JPH09192963A - Machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationally realize tool gripping force of a collet by providing a tool unclamping means for releasing gripping force for a tool by pressing the collet forward in the axial direction of a main shaft by making use of pressure of coolant. SOLUTION: Clamping of a small-diameter tool is performed by using stable energizing force of a bellevill spring 51. In unclamping of the small-diameter tool, when coolant (normally, gas such as compressed air) to serve as an operating medium is fed from a coolant supplying source, it enters a cylinder chamber part 43b on the back pressure side of a piston member 47 from an introducing pipe part through a draw bar and a diameter extending part, so as to advance the piston member 47 while competing with the bevel spring 51. Therefore, a part whose diameter is contracted of a spring collet 31 is elastically returned to the original diameter, and clamping of the small-diameter tool is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to attachment / detachment of a tool holder to / from a spindle, automatic exchange of tools, storage of tools in a tool magazine, clamping / unclamping of tools in a tool holder, and the like.
The present invention relates to a machine tool and a tool holder having various functions related to tool exchange.

[0002]

2. Description of the Related Art In a machine tool having a tool changing function, a tool is usually attached to a spindle of a machine tool with a tool holder assigned to the tool, and is used with a tool holder after use. It is stored in the tool magazine as it is. As an example of such a tool holder, an actual fair 7-18
Japanese Patent No. 515 discloses a tool holder including a collet for holding a tool and a mechanism for reducing the diameter of the collet by manually screwing a ring. This tool holder is
Further, a cutting passage (coolant) supplied from a cutting fluid supply device (through spindle coolant supply device) through an oil passage (coolant passage) provided in the machine tool spindle is provided inside to provide a flow passage. There is.

[0003]

However, as described above, the tool and the tool holder are always handled as a unit.
It is wasteful of space and uneconomical. That is, for example, in the case of a machine tool system that uses a large number of small-diameter tools, it is necessary to install a large-sized tool magazine so that the small-diameter tools are small in size but eventually fit into a tool holder having a larger size. However, it is not preferable in terms of equipment space and economy. In order to solve this problem, it is conceivable to provide a small-sized tool magazine for small-diameter tools that stores a single tool with the tool holder removed. It does not need to be unnecessarily enlarged. However, in that case, automatic attachment / detachment work between a large number of small-diameter tools and a common tool holder is unavoidable, and a mechanism for performing this attachment / detachment operation and its operation source are separately required, which in turn increases the equipment cost. There is fear.

In view of this, the present invention basically follows the idea of storing this specific tool (for example, a small diameter tool) separately from the tool holder, and at the same time, it is rational for the automatic attachment / detachment of such a tool. The task is to develop and introduce simple and simple means to realize a practical and economical machine tool system with high space efficiency.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, it is desired to perform relative motion between a tool attached to the front end of a spindle via a tool holder and a workpiece attached to a table. In a machine tool for machining into a shape, a tool holder for attaching a tool is detachably mounted, and a coolant from a coolant supply source is passed through a coolant passage provided in the spindle or through a coolant passage provided outside the tool. A coolant supply means for supplying into the holder, a collet type tool holder attached to the spindle and having a collet for detachably gripping a tool at the front end, and a collet type tool holder built in the collet type tool holder, and the collet is always attached to the spindle. Tool clamping means for applying a gripping force of the tool to the collet by urging the collet in the axial direction rearward, And a tool unclamp means for releasing the gripping force of the tool by pressing the collet forward in the axial direction of the main spindle by utilizing the pressure of the coolant supplied by the coolant supply means. What is done is a feature of the configuration.

With this structure, the tool holding force of the collet provided by the tool clamping means of the collet type tool holder utilizes the pressure of the coolant (gas such as liquid or compressed air) supplied by the coolant supply means. Reasonably released by unclamping means.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. First, an example of a spindle structure to which the present invention is applied will be briefly described with reference to FIG.
A hollow spindle 3 is coaxially arranged inside a hollow spindle housing 1 incorporated in a spindle head stock (not shown). The spindle 3 is rotatably supported by a pair of bearings 7 on the tip side of the spindle whose axial position is regulated by a bearing retainer 5 and a pair of bearings (not shown) on the rear end side of the spindle. The rear end portion is integrally connected to an output shaft of a spindle motor (not shown) attached to the spindle housing 1 (headstock).

