JPH09242766A - Bearing for pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of lubricants from the internal part of a bearing by providing a recessed groove in the peripheral surface of a locus side, forming a flange part extended toward a rotational side locus ring in one end side of a fixed side locus ring and forming a labyrinth seal between the flange part and the end surface of the rotational side locus ring. SOLUTION: A recessed groove 8 for suppressing the movement of a lubricant 7 to the upper end part of an inner ring 1 along a peripheral surface 12 is formed in the peripheral surface of the upper side in the peripheral surface of the locus 11 side of the inner ring 1. An inward flange part 22 extended to the inner ring 1 side is projectingly provided in the upper end part of an outer ring 2 and a labyrinth seal B is formed between the flange part 22 and the end surface 13 of the inner ring 1. Thus, the lubricant 7 moved through the outer peripheral surface of the inner ring 1 to its upper layer part is stopped by the recessed groove 8 and the transfer of a great deal of lubricant 7 to its upper end part is prevented. Also, the leakage of the lubricant 7 moved to the upper end side of a bearing A to the outside of the bearing A is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing for a pump used under high speed rotation.

[0002]

2. Description of the Related Art Conventionally, for example, a pump bearing for supporting a rotor shaft of a turbo molecular pump is used at a high speed of about tens of thousands of revolutions per minute in a vacuum atmosphere. Lubrication between a raceway and a rolling element such as a ball interposed between the raceways is performed with a lubricant such as grease or oil. Since the oil seal cannot withstand the use of the pump bearing under high speed rotation, the inside of the bearing is sealed by a metal shield.

[0003]

However, since the shield cannot secure the sealing performance as good as that of the oil seal, the lubricant scattered by the centrifugal force caused by the rotation of the bearing ring is, for example, shielded. It is easy to leak to the outside of the bearing through the gap between the inner ring and the inner ring, or the gap between the shield and the outer ring shield groove into which the shield is fitted. For this reason, the lubricant leaking from the bearing contaminates the space where oil is disliked,
There is a problem in that the lubricant is likely to be consumed at an early stage to cause poor lubrication of the bearing. The present invention has been made in view of the above problems, and an object of the present invention is to provide a bearing for a pump that can prevent lubricant from leaking from the inside of the bearing.

[0004]

In order to achieve the above object, a pump bearing according to a first aspect of the present invention has rolling elements interposed between respective races of a pair of bearing rings, and In a pump bearing that lubricates rolling elements with a lubricant, at least one raceway peripheral surface of the pair of raceways is provided with a concave groove that suppresses the lubricant from migrating to one end side, A collar portion extending toward the rotary side race ring is formed on the one end side of the fixed side race ring, and a labyrinth seal is formed between the collar portion and the end surface of the rotary side race ring. To do.

According to the pump bearing having the above structure, the lubricant inside the bearing is transferred to the one end side of the bearing ring by the concave groove provided on at least one circumferential surface of the bearing ring. Can be suppressed. Further, the labyrinth seal formed between the flange portion provided on the one end side of the fixed side race ring and the end surface of the rotating side race ring can seal the one end side of the bearing. Therefore, the concave groove and the labyrinth seal cooperate to effectively prevent the lubricant inside the bearing from leaking from the one end side of the bearing.

Further, in the pump bearing according to the second aspect of the present invention, the rolling element is interposed between the respective races of the pair of races, and the race of each race and the rolling element are lubricated with a lubricant. In the bearing for use, the one end side of the pair of bearing rings is closed with a shield, and the lubricant is prevented from migrating to the shield side on at least one of the pair of bearing rings. Is formed on the other side of the fixed-side race, and a flange extending toward the rotating-side race is formed, and a labyrinth seal is formed between the flange and the end surface of the rotating-side race. It is characterized by that.

According to this pump bearing, migration of the lubricant inside the bearing to the shield side can be suppressed by the concave groove provided on at least one raceway side circumferential surface of the pair of raceways. Therefore, it is possible to prevent the lubricant from leaking through the gap between the shield and the bearing ring. Further, a collar portion provided on the other end side of the fixed side race ring,
The labyrinth seal formed between the end surface of the bearing ring on the rotating side seals the other end of the bearing and prevents the lubricant inside the bearing from leaking from the other end.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG.
FIG. 3 is a cross-sectional view of a main part of a turbo molecular pump incorporating the pump bearing of the present invention. The pump bearing A supports the lower end of the rotor shaft S that supports the rotor blades of the turbo molecular pump, and includes the inner ring 1 as the rotating side race ring and the outer ring 2 as the fixed side race ring. A ball bearing having balls 3 as rolling elements interposed between the raceways 11 and 21 is formed.

