DE29912193U1 - The arrangement of lubricating nozzles in high-speed rolling bearings - Google Patents

Description

National Science Council, Taipei/**T*iwan'(R .*0 . C . )"

The arrangement of lubrication nozzles in high-speed rolling bearings

BACKGROUND OF THE INVENTION Field of application of the invention

This invention relates to the arrangement of lubrication nozzles in oil-air or oil-mist lubrication systems for high-speed rolling bearings.

Background of the invention

The operation of the rolling bearing is directly dependent on the lubrication system. A good lubrication system improves ball movement, extends the service life of the bearing and can contribute to a significant reduction in energy consumption. Grease, oil injection, oil-air and oil-mist systems are currently used in rolling bearing lubrication systems. High-viscosity grease is used in lubricating bearings. During the operation of the bearing, the grease spreads over the entire bearing surface. Since the heat dissipation of greases is very low, this technique can only be used in rolling bearings with low and medium speeds.

Heat dissipation is an important consideration for rotational speeds in rolling bearings. Most damage to high-speed rolling bearings can be traced back to insufficient heat dissipation. Two lubrication systems are currently used for such rolling bearings. One involves injecting low-viscosity lubricating oil directly into the bearing, then cooling and filtering the oil so that an oil circuit can be formed. This is the so-called injection lubrication system. High speeds can be achieved using this system, but it is very expensive and consumes a lot of energy. In addition, space must be made for the oil seals.

Therefore, the second method, mixing air with lubricating oil, is more commonly used. These lubrication systems are divided into oil-air and oil-mist systems. In both systems, highly compressed air containing a certain amount of lubricating oil is injected directly into the bearing.

Oil-air systems differ from oil-mist systems in the way the mixture is produced. The most important difference is that in oil-air systems, lubricating oil and air enter the mixing container through two independent channels. The compressed air then carries the lubricating oil into the access channel. Both substances

are then injected directly into the bearing. In oil-mist systems, however, the highly compressed air enters the Venturi tube. The pressure difference then leads to an oil-mist mixture being formed from lubricating oil and air inside the Venturi tube.

In order to inject the lubricating oil more precisely into the lubrication point, the access channel is sometimes connected to a lubricating nozzle. The narrow nozzle opening supplies a small area of the ball surface with precise lubricating oil. Since oil injection systems make the installation of a lubricating nozzle very complicated and also have a higher energy consumption, the invention presented here is aimed primarily at use in oil-air and oil-mist systems with lubricating nozzles.

Most nozzle systems are used in one-point or two-point high-speed rolling bearings. This means that one or two nozzles are used to lubricate one bearing. However, this design can lead to irregular heat dissipation, which in turn causes different thermal conditions in the bearing, which can ultimately lead to deformation of the bearing or inaccuracies in the bearing. Stresses in the rolling bearing are also a possible result. This can affect the life of the bearing. Due to its close proximity to the bearing, the nozzle also heats up. Lubricating oil deposits in the correspondingly shaped nozzle body cause unnecessary temperature increases and oil capacity fluctuations, which affect the entire system. If the nozzle is then also used with a spindle (with the motor installed in the spindle), the temperature increase will be even more drastic.

Air injection has proven to be very effective for cooling bearings. Oil-air and oil-mist systems use large volumes of air to cool the bearing. If the nozzle can inject a maximum amount of air under certain pressure conditions, this will not have a negative effect on the delivery of lubricating oil to the lubrication point, but will improve the cooling of the system and the achievable speeds.

Based on the reasons presented here, the aim of this invention is to present a lubricating nozzle that should make the heat exchange in the bearing more efficient, compensate for the temperature rise and also help to avoid oil deposits.

Description of the technology used so far

The principle of oil-air lubrication was described in U.S. Patent No. 4,785,913 as a "spindle lubrication system." The oil injector was controlled by a timer that injected the lubricant into an oil-air mechanism at a set time. The compressed air then carried the lubricant into the nozzle and on to the rolling bearing.

Since this oil-air system supplies the bearing with lubricant at intervals, it was assumed that the lubricant would stick to the spring, balls and screw threads, but that the inflow of compressed air would gradually remove these residues. This would guarantee continuous lubrication. In practice, however, it has been shown that oil capacity fluctuations occur in the oil-air lubrication system for the reasons mentioned above. The system described in the U.S. patent cannot therefore be described as ideal. The stability of the oil supply can be improved by using more viscous lubricant, an ideal length of the supply line, reducing the oil injection capacity and shortening the injection interval.