The tip of the main shaft has a tapered hole 9 for mounting a tool holder, which is arranged concentrically with the axis and has a tapered shank portion 11 complementary to the tapered hole 9.
A characteristic collet type tool holder 13 (details of which will be described later) as shown in FIG. The principle that both tool holders are taper-engaged with the main spindle 3 and clamped (integrated) is as follows.
The expandable and retractable collet part 17 partially inserted in the stepped cavity part 15 inside the tapered shank part 11 is attached to the hollow drawbar 21 which is biased (pulled in) toward the main shaft rear end side by a large number of disc springs 19. The diameter of the joined hollow expanded portion 23 is expanded by the wedge action, and the tapered shank portion 11 (stepped hollow portion 15) is pulled inward. On the other hand, when the illustrated tool holder 13 is unclamped, a cylinder mechanism (not shown) connected to the rear end portion of the drawbar causes the drawbar 21 (and the expanded diameter portion 23) to rotate so as to overcome the biasing force of the disc spring 19. The collet part 1 is configured to be advanced to the tip side.
7 The expanded diameter part of the tip returns to the original diameter, and the tool holder 13
The stepped cavity portion 15 in the taper shank portion 11 is no longer constrained (functions to pull in).

Next, the characteristic internal structure of the collet type tool holder 13 for small-diameter tools (hereinafter referred to as the small-diameter holder 13) will be described in detail with reference to FIG. As described above, the small-diameter holder 13 has the stepped cavity portion 15 inside the right taper shank portion 11, and the collet portion 17 of the spindle 3 expands and contracts in the stepped cavity portion 15 so that the small-diameter holder 13 with respect to the spindle 3. 13 clamps / unclamps are performed.

A large-diameter flange portion 27 is provided adjacent to the taper shank portion 11, and a grip groove 29 for an automatic tool changing (ATC) arm (not shown) is provided on the center outer periphery thereof. . At the center of the inside of the holder housing 31 at the left end of the small-diameter holder 13, a conical surface 33 whose diameter becomes smaller toward the inner side in the axial direction is formed. In this conical surface portion, a small-diameter tool (for example, small diameter such as φ6, φ8, etc.) is formed. The complementary surface portion of the retractable spring collet (chuck) 37 for holding the straight shank portion of the drill is in surface engagement.

A cylinder mechanism 41 for driving (expanding and contracting) the spring collet 37 is incorporated in the center of the middle portion of the holder housing 31, and this is a cylindrical cylinder chamber formed inside the holder housing 31. 43 (43a, 43b) includes a piston member 47 which can slide in a fluid-tight manner via an O-ring 45. At the center of the left side of the piston member 47, the spring collet 37
The root portion of is inserted and both members (37, 47) are integrally connected by a connecting bolt 49. The cylinder chamber 43 divided into two by the piston member 47, the cylinder chamber portion 43a on the left side where the connecting portion of both members is present
A disc spring 51 is attached to the disc spring 51. The disc spring 51 always attaches the piston member 47 (and the spring collet 37) to the taper shank 11 side in the direction in which the diameter of the spring collet 37 is reduced due to the small-diameter tool clamp. I am energetic.

On the other hand, for unclamping a small diameter tool,
The piston member 47 is overcome by overcoming the biasing force of the disc spring 51.
As a mechanism for advancing (and the spring collet 37) to the tip side, a working medium (coolant) for driving (back pressure) of the piston member 47 is introduced into the cylinder chamber portion 43b on the right side (back pressure side) of the piston member 47. An introducing pipe portion 53 for performing the operation is provided. The rear end portion of the introduction pipe portion 53 is shown in FIG.
When the small-diameter holder 13 is clamped with respect to the main shaft 3 shown in FIG. 2, the small-diameter holder 13 can be fluid-tightly fitted into the central hole 23a of the enlarged-diameter portion 23 at the tip of the drawbar 21 and can be communicated with the coolant supply source 57 connected to the rear end of the drawbar 21. Is configured. Therefore, when the coolant (usually a gas such as compressed air, which is a liquid in some cases) serving as the working medium is delivered from the coolant supply source 57, it is passed from the introduction pipe portion 53 through the draw bar 21 and the enlarged diameter portion 23. The piston member 47 enters the cylinder chamber portion 43b on the back pressure side, and advances the piston member 47 while competing with the disc spring 51. As a result, the reduced diameter portion of the spring collet 37 elastically returns to its original diameter, and the small-diameter tool is released (unclamped).