The inner ring 1 is fitted to the rotor shaft S so as to be integrally rotatable, and the outer ring 2 is fitted to a casing 4 of the turbo molecular pump. The inner ring 1 is sandwiched between the step portion S1 of the rotor shaft S and the nut 5 screwed into the male screw S2 at the lower end portion of the inner ring 1 to restrict movement in the axial direction. Further, the outer ring 2 is fitted into the casing 4 in a state where the outer ring 2 is allowed to move in the axial direction, and a preload is applied by a preload spring 6.

The outer periphery of the nut 5 is formed by a tapered surface 51 so that the outer diameter of the upper portion of the nut 5 gradually increases.
The lower side of the nut 5 is the oil sump 4 at the bottom of the casing 4.
1 is immersed in the lubricant 7 housed in No. 1 and the lubricant 7 is sequentially supplied upward along the tapered surface 51 as it rotates, and the respective raceways 11 of the inner ring 1 and the outer ring 2 are supplied. , 21 and the ball 3 can be lubricated. Oil or grease is used as the lubricant 7.

A peripheral surface (outer peripheral surface) of the inner ring 1 on the raceway 11 side.
The lubricant 7 is applied to the peripheral surface 12 on the upper side of the peripheral surface 1.
A concave groove 8 is formed along the line 2 to prevent the inner ring 1 from moving toward the upper end side. The concave groove 8 is formed on the entire circumference of the peripheral surface 12, and has a cross-sectional shape of
The upper side 81 is formed in a wedge shape that is substantially orthogonal to the axis of the inner ring 1. The inner ring 1 is attached to the upper end of the outer ring 2.
An inward flange-shaped flange portion 22 extending toward the side is provided so as to project, and a labyrinth seal B is formed between the flange portion 22 and the end surface 13 of the inner ring 1. The gap between the collar portion 22 and the end surface 13 of the inner ring 1 is set to 0.1 to 0.3 mm, for example.

With the above-mentioned structure, the lubricant 7 that moves along the outer peripheral surface of the inner ring 1 toward its upper end is dammed by the concave groove 8 formed in the inner ring 1 and a large amount of the lubricant 7 is formed. Can be prevented from moving to its upper end. Further, the lubricant 7 that has moved to the upper end side of the bearing A irrespective of the groove 8 is provided by the labyrinth seal B formed by the flange portion 22 of the outer ring 2 and the end surface 13 of the inner ring 1 of the bearing A. It is prevented from leaking to the outside. Therefore, the groove 8 and the labyrinth seal B cooperate with each other to effectively prevent the lubricant from leaking from the upper end of the bearing A. Therefore, it is possible to prevent the surroundings of the bearing A from being contaminated with the lubricant 7, and the lubricant 7 from being consumed at an early stage to cause poor lubrication of the bearing A. The concave groove 8 may be formed on the peripheral surface (inner peripheral surface) 23 of the outer ring 2 on the raceway 21 side (see FIG. 2).
It may be formed on the peripheral surfaces 12, 23 of the outer race 2 and the outer race 2 on the side of the raceways 11, 21 (see FIG. 3).

FIG. 4 is a sectional view showing another embodiment of the pump bearing A of the present invention. This pump bearing A is
The inner ring 1 and the outer ring 2 are closed by a shield 9 between the ends on one side, and the inner peripheral surface of the outer ring 2 on the side closer to the shield 9 is closer to the inner surface of the bearing A. A concave groove 8 having a semicircular cross section is provided to prevent the grease 71 as a lubricant, which has been filled in, from moving to the shield 9 side. On the other end side of the outer ring 2 as the fixed side race ring, a flange portion 22 that extends toward the inner ring 1 as the rotation side race ring is provided so as to project. The flange portion 22 and the end surface of the inner ring 1 are A labyrinth seal B is formed between them. In addition,
The inner ring 1 is rotated by a nut 5A to rotate the pump shaft SA.
The outer ring 2 is fitted into the casing 4A of the pump in a state where a preload is applied by the preload spring 6.

