JP2002036066A - Main spindle device of machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a main spindle device capable of eliminating the vibration of a first sleeve even at a high speed and preventing a heat generated by a built-in motor from transferring to a main spindle. SOLUTION: This main spindle device 20 of the machine tool comprises a nose 5 rotatably supporting the main spindle 4, having a tool mounting tapered hole 3 at the tip part thereof, on the inner diameter part thereof, a built-in motor 6 adjacent to the rear end of the nose 5 and rotating the main spindle, a cylinder 11 fitted to the inner diameter part of the spindle 4 through sleeves 8 and 22 and positioned adjacently to the rear end of the built-in motor 6 axially moving forward and backward a draw bar 10 controllably opening and closing a collect 9 for holding and releasing a tool 2 on and from the spindle 4, and a cooling device feeding cooling medium from a cooling medium source located on the outside of the device to the inside of the spindle through a rotary joint 12 fitted to the cylinder 11. Insulating material 21 is installed on the nose 5 side of the built-in motor 6, and an axial cooling passage is provided in the first sleeve 22.

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 to which a built-in motor for rotational driving and a cooling device are mounted.

[0002]

2. Description of the Related Art A main shaft of a machine tool becomes high in temperature due to cutting heat generated through a tool, frictional heat of a bearing generated by rotation, and heat generated by a built-in motor. A cooling device for correcting the temperature is provided so that an error is not caused in the positioning accuracy of the device and high-precision processing cannot be performed.

A conventional cooling device for a spindle will be described with reference to FIGS. 6 and 7. The spindle device 1 has a spindle 4 having a tapered hole 3 for mounting a tool 2 indicated by a dashed line at a tip end rotatably supported on an inner diameter portion. And a built-in motor 6 that is adjacent to the rear end of the nose 5 and rotates the spindle 4.
And a draw bar 10 that is fitted to the inner diameter portion of the main shaft 4 via first and second sleeves 7 and 8 and that controls opening and closing of a collet 9 that grips and releases a tool in the tapered hole 3 of the main shaft 4. Through a cylinder 11 adjacent to the rear end of the built-in motor 6 that advances and retreats in the axial direction, and a rotary joint 12 attached to the cylinder 11, coolant from a coolant source 13 outside the apparatus is introduced into the main shaft 4. And a cooling device for supplying.

In this cooling device, a cooling liquid such as oil from a cooling liquid source 13 is supplied through a rotary shaft 14 of a rotary joint 12 as shown by an arrow a to a groove-shaped groove formed on the outer peripheral surface of a draw bar 10 and a second sleeve 8. It is led to the spiral groove 16 as shown in FIG. 7 provided on the outer peripheral surface of the passage 15 and the first sleeve 7,
After cooling the heat generated by the built-in motor 6, the frictional heat of the bearing 28, and the cutting heat by the tool 2 inserted into the tapered hole 3 at the tip of the main shaft 4, the cooling liquid source 1 passes through the passage 24.
Returning to 3 has been performed.

[0005]

However, since the spiral groove 16 as shown in FIG. 7 is machined on the outer peripheral surface of the first sleeve 7, the main shaft 4 has a length of about 20,000 min.
^When rotating at a high speed of about ^-1, the first along the spiral of the groove 16
The sleeve 7 itself is twisted and vibrates, and the heat generated by the built-in motor 6 is transmitted to the nose 5 and the nose 5
Was stretched in the axial direction and could not be processed with high precision. In addition, the heat generated by the built-in motor 6 is transmitted to the nose 5, and the heat may damage the bearing 28.

An object of the present invention is to eliminate the disadvantage that the first sleeve vibrates when the high-speed rotation is performed, and the heat generated by the built-in motor is transmitted to the nose, so that high-precision machining cannot be performed. An object of the present invention is to provide a spindle device in which the first sleeve does not vibrate and the heat generated by the built-in motor is hardly transmitted to the nose.

[0007]

According to the present invention, there is provided a nose for rotatably supporting a main shaft having a tapered hole for attaching a tool of a machine tool at an end portion to an inner diameter portion, and a rear end of the nose. A built-in motor that rotates the main shaft adjacent to the main shaft, and a built-in motor that is fitted through a sleeve to the inner diameter of the main shaft through a sleeve to control opening and closing of a collet that grips and releases a tool to and from the main shaft in the axial direction. In a spindle device having a cylinder adjacent to a rear end and a cooling device that supplies a cooling medium from a cooling medium source outside the device into a main shaft via a rotary joint attached to the cylinder, a built-in motor is provided. After attaching the heat insulating material to the nose side and flowing the cooling medium from the non-tool mounting side to the tool mounting side on the outer diameter surface of the sleeve,
A spindle device for a machine tool, wherein a plurality of passages returning from a tool mounting side to a counter tool mounting side are provided in an axial direction.

