JPS61103012A - High speed rolling bearing device - Google Patents

Abstract

PURPOSE:To reliably perform lubrication by providing a nozzle for jetting air oil to a bearing on a spacer interposed between bearings. CONSTITUTION:A spindle 12 is inserted in a housing 11, and rotatably supported by a bearing 13. An annular passage 27 is disposed on the outer peripheral surface of an outer race spacer, and a nozzle 26 is formed by the first opening 28 facing between an inner race 17 and a non-guide surface of a retainer 19 and the second opening 30 facing between the retainer guide surface 16a of an outer race 16 and the retainer through an oil feed hole 28. In this arrangement, lubrication to the guide surface of the retainer can be reliably accomplished by utilizing an oil lubrication.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention uses a high-speed rolling bearing device for supporting the spindle of a machine tool, more specifically, an angular contact ball bearing,
The present invention relates to a bearing device that uses air-oil lubrication to significantly increase the limit rotational speed.

[Conventional technology]

In spindle devices for machine tools, in recent years there has been a demand for faster spindle rotation, but the above demand cannot be met unless the limit rotational speed of the bearing device that supports the rotating part of the spindle is increased.

A bearing device can be made to withstand high-speed rotation by reliably supplying a lubricant to prevent seizure from occurring on the raceway surfaces of the bearing and the guide surface of the cage.

Conventionally, jet lubrication, which uses a large amount of oil, has been common for supplying lubricant to bearings. Because oil is circulated, lubrication costs are high and friction loss is large.In addition, in the case of spindles for vertical machine tools, it is extremely difficult to seal the oil, so lubrication that uses as little oil as possible is required. It is hoped that the method will be put to practical use.

Oil mist lubrication is a method of lubrication that reduces the amount of oil used, but there is a problem in that the oil mist contaminates the working environment. As a lubrication method to solve this problem, air-oil lubrication has recently been proposed in which oil is supplied to lubrication points by intermittently adding very small amounts of oil to compressed air.

FIG. 6 shows a nozzle structure for jet lubrication of a bearing, and it is conceivable that this nozzle structure can be used as is for air-oil lubrication.

In the figure, a bearing 1 includes a plurality of balls 4 installed between an inner race 2 (hereinafter referred to as the inner race) that supports a spindle and an outer raceway 4 3 (hereinafter referred to as the outer race), and a cage that holds each ball 4. This is an angular contact ball bearing in which a bearing 5 is guided by an outer ring 3, and a nozzle 6 for supplying lubricating oil to the bearing 1 is provided in an outer ring spacer 7 in contact with the outer ring 3.

The nozzle 6 is formed to open between the inner ring 2 and the non-guiding surface of the cage 5 to inject oil into the bearing 1. In the case of jet lubrication that uses a large amount of oil, the nozzle The oil is injected between the non-guiding surfaces of the retainer 5 and penetrates in the directions of arrows A and B in the same figure, and a portion of the oil that hits the balls 4 is blown off in the radial direction by centrifugal force, and the droplets are directed in the direction of arrow C. 47467 of the retainer guide surface 3a of the outer ring 3 in a U-turn shape as shown in the figure.
It is considered most effective to contribute to

[Problem that the invention seeks to solve]

By the way, when air-oil lubrication is performed using the above nozzle structure, the air flows easily in the directions of arrows A and B with less resistance in the figure, but as the rotation speed increases, the cage guide of the outer ring 3 The pressure at the surface 33 increases, and the flow of mixed air in the direction of arrow C, which makes a U-turn, is not generated, resulting in poor lubrication of the cage guide surface 3a, which generates heat, and the guide surface 3a seizes. This makes it impossible to obtain high-speed rotation, and there is a problem in that the nozzle structure for jet lubrication cannot be used as is for air-oil lubrication.

In addition, in jet lubrication, when supplying oil to multiple bearings, one oil supply inlet is connected to each bearing through a branch passage, and the oil is supplied from one place, but in air-oil lubrication, air is supplied from one place. There is a problem in that the amount of air or oil flowing into each bearing varies depending on the size and type of the bearing, the length of the air passage, etc., and it is not possible to maintain each bearing in an optimal lubricated state.

