. 2B, the first drawbar 10 moves downward, and the first ball 42 in the first through hole 41 is permitted to move toward the first recess 45, resulting in an unclamped state. On the other hand, the second ball 44 in the second through hole 43 remains in the clamping position where movement toward the second recess 47 is not allowed.

C. When the connecting pin 26 moves further downward and the first disc spring assembly 12 is compressed to the maximum, or when the biasing force due to the compression exceeds the biasing force of the second disc spring assembly 13, The second drawbar 11 is pressed downward through the first drawbar 10 . At this stage, the downward movement of the connecting pin 26 causes the second draw bar 11 to move downward against the biasing force of the second disk spring assembly 13 pushing the second draw bar 11 upward. FIG. 2C shows a state in which the first drawbar 10 has moved to a position S3 which is lower than S1 and S2, and a state in which the second drawbar 11 has moved most downward. The piston portion 10F also moves downward by a distance of S2 to S3.
At this time, as shown in FIG. 4B, the first ball 42 in the first through hole 41 is allowed to move toward the first recess 45 and is in the unclamped position. The second ball 44 in the second through hole 43 is also allowed to move toward the second recess 47 and is in the unclamped position. That is, the chuck holder 51 becomes connectable.

Next, the following D. ~H. , the control operation when clamping and unclamping the chuck holder 51 in cooperation with the cylinder device 37 will be described.
D. As shown in FIG. 2D, the spindle device 2 is a C.I. 2, the chuck holder 51 is mounted in the holder mounting hole 29 of the spindle device 2 by a predetermined control operation. Even if the mounting portion 53 and the pull stud 55 extend to the back side of the holder mounting hole 29, as shown in FIG. Advancement is not hindered by interference with the second ball 44).
E. After the chuck holder 51 is completely attached to the holder attachment hole 29 of the spindle device 2, the piston 21 of the cylinder device 7 is moved upward by a predetermined control operation. Then, as shown in FIG. 2E, the second disc spring assembly 13, which had been compressed as the weight was released, releases its strong biasing force, and pushes the second drawbar 11 upward again. The position at this time is assumed to be S4 which is higher than S3. As the second drawbar 11 moves upward, the constricted portion 58 at the rear end of the mounting portion 53 of the chuck holder 51 is clamped (by the second balls 44) by the second clamping mechanism (state shown in FIG. 4D). However, at this stage, the first clamping mechanism side has not yet operated.

F. When the piston 21 of the cylinder device 7 moves further upward, the first conical spring assembly 12, which had been compressed with the release of the load, releases its strong biasing force, and the first draw bar 10 moves upward again as shown in FIG. 2F. will be pushed up to As a result, the first drawbar 10 is relatively retracted, so that the first recessed portion 45 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 moved to the first position. is clamped (by the first ball 42) by the clamping mechanism of (state of FIG. 4E).
In this way, the pull stud 55 is clamped by the operation of the first clamping mechanism, and subsequently (actually, instantaneously as the piston 21 moves upward), the first drawbar assembly 12 by the first disk spring assembly 12 is pulled. The pull stud 55 is pulled out rearward (upward) by pushing up (that is, retreating upward) the pull stud 10, and the claw portion 54 of the chuck holder 51 is closed. The position of the first drawbar 10 at this time is assumed to be S5 higher than S4. Since the chuck holder 51 is clamped, S5 is positioned lower than S1. In FIG. 2F, it is assumed that a workpiece (not shown) is chucked in the states of FIGS. Therefore, here, the claw portion 54 is not closed as much as in FIGS. 7(a) and 7(b).
Next, when the position of S5 of the first drawbar 10 is detected by a proximity sensor (not shown), the computer device controls the solenoid valve of the hydraulic pump device based on the detection signal to move the piston portion 10F in the cylinder device 37. Hydraulic oil is supplied from the first flow path 35 into the lower hydraulic chamber. The piston portion 10F is pushed upward by the pressure generated by the supply of hydraulic fluid. As a result, in addition to the urging force of the first coned disc spring assembly 12 , the hydraulic force that pushes the first drawbar 10 upward acts on the first drawbar 10 . In this embodiment, FIG. 2F shows a state in which the pull stud 55 is pulled out to the maximum only by the biasing force of the first disc spring assembly 12, and the first drawbar 10 does not move upward any more. That is, the force of pulling the pull stud 55 rearward (upward) is increased by the pressure of the cylinder device 37 applied to the piston portion 10F.

