JP2012016786A - Main spindle device of machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably detect the leakage of a cutting fluid.SOLUTION: A main spindle device 1 includes a pressure sensor 16 for detecting pressure in an air supplying route 13 for blowing air in a housing 2. A control device determines the leakage of the cutting fluid from a cutting fluid supplying route if the pressure sensor 16 detects prescribed fluid pressure in the air supplying route 13 during the rotation of a main spindle 3.

Description

  The present invention relates to a spindle device that is provided in a machine tool such as a machining center and includes a spindle that is mounted with a tool and rotates.

FIG. 2 shows an example of a spindle device used in a machine tool such as a machining center. The main shaft device 1 includes a hollow main shaft 3 that is supported by bearings 4, 4. ing. A tapered hole 6 into which a tapered tool holder 7 for holding a tool can be inserted is formed at the lower end of the main shaft 3 (lower side in FIG. 2). A pull stud 8 provided at the rear end of the tool holder 7 is colleted 5 can be clamped.
In addition, a cutting fluid supply rod 9 that is coaxially in contact with the rear end of the pull stud 8 in a state where the tool holder 7 is clamped is disposed at the shaft center of the main shaft 3. A cutting fluid supply path 10 is formed in the axial center of the supply rod 9, and communicates with a supply path 11 formed in the axial center of the pull stud 8 and the tool holder 7 in a contact state with the pull stud 8. As indicated by the solid line arrow, the cutting fluid can be supplied to the tool side. When the supply path 10 is opened at the front end of the supply rod 9, a seal ring 12 is provided that contacts the rear end of the pull stud 8 and prevents leakage of cutting fluid.

On the other hand, the spindle device 1 is connected to a plurality of through holes formed in the housing 2 and the spindle 3 so that air is supplied from the outside and blown from the vicinity of the end of the tapered hole 6 toward the tool holder 7 side. The air supply path 13 is formed. This air supply path 13 prevents dust and the like from entering between the tool holder 7 and the tapered hole 6 by supplying air into the main shaft 3 as indicated by the dotted arrow when the tool is changed. .
Control of a compressor for performing this air blow, a pump for supplying cutting fluid, a servo motor for rotating the main shaft 3, and the like are performed by a control device (not shown).

  In such a spindle device 1, the cutting fluid may leak from between the supply rod 9 and the pull stud 8 due to deterioration of the seal ring 12 provided on the supply rod 9, poor contact of the pull stud 8, or the like. (Two-dot chain arrow A). The leaked cutting fluid enters the disc spring portion that urges the draw bar at the rear portion of the main shaft 3 or flows into the air supply path 13 and enters the bearing 4 to cause damage or deterioration of the components. Become. Therefore, in Patent Document 1, an outlet passage hole that opens to the end surface of the main shaft and a ball that normally closes the outlet passage by spring biasing are provided in the middle of the air supply path, and the pressure of the invading cutting fluid. The invention makes it possible to visually check the leakage of the cutting fluid by allowing the ball to be pressed and discharged from the outlet through hole.

Japanese Patent Laid-Open No. 10-94942

  However, during machining, a large amount of cutting fluid is supplied from the tool and splashes to the front end of the spindle, so the cutting fluid leaking from the outlet through hole should be distinguished from the cutting fluid supplied from the tool. Is difficult, and there is a possibility that reliable confirmation cannot be performed.

  Therefore, an object of the present invention is to provide a spindle device for a machine tool that can reliably detect leakage of a cutting fluid.

In order to achieve the above object, the invention described in claim 1 is provided with a pressure sensor for detecting a fluid pressure in the air supply path, and the control device is provided in the air supply path by the pressure sensor during rotation of the main shaft. When a predetermined fluid pressure is detected, it is determined that the cutting fluid leaks from the cutting fluid supply path.
According to a second aspect of the present invention, in the configuration of the first aspect, the pressure sensor is a pressure sensor for confirming seating of the tool on the end of the main shaft.

According to the first aspect of the present invention, the leakage of the cutting fluid can be reliably detected using the pressure sensor. Therefore, the defective seal portion can be replaced before the main shaft is damaged, and it is possible to reduce the stop time due to damage to the machine and the cost for replacement repair.
According to the second aspect of the invention, in addition to the effect of the first aspect, the seating confirmation pressure sensor can be used as it is for the leakage judgment of the cutting fluid. This is advantageous in terms of cost.

It is a partial cross section figure of a main shaft device. It is a partial cross section figure of the conventional main shaft device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partial cross-sectional view showing an example of a spindle device 1 of a machining center. Since the basic structure is the same as that of the conventional spindle device 1 described in FIG. 2, the same components are denoted by the same reference numerals. Thus, duplicate explanations are omitted.
The spindle device 1 also has a cutting fluid supply passage for supplying cutting fluid from an externally provided pump to the tool by the supply passage 10 of the supply rod 9 and the supply passage 11 of the tool holder 7.
Further, by connecting a plurality of through holes formed in the housing 2 and the main shaft 3, air is supplied from an external compressor and blown from the vicinity of the end of the tapered hole 6 toward the tool holder 7 side. An air supply path 13 is formed.

  Here, the air supply path 13 in the housing 2 is formed by an axial through hole 14 and a radial through hole 15 connected at the front end of the through hole 14. Instead of the plug, a pressure sensor 16 having a tip projecting from the connecting portion with the through hole 14 is provided.