In the illustrated small-diameter holder (collet type tool holder) 13 having such a structure, the small-diameter tool is clamped by using the stable biasing force of the disc spring 51, and the small-diameter tool is unclamped ( Through-spindle) It is very rational and economical to do well with the coolant supplied by the coolant source 57. In addition, one (or a plurality) of air passages 61 is formed in the holder housing 31 of the small-diameter holder 13, and one end of the air passage 61 is opened to the conical surface 33 of the holder housing 31 with which the spring collet 37 is surface-engaged. However, the other end is open to the stepped cavity portion 15 inside the tapered shank portion 11. The air passage 61 communicates with a gap space 65 extending toward the tip of the spindle along the axis of the spindle 3 when the small-diameter holder 13 is clamped to the spindle 3 shown in FIG. To be connected to
The compressed air sent from the air supply source 67 is configured so as to be finally ejected from the opening of the conical surface 33 portion of the small diameter holder 13. Therefore, the spring collet 3
7 and the piston member 47 are advanced, when unclamping the small diameter tool, a slight gap is formed between the conical surface 33 portion of the holder housing 31 and the spring collet 37, and the opening is opened. Compressed air is ejected from this opening, whereby dust, chips, and the like that may be caught in the spring collet 37 can be effectively eliminated in advance.

Finally, an example of a machine tool system constructed by using the characteristic small diameter holder (collet type tool holder for small diameter tools) 13 will be briefly described with reference to FIGS. 3 to 7. Although not shown, a tool magazine (first tool magazine) accommodating a plurality of large-sized tools fixed to a normal tool holder is arranged on the side of the machine tool main body (not shown). At least one small-diameter holder 13 is housed in this first tool magazine, and like the other ordinary tool holders, it is exchanged with the spindle 3 by an automatic tool exchanging device (not shown).

On the front side of the machine tool main body (spindle 3), as shown in FIGS. 3 to 5, there is provided a square column-shaped scale 75 mounted on a (XYZB) indexing table 71 via a pallet 73. It is arranged. If necessary, a plurality of workpieces (workpieces) W are fixed to the three side surface portions of the squid 75, and the remaining one side surface portion has a small diameter tool T (for example, a small diameter straight shank such as φ6 or φ8). Various drills, end mills, taps, etc. consisting of parts are regularly and rack-shaped in a grid pattern (in the illustrated example,
A box-shaped small-diameter tool magazine (second tool magazine) 83 having a tool storage rack portion 81 capable of storing 80 pieces at the center is arranged.

The tool storage rack portion 81 in the small diameter tool magazine 83 has a metal long plate-shaped base plate 87 in which a plurality of portions for receiving the small diameter tools T are provided at a predetermined pitch.
It has a structure in which it is arranged in parallel with a vertically-arranged magazine base 89 and arranged in a shape of goodwill. As shown in FIGS. 6 and 7, each base plate 87 has a plurality of circular holes 91 formed at a predetermined pitch capable of receiving the collar TC press-fitted into the small-diameter tool T, and is fitted into each circular hole 91. A small-diameter tool receiving portion is formed by a hollow stepped bush 93 and a pair of spring-biased balls B such as so-called ball plungers arranged so as to face each other in the circular hole 91 by 180 degrees. . Tool T to be inserted into small diameter tool receiving part
The collar TC is detachably fixed and held by being sandwiched between the bush 93 and both balls B.

A touch sensor 97 is provided in the lower portion of the tool storage rack 81, and the touch sensor 97 detects the relative movement amount (so-called Z-axis direction) between the spindle side and the magazine side. The tool length of the tool T is measured in cooperation with a position reading device (not shown). The measured value obtained thereby is stored as a correction value in the storage unit of the control device (not shown).

As shown in FIGS. 3 to 5, a cover opening / closing mechanism 103 is incorporated in the upper portion of the tool storage rack 81 via a bracket 101 provided on a magazine base 89. The cover opening / closing mechanism 103 is reciprocally supported in the longitudinal direction via guide rollers (105, 107), and is operated by a pair of rods (109, 111) which are parallel to each other and project toward the machine tool body. To be done.

By pushing the right rod (open rod) 109 of both rods, the pinion (gear) 115 is rotated by the rack at the end of the rod and the pinion 115 is rotated.
The right arm 119 rotates via the right gear 117 that meshes with the right cover portion 120 to open to the right side, and at the same time, through the left gear series (121 to 127) that meshes with the pinion 105. The left arm 129 rotates,
The left cover portion 130 opens laterally to the left, so that the magazine front covers (120, 130) as a whole are completely opened. At the same time, the left rod 111 projects.

