JPH0675639U - Lubricator for bearings of ultra-high speed rotating shaft - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is that the jet flow of oil air or the like hardly receives the air flow by the bearing due to the ultra-high speed rotation of the main shaft, and the contact of the rolling elements on the rolling surface of the bearing. The purpose is to sufficiently supply lubricating oil to the points and to keep the shaft power loss as small as possible. [Structure] A hollow hole is formed in a rotary shaft along the axial direction, and a lubricating hydraulic feed pipe is arranged inside the hollow hole of the rotary shaft in a non-contact state with an inner wall surface of the hollow shaft. , A lubricating oil supply hole that penetrates from the inner wall surface toward the outer periphery and communicates with the lubricating hydraulic pressure pipe is formed.One end of the bearing inner ring communicates with the lubricating oil supply hole of the rotating shaft and the other end of the bearing rotates. An injection small hole opening near the moving body was formed through the bearing inner ring.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a lubricating device for a bearing of a super high speed rotating shaft of a machine tool or the like.

[0002]

[Prior art]

 For example, for a rotating shaft that rotates at an extremely high speed such as a main shaft of a machine tool or a turbine blower shaft of an exhaust turbine supercharger, a lubricating method called jet lubrication or underless lubrication (see Japanese Utility Model Laid-Open No. 4-136323) is used. It is adopted, but in this case, there is a problem that the shaft power loss caused by stirring a large amount of lubricating oil is very large. Therefore, it is difficult for a small output motor to rotate at an ultra-high speed because of this power loss.

Therefore, oil mist lubrication or oil-air lubrication is used when the rotating shaft rotates at an extremely high speed. For example, as shown in FIG. 4, an oil supply nozzle is provided near a bearing 102 that supports a main shaft 101 of a machine tool. 103 is arranged, and oil mist or oil air is jetted from the injection port 103A of the oil supply nozzle 103 onto the rolling surface 104A of the inner ring 104 of the bearing 102 by the air pumping force, and the lubricating oil is supplied to the bearing 102.

[0004]

[Problems to be solved by the device]

 However, in the conventional lubrication device for a bearing of an ultra-high speed rotating shaft, when the bearing 102 is rotated at an ultra-high speed, air near the side surface of the bearing 102 is agitated by the rolling elements 105 and the cage 106, causing a violent air flow. Occurs, and the jet flow of oil air tends to flow to the one with less resistance. Therefore, it becomes difficult for a small amount of lubricating oil injected together with a large amount of compressed air flow to be introduced into the inside of the bearing 102 from the injection port 103A of the oil supply nozzle 103, and in the rolling element 105 on the rolling surface 104A of the bearing 102. There was a problem that it was difficult for sufficient lubricating oil to reach the contact point 104B. As a result, abnormal heat may be generated or the bearing 102 may be burned.

For example, in the case of the main shaft 101 rotating at 100,000 revolutions / minute, the rolling element 105 revolves around its own axis and its revolution speed becomes about half the revolution of the main shaft 101, while the retainer 106 The peripheral speed is as high as 90 to 100 m / sec, and a violent air flow (film) is generated in the vicinity thereof, but there is a gap between the end surface of the bearing 102 and the injection port 103A, and the injection port 103A rolls. Since it is located radially outward from the moving surface 104A, the distance L from the injection port 103A of the refueling nozzle 103 to the contact point 104B of the rolling element 105 on the rolling surface 104A becomes longer. Even if a small amount of lubricating oil is injected from the oil supply nozzle 103 with a subsonic compressed air flow, the lubricating oil contacts the rolling element 105 at the contact point. 10 4 It is difficult to reach B.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is that an injection flow of oil air or the like hardly receives an air flow due to a bearing accompanying the super-high speed rotation of a main shaft. To provide a lubrication device for a bearing of an ultra-high speed rotating shaft, which can sufficiently supply lubricating oil to a contact point of a rolling element on a rolling surface of the bearing and can suppress a shaft power loss as small as possible. Is.

[0007]

[Means for Solving the Problems]

 The present invention relates to a bearing lubricating device for an ultra-high speed rotating shaft, which supplies lubricating oil to a bearing supporting the rotating shaft via air pressure feeding force, wherein a hollow hole is formed in the rotating shaft along the axial direction thereof. A lubricating oil pressure feed pipe is placed inside the hollow hole of the rotary shaft in a non-contact state with the inner wall surface of the hollow hole, and penetrates through the rotary shaft from the inner wall face toward the outer periphery to communicate with the lubricating hydraulic pressure feed pipe. A lubricating oil supply hole is formed in the bearing inner ring, and one end of the bearing inner ring communicates with the lubricating oil supply hole of the rotating shaft and the other end penetrates the bearing inner ring through an injection small hole opened near the rolling element of the bearing. It is characterized by being formed.