The lubrication system shown in U.S. Patent No. 4,057,371, "Gas Turbine High Speed Centrifugal Compressor Unit," was for a journal bearing. The basic idea of this invention was to inject high pressure lubricant between the journal bearing wall and the journal bearing using an oil pump. When the bearing shaft rotates, a wedge thrust effect is created between the main shaft and the balls. The lubricant creates a positive pressure between the main shaft and the balls, lubricating the shaft and balls individually. The entire lubrication process is accomplished in one operation. However, the lubricant can be reused after it has flowed back into the oil reservoir, and a cooling mechanism is involved to keep the lubricant at the optimum temperature.

Other patents to be mentioned in this area would be: R.O.C. Patent No. 71,973 "Aerosol Cooling and Lubrication System", R.O.C. Patent No. 154,639 "Emergency Aerosol Lubrication System" and U.S. Patent No. 3,939,944 "Oil Mist Lubrication System", U.S. Patent No. 4,137,997 "Lubrication and Cooling System for Spindle Bearing Assemblies", U.S. Patent No. 4,006,944 "Spindle with Oil Injection Based Bearing", U.S. Patent No. 4,284,171 "Emergency Oil/Mist System", U.S. Patent No. 4,342,489 "Ball Bearing Lubricant Injector", U.S. U.S. Patent No. 4,759,427 "Nozzle arrangement for constant fine lubrication" and U.S. Patent No. 4,343,378 "Methods and apparatus for lubricating bearings". All of these patents relate to different areas of oil-air, oil-mist and oil-injection lubrication systems. However,

These patents all relate to the invention presented in this letter.
ESSENTIAL INFORMATION ON THE INVENTION

- This invention relates to the configuration of lubricating nozzles in
High speed bearings. The main purpose of this invention is to improve the nozzle shape used so far, to increase the precision with which lubricant is applied to the lubrication point in oil-air/oil-mist systems, to improve heat dissipation in the bearing
and prevent oil deposits.

Rolling bearings are used in high-speed bearings due to their low friction, precise rotation and durability. However, lubrication is the crucial element for high-speed bearings.

Oil-air and oil-mist systems are preferred for lubrication in high-speed bearings. The DN value can be over 1.2 X 10 ⁶ . The DN value is the product of the rolling circle diameter of the balls (mm) and the number of revolutions (rpm). In addition to the parameters resulting from the operation of the lubrication system, the nozzle shape, oil line shape, arrangement and number of nozzles are also important factors in increasing the possible speed and the service life of the rolling bearing.

To meet this purpose, the following aspects were taken into account when designing a new type of lubricating nozzle:

1. Even distribution of temperature in the warehouse.

2. Prevention of oil deposits in the oil line.

3. Supply of cooling air in large quantities.

4. The oil-air or oil-mist lubricant can penetrate into the bearing without damaging it.

to hinder the way of working.

Short description of the pictures:

The following detailed illustrations of the arrangement and function of the nozzles in this invention are attached:

Figure 1. Partial view of the invention for a rolling bearing lubrication system in integrated high-speed spindles for machine tools.

Figure 2. Side view of the ring in the T-cut between the ball bearing and the ball space in Figure 1.

Figure 3. Partial view of the �Igr;�Pgr;-�Pgr;�Igr; cutout, partial top view of the entire lubrication nozzle.

Reference numbers for the attached figures:

1,2, 3 .... ball bearings

4, 5, 6 .... Lubrication nozzle (annular space)

7 Core round column

8 (Large caliber) access line

9 Semi-circular access line

10, 11, 12, 13, 14, 15 .... Oil injection channel,

Detailed description of the invention:

The shape for the lubricating nozzle, which is described in the patent application "The arrangement of

Lubrication nozzles in high speed rolling bearings" refers to

High-speed rolling bearings that are lubricated by an oil-air or oil-mist lubrication system.

This invention for the arrangement of lubrication nozzles in high-speed rolling bearings describes a large access line that is coupled to an external oil supply line. This is followed by a semicircular ring line that is connected to a large access line and has three L-shaped nozzle pipes that are arranged at a distance of 120° between the adjacent channels and ensure the connection between the annular access line and the outlet opening. The large access line, which serves to connect to the external oil supply line, also has the task of generating a preload for the rolling bearing and core column. The semicircular ring line and the three nozzle pipes, which are arranged at an angle of 120° between the adjacent channels and the annular access line or the nozzle opening, are attached to the circle of the T-cutout of the rolling bearing and the gap.

