JP2008075882A - Bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device attaining further silence by suppressing noise such as wind-ripping sound. <P>SOLUTION: An outer peripheral surface 12a of an inner ring 12 is extended axially outward from the end face of an outer ring 11 and formed to be enlarged in diameter toward a ball 13. Lubricating oil jetted with air and supplied to the outer peripheral surface 12a of the inner ring 12 is supplied along the outer peripheral surface 12a to the ball 13 by centrifugal force. The wind-ripping sound can thereby be reduced while maintaining the amount of lubricating oil per unit time supplied into an angular contact ball bearing 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bearing device in which lubrication is performed using, for example, oil air / oil mist lubrication in order to support a spindle of a machine tool rotating at a high speed.

  As modes of bearing lubrication, there are mainly grease lubrication and oil lubrication. Since grease lubrication is performed using grease sealed in the bearing, the structure around the bearing to be lubricated is generally compared to oil lubrication in which lubrication is performed using lubricating oil supplied from the outside. It is excellent in that it can be simplified and foreign matter from the outside of the bearing can be suppressed, but there is a problem that it is difficult to cool the inside of the bearing and it is difficult to cope with high-speed rotation.

  On the other hand, oil lubrication can be actively cooled from the inside of the bearing by supplying lubricating oil at a relatively low temperature from the outside, whereby a sufficient lubricating oil film can be formed. Oil air / oil mist lubrication, which is one type of oil lubrication, has a feature that lubrication can be performed more efficiently because the lubricating oil can be conveyed into the bearing device by compressed air.

  By the way, oil-air / oil mist lubrication is performed via a nozzle that ejects lubricating oil together with air. However, there is a problem that wind noise (Z · Fc component) becomes conspicuous as the rotation increases due to the air ejected from the nozzle. For this reason, in oil-air / oil mist lubrication, attempts have been made to reduce noise by finely adjusting the position, shape, number, etc. of the nozzles, but sufficient noise reduction has not been achieved yet. Is the current situation.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a bearing device that can suppress noise such as wind noise and can be made more silent.

In order to achieve such an object, the bearing device according to the present invention provides:
In a bearing device having an inner ring, an outer ring, and a plurality of rolling elements rotatably disposed between the inner ring and the outer ring,
The outer peripheral surface of the inner ring extends outward in the axial direction from the end surface of the outer ring, and has a shape that expands toward the rolling element,
A lubricating oil supply member having a supply path for supplying lubricating oil to the outer peripheral surface together with air and an air pool formed in a supply port of the supply path is provided on the outer ring side,
In addition, an exhaust groove for reducing the pressure in the air reservoir is provided,
Lubricating oil that is jetted together with air from the supply path toward the air pool and is supplied to the outer circumferential surface of the inner ring is transmitted to the rolling element by centrifugal force along the outer circumferential surface. It is what.

  According to the results of research by the present inventors, wind noise in oil-air / oil mist lubrication is caused by the fact that the nozzle is directed from the side to the inside of the bearing and the lubricating oil is directly jetted into the bearing rotating at high speed. It was found that it occurred remarkably. However, if the nozzle is not directed to the inside of the bearing, the wind noise is reduced, but the amount of lubricating oil per unit time supplied to the inside of the bearing is also reduced, which causes a problem that efficient lubrication cannot be performed.

  On the other hand, according to the bearing device according to the present invention, the outer peripheral surface of the inner ring extends outward in the axial direction from the end surface of the outer ring and expands toward the rolling element, and is ejected together with air. The lubricating oil supplied to the outer peripheral surface of the inner ring is transmitted to the rolling element through the outer peripheral surface by centrifugal force, thereby maintaining the amount of lubricating oil supplied per unit time inside the bearing. However, wind noise can be reduced. The inner ring here includes, for example, a combination of an inner ring and an inner ring spacer arranged adjacent to the inner ring.

  Further, the bearing device has a supply path for supplying lubricating oil together with air to the outer peripheral surface, and if an air pool is formed at the supply port of the supply path, the bearing apparatus is provided inside the bearing. The air pressure can be relaxed, and wind noise can be further reduced.

  The bearing device has a supply path for supplying lubricating oil to the outer peripheral surface together with air, and an air vent path is formed in a space communicating with the supply port of the supply path. The air pressure applied to the inside can be relaxed, and wind noise can be further reduced. At this time, when an air pool is formed at the supply port of the supply path, it is preferable to shift the phase of the arrangement of the air vent path and the air pool.

