JP6623964B2 - Oil lubricated bearing device and vacuum pump - Google Patents

Description

  The present invention relates to an oil-lubricated bearing device and a vacuum pump.

  In a high-speed rolling bearing, it is required that the lubrication of the rolling surface is maintained by continuously supplying a small amount of lubricating oil, and that the lubricating oil is prevented from adhering to the rolling surface more than necessary. If more lubricating oil than necessary for lubrication adheres to the rolling surface, agitation resistance of the lubricating oil is generated, causing heat generation.

  As a method of lubricating rolling bearings in a vacuum pump, a method as described in Patent Document 1 has been proposed. In the rolling bearing described in Patent Literature 1, a tapered cone-shaped member is provided on a shaft that rotates together with the inner ring, and a felt-shaped member provided in a lubricating storage device is brought into contact with the tapered cone-shaped surface, and centrifugal force is applied. A structure for supplying lubricating oil to the inner ring is employed. The lubricating oil is supplied from the rolling surface of the inner ring (also referred to as a raceway surface) to the rolling surface of the outer ring via the rolling elements (balls), and excess lubricating oil overflowing from the rolling surface of the outer ring is supplied to the lubrication storage device. It is configured to return.

Japanese Patent No. 5303137

  However, since the excess lubricating oil that overflows from the rolling surface is returned to the lubrication storage device, when the lubricating oil overflows, there is more lubricating oil than is required for lubrication on the rolling surface. And the generation of stirring resistance is inevitable.

An oil-lubricated bearing device according to a preferred embodiment of the present invention includes an inner ring, an outer ring, a rolling element, and a retainer for maintaining a spacing between the rolling elements, a rolling bearing that supports a rotating shaft, and the inner ring being fixed. A tapered member provided on a rotating shaft and having a first inclined surface having an upward slope (inclined to increase the radius of rotation) toward the inner ring; and the tapered member provided on the inner ring. A lubricating oil storage unit disposed on the outer side, and a contact unit that contacts the tapered surface and supplies the lubricating oil of the lubricating oil storage unit to the first inclined surface. A pocket having an inner ring side opening and holding the rolling element, a lubricating oil scraper formed on the inner peripheral surface of the pocket and scraping lubricating oil attached to the surface of the rolling element, and the outer ring Formed on the inner peripheral surface along the side opening , And a second inclined surface of the upward gradient toward the lubricating oil reservoir.
In a further preferred embodiment, the lubricating oil scraping portion includes a plurality of protrusions formed in a circumferential direction in a region of the inner peripheral surface on the side of the outer ring side opening.
In a further preferred embodiment, a projection protruding from the inclined surface is formed on the second inclined surface.
In a further preferred embodiment, the tapered member is an inner ring fixing member that is detachably provided on the rotating shaft and fixes the inner ring to the rotating shaft.
In a further preferred embodiment, a lubricating oil that is disposed closer to the outer ring than the retainer and contacts the lubricating oil storage unit and the outer ring to guide the lubricating oil scattered from the second inclined surface to the lubricating oil storage unit. A guide unit is provided.
An oil-lubricated bearing device according to a preferred embodiment of the present invention includes an inner ring, an outer ring, a rolling element, and a retainer for maintaining a spacing between the rolling elements, a rolling bearing that supports a rotating shaft, and the inner ring being fixed. A tapered member provided on a rotating shaft and having a first inclined surface having an upward slope toward the inner ring; a lubricating oil storage unit disposed on a side provided with the tapered member with respect to the inner ring; A contact portion that contacts the first inclined surface to supply the lubricating oil of the lubricating oil storage portion to the first inclined surface, and wherein the retainer penetrates from the retainer inner peripheral surface to the retainer outer peripheral surface. A pocket for holding the rolling element, a second inclined surface formed on the outer peripheral surface of the retainer, the distance from the axis increases as approaching the lubricating oil storage portion, and an inner peripheral surface of the retainer. At a distance from the lubricant reservoir. A third slope having a downward slope whose distance from the axis increases increases, and is formed at an end of the cage opposite to the lubricating oil storage unit, and connects the second slope and the third slope. A connection surface.
In a further preferred embodiment, a projection is formed on the second inclined surface so as to extend between the pair of adjacent pockets and extend from the side of the connection surface in the direction of the lubricating oil storage portion in a peak-like manner. ing.
In a further preferred embodiment, at least one portion of the pocket penetrates from the inner ring side opening having a closed periphery to the outer ring side opening having a closed periphery.
In a further preferred embodiment, the retainer is integrated by combining two or more members.
A vacuum pump according to a preferred embodiment of the present invention includes the oil-lubricated bearing device described above and a pump rotor provided with the rotating shaft.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of stirring resistance can be suppressed.

FIG. 1 is a sectional view of a turbo-molecular pump. FIG. 2 is an enlarged view of a portion of the oil-lubricated bearing device. FIG. 3 is a perspective view showing the external shape of the cage. FIG. 4 is a diagram illustrating the movement of the rolling elements and the retainer. FIG. 5 is a diagram illustrating a lubricating oil circulation path. FIG. 6 is a diagram illustrating a specific example of the shape of the scraping portion. FIG. 7 is a diagram illustrating a modified example of the scraping unit. FIG. 8 is a diagram illustrating a third modification of the scraping unit. FIG. 9 is a diagram illustrating the protrusion formed on the tapered surface. FIG. 10 is a diagram illustrating another example of the inclined surface formed on the retainer. FIG. 11 is a diagram showing another example of the lubricating oil guide. FIG. 12 is a diagram illustrating an oil-lubricated bearing device according to the second embodiment. FIG. 13 is an exploded perspective view of the retainer. FIG. 14 is a diagram illustrating the surface shape of the cage. FIG. 15 is a diagram illustrating the retainer when the upper side of the pocket in the retainer axial direction is open. FIG. 16 is a diagram illustrating a modification of the second embodiment.

Hereinafter, embodiments for implementing the present invention will be described with reference to the drawings.
-1st Embodiment-
FIG. 1 is a view showing one embodiment of an oil-lubricated bearing device according to the present invention, and is a cross-sectional view of a turbo-molecular pump 1 equipped with the oil-lubricated bearing device. A power supply unit for supplying electric power is connected to the turbo molecular pump 1, but is not shown in FIG.

  The turbo molecular pump 1 shown in FIG. 1 includes, as exhaust function units, a turbo pump unit P1 having turbine blades and a Holweck pump unit P2 having a spiral groove. Of course, the present invention is not limited to the vacuum pump having the turbo pump section P1 and the Holweck pump section P2 in the exhaust function section, but may be a vacuum pump having only turbine blades or only a drag pump such as a Siegbahn pump or a Holweck pump. The present invention can also be applied to a vacuum pump provided with the vacuum pump and a vacuum pump combining them.

  The turbopump section P1 includes a plurality of stages of rotating blades 30 formed on the pump rotor 3 and a plurality of stages of stationary blades 20 arranged on the base 2 side. On the other hand, the Holweck pump section P2 provided on the exhaust downstream side of the turbo pump section P1 includes a cylindrical section 31 formed on the pump rotor 3 and a stator 21 arranged on the base 2 side. A spiral groove is formed on the inner peripheral surface of the cylindrical stator 21. The plurality of stages of the rotating blades 30 and the cylindrical portion 31 constitute a rotating side exhaust function unit, and the plurality of stages of the fixed blades 20 and the stator 21 constitute a fixed side exhaust function unit.

  The pump rotor 3 is fastened to a shaft 10, and the shaft 10 is driven to rotate by a motor 4. For example, a DC brushless motor is used as the motor 4, a motor stator 4b is provided on the base 2, and a motor rotor 4a is provided on the shaft 10 side. The rotating unit R including the shaft 10 and the pump rotor 3 is rotatably supported by a permanent magnet magnetic bearing 6 using permanent magnets 6a and 6b and a ball bearing 8 as a rolling bearing.

  The permanent magnets 6a and 6b are ring-shaped permanent magnets magnetized in the axial direction. The plurality of permanent magnets 6a provided on the pump rotor 3 are arranged in the axial direction such that the same poles face each other. On the other hand, the fixed permanent magnets 6 b are mounted on a magnet holder 11 fixed to the pump casing 12. A plurality of these permanent magnets 6b are also arranged in the axial direction so that the same poles face each other. The axial position of the permanent magnet 6a provided on the pump rotor 3 is set to be slightly higher than the position of the permanent magnet 6b disposed on the inner peripheral side. That is, the magnetic pole of the rotating permanent magnet is axially displaced by a predetermined amount from the magnetic pole of the fixed permanent magnet. The supporting force of the permanent magnet magnetic bearing 6 varies depending on the predetermined amount. In the example shown in FIG. 1, since the permanent magnet 6a is disposed on the upper side in the figure, the support force in the radial direction and the upward direction in the axial direction (pump exhaust port side direction) are generated by the repulsive force of the permanent magnet 6a and the permanent magnet 6b. ) Is acting on the rotator unit R.

  A bearing holder 13 that holds the ball bearing 9 is fixed to the center of the magnet holder 11. Although deep groove ball bearings are used for the ball bearings 8 and 9 in FIG. 1, the present invention is not limited to this. For example, angular contact bearings may be used. The ball bearing 9 functions as a touch-down bearing that limits the radial deflection of the upper part of the shaft. In a steady rotation state, the shaft 10 and the ball bearing 9 do not come into contact with each other, and when a large disturbance is applied, or when the whirling of the shaft 10 becomes large at the time of acceleration or deceleration of rotation, the shaft 10 Touch 9

  The ball bearing 8 is held by a bearing holder 114 that is bolted to the base 2. A ring-shaped radial damper 116 is provided on the outer peripheral side of the ball bearing 8. An elastomer such as rubber is used as a material of the radial damper 116. The ball bearing 8 is an oil-lubricated rolling bearing and includes a wick 101 serving as a lubricating oil storage unit for supplying lubricating oil to the ball bearing 8. The wick 101 is held between the bearing holder 114 and the lower lid 15.

  FIG. 2 is an enlarged view of a portion of the oil-lubricated bearing device 100 including the ball bearing 8, the wick 101, and the like. The ball bearing 8 has an inner ring 82 fixed to the shaft 10 by a cone-shaped nut 102 functioning as a tapered member. The cone-shaped nut 102 is detachably provided at a lower end of the shaft 10 on which a male screw is formed. The outer ring 81 of the ball bearing 8 is fixed to a bearing holder 114 by a bearing retainer 103. The rolling elements 83 are held by a holder 84.

  The outer peripheral surface of the cone-shaped nut 102 is a tapered surface 102a that tapers from the side that comes into contact with the inner ring 82 of the ball bearing 8 toward the tip. That is, the tapered surface 102a is an inclined surface having an upward slope toward the inner ring 82. A contact portion 101a protruding inward is formed on the inner peripheral surface of the ring-shaped wick 101, and the contact portion 101a is in contact with the tapered surface 102a of the cone nut 102. The wick 101 is formed of a felt-like or sponge-like member capable of holding the lubricating oil, and holds the lubricating oil. A circular pipe member 104 is provided between the outer ring 81 of the ball bearing 8 and the wick 101 so as to contact them. The circular pipe member 104 is a member that transmits the lubricating oil of the outer race 81 to the wick 101 by utilizing the capillary phenomenon. For example, a porous body may be formed on the inner peripheral surface of a circular tube, a fibrous material such as felt may be used, or a porous material such as sponge or sintered metal may be used. It may be.

  FIG. 3 is a perspective view showing an external shape of the retainer 84. A plurality of pockets 840 for holding the rolling elements 83 are formed in the retainer 84. The retainer 84 shown in FIG. 3 is a crown type retainer, and the pocket 840 is a through hole in which a part of the retainer 84 on the upper side in the axial direction is opened. In this embodiment, a crown type cage will be described as an example, but the present invention is not limited to this type of cage.

  A tapered surface 841 is formed on the outer peripheral surface of the retainer 84 so as to be adjacent to the outer ring side opening 840c of the pocket 840. As shown in the cross-sectional view of FIG. 2, the tapered surface 841 becomes closer to the end 840 e (see FIG. 3) of the cage 84 on the side of the lubricating oil storage section (wick 101) (see FIG. 3). ). That is, the tapered surface 841 is formed on the outer peripheral surface of the cage adjacent to the outer ring side opening 840c, and is an inclined surface having an upward slope toward the wick 101. The outer peripheral surface below the lower end 841 a of the tapered surface 841 is a tapered surface 842 having a reduced radius, and the lower end 841 a of the tapered surface 841 is the outermost diameter of the retainer 84.

  In addition, a scraping portion 840b for scraping the lubricating oil attached to the surface of the rolling element 83 is formed on the inner peripheral surface 840a of the pocket 840. Note that the scraping portion 840b has a minute uneven shape, and FIG. 3 shows a range in which the scraping portion 840b is formed by a dotted line (the same applies to FIG. 4 described later). The specific shape of the scraping section 840b will be described later.

  FIG. 4 is a diagram illustrating the movement of the rolling element 83 and the retainer 84 when the ball bearing 8 rotates. FIG. 4A is a plan view, and FIG. The rolling element 83 is in contact with the rolling surface 82a of the inner race 82 and the rolling surface 81a of the outer race 81. When the inner ring 82 rotates counterclockwise as indicated by an arrow R1, the rolling element 83 revolves counterclockwise while rotating clockwise. When the rolling element 83 revolves counterclockwise, the retainer 84 also rotates counterclockwise so as to be pushed by the rolling element 83. The scraping portion 840b formed on the inner peripheral surface 840a of the pocket 840 is formed on the inner peripheral surface 840a on the revolving direction side. In FIG. 4, similarly to FIG. 3, a broken line denoted by reference numeral 840b indicates a range in which the scraping portion 840b is formed.

  As described above, the rolling element 83 that revolves in the R1 direction rotates in the R2 direction while abutting on the inner peripheral surface 840a of the retainer 84 on the side where the scraping portion 840b is formed. Therefore, a part of the lubricating oil adhering to the surface of the rolling element 83 is scraped off by the scraping unit 840b. Since the retainer 84 is rotating in the R1 direction at a high speed, centrifugal force acts on the scraped lubricating oil, so that the lubricant passes through the gap between the rolling element 83 and the inner peripheral surface 840a of the retainer 84 and the outer peripheral side. Move to The retainer 84 is rotating at half the angular velocity of the inner ring 82 in the R1 direction. As long as the rolling element 83 rotates by rolling without slipping, the inner ring contact point of the rolling element 83 has the same angular velocity as the shaft (shaft 10), and the angular velocity is zero at the outer ring contact point. Becomes the half angular velocity of the inner ring 82.

  FIG. 5 is a diagram illustrating a lubricating oil circulation path. An arrow R3 indicates a movement path (circulation path) of the lubricating oil. As described above, the lubricating oil is stored in the wick 101. When the contact portion 101a formed on the wick 101 contacts the tapered surface 102a of the cone nut 102, the lubricating oil of the contact portion 101a adheres to the tapered surface 102a. The tapered surface 102 a is a tapered surface whose diameter increases as it approaches the inner ring 82 from the tip of the cone-shaped nut 102, that is, a tapered surface that slopes upward toward the inner ring 82. Therefore, when the cone type nut 102 rotates at a high speed integrally with the shaft 10, the lubricating oil on the tapered surface 102a moves in a direction with a larger radius due to the action of the centrifugal force. That is, the lubricating oil moves on the tapered surface 102a in the direction of the inner ring 82 as indicated by the arrow R3.

  The lubricating oil that has moved from the tapered surface 102a to the inner race 82 enters the rolling surface 82a of the inner race 82, lubricates the rolling surface 82a, and adheres to the rolling elements 83. When the rolling element 83 with the lubricating oil rotates, as described above, part of the lubricating oil attached to the rolling element 83 is scraped off by the scraping portion 840b formed on the retainer 84. When the scraped lubricating oil moves to the tapered surface 841 formed on the outer peripheral side of the retainer 84, the lubricating oil moves on the tapered surface 841 to the lower side in the drawing (wick side) having a larger diameter due to centrifugal force. When the lubricating oil that has moved downward on the tapered surface 841 reaches the lower end 841a, the lubricating oil is scattered by centrifugal force and adheres to the inner peripheral surface of the outer ring 81 and the circular pipe member 104.

  As described above, the circular tube member 104 is a member that guides the lubricating oil scattered toward the inner peripheral surface of the outer ring 81 or this surface to the wick 101 by utilizing the capillary phenomenon. The lubricating oil scattered from the retainer 84 can be returned to the wick 101 without being affected by the mounting posture of the wick 101. As described above, the lubricating oil is supplied from the wick 101 to the ball bearing 8 and collected from the ball bearing 8 to the wick 101.

  By the way, in the case of a conventional cage without the scraping portion 840b, the lubricating oil supplied to the rolling surface 82a of the inner race 82 moves to the rolling surface 81a of the outer race 81 by the rotation of the rolling element 83. The lubricating oil on the rolling surface 81a of the outer ring 81 also adheres to the rotating rolling element 83 and moves to the inner ring side. However, since the inner ring 82 and the retainer 84 of the ball bearing 8 are rotating at high speed, the lubricating oil is Lubricating oil tends to accumulate on the outer ring side due to the acting centrifugal force. As a result, the lubricating oil tends to be excessive on the rolling surface 81a of the outer race 81, and heat generation due to generation of stirring resistance becomes a problem.

  On the other hand, in the present embodiment, a part of the lubricating oil adhered to the rolling element 83 by the scraping portion 840b, particularly when the amount of the lubricating oil increases and the oil film thickness formed on the surface of the rolling element 83 increases. Accordingly, the scraping is performed accordingly, so that the lubricating oil on the rolling surface 81a of the outer race 81 can be prevented from being excessive, and the generation of stirring resistance can be reduced.

  Further, since the outer peripheral surface of the retainer 84 is formed with a tapered surface 841 having a shape that expands toward the wick side (that is, an upward slope toward the wick side), the lubricating oil scraped off by the scraping portion 840b does not have centrifugal force. The action moves the tapered surface 841 to the wick side. The lubricating oil that has moved to the wick side scatters from the lower end 841a of the tapered surface 841 and is eventually collected by the wick 101.

(Specific shape of scraping part 840b)
FIG. 6 is a diagram illustrating a specific example of the shape of the scraping unit 840b. FIG. 6A is a diagram illustrating a part of the retainer 84, that is, a part of the pocket 840 where the scraping portion 840b is formed. FIG. 6B is a diagram showing the inner peripheral surface 840a in which the scraping portion 840b is formed and developed in a planar shape. The circle indicated by the two-dot chain line indicates the rolling element 83. Although the inner peripheral surface 840a of the pocket 840 is curved according to the spherical surface of the rolling element 83, FIG. 6B shows the curved inner peripheral surface 840a in a plan view.

  In the example shown in FIG. 6, the scraping portion 840b has a plurality of elongated convex portions 843 having a rectangular cross section arranged in the circumferential direction of the inner peripheral surface 840a at intervals. In FIG. 6A, illustration of a part of the plurality of convex portions 843 is omitted. The extending direction (longitudinal direction) of the convex portion 843 is a direction substantially orthogonal to the axial direction of the retainer 84. The plurality of projections 843 are arranged along the edge of the inner peripheral surface 840a in the circumferential direction of the outer ring side opening 840c. The rolling element 83 rotates in a direction orthogonal to the axial direction as shown by a broken arrow R2. A dashed line indicated by reference numeral 830 is a line corresponding to the so-called equator of the rolling element 83 that rotates, and the moving speed of the surface of the rolling element in the rotational direction is the highest near the equator, and decreases as the distance from the equator increases. Therefore, the plurality of convex portions 843 are arranged vertically above and below the line 830 so that the lubricating oil can be effectively scraped off.

  The lubricating oil 90 scraped off by the protrusions 843 of the scraping portion 840b creates a gap 844 between the protrusions 843 by viscous force between the rolling element surface and the lubricating oil 90 and centrifugal force acting on the lubricating oil. Then, it moves to the tapered surface 841 side. The lubricating oil 90 that has moved to the tapered surface 841 moves in a direction in which the diameter of the tapered surface 841 is larger (downward in the figure) due to centrifugal force. As shown in FIG. 5, the wick 101 is arranged on the lower side in the figure. Although the groove depth of the gap 844 may be constant as shown in FIG. 6, the groove depth is set to be deeper toward the tapered surface 841 so as to cope with the case where the amount of lubricating oil scraped increases. May be.

  FIG. 7 is a diagram showing a modification of the scraping unit 840b shown in FIG. In the configuration shown in FIG. 6, a plurality of protrusions 843 arranged vertically in the figure are arranged along the right end (outer ring side opening 840c) of the inner peripheral surface 840a along the tapered surface 841. On the other hand, in the first modified example shown in FIG. 7A, a plurality of convex portions 843 are arranged along the axial direction of the retainer 84. However, if the distance between the convex portion 843 and the tapered surface 841 is too large, the lubricating oil that has moved to the right in the drawing through the gap 844 may not adhere to the tapered surface 841 but adhere to the rolling elements 83 again. Therefore, as shown in FIG. 6, it is preferable to dispose the convex portion 843 close to the tapered surface 841.

  FIG. 7B is a diagram showing a second modification of the scraping portion 840b, and shows a case where the cross-sectional shape of the convex portion 843 is a triangle. Strictly speaking, the rolling element 83 and the inner peripheral surface 840a of the pocket 840 do not come into contact with each other on the entire curved surface, but generally at the equator portion (the part indicated by reference numeral 830 in FIG. 6) of the rolling element 83 which rotates. It is in contact with the inner peripheral surface 840a. Therefore, when the convex portion 843 is provided only in the region corresponding to the equator portion, when the rolling element 83 and the inner peripheral surface 840a relatively move in the axial direction (vertical direction in the drawing), the lubricating oil generated by the convex portion 843 Is insufficiently scraped. For this reason, in the present embodiment, the convex portion 843 is arranged not only in the central position corresponding to the equator portion but also in a region vertically displaced from the central position.

  FIG. 8 shows a third modification of the scraping section, and FIG. 8B is a cross-sectional view taken along the line CC. In the third modification, a hemispherical convex portion 843b is formed. In the example shown in the developed view of FIG. 8A, a plurality of convex portions 843b arranged along the inner peripheral surface 840a are arranged in two rows in the rotation direction R2 of the rolling element 83. The number of rows in the rotation direction R2 is not limited to two, but may be one row as shown in FIG. 8C or three or more rows.

  Note that the shape of the scraping portion 840b is not limited to the configuration shown in FIGS. 6 to 8, and various shapes are possible.

According to the above-described embodiment, the following operation and effect can be obtained.
(1) The oil-lubricated bearing device 100 is provided on the shaft 10 to which the inner ring 82 is fixed, and includes a cone-shaped nut 102 which is a tapered member having a tapered surface 102 a having an upward slope toward the inner ring 82. The wick 101 includes a wick 101 disposed on the side where the cone nut 102 is provided, and a contact portion 101a that contacts the tapered surface 102a and supplies the lubricating oil of the wick 101 to the tapered surface 102a. As shown in FIG. 3, the retainer 84 is formed on a pocket 840 having an outer ring side opening 840c and an inner ring side opening 840d to hold the rolling element 83 and an inner peripheral surface 840a of the pocket 840. It has a scraping portion 840b for scraping the lubricating oil attached to the surface of the moving body 83, and a tapered surface 841 formed on the outer peripheral surface of the cage adjacent to the outer ring side opening 840c and having an upward slope toward the wick 101.

  By providing the scraper 840b in the retainer 84 in this way, it is possible to suppress the lubricating oil moving from the rolling element 83 to the rolling surface 81a of the outer race 81. As a result, it is possible to prevent the lubricating oil from becoming excessive on the rolling surface 81a of the outer race 81, and to suppress heat generation due to stirring resistance. In particular, in a pump operated by changing the rotation speed according to the exhaust load, the amount of the lubricating oil transported by the cone-shaped nut 102 also fluctuates. At the maximum rotation speed, the transport liquid amount becomes more than necessary at the maximum rotation speed, but the temperature rise due to the stirring resistance becomes remarkable. Therefore, ensuring the amount of scraping even when the rotation speed is high is an important factor for maintaining rotation. However, when the rotation speed is high, the rolling element 83 is attached to the scraping portion 840b of the retainer 84. This is convenient because the number of contact increases.

  Further, since the tapered surface 841 having an upward slope toward the wick 101 is formed on the outer peripheral surface of the cage adjacent to the outer ring side opening 840c of the pocket 840, the lubrication that is scraped off by the scraping portion 840b and adheres to the tapered surface 841 is formed. The oil moves in the direction of the wick 101 and scatters. As a result, the lubricating oil discharged from the ball bearing 8 as extra lubricating oil is collected by the wick 101, and a lubricating oil circulation system capable of supplying and collecting the lubricating oil can be configured.

  Further, in a configuration in which the lubricating oil is discharged in a different direction from the lubricating oil storage unit as in the device described in Patent Literature 1, a path for returning the discharged lubricating oil to the lubricating oil storage unit is formed on the pump base side. This necessitates a complicated configuration and increases costs. However, in the above-described embodiment, the lubricating oil scraped from the retainer 84 in which the scraping portion 840b is formed is discharged to the lubricating oil storage unit (wick 101) side. There is no need to form complicated routes.

  In addition, in the cage 84 shown in FIG. 3, the tapered surface 841 is formed over one circumference of the outer peripheral surface of the cage 84. However, as shown in FIG. 10, only the peripheral outer peripheral surface adjacent to the outer ring side opening 840 c of the pocket 840 may be an inclined surface (taper surface 841) having an upward slope toward the wick 101.

  Further, in the example shown in FIG. 3, the scraping portion 840b is formed in a region where the rotation direction R2 is from the inner ring side to the outer ring side in the inner peripheral surface 840a. The reason is that, as shown in FIG. 4B, when the inner race 82 rotates in the R1 direction, the rolling elements 83 generally come into contact with this area. However, when the inner ring 82 rotates in the R1 direction, the rolling element 83 does not always contact the side where the scraping portion 840b is formed in FIG. There are also rolling elements 83 that are moving. Therefore, as shown in FIG. 9, not only the inner peripheral surface 840a on the side of the rotation direction R1 (the rotation direction of the holder 84 at the time of the forward rotation) but also the inner peripheral surface 840a on the opposite side to the rotation direction R1 are scraped off. The portion 840b may be formed.

(2) As shown in FIG. 6, for example, the scraping portion 840b for scraping the lubricating oil includes a plurality of protrusions 843 formed in a region on the inner peripheral surface 840a on the side of the outer ring side opening 840c in a circumferential direction. Is provided. By forming the convex portion 843 of the scraping portion 840b in the region on the outer ring side opening 840c side, the scraped lubricating oil effectively moves to the tapered surface 841. Further, the rolling element 83 has a plurality of convex portions 843 formed so as to be aligned in the circumferential direction since a region centered on the axial center portion thereof is in contact with the rolling surfaces 81a and 82a of the outer ring 81 and the inner ring 82. Thus, the lubricating oil attached to the rolling elements 83 can be efficiently scraped off. In addition, the shape of the scraping portion 840b is not limited to the configuration illustrated in FIGS.

(3) Further, as shown in FIG. 9, a protrusion 845 may be formed on the tapered surface 841. In the example shown in FIG. 9, a protrusion 845 is formed at the end of the tapered surface 841 on the wick 101 side. The protrusion 845 has inclined surfaces 845a and 845b, and has a sharp top 845c on the side closest to the wick 101 (the lower end in the figure). The lubricating oil 90 scraped off by the scraping portion 840b and attached to the tapered surface 841 moves down the tapered surface 841 as shown by, for example, an arrow D by the action of the centrifugal force and rises up the slopes 845a, 845b of the projection 845 to the top. Move to 845c. Such lubricating oil adhering to the top 845c is more likely to scatter than lubricating oil adhering to the surface. Although the top 845c is sharp in the example shown in FIG. 9, it does not have to be sharp.

  As a place where the projection 845 is formed, a region where the lubricating oil scraped off by the scraping portion 840b is easy to collect is preferable, for example, on the tapered surface 841 close to the scraping portion 840b and the largest diameter of the tapered surface 841. It is good to form in the end area which became large.

(4) As shown in FIG. 5, lubrication that is disposed on the outer peripheral side of the outer peripheral surface of the cage 84 and contacts the wick 101 and the outer ring 81 and guides the lubricating oil scattered from the tapered surface 841 to the wick 101. It is preferable to include a circular pipe member 104 as an oil guide. By providing such a tubular member 104, the lubricating oil scattered from the tapered surface 841 can be reliably collected on the wick 101. As a result, it is possible to reliably collect the lubricating oil in the wick 101 even when the pump is used in a horizontal posture or an inverted posture, regardless of the pump posture.

  Although the circular pipe member 104 shown in FIG. 5 is configured to reach the inner peripheral surface of the outer ring 81, the lower end surface of the outer ring 81 contacts the wick 101 as shown in FIG. The pipe member 104 may be provided so as to perform the operation. Further, as shown in FIG. 11B, a bearing retainer 106 may be provided below the outer ring 81, and the bearing retainer 106 may be formed of a porous material such as a sintered metal. Alternatively, a metal plate subjected to porous electrolytic plating may be used as the bearing retainer 106. The lubricating oil is guided to the wick 101 by the porous electrolytic plating layer.

  In the case of applying the porous electrolytic plating, if a porous electrolytic plating layer is formed on the base portion interposed between the outer ring 81 and the wick 101 in the configuration shown in FIG. It can be used as a guide.

-2nd Embodiment-
By the way, in a bearing rotating at a high speed, the moving speed of the rolling element becomes extremely high. Then, depending on conditions at that time, the amount of lubricating oil jumped up by the rolling elements from the rolling surface of the inner ring may be larger than the amount of lubricating oil adhering to the rolling elements. Since the centrifugal force acts on the rolling surface of the inner ring, the passage of the rolling element becomes a trigger, especially when there is a portion near the end of the groove of the rolling surface where the lubricating oil is a little more than others. Such a phenomenon is likely to occur. If the lubricating oil jumped up by the rolling elements adheres to the inner peripheral surface of the outer ring, the amount of lubricating oil on the outer ring rolling surface may become excessive.

  In the second embodiment, an oil lubricated bearing device that can effectively prevent excess lubricating oil on the outer race side rolling surface due to such splashed lubricating oil will be described. FIG. 12 is a sectional view showing an oil-lubricated bearing device 100 according to the second embodiment. FIG. 12 is a cross-sectional view of a portion similar to FIG. 5 described above. The oil-lubricated bearing device 100 includes a ball bearing 8, a cone-shaped nut 102 having a tapered surface 102a, a wick 101 having a contact portion 101a, and a circular pipe member 104.

  In the second embodiment, the cone nut 102, the wick 101, and the circular pipe member 104 have the same configuration as the corresponding members of the first embodiment described above, and the configuration of the cage 84 of the ball bearing 8 is described. Are different from the first embodiment.

  FIG. 13 is an exploded perspective view of the retainer 84. The retainer 84 is composed of two parts (84a, 84b). Hereinafter, these two parts will be referred to as a lower holder 84a and an upper holder 84b. The lower holder 84a and the upper holder 84b can be made of various materials, and are formed of, for example, a synthetic resin material such as polyimide.

  A through hole 847a is formed on one of a pair of surfaces where the lower retainer 84a and the upper retainer 84b are in contact with each other, and a snap-fit type coupling portion 847b is formed on the other surface. In the example shown in FIGS. 12 and 13, a through hole 847a is formed in the contact surface 846 of the lower retainer 84a, and a coupling portion 847b is formed in the contact surface 846 (not shown) of the upper retainer 84b. . By coupling the coupling portion 847b to the through hole 847a, the lower retainer 84a and the upper retainer 84b are integrated.

  In the examples shown in FIGS. 12 and 13, the retainer 84 has a configuration in which two parts are combined and integrated. However, one piece may be integrated, or three or more parts may be integrated and integrated. Is also good. Further, the coupling structure is not limited to the snap-fit method as shown by the coupling portion 847b and the through hole 847a, and various methods can be used.

  FIG. 14 is a diagram illustrating the surface shape of the retainer 84. The outer peripheral surface of the retainer 84 facing the outer ring 81, that is, the outer peripheral surfaces of the integrated lower retainer 84a and upper retainer 84b are tapered surfaces having the same shape as the first embodiment. 841 are formed. That is, the distance from the axis J of the retainer 84 increases as the taper surface 841 approaches the wick 101 serving as the lubricating oil storage portion, and is a slope inclined upward toward the wick 101. At the lower end of the tapered surface 841 of the lower retainer 84a, a ring-shaped projection 841b projecting outward from the tapered surface 841 is formed.

  On the other hand, on the inner peripheral surface of the retainer 84 facing the inner ring 82, that is, the inner peripheral surfaces of the lower retainer 84a and the upper retainer 84b, the distance from the axis J increases as the distance from the wick 101 in the axial direction increases. An inclined surface (848a, 848b) having a downward slope is formed toward the upper side in the figure. In the example shown in FIG. 14, an inclined surface 848a is formed on the inner peripheral surface of the lower retainer 84a, and an inclined surface 848b is formed on the inner peripheral surface of the upper retainer 84b. Further, a curved connection surface 849 that connects the tapered surface 841 and the inclined surface 848b is formed at an end of the retainer opposite to the wick 101 (an end of the retainer on the upper side in FIG. 14). The surface such as the inclined surface 848b and the tapered surface 841 of the inner peripheral surface and the curved connection surface 849 connecting these may be subjected to surface modification to improve lipophilicity. Modification methods include forming a polymer film containing a large number of alkyl groups with excellent affinity for lubricating oil by painting, heat sealing, coating, etc., or forming a surface layer of fine fibers such as polyolefin. There is. With this configuration, the lubricating oil once adhered moves to the protrusion 841b without being scattered by the centrifugal force in the middle of the movement, and scatters from here, so that an effect of more reliably returning the lubricating oil can be expected.

  The lubricating oil supplied from the wick 101 to the tapered surface 102a of the cone-shaped nut 102 moves on the tapered surface 102a in the direction of the inner ring 82 by the action of the centrifugal force, as shown by the dashed arrow R3 in FIG. . The lubricating oil that has moved from the tapered surface 102a to the inner race 82 enters the rolling surface 82a of the inner race 82. The lubricating oil accumulated on the rolling surface 82a of the inner race 82 is jumped up by the rolling element 83 moving at a high speed, and scatters from the edge of the rolling surface 82a as indicated by arrows R4 and R5. The scattered lubricating oil adheres to inclined surfaces 848a and 848b formed on the inner peripheral surface of the cage 84 facing the inner ring 82.

  Since the retainer 84 rotates at a high speed together with the rolling elements 83, the lubricating oil adhering to the inclined surface 848a moves upward in the drawing where the distance from the axis increases due to the action of the centrifugal force. The moved lubricating oil adheres to the rolling elements 83. Note that the inclined surface 848a of the lower retainer 84a may not have this portion. That is, when there is no portion of the inclined surface 848a or when it is short, most of the lubricating oil scattered in the direction of the arrow R4 scatters in the wick 101 direction, and thus does not affect the lubricating oil excess on the outer ring.

  On the other hand, the lubricating oil that has adhered to the inclined surface 848b moves upward in the drawing where the distance from the axis J increases due to the action of the centrifugal force, and moves from the inclined surface 848b to the connection surface 849 as indicated by an arrow R7. Since the connection surface 849 is connected to the tapered surface 841 formed on the outer peripheral surface of the retainer 84, the lubricating oil on the connection surface 849 moves as shown by the arrow R7 and moves to the tapered surface 841.

  The distance from the axis J increases as the taper surface 841 approaches the wick 101, and is a slope inclined upward toward the wick 101. Therefore, the lubricating oil on the tapered surface 841 moves by the centrifugal force in the downward direction in the drawing, where the distance from the axis J increases. The lubricating oil that has reached the lower end of the tapered surface 841 collects at the tip of the protrusion 841b due to the centrifugal force and scatters in the outer ring direction as indicated by an arrow R8. The scattered lubricating oil returns to the wick 101 via the circular pipe member 104 as indicated by an arrow R9.

  Thus, the lubricating oil scattered from the rolling surface 82a of the inner race 82 is captured by the inclined surfaces 848a and 848b. In particular, the lubricating oil scattered in the direction of the arrow R5 is likely to reach the outer ring 81 and adhere to the outer ring 81 if the upper retainer 84b is not mounted and is not captured by the inclined surface 848b. In that case, there is a problem that the lubricating oil becomes excessive on the rolling surface 81a of the outer ring 81, and the stirring resistance increases.

  In the case of the present embodiment, since the lubricating oil captured on the inclined surface 848b is connected to the tapered surface 841 via the connection surface 849, the lubricating oil adhered to the inclined surface 848b is separated from the inclined surface 848b by centrifugal force. 848b → connection surface 849 → tapered surface 841 → projection 841b → circular pipe member 104 ”. As a result, the lubricating oil scattered in the R5 direction can be returned to the wick 101 using the surface of the retainer 84. Thus, in the present embodiment, it is possible to prevent the lubricating oil on the rolling surface 81a from being excessive due to the scattered lubricating oil.

  In the present embodiment, the retainer 84 is composed of two parts (a lower retainer 84a and an upper retainer 84b) which are vertically divided. Generally, in the case of a deep groove ball bearing, it is possible to assemble it by adopting such a divided structure. Of course, the retainer 84 may be formed integrally, and in particular, in the case of an angular contact type ball bearing, even if it is an integral type, it can be easily assembled.

  Also, as shown in FIG. 15, the present invention can be similarly applied to a case where the pocket 840 is a through hole in which a part of the retainer 84 on the upper side in the axial direction is open. That is, the inclined surfaces 848a and 848b are formed on the inner peripheral surface of the retainer 84. A protrusion 841b is formed at the lower end of the tapered surface 841. Since the connection surface 850 formed at the upper end of the retainer 84 is planar, the connection between the connection surface 850, the tapered surface 841, and the inclined surface 848b has a pointed shape. Thus, if there is a pointed portion, the lubricating oil tends to collect and scatter from there. For this reason, it is preferable that the connecting surface 849 be smoothly connected to the tapered surface 841 and the inclined surface 848b by forming a curved surface shape like a connecting surface 849 indicated by a two-dot chain line. In this figure, the connection surface 849 indicated by a two-dot chain line is shown in a ring shape, but may be in a shape that leaves the opening of the pocket 840. Although the effect is reduced because splashed oil passing through the opening cannot be captured, an effect of returning a certain amount of splashed oil can be expected.

(Modification)
FIG. 16 is a diagram illustrating a modification of the second embodiment. In the above-described second embodiment, the tapered surface 841 is formed on the outer peripheral surface of the retainer 84, the inclined surfaces 848a and 848b are formed on the inner peripheral surface, and the tapered surface 841 is connected to the inclined surface 848b. A surface 849 was formed. In the modification shown in FIG. 16, a projection 851 is further formed on the tapered surface 841 on the outer peripheral side. The protruding portion 851 is formed to extend in a peak-like manner in the direction from the connection surface 849 to the end on the wick 101 side (the end where the protrusion is formed).

  In the case of the projection 851 shown in FIG. 16, the projection 851 is formed from the connection surface 849 to the projection 841b, but the axial length may be shorter. In addition, the protrusion 851 has a convex shape having a sharp peak where two slopes 851a and 851b intersect, but may have a convex shape having a gentle peak.

  As shown by a dashed arrow R10 in FIG. 16, the lubricating oil that has moved from the inner peripheral surface side inclined surface 848b to the outer peripheral surface side via the connecting surface 849 moves from the connecting surface 849 to the inclined surface 851a of the protrusion 851. This is because a larger centrifugal force acts on the lubricating oil because the protrusion 851 has a greater distance from the axis J than the tapered surface 841. The lubricating oil on the slope 851a moves in the direction of the protrusion 841b while approaching the top of the protrusion 851 due to centrifugal force. And finally, it scatters in the outer ring direction from the projection 841b.

  Therefore, the lubricating oil that has moved from the inner circumferential surface side to the outer circumferential surface side of the retainer 84 has a low probability of adhering to the rolling elements (not shown) in the pocket 840 again, and most of the lubricating oil passes through the protrusion 851 in the outer ring direction. It is scattered and returned to the wick 101 as indicated by an arrow R9 in FIG. By providing the protrusion 851 in this manner, the lubricating oil guided to the outer peripheral surface by the inclined surface 848b is effectively returned to the wick 101 without collecting on the rolling surface 81a of the outer ring 81. In the case of the retainer shape shown in FIG. 15, the same effect can be obtained by providing the projection 851 on the tapered surface 841 on the outer peripheral side.

  As described above, in the second embodiment, as shown in FIG. 14, the lubricating oil scattered in the direction of arrow R5 from the rolling surface 82a of the inner race 82 is applied to the inclined surface 848b formed on the inner circumferential surface of the cage. Adhere to. The inclined surface 848b is a downwardly inclined surface in which the distance from the axis J increases as the distance from the wick 101, which is the lubricating oil storage unit, increases, so that the inclined surface 848b moves in the direction of the connection surface 849 so as to move away from the wick 101. The connecting surface 849 formed on the end of the cage opposite to the wick 101 connects the tapered surface 841 formed on the outer peripheral surface of the cage and the inclined surface 848b, and thus has moved in the direction of the connecting surface 849. The lubricating oil moves to the tapered surface 841 through the connection surface 849. Since the tapered surface 841 is an upwardly sloping surface in which the distance from the axis J increases as approaching the wick 101, the lubricating oil that has moved to the tapered surface 841 moves on the tapered surface 841 in the direction of the wick 101, and the tapered surface 841 From the wick side end (lower end in the axial direction).

  As described above, the lubricating oil scattered from the rolling surface 82a of the inner ring 82 and adhered to the inclined surface 848b is scattered from the wick side end of the tapered surface 841 on the outer peripheral surface side. Lubricating oil can be prevented from becoming excessive.

  Further, as shown in FIG. 16, a protrusion 851 is formed on the tapered surface 841 so as to extend between the pair of adjacent pockets 840 and extend from the connection surface 849 side toward the wick 101 in a peak-like manner. I have. As a result, the lubricating oil that has moved from the inclined surface 848b on the inner peripheral surface side to the tapered surface 841 moves in the direction of the protrusion 851 due to the centrifugal force, and moves to the wick side end along the peak of the protrusion 851. . Therefore, it is possible to suppress the lubrication oil from entering the outer ring side opening of the pocket 840 from the tapered surface 841.

  Further, in FIG. 16, the pocket 840 penetrates from the inner ring side opening having a closed periphery to the outer ring side opening having a closed periphery, so that the upper side of the pocket 840 (the wick 101 is disposed as shown in FIG. 15). The strength of the retainer is improved as compared with the case of the pocket 840 having the open side (opposite side). Further, when the upper side of the pocket 840 is open as shown in FIG. 15, there is a disadvantage that the lubricating oil scattered at that portion easily reaches the outer ring side, but when the pocket 840 is closed as shown in FIG. Scattering to the outer ring side can be prevented. As for the pockets 840, it is not necessary that all the pockets 840 penetrate from the inner ring side opening with the periphery closed to the outer ring side opening with the periphery closed, and the upper part of the pockets 840 may be open. The number of open pockets 840 is selected according to the strength of the retainer and the effect of preventing the lubricating oil from scattering.

  Although various embodiments and modifications have been described above, the present invention is not limited to these contents. For example, in the above-described embodiment, the turbo molecular pump has been described as an example. The present invention can be applied. Other embodiments that can be considered within the scope of the technical idea of the present invention are also included in the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... turbo molecular pump, 3 ... pump rotor, 8, 9 ... ball bearing, 10 ... shaft, 81 ... outer ring, 81a, 82a ... rolling surface, 82 ... inner ring, 83 ... rolling element, 84 ... cage, 84a ... Lower retainer, 84b Upper retainer, 90 Lubricating oil, 100 Oil lubricated bearing device, 101 Wick, 101a Contact portion, 102 Cone nut, 102a, 841, 842 Tapered surface, 104 Round pipe Member, 840: pocket, 840a: inner peripheral surface, 840b: scraping portion, 840c: outer ring side opening, 840d: inner ring side opening, 843, 843b: convex portion, 845: protrusion, 847a: through hole, 847b: coupling portion , 849,850... Connection surface, 851 point projection

Claims (10)

An inner ring, an outer ring, a rolling element having a retainer for maintaining a spacing between the rolling elements and the rolling elements, and supporting a rotating shaft,
A taper member provided on the rotating shaft to which the inner ring is fixed, and having a first inclined surface having an upward slope toward the inner ring;
A lubricating oil storage unit disposed on the side provided with the tapered member with respect to the inner ring,
A contact portion that contacts the first inclined surface and supplies the lubricating oil of the lubricating oil storage unit to the first inclined surface;
The retainer is
A pocket having an outer ring side opening and an inner ring side opening and holding the rolling element,
A lubricating oil scraper formed on the inner peripheral surface of the pocket and scraping lubricating oil attached to the surface of the rolling element;
An oil-lubricated bearing device, comprising: a second inclined surface formed on an outer peripheral surface of the cage adjacent to the outer ring side opening and having an upward slope toward the lubricating oil storage portion. The oil-lubricated bearing device according to claim 1,
The oil-lubricated bearing device, wherein the lubricating oil scraping portion includes a plurality of convex portions formed in a region of the inner peripheral surface on the side of the outer ring-side opening so as to be arranged in a circumferential direction. The oil-lubricated bearing device according to claim 1,
An oil-lubricated bearing device, wherein a protrusion protruding from the second inclined surface is formed on the second inclined surface. The oil-lubricated bearing device according to claim 1,
The oil-lubricated bearing device, wherein the tapered member is an inner ring fixing member that is detachably provided on the rotating shaft and fixes the inner ring to the rotating shaft. The oil-lubricated bearing device according to claim 1,
An oil that is disposed closer to the outer ring than the retainer and is in contact with the lubricating oil storage unit and the outer ring, and includes a lubricating oil guiding unit that guides lubricating oil scattered from the second inclined surface to the lubricating oil storage unit. Lubricated bearing device. An inner ring, an outer ring, a rolling element having a retainer for maintaining a spacing between the rolling elements and the rolling elements, and supporting a rotating shaft,
A taper member provided on the rotating shaft to which the inner ring is fixed, and having a first inclined surface having an upward slope toward the inner ring;
A lubricating oil storage unit disposed on the side provided with the tapered member with respect to the inner ring,
A contact portion that contacts the first inclined surface and supplies the lubricating oil of the lubricating oil storage unit to the first inclined surface;
The retainer is
A pocket that penetrates from the retainer inner peripheral surface to the retainer outer peripheral surface and retains the rolling element;
A second inclined surface formed on the outer peripheral surface of the retainer and having an ascending slope in which a distance from an axis increases as approaching the lubricating oil storage portion;
A third inclined surface formed on the inner circumferential surface of the retainer and having a downward slope in which a distance from an axis increases as the distance from the lubricant oil storage unit increases;
An oil-lubricated bearing device, comprising: a connection surface formed at an end of the cage opposite to the lubricating oil storage unit and connecting the second inclined surface and the third inclined surface. The oil-lubricated bearing device according to claim 6,
An oil-lubricated bearing, wherein the second inclined surface is formed with a protrusion that extends between the pair of adjacent pockets and extends in a peak shape from the connection surface side toward the lubricating oil storage unit. apparatus. The oil-lubricated bearing device according to claim 6 or 7,
An oil-lubricated bearing device, wherein at least one portion of the pocket penetrates from an inner ring side opening with a closed periphery to an outer ring side opening with a closed periphery. The oil-lubricated bearing device according to claim 8,
The oil-lubricated bearing device, wherein the retainer is integrated by combining two or more members. An oil-lubricated bearing device according to any one of claims 1 to 9,
A vacuum pump comprising: a pump rotor provided with the rotating shaft.

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