In the arrangement shown above, the inner diameter for the nozzle tubes can be between 2.0 mm 3.0 mm. The size of the discharge opening must not exceed 2.0 mm. The large access line drilled into the core round column should have a larger diameter than the external oil supply line, and a smaller diameter than the semi-circular ring line.

The DN value (product of the rolling circle diameter of the balls and the rotational speed) of the rolling bearing in the arrangement for the lubrication nozzles in high-speed rolling bearings is limited to 2.0X10 ⁶ .

Figure 1 describes the partial view of the invention as it is intended for integrated high-speed spindles in machine tools. The ball bearings 1, 2 and 3 are individually lubricated by the lubrication nozzles of the rings 4, 5 and 6. The shape of the internal access line is absolutely identical for each of the nozzles 4, 5 and 6.

Figure 2 describes a partial view of the side of the ring 4 of the T-cutout between the ball bearing and the ball space from Figure 1. The oil injection pipes 10 (also 11, 12 see Figure 3) and 13 (also 14, 15 see Figure 3) are arranged perpendicular to each other. The pipe diameters decrease in order to accelerate the oil-air or oil-mist lubricant mixture and bring it to the lubrication point at high speed. The small diameter of the oil injection channel can overcome the air layer outside the balls to a certain extent. Therefore, the diameter of the oil injection pipes 10 (11, 12) was specified as 2.0 mm to 3.0 mm, while the diameter of the oil injection pipes 13 (14, 15) should not exceed 2.0 mm.

Figure 3 shows a partial plan view of the entire lubrication nozzle, which corresponds to the Π-Γ cutout in Fig. 1. The large access line 8 is drilled into the core round column 7 to fix the ball bearings and to create a preload. It also connects the external oil supply line for the oil-air or oil-mist mixture to the semicircular ring line 9. The diameter of the large access line should be larger than that of the external supply line and smaller than that of the semicircular ring line to avoid oil deposits on the connection point. The surface of the T-cut of the ball bearing and the gap 4, which is located on the semicircular ring line, is round and smooth so that the oil-air or oil-mist mixture can be evenly distributed into the three nozzle tubes 10, 11, 12, which are arranged at an angle of 120° between adjacent channels. Originally, the semi-circular ring line 9 was to be laid inside the core round column 7 in order to fix the ball bearing and create a preload. However, since this would have led to problems during production, this access line was mounted on the surface of the ring 4 of the T-cutout of the ball bearing and ball space.

The essence of this invention is that the access pipe thickens from the oil-air/oil-mist supply pipe to the semi-circular ring pipe and the three nozzle pipes. This can effectively reduce the temperature rise in the ball bearing, reduce the stress caused by different temperatures, reduce the fluctuations in oil supply and oil deposits, and prevent the temperature rise inside the nozzle. At the same time, the speed and service life of the rolling bearing are increased.

Claims (4)

1. An arrangement for lubricating nozzles in high speed rolling bearings, wherein:
a large access line is connected to an external oil supply line;
a semi-circular ring line connected to the above-mentioned large access line; and
three L-shaped nozzle pipes arranged in a ring at an angular distance of 120° from each other, with the ring being connected to the nozzle pipes. The large access line mentioned above is embedded in a core circular column that is delimited by the inner core shell. Furthermore, the semicircular ring line mentioned above and the three nozzle pipes also mentioned above are integrated into the ring in the inner core chamber. 2. The arrangement of the lubrication nozzles as described under 1., whereby the diameter of the nozzle pipes is between 2.0 mm and 3.0 mm. However, the discharge opening of each of the nozzle openings does not exceed 2.0 mm. Furthermore, the diameter of the large access line is larger than the diameter of the external oil supply line and smaller than the diameter of the semi-circular ring line described above. 3. A lubrication system, whereby:
The core round column is equipped with a large access line and an inner chamber; and
a ring is positioned in this inner chamber, which accommodates a semi-circular ring line on the outside, which in turn is connected to the large access line of the core circular column.
The ring mentioned has three nozzle pipes arranged at an angle of 120° to each other. Each nozzle pipe has an outlet and an inlet, whereby the inlet is connected to the ring line. This ensures the connection from the above-mentioned large access line of the core round column via the ring line to the inlet of each nozzle pipe and further to the outlet opening of the nozzle pipes. 4. A lubrication system as described in 3, wherein the inner diameter of the nozzle tubes is 2.0 mm to 3.0 mm and the size of the outlet opening does not exceed 2.0 mm.