JPH1094942A - Spindle device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily confirm the leakage of the cutting liquid to the inside of a main spindle from a cutting liquid supply path inside of the main spindle, by comprising a leakage of cutting liquid confirming means which confirms the leakage of the cutting liquid from a contact face of a coolant rod and a rear part of a tool holder. SOLUTION: A cutting liquid is flowed into a leakage path 14b with the corresponding pressure, when an O ring 24b between a coolant rod 24 and a pull stud 18b, is worn or dropped. Accordingly, a ball 66a is moved to an open position against the energuized force of a spring 66b by the pressure, and the cutting liquid is flowed outside from an outlet hole 68a. Thereby the generation of the leakage of the cutting liquid can be known by the generation of the trouble of the O ring 24b. A ball 76 of mounting face cleaning means 62 is pressed by an O ring 80, by the pressure of the leaked cutting liquid, and an air pressure supply hole 72 is blocked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device of a machine tool for supplying a cutting fluid to a tip of a tool via a spindle and a tool holder.

[0002]

2. Description of the Related Art Generally, when a deep hole or a deep groove is machined with a tool such as a drill or an end mill, a cutting fluid is ejected and supplied from an external device such as a nozzle toward a machined portion. The cutting fluid is not supplied enough to the machine. Therefore, the cutting fluid supply path extending in the axial direction is penetrated and formed inside the main spindle and the tool holder, and the cutting fluid is supplied directly to the cutting edge of the tool via the cutting fluid supply path. There is a main spindle device of a machine tool adopting a through spindle coolant system.

In a spindle device of a machine tool adopting the through spindle coolant system, when a tool holder having a tool attached to the spindle is mounted during automatic tool change, a pull stud provided at a rear portion of the tool holder and a spindle are provided. By contact with a coolant rod provided inside, a cutting fluid supply path from the cutting fluid supply source to the cutting edge of the tool is formed. However, if the pull stud and the coolant rod are simply brought into contact with each other, there is a possibility that the cutting fluid leaks into the inside of the spindle and the inside of the spindle becomes dirty. A spindle device of a machine tool adopting a through spindle coolant system which solves this problem is disclosed in Japanese Utility Model Publication No. 62-21 by the present applicant.
No. 403 discloses this. In this spindle device, a sealing member such as an O-ring is fitted into an annular concave groove formed at the tip of a coolant rod, and the contact surface between the coolant rod and the pull stud is air-tightly and liquid-tightly sealed. The cutting fluid passing through the fluid passage is supplied to the cutting edge of the tool through the through passage of the pull stud without leaking into the main shaft.

Further, when the tool holder on which the tool is mounted is mounted on the spindle during automatic tool change, chips and cutting fluid attached to the tapered portion of the tool holder are removed to improve the mounting accuracy of the tool holder on the spindle. Improvement is an important factor in improving processing accuracy. In view of this, a spindle device of a machine tool for improving the mounting accuracy of a tool holder on a spindle is disclosed in Japanese Utility Model Laid-Open No. 7-40053 by the present applicant. This spindle device is provided with an annular ring formed in a tapered hole at the tip of the spindle that comes into contact with a tapered portion of a tool holder from a pressurized air supply passage provided in a housing of the spindle immediately before a tool is mounted during automatic tool change. The pressurized air is supplied toward the groove, and the pressurized air is jetted toward the tapered portion of the tool holder. If necessary, the pressurized air is jetted toward the flange contact surface of the tool holder. The chip and the cutting fluid attached to the tapered portion and the flange contact surface are removed, and the reference mounting surface between the tool holder and the spindle is cleaned.

[0005]

Problems to be Solved by the Invention
In the spindle device disclosed in Japanese Patent Publication No. 3 (1993), a rubber seal member such as an O-ring is generally used as a seal member for sealing a contact surface between a coolant rod and a pull stud. However, by repeating the automatic tool change, the rubber seal member may be worn or fall off from the contact surface between the coolant rod and the pull stud. In this case, the cutting fluid flowing through the cutting fluid passage of the coolant rod leaks into the main shaft from the contact surface between the coolant rod and the pull stud. In the conventional spindle device, the peripheral portion of the spindle must be disassembled in order to confirm the wear or the falling off of the rubber seal member, so that there is a problem that the maintenance work is complicated and time-consuming.