On the other hand, when the left rod (closed rod) 111 is pushed with the cover open, the pinion (gear) 125 is reversely rotated by the rack at the end of the rod, and the left gear that meshes with the pinion 125 is rotated. The left arm 129 reversely rotates via 127, the left side cover portion 130 that has been opened to the left side returns to the original position, and at the same time, the previous pinion 1
25 series of gears on the right side (123, 121, 1
05, 117), the right arm 119 rotates in the reverse direction, and the right side cover part 120 that has been opened to the right returns to the original closed position. As a result, the magazine front cover (120, 130) as a whole is completely closed. Will be closed. At the same time, the right rod 109 projects.

Both rods 109 for opening and closing the cover,
The pressing operation of 111 can be easily performed by, for example, the front surface of the small-diameter holder 13 mounted on the machine tool spindle 3 serving as a pressing surface, and preliminarily programmed relative approach movement between the spindle side and the magazine side. The main steps of the tool changing operation of the small-diameter holder in the machine tool system of this embodiment having such a configuration will be briefly described below.

First, the small-diameter holder 13 is attached to the machine tool spindle 3 from the first tool magazine by the first tool exchanging means,
The small-diameter tool magazine 83 is indexed by the indexing table 71 to a position facing the spindle. Then, the cover (120, 130) of the small diameter tool magazine 83 is opened by the above-described operation procedure. Next, the spindle 3 (small diameter holder 13) is moved to a position facing the tool storage position of the small diameter tool T to be gripped,
After that, the spindle 3 is moved to the front side in the Z-axis direction, and the tip end side of the tool T is inserted into the small diameter tool receiving portion of the tool storage rack portion 81. Next, (through spindle) coolant supply source 5
7 is operated to unclamp the tool T, and at that time, compressed air from the air supply source 67 is ejected from the vicinity of the spring collet to blow off chips and the like. Then, only the spindle 3 is moved to the rear side in the Z-axis direction with the tool T left in that position, and the spindle 3 is moved to a position facing the tool storage position of the next commanded small-diameter tool T. After that, set the spindle 3 to Z
The straight shank portion of the small-diameter tool T is inserted into the spring collet 37 of the small-diameter holder 13 by moving it to the front side in the axial direction, and the (through spindle) coolant supply source 5
The tool T is clamped by substantially stopping 7. At that time, the ejection of compressed air from the vicinity of the spring collet is stopped. Next, the spindle 3 is moved toward the touch sensor 97, and the tool length is measured there. After that, the cover (120, 120,
130) is closed. With the above steps, the tool exchanging work for the small diameter holder 13 is completed, and the machining operation is started. The coolant used in the present invention may be a liquid such as a working liquid or a gas such as compressed air.

In the above-described embodiment, the machine tool provided with the so-called through spindle coolant device having the coolant passage in the main spindle 3 has been described, but the coolant passage is provided outside the main spindle 3 and the tool holder is provided in the main spindle. When mounted on the front end of 3, the coolant from the coolant supply source is introduced into the tool holder through the coolant passage provided outside the coolant, and flows in the tool holder.
There is a so-called through holder coolant device that is jetted along a through hole formed in the axis of the gripping tool or along the outer periphery of the shank of the gripping tool. FIG. 8 shows a cross-sectional view when a collet type tool holder (small diameter holder) 13 using this through holder coolant device as tool unclamping means is mounted on the spindle 3. In FIG. 8, a portion different from the configuration of FIG. 1 is that a coolant passage 28 communicating with the cylinder chamber 43b is provided inside the flange portion 27 of the small diameter holder 13, and the other end portion of the coolant passage 28 is L-shaped.
This is the point where the coolant introduction pipe 30 of the shape is screwed, and the coolant introduction pipe 30 is engaged with the coolant oil supply block 32 fixed to the bearing retainer 25. The coolant supplied from the coolant supply source is introduced into the cylinder chamber 43b through the oil supply block 32, the coolant introduction pipe 30, and the coolant passage 28. The coolant introduction pipe 30 and the oil supply block 32 can be engaged and disengaged in conjunction with the tool changing operation. Therefore, the present invention also applies to a machine tool provided with a through holder coolant device.