This invention was made to solve the above-mentioned problems, and it is possible to reliably supply lubrication to the cage guide surface of the bearing using air-oil lubrication, and to supply air and oil to each bearing independently. The purpose is to provide a high-speed rolling bearing device that can be controlled by

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention rotatably supports a spindle in a housing with a plurality of angular contact ball bearings held by a ring-guided retainer, and the housing is provided with an air-oil lubricant. An inlet is provided independently for each of the ball bearings, and a nozzle is formed in a spacer interposed between each ball bearing so as to open toward the space between the cage and the inner ring and the space between the cage and the outer ring of the corresponding ball bearing. This nozzle is connected in communication with the lubricant inlet for the corresponding ball bearing, and a lubricant discharge path is formed on the surface of the spacer that corresponds to the other ball bearing.

[Effect]

Air oil is supplied to each bearing individually and independently, and the air oil is injected toward the bearing from both the first and second openings of the nozzle, and the air oil injected from the first opening penetrates between the inner ring and the cage. do.

In addition, the air oil injected from the second opening is directly sprayed between the cage guide surface of the outer ring and the cage, and when passing through the cage guide surface, it performs an effective lubricating action, and air-oil lubrication is adopted. The spindle can be rotated at high speed.

Furthermore, by arranging the parallel angular contact ball bearings back to back at both ends of the spindle, the temperature rise of each bearing is more even than the commonly used combination of angular contact ball bearings and cylindrical roller bearings. It is low and can withstand large axial loads in both directions.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5 of the accompanying drawings.

1 and 2 show a vertical high-speed spindle structure for a machine tool, in which a spindle 12 is inserted into a cylindrical housing 11, and is assembled in parallel with the upper and lower parts of the housing 11, respectively. It is rotatably supported by a bearing 13 inserted therein.

The spindle 12 has a price cutter at its lower end.
e A taper hole 14 is provided for attaching an end mill tool, and a pulley 159.1 for interlocking with a drive source is provided on the upper end side protruding from the housing 11.
c+,,s・The bearing 13 has an outer ring 16 (!: inner ring 17
This is an angular contact ball bearing in which a plurality of balls are incorporated between the bearings, and a retainer 19 holding each ball 18 is guided by an outer ring 16. ing.

Among the bearings 13, a short outer ring spacer 20 and an inner ring spacer 21 are installed between the bearings 13a and 13b and between the bearings 13C and 13d, which are arranged in parallel. End plates 24, 25 that maintain the thrust direction of the seat group are fixed. - Bearings 13a of the short outer ring spacers 20 and 20.

13d and both ends of the long outer ring spacer 22,
A nozzle 26 is provided for injecting air oil to each corresponding bearing.

Figures 3 and 4 show the nozzle provided on the short outer ring spacer 20.
Further, FIG. 5 shows nozzles provided at both ends of the elongated outer ring spacer 22, and each nozzle 26 has the same structure and is given the same reference numeral.

An annular passage 27 is provided on the outer peripheral surface of the outer ring spacer.

Two oil supply holes are drilled in the bottom of this passage 27, and the nozzle 26
A first opening 29 faces from this oil supply hole 28 between the inner ring 17 and the non-guiding surface of the cage 19, and a second opening 3o faces between the cage guide surface 16a of the outer ring 16 and the cage 19. It is formed.

A plurality of the nozzles 26 may be provided in the circumferential direction depending on the air capacity, the size of the bearing, etc., and the openings 29 and 30 may be arranged out of phase with each other in the circumferential direction. .

Further, on the surface of the short outer ring spacer 20 opposite to the nozzle 26 and on the surface of the upper and lower end plates 24.25 facing the bearings 13a, 13d, an annular discharge passage 31 for receiving air oil that has passed through the bearings is provided. The annular discharge passage 31 of the spacer 20 connects to the discharge passage 34 of the housing 11 via the slit 32 and the horizontal hole 33.
The annular discharge passage 31 of the upper and lower end plates 24, 25 also communicates with the discharge passage 34 through a through hole 35.

Each bearing 13 is provided on the housing 11 and the upper end plate 24.
A, 13b, 13C, and 13d are each provided with an independent air-oil inlet 36, and each port 36 communicates via an oil supply path 37 with a passage 27 of a nozzle 26 that supplies air-oil to the corresponding bearing. Air oil can be separately supplied to predetermined bearings 13 from the bearings 13.

Therefore, each bearing 13a, 13b, 13c, 13d +
For C, the air amount and oil amount can be easily controlled independently.