According to this embodiment, the grease 71 inside the bearing A is prevented from migrating to the shield 9 side by the concave groove 8 provided along the peripheral surface 24 of the outer ring 2 to prevent a large amount of grease 71. , It is possible to prevent the shift to the shield 9 side. Regarding the grease 71 that has moved in the direction opposite to the shield 9, the labyrinth seal B formed by the flange portion 22 of the outer ring 2 and the end surface 13 of the inner ring 1 prevents the grease 71 from leaking to the outside of the bearing A. You can

In this embodiment, the concave groove 8 is
It may be formed on the peripheral surface 14 of the inner ring 1 on the side closer to the shield 9 among the peripheral surfaces on the side of the track 11 (see FIG. 5), and the peripheral surface 14 on the side of the tracks 11, 21 of both the inner ring 1 and the outer ring 2. , 24 may be formed (see FIG. 6). The groove 8 may be provided not only on the shield 9 side but also on the peripheral surface on the labyrinth seal B side. In this case, it may be formed on the peripheral surface 23 of the outer ring 2 (see FIG. 7) or the inner ring. 1 is formed on the peripheral surface 12 (see FIG. 8).
It can be formed on the peripheral surfaces 12 and 23 of both the inner ring 1 and the outer ring 2 (see FIG. 9). Furthermore, the pump bearing of the present invention can be applied to and carried out in bearings other than the above ball bearings.

[0016]

As described above, according to the pump bearing of the first aspect, the lubricant inside the bearing can be prevented by the concave groove provided along at least one of the pair of bearing rings on the circumferential surface of the bearing. It is possible to suppress the transition to one end side of the bearing ring, and by the labyrinth seal configured between the flange portion provided at one end of the fixed side bearing ring and the end surface of the rotating side bearing ring, The one end side of the bearing can be sealed. Therefore, the cooperation of the concave groove and the labyrinth seal can effectively prevent the lubricant inside the bearing from leaking from the one end side of the bearing. Therefore, it is possible to prevent the surroundings of the bearing from being contaminated with the lubricant, and the lubricant from being consumed at an early stage to cause poor lubrication of the bearing.

Further, according to the pump bearing of the second aspect, the lubricant inside the bearing is transferred to the shield side by the concave groove provided on at least one raceway side peripheral surface of the pair of raceways. Since it can be suppressed, it is possible to prevent the lubricant from leaking through the gap between the shield and the bearing ring. In addition, the labyrinth seal configured between the flange portion provided on the other end side of the fixed side race ring and the end surface of the rotating side race ring seals the other end side of the bearing, and It is possible to prevent the lubricant from leaking from the other end side. Therefore, the groove and the labyrinth seal can effectively prevent the lubricant inside the bearing from leaking from both ends of the bearing. As a result,
It is possible to prevent the surroundings of the bearing from being contaminated with the lubricant, and the lubricant from being consumed at an early stage to cause poor lubrication of the bearing.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part showing one embodiment of a pump bearing of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment.

FIG. 3 is a sectional view showing still another embodiment.

FIG. 4 is a sectional view showing still another embodiment.

FIG. 5 is a cross-sectional view of an essential part showing still another embodiment.

FIG. 6 is a cross-sectional view of an essential part showing still another embodiment.

FIG. 7 is a main-portion cross-sectional view showing still another embodiment.

FIG. 8 is a main-portion cross-sectional view showing still another embodiment.

FIG. 9 is a cross-sectional view of main parts showing still another embodiment.

[Explanation of symbols]

 1 Inner ring 11 Raceway 12 Circumferential surface 13 End surface 14 Circumferential surface 2 Outer ring 21 Raceway 22 Collar section 23 Circumferential surface 24 Circumferential surface 3 Ball (rolling element) 7 Lubricant 8 Recessed groove 9 Shield B Labyrinth seal

Claims (2)

[Claims] 1. A pump bearing in which rolling elements are interposed between respective races of a pair of races, and the races of the respective races and the rolling elements are lubricated with a lubricant. At least one raceway side peripheral surface is provided with a concave groove that suppresses the migration of the lubricant to the one end side, and a flange portion extending toward the rotating side raceway ring is provided on the one end side of the fixed side raceway wheel. A bearing for a pump, characterized in that a labyrinth seal is formed between the flange portion and the end surface of the rotating side bearing ring. 2. A pump bearing in which rolling elements are interposed between respective races of a pair of races, and the races of the respective races and the rolling elements are lubricated with a lubricant. A shield is used to block the gap between the ends on one side, and a groove is formed on at least one of the pair of raceways on the circumferential surface of the raceway to prevent lubricant from migrating to the shield side. A bearing for a pump, characterized in that a flange portion extending toward the rotation-side race ring is formed on the other end portion side of the, and a labyrinth seal is formed between this flange portion and the end surface of the rotation-side race ring. .