G. When the chuck holder 51 is removed (unclamped) from the state where the chuck holder 51 is attached to the spindle device 2, first, the computer device (not shown) advances (lowers) the piston 21 of the cylinder device 7, and F. in order from A. control to reach F. to D. When the first drawbar 10 is displaced to , the computer device controls the solenoid valve of the hydraulic pump device in synchronization with the advance of the piston 21 of the cylinder device 7 to control the hydraulic pressure below the piston portion 10F in the cylinder device 37. Hydraulic oil is supplied from the second flow path 36 into the room. The piston portion 10F is pressed downward by pressure due to the supply of hydraulic fluid. As a result, in addition to the hydraulic force of the cylinder device 7, the hydraulic force that pushes the first drawbar 10 downward acts on the first drawbar 10. As shown in FIG. Therefore, the first drawbar 10 moves downward more quickly than the cylinder device 7 alone.
H. FIG. 3A shows the F.F. 7A and 7B show the operation when the chuck holder 51 does not chuck the workpiece, that is, the movement of the claw portion 54 is large as shown in FIGS. 7(a) and 7(b). Since the workpiece is not chucked, the pull-out margin of the pull stud 55 is larger than that in FIG. 2F, and the first drawbar 10 is placed at the position S1, which is the initial advance position higher than S5 (FIG. 3B). state). H. In this case, the computer device (not shown) controls the electromagnetic valve (not shown) of the hydraulic pump device (not shown) based on the detection signal so that hydraulic oil is supplied from the first flow path 35 into the hydraulic chamber below the piston portion 10F. 10F is pushed upward by the pressure of the hydraulic oil.
In the above description, the first draw bar 10 and the second draw bar 11 move separately to explain each stage of movement. Since the urging force of the disk spring assembly 12 and the second disk spring assembly 13 is released, and the movement of pressurizing the hydraulic pump device is instantaneous, in practice, when the chuck holder 51 is attached, the first The actuation of the first clamping mechanism and the second clamping mechanism are performed substantially simultaneously.

By configuring as described above, the spindle unit 1 of Embodiment 1 has the following effects.
(1) In order to clamp the chuck holder 51 having the inner and outer (and front and rear) double clamped portions, it is possible to drive and clamp only one cylinder device 7 as a pushing means. Since only one cylinder device 7 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 draw bar 11 via the first draw bar 10 only by advancing and retracting the piston 21. The first draw bar 10 is the first disc spring assembly 12, and the second draw bar Since the draw bar 11 advances and retreats with the second coned disc spring assembly 13, it has a simple structure and is less likely to break down.
(3) The pull stud 55 of the chuck holder 51 can be clamped by the first clamping mechanism only by the biasing force of the first disc spring assembly 12 and pulled upward (rearward). Contributes to miniaturization and weight reduction.
(4) When the first drawbar 10 is moved upward, the hydraulic force of the cylinder device 37 that pushes the first drawbar 10 upward acts in addition to the biasing force of the first disc spring assembly 12. The resultant force increases the force that pulls the pull stud 55 rearward (upward). As a result, firm clamping can be achieved in machining with a large load.
(5) When the first drawbar 10 is moved downward, the hydraulic force of the cylinder device 37, which pushes the first drawbar 10 downward, acts in addition to the cylinder device 7. It can be separated quickly, and work such as replacement of the chuck holder 51 can be quickly performed.
(6) Since the first drawbar 10 and the second drawbar 11 are arranged in series and partly overlapped, the overall length and width of the spindle device 2 can be reduced.
(7) In the clamping operation, first, the second clamping mechanism by the second drawbar 11 operates the attachment portion 53 of the chuck holder 51 , and then the pull stud 55 of the chuck holder 51 is clamped by the first drawbar 10 . Since the clamping operation is performed with a time difference so that the clamping mechanism 1 operates and clamps, the chuck holder 51 can be securely fixed to the holder mounting hole 29 first, and the clamping malfunction of the pull stud 55, such as a pull Clamping errors such as the second ball 44 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.

