JP2004360639A - Bearing unit for vacuum pump and vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit constituted by making a connecting rod into a resin member and integrally fitting the connecting rod and a bearing incorporated into the connecting rod through a fitting structure. <P>SOLUTION: This bearing unit consists of the connecting rod 10 for converting an eccentric turning movement of an eccentric shaft 9 into a linear movement and the antifriction bearing 12 incorporated into the connecting rod. The connecting rod is formed out of a resin material, and the inside diameter of a shaft connection portion 11 of the connecting rod and the outside diameter of an outer ring 16 of the antifriction bearing 12 are integrally formed through the fitting structure 17, thus realizing prevention of creeping. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a bearing unit for a vacuum pump, comprising a connecting rod for converting an eccentric turning motion of an eccentric shaft into a linear motion, a rolling bearing incorporated in the connecting rod, and a vacuum pump including the unit. About.
[0002]
[Prior art]
In general, the structure of a vacuum pump (particularly, a diaphragm type vacuum pump) is such that an eccentric shaft of a rotating motor and a connecting rod are used on the same shaft via a rolling bearing, and an eccentric rotating motion of the eccentric shaft is linearly connected to the connecting rod. It is converted into motion (reciprocating motion) and transmitted to the diaphragm (for example, see Patent Document 1).
Since the connecting rod is used as an eccentric shaft due to its mechanism, a large load like a sinusoidal curve whose load direction is reversed is applied to the bearing. Further, although it is used for rotation of the inner ring due to its structure, a large outer ring rotation load is applied, so that the outer diameter of the outer ring and the inner diameter of the connecting portion of the connecting rod are tightly fitted. Further, in order to avoid creep with the outer diameter of the eccentric shaft, the fitting with the outer diameter of the inner ring is also used with a tight fit.
[0003]
[Patent Document 1]
JP-A-6-185466
[Problems to be solved by the invention]
However, as described above, the fitting between the inner diameter of the shaft connecting portion of the connecting rod and the outer diameter of the outer ring, and the fitting of the outer diameter of the eccentric shaft and the inner diameter of the inner ring are both tight fits, so that when assembling the bearing, indentations are likely to be formed on the raceway surface. However, there is a problem that it is difficult to assemble and it takes much time to assemble.
The present invention has been made in view of the above-described problems of the related art, and an object of the present invention is to form a resin into a connecting rod, and connect the connecting rod and a bearing incorporated in the connecting rod to a fitting structure. To provide a bearing unit that is integrally fitted through the bearing unit.
[0005]
[Means for Solving the Problems]
Technical means achieved by the present invention in order to achieve the above object, a connecting rod for converting the eccentric pivoting motion of the eccentric shaft into a linear motion, and a rolling bearing incorporated in the connecting rod, The connecting rod is formed of a resin material, and the inner diameter of the shaft connecting portion of the connecting rod and the outer diameter of the outer ring of the rolling bearing are integrally formed via a fitting structure.
A vacuum pump is provided with the bearing unit. A typical example of the vacuum pump is a diaphragm pump.
By providing the fitting structure between the bearing outer ring and the connecting rod as described above, it is possible to simplify the incorporation of the bearing into the connecting rod, to prevent creep, and to prevent indentation on the bearing raceway surface.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the bearing unit of the present invention and a vacuum pump incorporating the bearing unit will be described with reference to the drawings. Note that the present embodiment is merely an embodiment of the present invention, and is not to be construed as being limited to the embodiment. The design can be appropriately changed within the scope of the present invention.
[0007]
In the present embodiment, a diaphragm type vacuum pump will be described as an example of a vacuum pump, but the present invention is applicable to all vacuum pumps incorporating this type of bearing unit.
As shown in FIG. 1, the diaphragm type vacuum pump 2 includes an eccentric portion 8 (for example, an eccentric portion formed integrally with a part of the rotating shaft 6, An eccentric shaft 9 provided with an eccentric cam and the like; and a resin connecting rod 10 for converting the eccentric turning motion (direction of arrow M) of the eccentric shaft 9 into a linear motion (reciprocating motion of arrow S direction). The eccentric shaft 9 and the connecting rod 10 are connected via a rolling bearing 12. In addition, as the rolling bearing 12, for example, a ball bearing or a roller bearing can be arbitrarily applied according to a use environment, a use purpose, or a use.
As a resin material of the connecting rod 10, for example, a PPS resin (polyphenylene sulfide resin) can be mentioned as an example. However, the resin material is not particularly limited and can be appropriately changed within the scope of the present invention.