[0008]

[Action]

 In the present invention, oil air or oil mist is pressure-fed into the lubrication hydraulic pipe inside the hollow hole of the rotating shaft, and the oil air or oil mist passes from the lubricating oil supply hole of the rotating shaft through the injection small hole of the bearing inner ring. The oil air or oil mist is pumped to the bearing rolling surface inside the bearing, lubricated, and then discharged to the outside through the inside of the bearing.

[0009]

【Example】

 Hereinafter, a lubricating device for a bearing of a main shaft of a machine tool according to an embodiment of the present invention will be described with reference to FIGS.

In the drawing, reference numeral 1 is an outer cylinder provided in the spindle head H, and a ring-shaped front lid 2 is fixedly attached to the front end of the outer cylinder 1, and a thicker one is attached to the rear end of the outer cylinder 1. A meat-cylindrical rear lid 3 is fixedly attached.

A front bearing 4 is mounted in the through hole 2 A of the front lid 2, a sleeve 5 is mounted inside the rear lid 3, and a rear bearing 7 is mounted in the front portion of the sleeve 5. . A main shaft 8 is supported by the front bearing 4 and the rear bearing 7. A bearing retainer 9 is fixedly provided on the front end surface of the front lid 2.

A motor support member 10 is fitted on the inner peripheral surface 1 A of the outer cylinder 1 so as to be located between the front lid 2 and the rear lid 3, and a drive means 11 composed of a built-in motor is mounted on the motor support member 10. It is installed.

A ring member 12 is fixedly attached to the rear end portion 3A of the rear lid 3, and the ring member 12 has a shaft portion 13 on its center line and the outer peripheral side of the shaft portion 13. An air outlet 14A is provided in the air passage 14, an air passage 14B penetrates through the central axis of the shaft portion 13, and a lubricating hydraulic feed pipe 20 described later is inserted and fixed to the front side portion of the air passage 14B. The rear end of the air passage 14B is connected to a lubricating oil supply source (not shown) via a pipe or the like.

A hollow hole 15 is formed in the main shaft 8 along the axial direction thereof, and a female screw portion 16 and a first annular groove 17 are formed on the front end side of the hollow hole 15. The second annular groove 18 is formed on the rear end side, and the labyrinth groove 19 is located on the rear end side of the second annular groove 18 on the outer peripheral surface of the lubricating hydraulic feed pipe 20. It is formed in multiple stages. The labyrinth groove 19 has a non-contact type air seal structure, which makes it difficult for the lubricating oil to leak from between the rear end portion of the main shaft 8 and the lubricating hydraulic feed pipe 20.

A lubricating hydraulic feed pipe 20 is arranged inside the hollow hole 15 of the main shaft 8, and a through-flow passage consisting of an annular gap in cross section between the pipe outer wall surface 20 A of the lubricating hydraulic feed pipe 20 and the inner wall surface of the hollow hole 15. 21 is formed along the axial direction. The through channel 21 communicates with the first and second annular grooves 17 and 18.

A supply passage 22 is formed inside the lubricating hydraulic feed pipe 20, a front end portion of the lubricating hydraulic feed pipe 20 is located in the first annular groove 17 of the hollow hole 15, and a front end of the supply passage 22 is It is closed with a lid 22A. A plurality of through holes 23 penetrating the wall body 20B are formed in a cross shape from the supply passage 22 at the front end portion of the lubricating hydraulic feed pipe 20, and each through hole 23 is formed in the first annular groove 17 of the hollow hole 15. It is in communication.

A screw-in type cutting tool 24 is screwed and fixed to the female screw portion 16 of the main shaft 8. The cutting tool 24 closes the end of the supply passage 22 to supply lubricating oil to the main shaft 8. It is designed so that it does not leak from the road 22.

Further, the main shaft 8 is formed with a lubricating oil supply hole 25 on the front side facing the first annular groove 17 of the hollow hole 15 of the main shaft 8. A front side lubricating oil supply hole 25 penetrating the wall 8A is formed in the main shaft 8, the lubricating oil supply hole 25 faces the first annular groove 17 of the hollow hole 15, and the lubricating oil pressure is passed through the through hole 23. It communicates with the supply path 22 in the pipe 20.