<Embodiment 2>
The second embodiment is a variation of the first embodiment. In the first embodiment, the configuration is of a double action specification in which hydraulic oil is supplied from two passages, the first passage 35 and the second passage 36, to the upper and lower spaces of one piston portion 10F. In the second embodiment, the passage is a single-acting specification case having a plurality of piston portions. Moreover, in Embodiment 2, coolant liquid is used instead of hydraulic oil. Further, members and portions having similar functions corresponding to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
As shown in FIG. 8, the spindle unit 71 of Embodiment 2 includes a spindle motor device (not shown) as a spindle rotation mechanism, and a coupling 72 connected to the spindle motor device is directly connected to the spindle cylinder 8 of the spindle device 2. ing. Thereby, the rotational force from the coupling 72 is transmitted to the spindle device 2 . The same cylinder device 7 as in the first embodiment is arranged above the spindle unit 71 so as to surround the spindle tube 8 .
The first drawbar 10 of the second embodiment is arranged below the connecting pin 26 . In the second embodiment, the first drawbar 10 has an upper slide portion 10B in which the first disk spring assembly 12 is arranged, and an upper slide portion extending downward (forward) from the upper slide portion 10B. A lower slide portion 10D having a diameter smaller than that of 10B and a tip slide portion 10E attached to the tip side of the lower slide portion 10D are provided. Two piston portions 10H projecting like flanges are formed on the upper slide portion 10B. A partition wall 73 is provided inside the main barrel 8 and between the two piston portions 10H.
A passage 75 through which coolant flows is formed inside (at the center) of the first draw bar 10 . The coolant liquid always flows at a predetermined pressure by a pump device (not shown) and flows outward from inside the spindle cap 28 below the first drawbar 10 and the second drawbar 11 . The passage 75 branches midway to form a first branch passage 75A and a second branch passage 75B, which communicate with the lower sides of the two piston portions 10H of the first drawbar 10, respectively. In the second embodiment, two upper and lower cylinder devices 77 are formed between the upper piston portion 10H and the partition wall 73, and between the lower piston portion 10H and the partition wall 32 and the wall surface of the surrounding main barrel 8. As shown in FIG.

In such a configuration, the upper surface of the slider 25 is pressed against the bottom surface of the piston 21 to move the first drawbar 10 downward against the urging force of the first disk spring assembly 12 through the connection 26. be done. When the piston 21 compresses the first disk spring assembly 12 to the maximum, or when the biasing force due to the compression exceeds the biasing force of the second disk spring assembly 13, similar to the first embodiment, The second drawbar 11 is pushed downward through the first drawbar 10 which is moved downward to the maximum.
After the chuck holder 51 is accommodated in the holder mounting hole, the hydraulic pressure of the cylinder device 7 is controlled to raise the piston 21 and remove it from the slider 25, thereby forming the first disk spring assembly 12 and the second disc spring assembly 12 in the same manner as in the first embodiment. The two disk spring assemblies 13 can operate both the first clamping mechanism and the second clamping mechanism with a time lag. Furthermore, when the first drawbar 10 moves upward, the coolant liquid flows into the cylinder device 77 from the first branch passage 75A and the second branch passage 75B to increase the internal pressure.
In the second embodiment, unlike the first embodiment, the force pushing the first draw bar 10 upward by the coolant liquid having a lower pressure than the hydraulic oil is combined with the biasing force of the first disc spring assembly 12. However, even with such a spindle unit 71, the same effects as those of the spindle unit 1 of the first embodiment can be obtained.

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. 9(a) and 9(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. This is particularly advantageous in machining with a tool (not shown) with a large load, because the pressure from the cylinder device is combined to provide firm clamping.