In the spindle device disclosed in Japanese Utility Model Laid-Open Publication No. 7-40053, when cutting fluid leaks from the contact surface between the coolant rod and the pull stud into the inside of the spindle for some reason, the cutting fluid is supplied to the tool holder. Into the tapered mounting surface of the spindle and the spindle, and further, through the annular groove provided in the tapered hole at the tip of the spindle, into the pressurized air supply path provided in the housing of the spindle, and with the tool holder. This may cause a failure of a pressurized air supply device such as a pump or a compressor that supplies pressurized air for cleaning a mounting reference surface with the main shaft.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spindle device of a machine tool capable of easily and surely confirming leakage of cutting fluid from a cutting fluid supply path provided inside the spindle into the spindle. Further, the present invention provides a spindle device of a machine tool in which a mounting surface of a tool holder and a spindle can be reliably cleaned at the time of tool change, and further, a cutting fluid does not enter a pressurized air supply path for cleaning. The purpose is.

[0008]

The object of the present invention is to form a passage communicating from the internal space of the main shaft to the outside of the main shaft, and when the cutting fluid leaks into the main shaft, the cutting fluid flows out of the main passage. The problem is solved by allowing the surrounding workers to visually check and confirm the leakage of the cutting fluid so as to know the leakage of the cutting fluid.

That is, the present invention relates to a spindle of a machine tool for supplying a cutting fluid to a tip of a tool attached to the tool holder via a cutting fluid passage formed in a spindle and a tool holder. In the device, a coolant rod provided so as to be able to rotate integrally with the main shaft, a cutting fluid supply path is provided therein, a seal member provided on a contact surface of the coolant rod with a rear portion of the tool holder, A passage communicating from the inside of the main shaft to the outside of the main shaft, a valve member provided in the middle of the passage, and pressing the valve member inward of the main shaft with a pressure smaller than a supply pressure of the cutting fluid to form the passage. A cutting fluid leakage confirming means for confirming leakage of cutting fluid from a contact surface between the coolant rod and a rear part of the tool holder, the cutting tool mainly comprising an elastic pressing member which is always closed. The equipment and spirit of the invention.

In order to prevent the cutting fluid leaking into the spindle from flowing into the upstream side of the pressurized air supply circuit through a supply path of pressurized air for cleaning the mounting surface between the spindle and the tool holder, A pressurized air supply path that opens to a mounting surface of the main shaft with the tool holder and supplies pressurized air to the mounting surface, and includes a check valve provided in the middle of the pressurized air supply path, The gist of the present invention is a spindle device of a machine tool further provided with a mounting surface cleaning means for supplying pressurized air to the mounting surface and cleaning the mounting surface before mounting the tool holder on the main spindle.

[0011]

After automatically attaching a tool holder having a tool attached to a main spindle during automatic tool change, a coolant rod having a cutting fluid supply path and a rear portion of the tool holder are brought into air-tight and liquid-tight contact with a seal member. By doing so, a cutting fluid supply path is formed. During machining, a cutting fluid is supplied to the tip of the tool via the inside of the spindle and the inside of the tool holder. At this time, when the seal member is worn or falls off and the cutting fluid leaks into the main spindle from the contact surface between the coolant rod and the rear portion of the tool holder, the pressure of the leaked cutting fluid leads from the inside of the main spindle to the outside of the main spindle. The valve member pressed by the elastic pressing means provided in the middle of the passage opens, and the leakage of the cutting fluid inside the main shaft can be visually and confirmed because the cutting fluid flows out from the opening.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The spindle device 10 of the machine tool according to the present embodiment includes a hollow housing 12 and the housing 1.
2 is provided with a hollow main shaft 14 rotatably supported via bearings 16a, 16b, 16c. The bearings 16a and 16b are arranged so that the collar 16d is sandwiched between the bearings 16a and 16b.
a, 56b held in the housing 12;
The bearing retainer 56a is attached to the front end of the housing 12 together with the bracket 58. To rotate the main shaft 14, a rotor 32 is fixed to the outer peripheral surface of the main shaft 14, and the stator 3 is fixed to the inner peripheral surface of the housing 12.
4 is fixed. At the tip of the main shaft 14, a tapered hole 14a that expands conically in the direction of the tip of the main shaft 14 is formed as a mounting reference surface for the tool holder 18, and a tool 20 in which the tool 20 is mounted is attached to the tapered hole 14a. Holder 18
Is abutted.