The bearing inner ring 26 of the front bearing 4 is formed with an injection small hole 27 penetrating the bearing inner ring 26, and one end (inner end) of the injection small hole 27 is lubricated on the front side of the main shaft 8. It communicates with the oil supply hole 25. The position of the injection opening at the other end of the injection small hole 27 is near the contact point 26C of the rolling element 4A on the rolling surface 26B of the bearing inner ring 26.

On the other hand, the main shaft 8 is provided with a rear side lubricating oil supply hole 28 facing the second annular groove 18 of the hollow hole 15, and the bearing inner ring 29 is attached to the bearing inner ring 29 of the rear bearing 7. A small injection hole 30 is formed therethrough, and one end (the other end) of the injection small hole 30 communicates with the lubricating oil supply hole 28 on the rear side of the main shaft 8. The position of the injection opening at the other end of the injection small hole 30 is near the contact point 29C of the rolling element 7A on the rolling surface 29B of the bearing inner ring 29.

An annular recess 9A communicating with the inside of the front bearing 4 is formed in the through hole of the bearing retainer 9, and the bearing retainer 9 has a first air discharge passage 9B communicating with the annular recess 9A. It is formed along the radial direction. Further, a second air exhaust passage 2B communicating with the first air exhaust passage 9B is formed in the front lid 2 along the radial direction, and a third air exhaust passage 1B communicating with the second air exhaust passage 2B is formed on the outer cylinder. No. 1 is formed along the axial direction, and a fourth air discharge path 3B communicating with the third air discharge path 1B is formed on the rear lid 3 along the axial direction thereof, and the fourth air discharge path 3B is formed. The rear lid 3 has an opening at the rear end surface.

The first air exhaust passage 9B, the second air exhaust passage 2B, the third air exhaust passage 1B, and the fourth air exhaust passage 3B constitute a front air exhaust passage 31. A rear air exhaust passage 32 is formed between the outer peripheral surface of the shaft portion 13 of the ring member 12 and the inner peripheral surface of the sleeve 5, and the inlet of the rear air exhaust passage 32 is located inside the rear bearing 7. The communication port is connected to the exhaust port 14A of the ring member 12.

The fourth air exhaust path 3B and the exhaust port 14A are connected to a forced exhaust device such as a vacuum pump (not shown) via a duct or the like. Therefore, in the present embodiment, oil air or oil mist is pressure-fed from the lubricating oil supply source to the supply passage 22 of the lubricating hydraulic feed pipe 20 in the hollow hole 15 of the main shaft 8, and part of the oil air or oil mist is From the through hole 23 of the lubricating hydraulic feed pipe 20, it is guided into the first annular groove 17 of the main shaft 8, and from this first annular groove 17 to the lubricating oil supply hole 25 on the front side and the injection small hole 27 of the bearing inner ring 26. It is injected through the inside of the front bearing 4. This oil air or oil mist is pressure-fed to the outer peripheral surface 6A of the bearing inner ring to lubricate the rolling elements 4A, and then is discharged through the inside of the front bearing 4 between the bearing inner ring 26 and the bearing outer ring 26A. It is guided to the outside through the front side air discharge passage 31 by the forced exhaust device.

On the other hand, the other part of the oil air or the oil mist in the first annular groove 17 of the main shaft 8 is introduced into the lubricating oil supply hole 28 on the rear side via the through passage 21 and the second annular groove 18. Further, after being injected into the inside of the rear bearing 7 through the injection small holes 30 of the rear bearing 7 and being pumped to the outer peripheral surface 6B of the bearing inner ring to lubricate the rolling elements 7A, the bearing inner ring 29 and the bearing outer ring 29A. The air is exhausted through the inside of the rear bearing 7 and is further guided to the outside via the rear side air exhaust passage 32 by the forced exhaust device.

In the above description, the first and second annular grooves 17 and 18 serve as an oil sump in which the lubricating oil supplied from the lubricating oil 20 is collected by the centrifugal force generated by the rotation of the main shaft 8 and serve as the lubricating oil supply holes. It acts to reliably guide the lubricating oil to 25 and 28.