In the first embodiment, the urging force of the first disc spring assembly 12 and the hydraulic force of the cylinder device 37 are used to retract the first drawbar 10 and pull the pull stud 55 rearward. The pull stud 55 may be pulled rearward only by the biasing force of the first disc spring assembly 12 or the hydraulic force of the cylinder device 37 without using both. Only the biasing force of the first disc spring assembly 12 refers to F. in paragraph 0033 above. As described above, in this embodiment, basically, the pull stud 55 can be pulled rearward only by the biasing force of the first disc spring assembly 12. For example, the cylinder device 37 is provided. However, the port of the solenoid valve of the hydraulic pump device should always be in the neutral position of the open center.
On the other hand, by removing the first disk spring assembly 12 in the configuration of the first embodiment, the first draw bar 10 can be retracted (upwardly moved) only by the hydraulic force of the cylinder device 37 .
A. When the cylinder device 7 is actuated and the connecting pin 26 is pressed by the piston 21 and moves downward, the first draw bar 10 is also pressed and moves downward in synchronism. The second drawbar 11 is pushed upwards by the biasing force of the second disc spring assembly 13, but is pushed by the first drawbar 10 and moves downward. At that time, both the hydraulic forces of the cylinder device 7 and the cylinder device 37 can be used as in the first embodiment, and the pull stud 55 can be quickly disconnected by the combined force of these forces.
B. Conversely, when the piston 21 moves backward, the second drawbar 11 moves upward due to the biasing force of the second disk spring assembly 13, but the first drawbar 10 does not have the first disk spring assembly 12. Therefore, the cylinder device 37 is used to move upward.
Specifically, the cylinder device 37 is controlled to inject oil from the first flow path 35 to the lower side of the piston portion 10F, and the upward movement of the piston portion 10F causes the entire first drawbar 10 to move upward. to For example, when the first drawbar 10 is raised to receive the chuck holder 51, the first drawbar 10 is moved so that the first ball 42 and the second ball 44 are at the unclamped position (the piston portion 10F 2B and 2E) are pressure controlled.

- In the first and second embodiments, the pistons 10F and 10H are integrally formed as a part of the first drawbar 10, but they may be formed separately and attached to the first drawbar 10. good.
In the first embodiment, when the piston 21 of the cylinder device 7 is lifted, the biasing force of the first disc spring assembly 12 is released after the second disc spring assembly 13 releases the biasing force and returns. It was released and then returned, and finally the cylinder device 37 was actuated and its pressure was combined with the urging force of the first disc spring assembly 12, but the first disc spring assembly 12 was attached. The control may be such that the force is released and the cylinder device 37 is operated at the same time.
- Both hydraulic and pneumatic cylinder devices 37 and 77 can be used.
- Other spring devices may be used as means or devices for urging the first and second drawbars 10 and 11 . Also, a cylinder device may be used as the urging device.
A multi-phase AC servomotor, for example, a six-phase AC servomotor, may be used as the motor device 17;
・In the above example, the first and second balls 42 and 44 were used as interference bodies that advance and retreat in the radial direction of the clamping mechanism. A clamping mechanism that advances and retreats may be used.
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 spindle device 7 Cylinder device as pushing means 8 Main barrel 10 First drawbar 10F, 10H Piston portion as piston 11 Second drawbar 12 First attachment Disc spring assembly as biasing means 13 Disc spring assembly as second biasing means 37 Cylinder device 51 Chuck holder as holder 60 Tool holder as holder 56 First A bulging portion as a clamped portion, 58 ... a constricted portion as a second clamped portion.

Claims (13)