A drawbar 22 is inserted into the hollow portion of the main shaft 14 so as to be slidable in the axial direction. More specifically, in the hollow portion of the main shaft 14, the guide tube 2
6 is inserted and fixed, and the drawbar 22 is inserted into the guide tube 26 and guided in the axial direction of the main shaft 14.
The draw bar 22 is formed in a hollow shape along the center axis thereof, and a coolant rod 24 is fitted in the hollow portion.

A coolant supply hole 24a is formed in the coolant rod 24 along the center axis thereof. The rear end of the coolant rod 24 is connected via a rotary joint 48 to a cutting fluid source 52 connected to a control device 54 of a machine tool provided with the spindle device 10. Pull stud 1
8b. On the tool holder 18 and the tool 20, the tool holder 18 is mounted on the tip of the spindle 14 and the tip of the coolant rod 24 and the pull stud 18 are attached.
When b contacts, a cutting fluid through hole 20a communicating with the cutting fluid supply hole 24a penetrates and is formed along the central axis (see FIG. 2). When the coolant rod 24 and the pull stud 18b come into contact with each other, the coolant rod 24 is prevented from leaking from the contact surface of the two.
An O-ring 24b is attached to the front end surface of the. More specifically, an annular groove is formed on the distal end surface of the coolant rod 24, and the O-ring 24 is formed in the annular groove.
b is inserted. During the cutting process, a high-pressure cutting fluid is supplied from the cutting fluid source 52 and flows through the rotary joint 48, the cutting fluid supply hole 24a, and the cutting fluid passage 20a, and the work (see FIG. (Not shown).

A disc spring 30 as an elastic means is disposed in a compressed state between the guide cylinder 26 and the draw bar 22, and the draw bar 22 causes the draw bar 22 to move along the central axis at the rear end of the main shaft 14. Biased in the direction. Drawbar 2
A collet 28 that can be engaged with a pull stud 18b provided at the rear end of the tapered portion 18a of the tool holder 18 is provided at the front end of the tool holder 18. The collet 28 engages with and pulls in the pull stud 18 b when the draw bar 22 is retracted within the main shaft 14, and holds the tool holder 18 at the tip of the main shaft 14. When the draw bar 22 moves forward, the collet 28 is expanded and disengaged from the pull stud 18b, and the tool holder 18 on which the tool 20 is mounted can be removed from the tapered hole 14a at the tip of the main shaft 14.

In order to move the draw bar 22 back and forth along the central axis, an unclamping device is provided in the rear end region of the main shaft 14 and the draw bar 22. The unclamping device includes an unclamping cylinder 44 fixed in a hollow portion of a bracket 42 provided on an upper part of the housing 12, a slidable disposition in the unclamping cylinder 44, and a rear end of the draw bar 22. And an unclamping piston 46 provided so as to be able to abut the part. The unclamping cylinder 44 has an axially separated 2
One hydraulic chamber is formed, and hydraulic pressure is applied to each hydraulic chamber of the unclamping cylinder 44 from a hydraulic source 50 connected to a control device 54 of a machine tool provided with the main spindle device 10.

By supplying hydraulic pressure to the hydraulic chamber on the front side of the unclamping cylinder 44, the unclamping piston 46 retreats and separates from the rear end of the drawbar 22, and the drawbar 22 retreats by the urging force of the disc spring 30. The collet 28 grips the pull stud 18b of the tool holder 18. By supplying the hydraulic pressure to the hydraulic chamber on the rear side of the unclamping cylinder 44, the unclamping piston 46 is supplied.
Moves forward and abuts the rear end of the drawbar 22,
The drawbar 22 is pressed forward against the urging force of the disc spring 30. As a result, the collet 28 expands, the pull stud 18b of the tool holder 18 is released, and the tool 20
Can be removed from the tapered hole 14a of the main shaft 14.