  Further, the bearing device has a supply path for supplying lubricating oil together with air to the outer peripheral surface, and on the opposite side of the bearing device across the supply path, the lubrication supplied into the bearing device is provided. If the discharge means for discharging the oil is formed, the problem that air is stored inside the bearing can be solved.

  Further, when the bearing device has a supply path for supplying lubricating oil to the outer peripheral surface together with air, and a storage portion for storing the lubricating oil supplied from the supply path is formed, for example, at the time of startup Metal contact sound that is likely to occur and the lubricating oil film is thin can be alleviated, and bearing seizure can be avoided even when the lubricating oil to be supplied is not supplied due to some trouble.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an axial sectional view of a bearing device according to a first embodiment of the present invention. In FIG. 1, a bearing device 100 includes an outer ring 11 attached to a housing (not shown), an inner ring 12 fitted to a shaft (not shown), and a rolling element that is rotatably arranged between both wheels 11 and 12. An angular contact ball bearing 10 including a plurality of balls 13 and a retainer 14 for holding the balls 13, a lubricant supply member 15 attached to a housing (not shown) adjacent to the outer ring 11, and the inner ring 12. It is comprised from the bush 16 fitted to the axis | shaft not shown adjacently.

  The inner ring 12 has an outer peripheral surface 12 a that extends rightward from the right end (outer end) in FIG. 1 of the outer ring 11 and expands in diameter toward the inside of the angular contact ball bearing 10. On the other hand, the lubricating oil supply member 15 includes an introduction path 15a that opens radially outward so as to be connected to the air / lubricating oil supply source P, a supply path 15b having a smaller diameter than the introduction path 15a, and a lubricating oil supply member. 15 and an air reservoir 15c which is a circumferentially continuous groove opened around the supply port of the supply passage 15b. The air reservoir 15c is disposed at a position facing the right end (outer end) of the outer peripheral surface 12a of the inner ring 12 in the drawing. Adjacent to the angular contact ball bearing 10 side of the air reservoir 15c, a facing surface 15d is formed that faces the outer peripheral surface 12a of the inner ring 12 with a slight gap.

  The operation of the bearing device 100 will be described. When a shaft (not shown) rotates with respect to a housing (not shown), lubricating oil in which air is mixed is pumped from the air / lubricating oil supply source P. It is supplied to the supply path 15b via the introduction path 15a. Here, since the inner diameter of the supply passage 15b is narrowed, the lubricating oil is supplied in an appropriate amount according to the rotational speed of the inner ring 12.

  Lubricating oil ejected from the supply passage 15b passes through the space in the air reservoir 15c and adheres to the outer peripheral surface 12a of the inner ring 12. At this time, since the gap between the outer peripheral surface 12a and the opposing surface 15d of the lubricating oil supply member 15 is formed small, the lubricating oil ejected from the supply passage 15b is prevented from jumping directly into the angular contact ball bearing 10. This prevents noise. On the other hand, since the inner ring 12 is rotating, the lubricating oil adhering to the outer peripheral surface 12a is transmitted there by centrifugal force, reaches the raceway surface 12b of the inner ring 12, and adheres to the outer peripheral surface of the ball 13 for lubrication. It is like that. Note that the amount of lubricating oil supplied to the balls 13 increases or decreases according to the centrifugal force received by the balls 13, that is, the rotational speed of the inner ring 12, so that a relatively large amount of lubricating oil is supplied when the rotational speed is high. On the other hand, when a rotational speed is low, it is possible to suppress agitation resistance and consumption of the lubricating oil by supplying a relatively small amount of lubricating oil when the rotational speed is low.

  Furthermore, according to the present embodiment, since the air reservoir 15c is formed on the inner peripheral side of the lubricating oil supply member 15, the pressure fluctuation of the air supplied mixed with the lubricating oil from the supply passage 15b is reduced. it can. When the air reservoir 15c is not provided, the lubricating oil is forced out to the angular contact ball bearing 10 side through the gap between the outer peripheral surface 12a and the opposing surface 15d of the lubricating oil supply member 15 due to unadjusted air pressure. However, by providing the air reservoir 15c, transmission of the lubricating oil is limited only to the outer peripheral surface 12a of the inner ring 12, and more stable lubrication can be performed.

  The noise reduction effect of this embodiment will be described. FIG. 2 is a cross-sectional view showing a comparative example similar to the present embodiment but different in the shape of the inner ring and the form of lubrication. In the angular contact ball bearing 10 ′, the outer peripheral surface of the inner ring 12 ′ does not protrude from the right end (outward end) in the drawing from the bearing 11, and the lubricating oil supply member 15 ′ is connected to the air / lubricating oil supply source P. It has a connected nozzle 15a '. The lubricating oil sprayed from the nozzle 15 a ′ jumps directly into the angular contact ball bearing 10 ′ and adheres to the outer peripheral surface of the inner ring 12 and the surface of the ball 13 for lubrication.