A spindle device that is used by attaching a tool or workpiece holder to its tip end, having a first clamped portion and a second clamped portion that are doubly arranged inside and outside, on the base side thereof,
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. The first drawbar and the second drawbar are arranged in series or partly overlapped in the series direction in the main shaft cylinder and are arranged so as to be able to advance and retreat. ,
A cylinder device is arranged so that the first draw bar, which is on the piston side, advances and retreats with the first draw bar and the main barrel using the main barrel as a cylinder. The introduction allows the piston to move axially within the main shaft cylinder,
The first drawbar is pushed forward by the pushing means to advance against the biasing force of the first biasing means, and the second drawbar advances the first drawbar. is directly or indirectly pushed by the first drawbar along with the second drawbar and is configured to be advanced against the biasing force of the second biasing means,
When the first drawbar advanced by the pushing means reaches a predetermined advance position, the first clamping mechanism is released, and the second drawbar pushed by the first drawbar is clamped. 2 clamping mechanism is also released,
As the pressing force of the pressing means is released, the first drawbar is retracted in the direction of the main shaft barrel base, the first clamping mechanism of the first drawbar is actuated, and the second drawbar is retracted. is retracted in the direction of the main barrel base portion by the biasing force of the second biasing means to operate the second clamping mechanism,
A main spindle device, wherein the pressing force of the pressurized fluid introduced into the cylinder device is applied to the first drawbar when the first drawbar advances or retreats. . As the pressing force of the pushing means is released, the first draw bar is retracted toward the base of the main barrel by the combined force of the pressing force of the cylinder device and the biasing force of the first biasing means. The first clamping mechanism of the first drawbar is actuated, the second drawbar is retracted toward the base of the spindle cylinder by the biasing force of the second biasing means, and the second clamping mechanism is activated. 2. The spindle assembly of claim 1, wherein the spindle assembly is actuated. When the first clamp mechanism is released by the first drawbar advanced by the pushing means, the thrust of the first drawbar in the forward direction causes the advance of the piston of the cylinder device. 2. The spindle device according to claim 1, wherein the generated pressing force is added. A spindle device that is used by attaching a tool or workpiece holder to its tip end, having a first clamped portion and a second clamped portion that are doubly arranged inside and outside, on the base side thereof,
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. The first drawbar and the second drawbar are arranged in series or partly overlapped in the series direction in the main shaft cylinder and are arranged so as to be able to advance and retreat. ,
A cylinder device is arranged so that the first draw bar, which is on the piston side, advances and retreats with the first draw bar and the main barrel using the main barrel as a cylinder. The introduction allows the piston to move axially within the main shaft cylinder,
The first drawbar is advanced by pushing means, and the second drawbar is pushed directly or indirectly by the first drawbar as the first drawbar advances and is pushed by the biasing means. configured to be advanced against a biasing force;
When the first drawbar advanced by the pushing means reaches a predetermined advance position, the first clamping mechanism is released, and the second drawbar pushed by the first drawbar is clamped. 2 clamping mechanism is also released,
As the pressing force of the pressing means is released, the first drawbar at the predetermined advanced position is retracted by the cylinder device toward the base of the main shaft cylinder, and the first clamping mechanism is actuated. A spindle device according to claim 1, wherein the second drawbar is retracted toward the spindle barrel base portion by the biasing force of the biasing means to operate the second clamping mechanism. When the first drawbar advanced by the pushing means releases the first clamping mechanism at a predetermined advanced position , the pressurized fluid introduced into the cylinder device is applied with a pressing force. The spindle device according to claim 4, characterized by: 2. The spindle device according to claim 1, wherein said cylinder device that operates in accordance with the release of the pressing force by said pushing means operates after said first urging means operates. 5. The spindle device according to claim 4 , wherein the cylinder device that operates with the release of the pressing force by the pushing means operates after the second urging means operates. When the first drawbar is retracted from the predetermined advanced position, the first clamping mechanism of the first drawbar is operated after the second clamping mechanism of the second drawbar is operated. The spindle device according to any one of claims 1 to 7, characterized in that: The first clamping mechanism has an interfering body that advances and retreats in the radial direction of the main barrel , and clamps the first clamped portion in a state in which the first drawbar is arranged at a first advanced position. 8. 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 interfering body that advances and retreats in the radial direction of the main barrel , and clamps the second clamped portion in a state in which the first drawbar is arranged at the first advanced position. 10. The second clamping mechanism is released by arranging the interfering body facing an accommodating portion formed in the inner peripheral surface of the main shaft cylinder. Spindle device. 8. The spindle device according to claim 1, wherein said holder is mounted in a holder mounting hole formed at the tip of said spindle cylinder. The holder for the workpiece has a structure in which the first clamped portion is formed on a lever member that can move back and forth. The lever member is pulled out through one clamped portion to clamp the work in the unclamped state, and the lever member is pushed back by advancing the first draw bar to unclamp the work in the clamped state. The spindle device according to any one of claims 1 to 7, characterized in that: A machine tool equipped with the spindle device according to any one of claims 1 to 7.

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