JP2002089473A - Seal device for bearing in compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent leakage of a lubricant of a bearing in a compressor or invasion of foreign matter into the bearing caused by abrasion of oil seals of the bearing in early stages by application of high pressure. SOLUTION: In this seal device, the oil seals 33 are attached to a needle bearing 21 supporting a hub part 23 of a rotor 22 in the double-tooth scroll type compressor 1. Circular clearance seals 36 are provided outside the oil seals 33 through low-pressure spaces 35, in both axial end parts of the hub part 23 such that minute clearance 38 is formed. The spaces 35 communicate with a suction space 29 via communication holes 39, 40 and have low pressure in operation. Accordingly, because high pressure is not applied to the oil seal 33, the abrasion in early stages is prevented to certainly protect the bearing 21. The seal device can be similarly applied to the oil seals or the like of main bearings 14, 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device for a bearing used in a fluid compressor such as a scroll compressor.

[0002]

2. Description of the Related Art In a fluid compressor, for example, a scroll type compressor, a needle bearing is provided on a portion for rotatably supporting a rotor by an eccentric shaft portion of a shaft or a portion for rotatably supporting a shaft by a housing. Bearings, such as roller bearings and ball bearings, are provided. If the compressor is oilless, these bearings are pre-filled with a lubricant such as grease. The bearing should be provided with an oil seal such as a lip seal type made of a material such as oil-resistant rubber at the axial end of the bearing to prevent the agent from leaking out of the bearing and deteriorating the performance of the bearing. Normal.
This oil seal not only prevents leakage of the lubricant but also prevents foreign substances from entering the inside of the bearing.

When the pressure difference between the inside and outside of the oil seal increases, the seal member such as a seal lip is strongly pressed against the other surface in sliding contact, for example, the surface of a rotating shaft. Is worn out early, causing leakage of the lubricant. Therefore, the smaller the pressure difference before and after the oil seal, the more advantageous it is in terms of maintaining the sealing performance and reliability of the oil seal. In addition, if an oil seal is provided in a part where the pressure is relatively low even inside the compressor, the pressure difference between the inside and outside of the oil seal is generally small, so that the wear of the seal member is reduced and the lubricant may leak out. Therefore, in many cases, the bearing and the oil seal thereof are arranged in a space where a low suction pressure acts in the compressor. For example, as disclosed in Japanese Patent Application Laid-Open No. 7-19183, a so-called "single-tooth" scroll type in which a spiral blade is formed only on one side of a rotor disk, that is, an end plate. In a compressor, a shaft is formed on the other side surface of the end plate, and a bearing for rotatably supporting the shaft is provided, so that a bearing for a rotor and an oil seal thereof are arranged in a low-pressure space. That makes it possible.

However, in a so-called "double-tooth scroll compressor" in which spiral blades are formed on both front and rear sides of the rotor disk in the axial direction, both the front and rear sides of the rotor disk are at high pressure. Since the bearing for supporting the center portion of the rotor by the eccentric shaft portion of the shaft is not provided in the high-pressure space together with the oil seal, it is difficult to maintain the sealing performance and reliability of the oil seal. Nevertheless, in the double-tooth scroll type compressor, the working chambers are formed on both sides of the rotor disk in the axial direction to perform the compression action. Since the load due to the pressure is offset, the axial support structure such as a thrust bearing is simplified, and the tooth height (axial height) of the spiral blade on both sides of the rotor disk is increased. Can reduce the amount of tooth deformation and the clearance between the fixed spiral blades can be reduced, resulting in higher efficiency as a compressor. It has the advantage of high performance and excellent performance, so if the reliability of the oil seal of the rotor bearing can be maintained, the advantages of the double-tooth scroll type compressor can be utilized.

[0005]

SUMMARY OF THE INVENTION The present invention addresses the above-described problems encountered in conventional oil seals for bearings in compressors and provides a novel oil seal that can maintain its reliability. It is intended to provide a means.

[0006]

According to the present invention, there is provided a method for solving the above-mentioned problems.
The invention provides a sealing device for a bearing in a compressor.

A sealing device for a bearing in a compressor according to the present invention comprises a cylindrical member used for a compressor, a rotating shaft penetrating the inside thereof and capable of rotating relative to the member, A bearing mounted on the bearing, an oil seal for closing the internal space of the cylindrical member in one of the axial directions of the bearing, and a low-pressure space formed outside the oil seal when viewed in the axial direction from the bearing. It comprises an annular clearance seal and a communication passage connecting the low pressure space and the low pressure portion. It is more effective if the clearance seal is configured as a labyrinth seal having an annular groove.

Since the seal device of the present invention has such a structure, a high pressure may act on the outside of the oil seal in the axial direction and a large pressure difference may occur between the oil seal and the bearing provided inside. However, since an annular clearance seal is provided outside the oil seal via a low pressure space, the high pressure is reduced by the minute clearance of the clearance seal, and the low pressure space communicates with the low pressure part and the low pressure Therefore, high pressure does not act on the outside of the oil seal. Therefore, the oil seal does not wear out early, so that it is possible to prevent the lubricant sealed in the bearing from leaking out and to prevent foreign matter from entering the inside of the bearing. Reliability can be maintained.