  FIG. 3 is a diagram showing the frequency analysis result of noise when the comparative example of FIG. 2 and the embodiment of FIG. 1 are operated under the same conditions (20000 rpm), with the horizontal axis representing the frequency and the vertical axis. The axis takes the strength of the sound. As shown in FIG. 3A, in the case of the comparative example, wind noise is generated at 3627 Hz. On the other hand, in the present embodiment, as shown in FIG. 3B, it can be seen that there is no peak waveform at the same frequency, that is, the wind noise has disappeared. Thus, according to the present embodiment, it is possible to provide a bearing device that can achieve further noise reduction.

  FIG. 4 is a view similar to FIG. 1 showing the second embodiment. The bearing device 200 according to the embodiment shown in FIG. 4 differs from the embodiment of FIG. 1 only in the configuration of the lubricating oil supply member, and the other components are denoted by the same reference numerals and description thereof is omitted. To do.

  In FIG. 4, the lubricating oil supply member 25 has the same configuration as that of the above-described embodiment with respect to the introduction path 25a, the supply path 25b, the air pool 25c, and the opposing surface 25d. The difference is that the groove 25e is provided at the left end (bearing side end) in the drawing of the lubricating oil supply member 25 so as to communicate the inner and outer peripheries. The air exhaust groove 25e is preferably arranged 180 degrees out of phase around the axis with respect to the supply path 25b, and is therefore indicated by a dotted line in FIG.

  According to the present embodiment, the air jetted from the supply passage 25b to the air pool 25c is discharged to the outside through the exhaust groove 25e, so that the pressure of the air pool 25c can be lowered. it can. When the pressure in the air pool 25c increases, the lubricating oil between the outer peripheral surface 12a of the inner ring 12 and the opposing surface 25d of the lubricating oil supply member 25 is pressurized and jumps into the angular contact ball bearing 10, However, such noise can be suppressed by providing the exhaust groove 25e. The cross-sectional area, phase, and number of the exhaust groove 25e are appropriately determined depending on the design rotation speed of the bearing and the number of supply passages 25b. It is preferable.

  FIG. 5 is a view similar to FIG. 1 showing the third embodiment. The bearing device 300 which is the embodiment shown in FIG. 5 is also different from the embodiment shown in FIG. 1 only in the configuration of the lubricating oil supply member. To do.

  In FIG. 5, the lubricating oil supply member 35 has the same configuration as that of the above-described embodiment with respect to the introduction path 35a, the supply path 35b, the air pool 35c, and the facing surface 35d, but the air exhaust path is an air exhaust path. The positions of the holes 35e are different. That is, the exhaust hole 35e is arranged on the right side in the drawing (the side far from the angular contact ball bearing 10) from the introduction path 35a, and communicates the inner and outer periphery of the lubricating oil supply member 35.

  According to the present embodiment, since the air jetted from the supply path 35b to the air pool 35c is discharged to the outside through the exhaust hole 35e, the pressure of the air pool 35c can be reduced. it can. At this time, the air flow passes through the annular space between the bushing 16 and the lubricating oil supply member 35 communicating with the air from the supply passage 35b through the air pool 35c, and reaches the exhaust hole 35e. Therefore, it does not act to push out the lubricating oil between the outer peripheral surface 12a of the inner ring 12 and the opposing surface 35d of the lubricating oil supply member 35, thereby suppressing the generation of noise. The diameter, phase, and number of the exhaust holes 35e are determined as appropriate according to the design rotation speed of the bearing and the number of supply passages 35b. It is preferable.

  FIG. 6 is a view similar to FIG. 1 showing the fourth embodiment. The bearing device 400 according to the embodiment shown in FIG. 6 differs from the embodiment shown in FIG. 1 only in that an inner ring spacer and an outer ring spacer are provided. A description thereof will be omitted.

  The outer ring spacer 42 in the present embodiment has a simple short cylindrical shape, but the inner ring spacer 41 has an outer periphery in which the angular contact ball bearing 10 side is cut out and the cross section shown in the figure is cut into an arc shape. It has a surface 41a. The outer peripheral surface 41a, which is a discharging means, can rotate together with a shaft (not shown) to form a negative pressure region based on the so-called slinger effect and forcibly suck out the lubricating oil inside the angular contact ball bearing 10. As a result, the heat inside the angular contact ball bearing 10 can be actively removed, and the introduction of lubricating oil having a low temperature can be promoted, whereby the bearing can be efficiently cooled. The cut of the outer peripheral surface 41a may be a straight line instead of an arc shape in the cross section shown in the figure.

  FIG. 7 is a view similar to FIG. 5 showing the fifth embodiment. The bearing device 500 according to the embodiment shown in FIG. 7 is different from the embodiment of FIG. 5 only in the shape of the bush.

  In FIG. 7, a protruding portion 56 a that is continuous in the circumferential direction is formed on the outer periphery of the bush 56 at a position away from the inner ring 12. Therefore, the lubricating oil ejected from the supply path 35b of the lubricating oil supply member 35 is stored in a storage portion formed between the inner peripheral surface 35f of the lubricating oil supply member 35 and the outer peripheral surface 56b of the bush 56, This is maintained even when the bearing device 500 is stationary. The lubricating oil stored in this way is immediately after the start of the bearing device 500, and the rotation of the outer peripheral surface 12a of the inner ring 12 even under a situation where the amount of lubricating oil ejected from the supply passage 35b is not sufficient. Since it is immediately supplied toward the angular contact ball bearing 10 based on the centrifugal force, it is effective in suppressing seizure. In addition, when the exhaust groove 35e is provided in the vicinity of the raised portion 56a, an effect of efficiently discharging air during the operation of the bearing device 500 can be expected.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, in the above-described embodiments, the lubricating oil supply member is provided with an air pool, but the air pool is not necessarily an essential configuration, and air and lubricating oil at a relatively constant and low pressure are provided. In the case of being supplied, the supply path 65b may be directly opposed to the outer peripheral surface 12a of the inner ring 12 without providing an air reservoir as in the lubricating oil supply member 65 shown in FIG. Further, the inner ring is not necessarily formed of a single member. As shown in FIG. 9, the inner ring member 72 having only a raceway surface and the inner ring member 77 having a tapered outer peripheral surface 77a are used in the present invention. The inner ring may be formed.

  According to the bearing device of the present invention, the outer peripheral surface of the inner ring extends outward in the axial direction from the end surface of the outer ring, and has a shape that increases in diameter toward the rolling element, and is ejected together with air. By supplying the lubricating oil supplied to the outer peripheral surface of the roller to the rolling elements by being transmitted through the outer peripheral surface by centrifugal force, while maintaining the amount of lubricating oil per unit time supplied to the inside of the bearing, The sound can be reduced.

1 is an axial sectional view of a bearing device according to a first embodiment of the present invention. Although it is similar to this Embodiment, it is sectional drawing which shows the comparative example from which the form of an inner ring | wheel differs from the form of lubrication. It is a figure which shows the frequency analysis result of the noise when operating the comparative example of FIG. 2 and embodiment of FIG. 1 on the same conditions (20000 rotation / min). It is a figure similar to FIG. 1 which shows 2nd Embodiment. It is a figure similar to FIG. 1 which shows 3rd Embodiment. It is a figure similar to FIG. 1 which shows 4th Embodiment. It is a figure similar to FIG. 5 which shows 5th Embodiment. It is a figure similar to FIG. 1 which shows the modification of this Embodiment. It is a figure similar to FIG. 1 which shows the modification of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Angular contact ball bearing 11 Outer ring 12 Outer ring bush 13 Ball 14 Cage 15, 25, 35, 65 Lubricating oil supply member 16, 56 Bush

Claims (4)

In a bearing device having an inner ring, an outer ring, and a plurality of rolling elements rotatably disposed between the inner ring and the outer ring,
The outer peripheral surface of the inner ring extends outward in the axial direction from the end surface of the outer ring, and has a shape that expands toward the rolling element,
A lubricating oil supply member having a supply path for supplying lubricating oil to the outer peripheral surface together with air and an air pool formed in a supply port of the supply path is provided on the outer ring side,
In addition, an exhaust groove for reducing the pressure in the air reservoir is provided,
Lubricating oil that is jetted together with air from the supply path toward the air pool and is supplied to the outer circumferential surface of the inner ring is transmitted to the rolling element by centrifugal force along the outer circumferential surface. Bearing device. The bearing device according to claim 1, wherein the supply path and the exhaust groove are arranged out of phase.   The bearing device according to claim 1, wherein a discharge unit that discharges the lubricating oil supplied into the bearing device is formed on the opposite side of the bearing device across the supply path.   The bearing device according to any one of claims 1 to 3, wherein a storage portion for storing lubricating oil supplied from the supply path is formed.

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