According to the present invention, the heat from the built-in motor is less likely to be transmitted to the nose side, and the cooling passage of the first sleeve is provided in the axial direction. Precision machining is now possible. Also, the bearings were not broken.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. At the time of explanation, the present invention has changed the first sleeve of the conventional device and added a heat insulating material. Therefore, the same members as those of the conventional example are denoted by the same reference numerals, and the description thereof has been omitted, and the device has been newly added. Only the members are assigned new numbers and will be described.

In the main spindle device 20, a heat insulating material 21 is attached to the nose 5 on the side of the built-in motor 6, so that heat from the built-in motor 6 is hardly transmitted. As shown in FIG. 1, FIG. 4 and FIG. 5, the cooling fluid which has passed through the passage 15 on the outer peripheral surface of the second sleeve 8 is applied to the outer peripheral surface of the first sleeve 22 as shown by an arrow d. After flowing from a plurality of non-tool mounting sides (right side in the figure) to the tool mounting side (left side in the figure), a plurality of axial passages 23 return from the tool mounting side to the non-tool mounting side. After being guided and collected at the inner diameter of the first sleeve 22, the rotary shaft 25 of the rotary joint 12 passes through a passage 24 formed between the inner diameter of the second sleeve 8 and the draw bar 10 as shown by an arrow e. Is led out of the apparatus through an outlet 27 through a passage 26 provided in
The cooling liquid is returned to the source 13. In the embodiment, the liquid is used as the cooling medium, but may be a gas.

With the above-described structure, the first sleeve has a passage for the coolant flowing from the helical shape to the axial direction, so that the first sleeve does not vibrate even during high-speed rotation. Also, the heat transmitted from the nose became difficult to be transmitted to the nose side, and the amount of heat transmitted was reduced to about 1/8.

[0012]

As described above, in the present invention, the first sleeve itself twists when the high-speed rotation initially set forth is twisted,
Vibration was generated, and in addition, the heat generated by the built-in motor was transmitted to the nose, and the nose was extended in the axial direction, so that high-precision machining was not possible. Also, the bearings were not broken.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a spindle device showing one embodiment of the present invention.

FIG. 2 is an explanatory view of a spindle device showing one embodiment of the present invention, and is a cross-sectional view taken along line AA of FIG. 1;

FIG. 3 is an explanatory view of a spindle device showing one embodiment of the present invention, and is a cross-sectional view taken along the line BB of FIG. 1;

FIG. 4 is a detailed view of a first sleeve of a spindle device showing an embodiment of the present invention, and a component diagram is shown in a cross-sectional view taken along line CC of FIG. 2;

FIG. 5 is an explanatory view of a spindle device showing one embodiment of the present invention, and is a developed view of a first sleeve.

FIG. 6 is an explanatory diagram of a conventional spindle device.

FIG. 7 is an explanatory view of a conventional spindle device, and is a detailed view of a second sleeve.

[Explanation of symbols]

 1, 20 Spindle device 2 Tool 3 Tapered hole 4 Spindle 5 Nose 6 Built-in motor 7, 22 First sleeve 8 Second sleeve 9 Collet 10 Drawbar 11 Cylinder 12 Rotary joint 13 Coolant source 14, 25 Rotating shaft 15, 23 , 24, 26 Passage 16 Spiral groove 21 Insulation 28 Bearing

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junya Ishibashi 2068-3 Ooka, Numazu-shi, Shizuoka Prefecture

Claims (2)

[Claims] 1. A nose for rotatably supporting a main shaft having a tapered hole for attaching a tool of a machine tool at an end portion to an inner diameter portion, a built-in motor adjacent to a rear end of the nose for rotating the main shaft, and a built-in motor. Adjacent to the rear end of the motor,
A cylinder that moves the drawbar that controls the opening and closing of the collet that grips and releases the tool that is fitted to the inner diameter portion of the main shaft via a sleeve and that opens and closes the collet, and a rotary joint attached to this cylinder to the outside of the device through the rotary joint A spindle device for a machine tool, comprising: a cooling device for supplying a cooling medium from a cooling medium source into a spindle; wherein a heat insulating material is attached to a nose side of a built-in motor. 2. A plurality of passages are provided in the axial direction on the outer diameter surface of the sleeve, in which a cooling medium flows from the side opposite to the tool mounting side to the side where the tool is mounted, and then returns from the side where the tool is mounted to the side opposite to the tool mounting side. The spindle device for a machine tool according to claim 1, wherein: