JPH0224598Y2 - - Google Patents

Description

[Detailed description of the invention] (1) Purpose of the invention (a) Industrial application field The present invention relates to a cooling device for the spindle head of a machine tool, particularly a machining center, for reducing thermal displacement of the spindle and improving machining accuracy.

(b) Prior Art Conventionally, a cooling system for a spindle head in a machine tool, particularly a machining center, has been designed to cool the main spindle head by circulating lubricating oil from the main cooling device through the jacket and around the spindle bearing via a manifold. Furthermore, a cooling device is known that lubricates the inside of the gear train, has a lubricating oil nozzle installed in the manifold, and discharges the lubricating oil nozzle toward the inner wall to reduce thermal displacement.

(c) Problems to be solved The conventional spindle head cooling device described above has little cooling effect, and the amount of change in thermal displacement of the spindle bearing increases over time, especially as spindle rotation speeds increase in recent years.
Furthermore, there were problems that the main shaft bearing could be damaged in a short period of time, or that machining accuracy could be adversely affected.

(D) Purpose The purpose of this invention was proposed in view of the above circumstances and to solve the problem.It aims to improve machining accuracy by minimizing thermal displacement of the main shaft bearing, and extend the life of the bearing. An object of the present invention is to provide a cooling device for a spindle head.

(2) Structure of the invention (a) Means for solving the problems The device of the present invention is an improved version of the conventional spindle head cooling device, and is particularly designed to store lubricating oil directly above the spindle on the inner wall of the spindle head. An oil sump is provided to allow overflow, and the overflowing lubricating oil flows along the inner wall, and an annular groove is provided in the main spindle motor mounting area, which is also a heat source, at the rear upper part of the main spindle head to prevent any cold water from flowing out. By cooling the gear with lubricating oil, it is possible to reduce the thermal displacement of the main shaft due to thermal effects on the column, and this is a main shaft head cooling device that has a much better cooling effect than conventional cooling devices.

(b) Embodiment An embodiment of the device of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a partial sectional view of a spindle head in a machining center for explaining the apparatus of the present invention.

In FIG. 1, a spindle motor 4 for rotating the spindle 2 is mounted at the rear upper part of the spindle head 1. As shown in FIG. A drive shaft 5 is attached to the main shaft motor 4, and a gear 6 is fitted onto the drive shaft 5. Rotation is transmitted via a gear 7 meshed with the gear 6 to a spline shaft 8 on which the gear 7 is fitted. The spline shaft 8 has gears 9a and 9b.
is fitted in a slidable manner, and a gear 9 is fitted on the main shaft 2.
Gears 10a and 10b that form a pair with a and 9b are configured to mesh with each other. Therefore, when changing the rotation of the main shaft 2, since the gear 9a and the gear 10a are currently meshed, the gear 9a is separated from the gear 10a, and the gear 9b is meshed with the gear 10b. Then, a tool holder 3 with a pull stud is inserted into the tip of the main spindle 2, a tool is attached to the tool holder 3, and the main spindle 2 is rotated to perform machining.

By applying rotation to the main shaft 2 from the main shaft motor 4 via the drive shaft 5, gears 6 and 7, and gears 9a and 10a or gears 9b and 10b, the bearing outer peripheral portion of the main shaft 2, gears 9a and 10a or gear 9b, Heat is generated from the meshing portion of the spindle 10b and the inner wall portion of the spindle head 1 to which the spindle motor 4 is attached, and as a result, the inside of the spindle head 1 is filled with heat. As a result, the main spindle 2 undergoes thermal displacement, which affects machining accuracy, so each of the above-mentioned parts is cooled, but the current situation is that conventional cooling devices do not provide a significant cooling effect.

The specific configuration of the cooling device of the present invention will be described.

The piping 11 is placed from the upper part of the main spindle head 1 in FIG. 1 into the inner wall at the tip of the main spindle head 1 as shown by the arrow in FIG. 1 through the jacket connected to the main cooling device 24. Piping 11 is connected to connecting member 12
is connected to the communication hole 13 through the communication hole 1.
3 communicates with the outer peripheral portion of the bearing at the tip of the main shaft 2. Each chamber 14a to 14g is provided in a lubricating oil jacket 14 having a spiral shape, for example, in the communication hole 13 on the outer circumferential portion of the bearing of the main shaft 2.
Flow lubricating oil from a to 14g toward the bearing to constantly cool the bearing. Communication hole 1 from jacket 14
5, it communicates with a pocket 16 which is an oil reservoir provided on the upper inner wall of the spindle head 1. The lubricating oil retained in the pocket 16 overflows to the side of the pocket 16 and flows out along the inner wall 17. The lubricating oil flowing out from the pocket 16 travels along the inner wall 17, drips downward while cooling the bearing fitted on the tip of the shaft 8, and further travels along the outer circumference of the main shaft 2, and then drips down the bearing installed on the lower surface of the shaft 8. The lubricating oil is collected in the lubricating oil recovery tank 18 . The lubricating oil collected in the lubricating oil recovery tank 18 is further transferred to the return pipe 19.
A so-called closed system is adopted, in which the air is sent to the main cooling device 24 through the circulation system.

Piping 1 placed above the spindle head 1
1 is branched into a pipe 20, and the other end of the pipe 20 is connected to a circumferential annular groove 21, as shown in FIG. ing. Several locations of the circumferential annular groove 21, for example, 22a, 22b, and 22
Nozzles are provided at three locations c to discharge lubricating oil toward the gears in the main shaft head 1, thereby cooling the gear-related parts. The released lubricating oil flows down into the lubricating oil recovery tank 18 and is recovered.

(c) Operation The operation of the cooling device of the present invention will be explained. The lubricating oil cooled to about -5 DEG to 0 DEG C. by the main cooling device 24 is sent to the pipe 11 disposed above the spindle head 1 through a pipe. The lubricating oil sent to the pipe 11 is first supplied to the circumferential annular groove 21 via a pipe 20 branched from the pipe 11. Nozzles 22a, 2 provided in the circumferential annular groove 21
Lubricating oil is released from 2b and 22c toward each gear, and the lubricating oil is
A lubricating oil recovery tank 1 provided on the bottom surface by cooling b.
It flows into 8. On the other hand, the lubricating oil sent to the piping 11 is passed from the upper inner wall of the spindle head 1 to the communication hole 13.
It is fed into the jacket 14 at the outer peripheral portion of the bearing, which is the tip of the main shaft 2. The cooled lubricating oil passes through each chamber 14a to 14g in the jacket,
Cool the bearing part. Next, lubricating oil is temporarily stored through the communication hole 15 in a pocket 16 provided on the upper inner wall of the spindle head 1 directly above the spindle.
When it is secured in pocket 16 and filled with lubricant,
The lubricating oil overflows and flows down the wall surface to the inner wall 17 of the spindle head 1, cools the outer peripheral portion from the upper part of the inner wall of the shaft 8 or the spindle 2, and is collected in the lubricating oil recovery tank 18.

The lubricating oil collected in the lubricating oil recovery tank 18 is sent to the main cooling device 24 through the return pipe 19, cooled by the main cooling device 24, and reused.

(3) Effects of the invention The cooling device of the present invention is different from the conventional cooling device by adding a pocket 16 on the upper inner wall of the spindle head 1 and a circumferential annular groove 20 on the rear upper part of the spindle head 1 where the spindle motor 3 is attached. By providing several nozzles 21a to 21c at the tip of the groove 20, the bearing part of the main shaft, the gear drive part, and the mounting part of the main shaft motor are actively cooled and cooled more than ever before. It was effective.

As an example of the cooling effect, the test bar 23 is inserted into the tool holder 3 shown in Fig. 1, and the spindle 2 is rotated.
Rotate at 6.000 rpm, stop the rotation of the main shaft 2 every hour for measurement, and set the length l of the test bar 23.
Attach a dial gauge to the 300mm tip of the
The change in thermal displacement of the main shaft 2 over time was measured every hour for 8 hours by applying it in the axial direction.

Figure 3 is a graph showing the above measurement results, where the solid line is the measurement data when using the cooling device of the present invention, and the dotted line is the measurement data under the same conditions when using the conventional cooling device. be.

As shown in FIG. 3, the amount of change in thermal displacement of the main shaft in the Y-axis and Z-axis directions indicates that a remarkable cooling effect is achieved compared to the conventional case.

Therefore, the cooling device of the present invention not only provides a more outstanding cooling effect than the conventional one, but also improves machining accuracy and increases work efficiency.

Furthermore, the bearings will not be damaged in a short period of time, and can be used for a long time even during high-speed operation, making it possible to maintain a long bearing life.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a spindle head in a machining center for explaining the apparatus of the present invention. Figure 2 shows the X of the annular groove 21 in Figure 1.
It is an arrow view. FIG. 3 is a graph showing the change over time in the thermal displacement of the main shaft measured by the device of the present invention and the conventional device, with time on the horizontal axis and thermal displacement of the main shaft on the vertical axis. 1...Spindle head, 2...Spindle, 3...Tool holder, 4...Spindle motor, 5...Drive shaft, 6,
7, 9a, 9b, 10a, 10b...gear, 1
1, 12, 13, 15, 19, 20...Piping, 1
4... Jacket, 14a-14i... Room, 1
6... Pocket (oil reservoir), 18... Lubricating oil recovery tank, 21... Circumferential annular groove, 22a to 22c
... Nozzle, 23 ... Test bar, 24 ... Main cooling device.

Claims (1)

[Scope of utility model registration request] A jacket is provided on the outer periphery of the spindle bearing of the machine tool spindle head and has a communication path for guiding lubricating oil from the main cooling device, and a jacket is provided at the bottom of the spindle head and circulates within the spindle head to provide a cooling effect. a recovery tank for collecting and storing the lubricating oil that has been used in the motor; It consists of a circumferential ring groove provided circumferentially on the side wall of the mounting portion and communicating with the communication path, and nozzles provided at several locations above the groove for discharging lubricating oil toward the inside of the spindle head. A cooling device for a spindle head, characterized in that a mechanical part of the spindle head is cooled with cooled lubricating oil.