Referring to FIG. 2, the spindle device 10 further includes a cutting fluid leak confirming means 60 and a mounting surface cleaning means 62 provided in a tip region of the spindle device 10. In the present embodiment, the cutting fluid leak confirming means 60 is provided in the inner space of the main shaft 14, in the illustrated embodiment, the inner space of the guide cylinder 26 fitted in the hollow portion of the main shaft 14, and the tapered hole in which the tool holder 18 contacts. A leak passage 14b is formed in the distal end region of the main shaft 14 to communicate the space above the 14a with the distal end surface of the main shaft 14. Leakage passage 14b
In the front end region of the main shaft 14, the front end region is an enlarged portion 14c having a large diameter, and a ball case 64 is formed inside the enlarged portion 14c by a fixing screw 68 having an outlet through hole 68a. It is fixed at a predetermined position.
In the ball case 64, a ball 66a is provided.
In FIG. 2B, the movable portion is disposed so as to be movable between a closed position for closing the opening to the expanding portion 14c and an open position for opening the opening. In the ball case 64, a spring 66b for urging the ball 66a toward the opening is further provided.

The mounting surface cleaning means 62 includes a bearing presser 5
6a and 56b in the transverse direction, the pressurized air supply hole 72 formed, and the annular groove 8 formed along the surface of the tapered hole 14a with which the tool holder 18 abuts on the main shaft 14.
4 and a pressurized air passage 82 formed through the main shaft 14 in a transverse direction between the annular groove 84 and the pressurized air supply hole 72. At the inner end of the pressurized air supply hole 72, an inner region communicating with the pressurized air passage 82 is an enlarged portion having a large diameter, and an O-ring 80 as a seal member is provided at the enlarged portion. Is provided. In the ball case 74, the ball 76 is O
The pressurized air supply hole 72 is provided so as to be movable in the center axis direction between a closed position in contact with the ring 80 and an open position separated from the O-ring 80. Ball 76 is spring 7
8 urges radially outward to the closed position and abuts the O-ring 80 to close the pressurized air supply hole 72. The outside end of the pressurized air supply hole 72 is connected to an air pressure source 34 such as a compressor connected to a control device 54 of a machine tool provided with the spindle device 10 via a pipe (not shown) such as a hose. It is connected.

When the spindle device 10 starts unclamping, the draw bar 22 is pushed out toward the tip of the spindle 14 by the unclamping devices 44 and 46, the collet 28 is opened, the pull stud 18b of the tool holder 18 is released, and the tool is released. The tool holder 18 with the attached 20 is the main spindle 1
4 can be withdrawn from the tapered hole 14a. Next, as shown in FIG. 3, the tool holder 18 is gripped by an automatic tool changer (not shown) and pulled downward. At this time, the coolant rod 24 separates from the pull stud 18b, the tool holder 18 separates from the tapered hole 14a of the main shaft 14, and the pressurized air supply hole 7 from the air pressure source 34.
2 is supplied with pressurized air. Due to the pressure of the supplied compressed air, the ball 76 moves to the open position to the left in FIGS. Thereby, the pressurized air flows through the pressurized air passage 82 and the annular groove 84 and is supplied substantially uniformly to the entire tapered hole 14 a of the main shaft 14, and the surface of the tapered hole 14 a and the tapered portion 18 a of the tool holder 18 are formed. Is cleaned.

In the automatic tool change, when the coolant rod 24 and the pull stud 18b separate from each other, the cutting fluid staying in the cutting fluid supply hole 24a flows into the internal space of the main shaft 14. Most of the fluid is discharged to the outside when the tool holder 18 is removed from the main shaft 14, and a part of the fluid flows into the leakage passage 14b. At this time, since the ball 66a is urged to the closed position by the spring 66b and the outlet of the leak passage 14b is closed, even if cutting fluid flows into the leak passage 14b due to such a normal automatic tool change, the outlet passage is closed. The cutting fluid does not flow out of the hole 68a. On the other hand, the coolant rod 2
When the O-ring 24b between the pin 4 and the pull stud 18b is worn out or falls off, the cutting fluid is subjected to a considerable pressure, and as shown in FIG.
Flows through the leak passage 14b as indicated by the arrow.
Accordingly, the ball 66a is moved to the release position by the pressure against the urging force of the spring 66b, and the cutting fluid is discharged from the outlet through hole 68.
a to the outside. In this way, it is possible to know that a defect has occurred in the O-ring 24b and that the cutting fluid has leaked. At this time, due to the pressure of the cutting fluid leaked into the internal space of the spindle 14, the ball 76 of the mounting surface cleaning means 62
And the ball 76 closes the pressurized air supply hole 72, so that the cutting fluid is prevented from flowing into the pressurized air supply hole 72.

Therefore, it is needless to say that the spring 66b has a spring constant selected so that a pressing force smaller than the supply pressure of the cutting fluid is applied to the ball 66b. More preferably, as long as the cutting fluid flowing out from the tip of the coolant rod 24 at the time of normal automatic tool change can be distinguished from the leakage of the cutting fluid caused by the wear or drop of the O-ring 24b of the coolant rod 24, the wear of the O-ring 24b It is desirable to select as small a spring constant as possible so that can be found early.

[0023]

When the seal member provided on the contact surface of the coolant rod with the rear part of the tool holder is worn out or falls off and the cutting fluid leaks into the main spindle, the cutting fluid flows out of the main spindle. Can be visually observed and confirmed, so that leakage of cutting fluid inside the spindle can be minimized. Also, the action of the mounting surface cleaning means for supplying pressurized air to the mounting surface between the spindle and the tool holder to remove chips and cutting fluid attached to the tapered portion of the tool holder is obstructed by the leaked cutting fluid. And improved mounting accuracy between the spindle and the tool holder.
Therefore, processing accuracy is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spindle device of a machine tool according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a mechanism of a cutting fluid leakage confirming means and a mounting surface cleaning means at the time of tool clamping of the spindle device of the machine tool of FIG.

FIG. 3 is an enlarged sectional view showing a mechanism of a mounting surface cleaning unit at the time of tool unclamping of the spindle device of the machine tool of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Spindle device 12 ... Housing 14 ... Spindle 14a ... Tapered hole 14b ... Leakage passage 18 ... Tool holder 18a ... Tapered part 18b ... Pull stud 20 ... Tool 20a ... Cutting fluid passage hole 22 ... Drawbar 24 ... Coolant rod 24a ... Cutting fluid Supply hole 24b O-ring 60 Cutting fluid leak confirmation means 62 Mounting surface cleaning means 66a Ball 66b Spring 68a Outlet hole 72 Pressurized air supply hole 76 Ball 78 Spring 80 O-ring 82 Compressed air passage 84: annular groove

Claims (2)

[Claims] 1. A spindle device of a machine tool for supplying a cutting fluid to a tip portion of a tool attached to a tool holder via a cutting fluid passage formed in a spindle and a tool holder. A coolant rod provided so as to be able to rotate integrally with the main shaft and provided with a cutting fluid supply path therein, a seal member provided on a contact surface of the coolant rod with a rear portion of the tool holder, and from inside the main shaft. A passage communicating with the outside of the spindle, a valve member provided in the middle of the passage, and an elasticity for constantly closing the passage by pressing the valve member inward of the spindle with a pressure smaller than a supply pressure of the cutting fluid. A cutting fluid leak confirming means for confirming leakage of cutting fluid from a contact surface between the coolant rod and the rear part of the tool holder. Axis devices. 2. A pressurized air supply path which opens on a mounting surface of the spindle with the tool holder and supplies pressurized air to the mounting surface, and a check provided in the middle of the pressurized air supply path. 2. The machine tool according to claim 1, further comprising a mounting surface cleaning means for supplying a pressurized air to the mounting surface and cleaning the mounting surface before mounting the tool holder on the spindle. Spindle device.