This pressure sensor 16 is connected to a control device (not shown) for controlling a servo motor for rotating the spindle 3, a pump for supplying cutting fluid to the supply passage 10, a compressor for pressure-feeding air to the air supply passage 13, and the like. The fluid pressure in the passage 13 can be detected.
Here, when changing the tool in which the main shaft 3 does not rotate, air of about 0.3 to 0.5 Mpa is supplied into the air supply path 13. Even if air pressure is detected, it is not judged that the cutting fluid has leaked.

  On the other hand, no tool change is performed while the main shaft 3 is rotating, and no air is supplied to the air supply path 13, so no fluid pressure is applied to the pressure sensor 16. However, when the cutting fluid leaks from the supply passage 10 into the main shaft 3 due to deterioration of the seal ring 12 or the like, the cutting fluid enters the air supply passage 13 by centrifugal force as indicated by a two-dot chain arrow B. The fluid pressure is applied to the pressure sensor 16. Therefore, the control device determines that the cutting fluid is leaked by detecting the fluid pressure during the rotation of the main shaft 3. In particular, since the supply pressure of the cutting fluid is 1 to 7 MPa and higher than the air pressure to the air supply path 13, the leakage of the cutting fluid can be reliably determined by the pressure sensor 16 detecting this. It should be noted that the rotation of the main shaft 3 may be stopped immediately after determining the leakage of the cutting fluid, but may be limited to notification by a lamp, a warning sound, or the like.

  Thus, according to the main shaft device 1 of the above embodiment, the pressure sensor 16 that detects the fluid pressure in the air supply passage 13 is provided, and the control device is operated by the pressure sensor 16 during the rotation of the main shaft 3. When the predetermined fluid pressure is detected, it is determined that the cutting fluid leaks from the cutting fluid supply passage, and therefore the leakage of the cutting fluid can be reliably detected using the pressure sensor 16. Therefore, it is possible to replace the defective seal portion before the main shaft 3 is damaged, and it is possible to reduce the stop time due to damage to the machine and the cost for replacement repair.

  In the above embodiment, an example in which a pressure sensor is provided in the air supply path for air blow is described. However, the present invention is not limited to this, and for example, the air and the pressure sensor are used for checking the seating of the tool. It can also be applied to the main spindle device. In this spindle device, when the tool is changed, air of a predetermined pressure is supplied to the taper hole 6 of the spindle, and the pressure is detected by a pressure sensor to check whether the tool holder 7 is securely seated in the taper hole 6 of the spindle. To do. Therefore, in the state where the seating is performed reliably, a pressure equivalent to the air pressure (about 0.3 to 0.5 MPa) is applied to the pressure sensor, and if the seating is incomplete and the air leaks, the pressure is The control device confirms the seating by lowering to about 0.2 Mpa or less, but this seating confirmation is also not performed while the main shaft is rotating (air is not supplied to the air supply path). If the fluid pressure is detected, it can be determined that the cutting fluid has leaked as in the previous embodiment.

As described above, even when the seating confirmation pressure sensor is used for determining the leakage of the cutting fluid, the leakage of the cutting fluid can be reliably detected as in the previous embodiment. Therefore, the defective seal portion can be replaced before the main shaft is damaged, and it is possible to reduce the stop time due to damage to the machine and the cost for replacement repair.
In particular, the pressure sensor for seating confirmation can be used as it is for the judgment of leakage of the cutting fluid, so that it becomes a rational configuration using the existing pressure sensor, which is more cost-effective than the previous form using the new pressure sensor. It will be advantageous.

In addition, the specific structure of the cutting fluid supply path, the air supply path, etc. is not limited to the above-described form, and can be changed as appropriate. It can be provided outside the housing by being incorporated into an air pipe connected to the housing.
In addition, the detection of the fluid pressure by the pressure sensor and the subsequent processing are also limited to notification when the first pressure is detected, for example, the fluid pressure is the first pressure and the second pressure higher than the pressure value. When the second pressure is detected, a change such as stopping the rotation of the main shaft is possible.

  Furthermore, the pressure sensor is not limited to one location, and is provided at a plurality of locations. Only when all the pressure sensors detect a predetermined fluid pressure, it is determined that the cutting fluid is leaked, or the pressure on the side close to the cutting fluid supply path It is also conceivable that when the predetermined fluid pressure is detected by the sensor, only notification is given, and the rotation of the main shaft is stopped when the far-side pressure sensor also detects the predetermined fluid pressure.

  1 .. Spindle device 2.. Housing 3.. Spindle 6. Tapered hole 7.. Tool holder 8. Pull stud 9 9 Supply rod 10 11 11 Supply path 12・ Seal ring, 13 ・ ・ Air supply path, 14, 15 ・ ・ Through hole, 16 ・ ・ Pressure sensor.

Claims (2)

A housing, a spindle that is pivotally supported by the housing, is driven to rotate by mounting a tool at an end thereof, and a control device that controls the rotation of the spindle, and the cutting fluid is supplied to the tool in the spindle. A cutting fluid supply passage is provided in the housing and the main shaft, and an air supply passage for supplying air to the end portion is provided, and the control device supplies the cutting fluid to the cutting fluid supply passage during rotation of the main shaft. A spindle device of a machine tool that performs supply control of supply of the air to the air supply path when rotation of the spindle is stopped,
A pressure sensor for detecting a fluid pressure in the air supply path, and the control device detects the predetermined fluid pressure in the air supply path by the pressure sensor during rotation of the main shaft; A spindle device for a machine tool, characterized in that it is determined that the cutting fluid leaks from a road.   The spindle device for a machine tool according to claim 1, wherein the pressure sensor is a pressure sensor for confirming seating of a tool on an end portion of the spindle.

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