According to the above-mentioned configuration, the bearing inner ring 26 of the front bearing 4 is formed with the injection small hole 27 penetrating the bearing inner ring 26. Bearing The distance to the contact point 26C of the rolling element 4A on the rolling surface 26B of the inner ring 26 becomes shorter, and the flow of the lubricating oil causes the rolling element 4A and the cage of the front bearing 4 to accompany the super-high speed rotation of the main shaft 8. The lubricating oil directly reaches the contact point 26C of the rolling surface 26B of the front bearing 4 and receives a sufficient amount of the lubricating oil with almost no air flow in the vicinity of 4B.

The rear bearing 7 also has the same effect as the front bearing 4. That is, since the injection small hole 30 penetrating the bearing inner ring 29 is formed in the bearing inner ring 29 of the rear bearing 7, rolling on the rolling surface 29B of the bearing inner ring 29 from the injection small hole 30 of the rear bearing 7. The distance to the contact point 29C of the body 7A becomes short, and the flow of the lubricating oil hardly receives the air flow near the rolling elements 7A and the cage 7B of the rear bearing 7 accompanied by the super-high speed rotation of the main shaft 8, The lubricating oil directly reaches the contact point 29C of the rolling surface 29B of the rear bearing 7 and can supply a sufficient amount of lubricating oil.

Since the lubricating hydraulic feed pipe 20 is arranged in the hollow hole 15 of the main shaft 8, the volume in the hollow hole 15 is reduced, and the hollow hole 15 of the main shaft 8 is filled with lubricating oil. There is no need, and even a small amount of lubricating oil that is pressure-fed from the lubricating hydraulic pressure feed pipe 20 can be reliably supplied to the lubrication site. Therefore, unlike the jet lubrication type lubrication device, a large amount of lubricating oil is not required, and the shaft power loss in the bearing portion can be suppressed to be small.

In this embodiment, a plurality of through holes 23 penetrating the wall body 20B from the supply passage 22 inside is formed in the lubricating hydraulic feed pipe 20, and the lubricating oil is supplied from each through hole 23. Lubricating oil is supplied to the supply holes 25 and 28, but even if the through hole 23 is not formed in the lubricating hydraulic pressure supply pipe 20, the end of the lubricating hydraulic pressure supply pipe 20 is opened and the lubricating oil is supplied from this opening. Lubricating oil can be supplied to the holes 25 and 28.

[0030]

[Effect of device]

 As described above, according to the present invention, the bearing inner ring is formed with the injection small hole penetrating the bearing inner ring, so that the contact point of the rolling element on the rolling surface of the bearing inner ring extends from the injection small hole of the bearing. Distance is shortened, the lubricating oil flow is hardly affected by the air flow near the rolling elements of the bearing and the cage accompanying the ultra-high speed rotation of the main shaft, and the lubricating oil does not increase the shaft power loss. Therefore, the contact point of the rolling surface of the bearing inner ring is directly reached, and a sufficient amount of lubricating oil can be supplied.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part showing the vicinity of a front bearing of a lubricating device for a bearing of an ultra-high speed rotating shaft according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part showing the vicinity of a rear bearing of a lubricating device for a bearing of an ultra-high speed rotating shaft according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing an entire lubricating device for a bearing of an ultra-high speed rotating shaft according to an embodiment of the present invention.

FIG. 4 is an enlarged sectional view of a main part of a conventional lubricating device for a bearing of an ultra-high speed rotating shaft.

[Explanation of symbols]

 4 Front Bearing 4A Rolling Element 7 Rear Bearing 7A Rolling Element 8 Spindle 8A Wall 15 Hollow Hole 20 Lubricating Hydraulic Pipe 25 Lubricating Oil Supply Hole 26 on Front Side 26 Bearing Inner Ring 27 Injection Small Hole 28 Rear Lubricating Oil Supply Hole 29 Bearing Inner ring 30 injection small holes

Claims (1)

[Scope of utility model registration request] 1. A lubrication device for a bearing of an ultra-high speed rotary shaft, which supplies lubricating oil to a bearing supporting the rotary shaft via air pressure feeding force, wherein a hollow hole is formed in the rotary shaft along the axial direction thereof. Inside the hollow hole of the rotary shaft, the lubricating hydraulic pressure pipe is arranged in non-contact with the inner wall surface of the hollow hole, and penetrates through the rotary shaft from the inner wall surface toward the outer periphery to communicate with the lubricating hydraulic pressure pipe. A lubricating oil supply hole is formed in the bearing inner ring, and one end communicates with the lubricating oil supply hole of the rotating shaft and the other end penetrates the bearing inner ring through an injection small hole opened near the rolling element of the bearing. A lubricating device for a bearing of an ultra-high speed rotating shaft, which is characterized by being formed.