In addition, since the outer ring 16 and the outer ring spacer 20.22 do not rotate, an O-ring for airtightness is incorporated in the outer ring spacer 20.22 and the upper and lower ends [24° 25] at a position close to the bearing 13. . Furthermore, a spiral groove 39 for circulating cooling oil for cooling is formed on the outer peripheral surface of the housing 11.

The bearing device of the present invention has the above-described configuration, and includes a bearing 1
When air oil is supplied to each inlet 36 while the spindle 12 supported by the spindle 3 rotates at high speed, the air oil is injected from each nozzle 26 toward the corresponding bearing 13.

The air oil injected from the first opening 29 penetrates between the inner ring 17 and the retainer 19, as shown by arrows A and B in FIGS. 3 and 5, and lubricates the moving parts of the balls 18.

The air oil injected from the second opening 30 passes between the cage 19 and the guide surface 163 of the outer ring 16 as shown by the arrow in the figure, and after lubricating the guide surface 16a, it passes between the inner ring 17 and the outer ring 16. It merges with air oil from B and flows out.

In this way, the injection of air oil from the first opening 29 and the second opening 30 enables the air oil to lubricate between the retainer 19 and the guide surface 162, and the retainer 19 and the guide surface 162 due to high-speed rotation can be The used air oil that has passed through each bearing 13 without causing any seizure is taken out from the discharge path 34 through the outlet 40.

By the way, the air oil conditions are as follows.

Original pressure 2.5, 9f/c+4 air flow rate 40ON//min. When lubrication is performed by injecting air oil under these conditions from the nozzle 26 aiming at I 0.36 CC, the temperature rise of the housing will be lower than that of the conventional nozzle structure using jet lubrication shown in Fig. 6.
For angular contact balls and bearings with an inner diameter of φ80, the temperature is 5°C to 8°C.
It is low and the rotation speed is 140 compared to 12000 rPm.
The limit rotation speed can be increased up to 00 rPm.

Regarding damage to the retainer guide surface 16a, conventional nozzle lubrication results in large abrasion, whereas air-oil lubrication using the nozzle 26 of the present invention does not cause wear, although break-in is observed. was in extremely good condition.

〔effect〕

As described above, according to the present invention, the spindle is rotatably supported using rolling ball bearings that guide the retainer with raceway rings, and a nozzle for injecting air oil to the bearing is provided in the spacer interposed between the bearings. Since the opening of this nozzle faces between the outer ring and the cage and between the cage and the inner ring, the cage guide surface can be reliably lubricated using air-oil lubrication.
The anti-seizure effect of the cage guide surface is improved, and the maximum rotational speed of the spindle can be increased.

In addition, since air oil is supplied to each bearing independently, the amount of air and oil to each bearing can be controlled, and the optimum air oil lubrication can be performed according to the size or type of bearing, ensuring reliable lubrication. performance can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a spindle device showing the usage state of the bearing device according to the present invention, FIG. 2 is a partially cutaway bottom view of the same as above,
Figure 3 is an enlarged sectional view of the short spacer part in the same as above;
The figure is a perspective view of a short spacer, FIG. 5 is an enlarged sectional view of a portion of the long spacer, and FIG. 6 is a sectional view showing a conventional nozzle structure. 11 is a housing, 12 is a spindle, 13 is a bearing, 1
6 is an outer ring, 17 is an inner ring, 18 is a ball, 19 is a retainer,
20 is a short outer ring spacer, 22 is a long outer ring spacer, 26 is a nozzle, 27 is a passage, 28 is an oil supply hole, 29 is a first opening, 3
0 is a second opening, and 31 is an annular discharge path.

Claims (2)

[Claims] (1) A spindle in a housing is rotatably supported by a plurality of rolling bearings in which a group of rolling elements housed between inner and outer raceway rings are held by a raceway guide type retainer, and an air-oil lubricant inlet is provided in the housing. are provided independently for each of the bearings, and a nozzle is formed in the spacer interposed between each bearing so as to open toward the space between the cage and the inner raceway ring of the corresponding bearing, and the space between the cage and the outer raceway ring of the corresponding bearing. A high-speed rolling bearing device, in which the nozzle is connected in communication with the lubricant inlet for a corresponding bearing, and a lubricant discharge path is formed on a surface of the spacer that corresponds to the other bearing. (2) The high-speed rolling bearing device according to claim 1, wherein the angular ball bearings are assembled in a back-to-back arrangement at both ends of the spindle, and the nozzle is formed in the spacer of the outer raceway ring.