[0008]
The rolling bearing 12 is mounted between the eccentric shaft 9 and the connecting rod 10, and is mounted on the inner ring 14 mounted on the outer diameter of the eccentric shaft 9 and on the inner diameter of the shaft connecting portion (ring) 11 of the connecting rod 10. An outer ring 16, a plurality of rolling elements (balls) 18 incorporated between the inner and outer rings 14, 16, and a retainer 20 for rotatably housing the plurality of rolling elements 18. In this case, the plurality of rolling elements 18 accommodated by the retainer 20 roll between the inner and outer rings (track surfaces 14a, 16a), so that the eccentric turning motion of the eccentric shaft 9 is connected to the connecting rod 10 via the rolling bearing 12. And the connecting rod 10 moves linearly. The diaphragm 1 swings due to the linear movement of the connecting rod 10, and the inside of the housing 3 is pulled by a negative pressure. The basic specifications of the rolling bearing 12 are not limited to the illustrated form.
[0009]
The rolling bearing 12 is configured such that the inner ring 14 rotates due to its structure, and the outer ring 16 has an outer diameter attached to the inner diameter of the shaft connecting portion 11 of the connecting rod 10 via a fitting structure 17. Have been. On the other hand, the inner diameter of the inner ring 14 is tightly fitted to the outer diameter of the eccentric shaft 9 in order to avoid creep with the eccentric shaft 9.
[0010]
The fitting structure 17 is a fitting structure for avoiding creep formed between the outer diameter of the bearing outer ring 16 and the inner diameter of the shaft connecting portion 11 of the connecting rod 10.
For example, as shown in FIG. 3, the connecting rod 10 has a circumferential continuous projection 17 a formed in the inner diameter of the shaft connecting portion 11 at a position eccentric from the center in the width direction (axial direction) A.
On the other hand, the outer ring 16 of the rolling bearing is formed on the inner diameter of the shaft connecting portion 11 of the connecting rod 10 at a position eccentric to the outer diameter from the center in the width direction (axial direction) A as shown in FIG. A circumferential continuous groove 17b fitted to the circumferential projection 17a is formed.
In the present embodiment, the circumferential continuous protrusion 17a and the circumferential continuous groove 17b are each formed in a rectangular shape in cross section having the same continuous width in the circumferential direction. As described above, since the circumferential projection 17a and the circumferential groove 17b are fitted and formed integrally at a position eccentric from the center in the width direction, the outer diameter of the bearing outer ring 16 and the connecting rod are reduced. Creep between the inner diameter of the shaft connecting portion 11 and the inner diameter of the shaft connecting portion 11 can be avoided. The eccentric direction may be on either the motor 4 side or the non-motor 4 side.
Further, the fitting structure 17 for preventing creep is not limited to the above embodiment, and the design can be changed within the scope of the present invention as long as the structure can avoid creep between the two. .
For example, the shapes of the circumferential continuous projection 17a and the circumferential continuous groove 17b may be a continuous meandering continuous protrusion and a continuous groove in which both can be fitted. Further, a fitting protrusion and a groove in which the circumferential protrusion and the groove are interrupted in the circumferential direction, respectively, may be used. The shapes of the protrusion and the groove in this case are not particularly limited and are arbitrary.
[0011]
Further, as shown in FIG. 4, a protrusion 17c in the width direction (axial direction) A is formed on one of the outer diameter of the bearing outer ring 16 and the inner diameter of the shaft connecting portion 11 of the connecting rod 10, and the protrusion is formed on the other. The groove 17d in the width direction (axial direction) A into which the portion is fitted may be formed. The shape of the projection 17c and the recess 17d in the width direction is not particularly limited. In this case, any number of the projections 17c and the grooves 17d may be provided at intervals in the circumferential direction. The same number of these width-direction projections 17c and concave grooves 17d are provided on both the outer diameter of the bearing outer ring 16 and the inner diameter of the shaft connecting portion 11 of the connecting rod 10, and creep prevention is achieved by fitting each of them. Is also possible. According to such a fitting structure 17 in the width direction, creep between the outer diameter of the bearing outer ring 16 and the inner diameter of the shaft connecting portion 11 of the connecting rod 10 can be avoided.
[0012]
In the present embodiment, the fitting structure 17 is formed by the protrusion (17a or 17c) provided on the inner diameter side of the connecting portion 11 of the connecting rod 10 and the concave groove (17b or 17d) provided on the outer diameter side of the outer ring. Although an example of the configuration is given, for example, a fitting groove is formed by providing a concave groove on the inner diameter side of the connecting portion 11 of the connecting rod 10 and providing a protrusion corresponding to the concave groove on the outer diameter side of the outer ring. It is well within the scope of the present invention.