As described above, the system according to the present embodiment has various advantages due to its characteristic structure and exerts a great effect. For example, because a small diameter tool magazine is used to store and manage a large number of small diameter tools without a tool holder,
Substantially reduces the size and space of the magazine as a whole. In addition, a large number of small-diameter tools can be easily automatically clamped and unclamped (removed) with a common small-diameter holder, and the operation source does not require the preparation of a special device. (Through spindle) Coolant supply device is simply used, which is extremely economical. Furthermore, the danger that the spring collet of the small-diameter holder will bite chips and the like due to the injection of compressed air can be easily eliminated.

[0025]

As described above, according to the present invention, the automatic tool clamp (attachment / detachment) of the tool holder can be performed simply and simply by diverting the coolant by the through-spindle coolant supply means or the through-holder coolant supply means normally held by the machine tool. Action) can be performed.
As a result, the entire machine tool can be configured more compactly and inexpensively.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a spindle unit of a machine tool according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a collet type tool holder according to the present embodiment.

FIG. 3 is a cross-sectional side view of essential parts of the machine tool system according to the present embodiment.

FIG. 4 is a sectional front view of the main part as seen from the direction of the arrow along the line IV-IV in FIG.

5 is a cross-sectional plan view of a main part as seen from the direction of the arrow along the line VV in FIG.

FIG. 6 is a front view of a main part of a tool storage rack section according to the present embodiment.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is a sectional view showing a tool holder according to another embodiment of the present invention.

[Explanation of symbols]

 1 ... Spindle housing 3 ... Spindle 11 ... Tapered shank portion 13 ... Collet type tool holder (small diameter holder) 15 ... Stepped cavity portion 17 ... Collet portion 19 ... Disc spring 21 ... Drawbar 23 ... Expanded portion 31 ... Holder housing 37 ... Spring collet 41 ... Cylinder mechanism 47 ... Piston member 57 ... Coolant supply source 61 ... Air passage 67 ... Air supply source 83 ... Small diameter tool magazine 97 ... Touch sensor 103 ... Cover opening / closing mechanism

Claims (5)

[Claims] 1. In a machine tool for machining a work into a desired shape by performing relative motion between a tool attached to the front end of a spindle via a tool holder and a work attached to a table, the tool holder to which the tool is attached is attached and detached. And a coolant supply means for supplying coolant from a coolant supply source into the tool holder through a coolant passage provided inside the main spindle or through a coolant passage provided outside the main spindle. , A collet type tool holder having a collet for detachably gripping a tool at a front end, and a collet type tool holder built in the collet type tool holder, which constantly biases the collet rearward in the axial direction of the spindle to grip the tool on the collet. A tool clamping means for applying force and a built-in collet type tool holder for supplying the coolant Machine tool being characterized in that anda tool unclamping means for releasing the gripping force of the tool to press the collet axially forward of the main spindle by using the pressure of the coolant supplied by the stage. 2. A first tool magazine for accommodating a plurality of tools attached to a normal tool holder and at least one of the collet type tool holders, and a tool magazine between the spindle and the first tool magazine. The machine tool according to claim 1, further comprising a first tool exchanging means for exchanging. 3. A second tool magazine for storing a plurality of tools mounted on the collet type tool holder, and a tool exchange between the collet type tool holder mounted on the spindle and the second tool magazine. The machine tool according to claim 1 or 2, further comprising a second tool exchanging means. 4. The second tool magazine is provided on the table of the machine tool, and covers the tool storage rack for storing a plurality of tools and the second tool magazine so that chips and the like generated during machining are not applied. A cover and a cover opening / closing mechanism that opens and closes the cover when the tool is changed, and the second tool changing means is built in the collet-type tool holder and relative movement between the spindle and the table. 4. The machine tool according to claim 3, wherein the tool is directly transferred between the tool storage rack and the collet type tool holder by using the clamped and unclamped means. 5. A collet type tool holder for a machine tool, which is detachably attached to a front end of a spindle and has a collet for gripping a tool, wherein the collet type tool holder communicates with a coolant passage and is attached from a coolant supply source when being attached to the spindle. Coolant introducing means for introducing the coolant of the inside, tool clamping means for constantly urging the collet to the spindle rear side to give a gripping force of a tool to the collet, and the pressure of the coolant introduced into the inside. And a tool unclamping means for releasing the gripping force of the tool by pressing the collet to the front side of the main spindle by utilizing the collet type tool holder.