In this embodiment, the fitting structure 17 is provided between the outer diameter of the bearing outer race 16 and the inner diameter of the shaft connecting portion 11 of the connecting rod 10 to prevent creep. It may be provided between the inner diameter of the inner ring 14 and the outer diameter of the eccentric shaft 9 to simultaneously prevent creep between the two.
[0013]
The rolling bearing 12 is provided with a sealing plate 22 for preventing foreign substances (for example, dust, water, dust, etc.) from entering the rolling bearing and for preventing leakage of the lubricant.
As the sealing plate 22, for example, in the present embodiment, as shown in FIG. 3, a non-contact rubber seal made of rubber containing a core metal 22 a and not in contact with the inner ring 14 is illustrated. A sealing plate according to the embodiment can be used as appropriate within the scope of the present invention, such as a non-contact metal shield that does not contact the inner ring or a contact rubber seal made of a cored rubber and non-contacting the inner ring.
[0014]
As the cage 20, any type of cage (for example, a crown type cage, a waveform type cage, a cage type cage, a combination type cage, etc.) can be applied according to a use environment and a purpose of use.
Further, the retainer material is not particularly limited, but is formed of a resin material in the present embodiment. In this case, as the resin material, for example, nylon 46, nylon 66, polyphenylene sulfide containing glass fiber, or the like can be used.
As described above, the cage 20 conventionally formed of a metal material is made of a resin material, so that a high-frequency collision sound between metals is changed to a low-frequency collision sound between a metal and a resin, and the sound is calmed. At the same time, the sound level can be reduced (quiet).
[0015]
A desired lubricant is sealed in the rolling bearing 12, and for example, urea-based grease is sealed in the present embodiment. In this case, as the urea-based grease, for example, “ENS grease (trade name)” manufactured by Nippon Oil Corporation can be applied.
As described above, by changing the lithium grease which has been conventionally sealed into the urea grease, the collision with the sliding between the rolling element 18 and the inner and outer rings (the raceway surfaces 14a and 16a) is repeated, and the rolling element 18 is formed. Even if the temperature of the inner and outer rings (the raceway surfaces 14a and 16a) rises and the temperature of the rolling bearing 12 rises, the durability of the rolling bearing 12 is not reduced, and the life can be extended. That is, the urea-based grease uses a urea-based compound as a thickener, has a high dropping point (° C.) and a small degree of oil separation (%) as compared with the lithium-based grease, and thus has excellent heat resistance. . As a result, the seizure life can be extended in long-term continuous use in a high-temperature environment.
[0016]
【The invention's effect】
Since the connecting rod of the vacuum pump is made of resin and is formed as a bearing unit integrally provided with a rolling bearing and a fitting structure, the present invention simplifies incorporation of the bearing into the connecting rod and reduces cost. It is possible to provide a vacuum pump which is excellent in productivity and which can eliminate creep of the bearing and prevent indentation of the bearing raceway surface.
[Brief description of the drawings]
FIG. 1 is a schematic overall view showing one embodiment of a vacuum pump bearing unit of the present invention and a vacuum pump incorporating the unit.
FIG. 2 is a front view of a state where a rolling bearing is incorporated in a connecting lot.
FIG. 3 is a schematic sectional view showing one embodiment of a fitting structure of a connecting rod and a rolling bearing.
FIG. 4 is a schematic cross-sectional view showing another embodiment of a fitting structure of a connecting rod and a rolling bearing.
[Explanation of symbols]
2: Diaphragm type vacuum pump 9: Eccentric shaft 10: Connecting rod 11: Shaft connecting part 12: Rolling bearing 14: Inner ring 16: Outer ring 17: Fitting structure

Claims (3)

A connecting rod for converting the eccentric pivoting motion of the eccentric shaft into a linear motion, and a rolling bearing incorporated in the connecting rod,
The connecting rod is formed of a resin material,
A bearing unit for a vacuum pump, wherein an inner diameter of a shaft connecting portion of the connecting rod and an outer diameter of an outer ring of the rolling bearing are integrally formed via a fitting structure. A connecting rod for converting eccentric pivoting motion of the eccentric shaft into linear motion,
A vacuum pump comprising a vacuum pump bearing unit including a rolling bearing incorporated between an eccentric shaft and a connecting rod,
The rolling bearing is at least composed of an inner ring incorporated into the outer diameter of the eccentric shaft, an outer ring incorporated into the inner diameter of the connecting rod, and a plurality of rolling elements incorporated between the inner ring and the outer ring,
A vacuum pump, wherein the connecting rod is formed of a resin material, and an inner diameter of a shaft connecting portion of the connecting rod and an outer diameter of an outer ring of the rolling bearing are integrally formed through a fitting structure. The vacuum pump according to claim 2, wherein the vacuum pump is a diaphragm pump.

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