More specifically, the present invention can be applied to a scroll compressor. In this case, the bearing is a main bearing that supports a driving rotary shaft, and the cylindrical member can be a bearing support formed on a part of the compressor housing. The present invention can also be suitably applied to a scroll compressor with two teeth. In this case, the rotating shaft may be an eccentric shaft portion formed on a part of the drive shaft of the compressor, and the cylindrical member may be a hub portion serving as a center of a disk in the two-tooth rotor, and the bearing may be eccentric. The hub may be rotatably supported by the shaft. In these cases, it is preferable to use the suction space of the compressor or the outside atmospheric pressure space as the low pressure part communicating with the low pressure space.

[0010]

FIG. 1 is a longitudinal sectional view showing the entire structure of a double-toothed scroll compressor 1 as a first embodiment of the present invention. The housing 2 of the compressor 1 includes a front housing 3 and a rear housing 4 integrally fastened thereto. Inside the front and rear housings 3, 4, fixed blades 5, 6 which appear to overlap in a spiral shape when viewed in the axial direction are formed so as to protrude so as to face each other in the axial direction at the mating surface 7. . A common short cylindrical suction port 8 is formed on a part of the outer periphery of the housing 2 so as to straddle both sides of the mating surface 7 so that a fluid to be pressurized can be introduced into the housing 2. A short cylindrical bearing support 9 is formed in front of the front housing 3 to protrude, and a short cylindrical protrusion 10 is formed in rear of the rear housing 4 symmetrically. The inside of the protrusion 10 is a discharge port 11,
Inside, a bottomed cylindrical bearing support 13 is supported by several radial stays 12.

The front and rear bearing support portions 9 and 13 respectively include:
A front bearing 14 and a rear bearing 15 are attached as main bearings.
5, one shaft 16 is rotatably supported. An eccentric shaft portion 17 is formed at a central portion of a shaft 16 inside the housing 2, and balance weights 18 and 19 are attached before and after the eccentric shaft portion 17.
A pulley 20 is attached to a front end of the shaft 16, and the shaft 16 is rotationally driven by an external power via a belt (not shown). Needless to say, the pulley 20
Alternatively, a prime mover such as a motor may be directly connected to the shaft 16.

A needle bearing 21 is provided on the eccentric shaft portion 17 of the shaft 16, and rotatably supports a cylindrical hub portion 23 at the center of the rotor 22. A rotor disk 24 is integrated with the hub 23. On both surfaces of the rotor disk 24, spiral-shaped blades 25 and 26 projecting in the axial direction are formed, respectively, and by meshing with the fixed spiral-shaped blades 5 and 6 described above, between them,
Multiple working chambers 2 that look like crescents when viewed in the axial direction
7, 28 are formed. In addition, a suction space 29 communicating with the suction port 8 is formed in a substantially annular shape on the outer periphery of the fixed blades 5 and 6 and the movable blades 25 and 26 that are engaged with each other inside the housing 2. Discharge port 11
Are formed before and after the discharge spaces 30 and 31 communicating with each other.
The discharge spaces 30 and 31 communicate with each other through some communication holes 32 that are open near the center of the rotor disk 24. Although not shown, a rotation preventing mechanism is provided between the rotor 22 and the housing 2 to prevent rotation of the rotor 22 and allow only rotation.

The above configuration is similar to a conventionally known double-tooth scroll compressor. With such a basic configuration, the scroll compressor 1 can be used as a conventional double-tooth scroll compressor. It has the same fluid compression action as the machine.
That is, first, the rotor 22 has the working chambers 27 and 2 in the outer peripheral portion.
When the opening 8 opens toward the outer suction space 29, the fluid introduced from the suction port 8 into the suction space 29 is taken into the working chambers 27 and 28. The shaft 16 is rotated by the power input from the pulley 20 or the like, and the eccentric shaft 17
Causes the rotor 22 to revolve via the needle bearing 21 of the hub portion 23 at an orbital radius substantially equal to the amount of eccentricity of the eccentric shaft portion 17.

When the rotor 22 revolves without rotation, the working chamber 2 opened toward the suction space 29 is rotated.
7 and 28 are closed, move toward the center while gradually reducing the volume, and finally open toward the discharge spaces 30 and 31 to discharge the pressurized fluid in the working chambers 27 and 28. . The pressurized fluid discharged to the front-side discharge space 30 joins the rear-side discharge space 31 through the communication hole 32. The fluid pressurized in this manner is supplied to the discharge space 3
1 to the outside through the discharge port 11. In addition, the masses of the front and rear balance weights 18 and 19 are balanced with the eccentric masses of the eccentric shaft portion 17 of the shaft 16 and the rotor 22 to prevent vibration.

A feature of the scroll type compressor 1 of the first embodiment lies in the structure of the hub portion 23 at the center of the rotor 22. The structure of this part is enlarged and shown in FIGS. That is, before and after the needle bearing 21 mounted between the eccentric shaft portion 17 of the shaft 16 and the hub portion 23 of the rotor 22 in order to allow the rotor 22 to revolve, the needle bearing 21 is previously provided inside the needle bearing 21. A lip seal type oil seal made of an elastic oil resistant rubber so as to prevent leakage of a lubricant such as grease filled therein and to prevent foreign matter from entering the inside of the needle bearing 21. 33 is attached to the inner surface of the hub 23. Accordingly, the front and rear portions of the needle bearing 21 in the axial direction are temporarily sealed, and the lip 34 of the oil seal 33 slides on the surface of the eccentric shaft portion 17 when the rotor 22 is driven to revolve.
If the pressure difference acting before and after is too large, the wear of the lip 34 proceeds early and the sealing action is impaired.

Therefore, in the first embodiment, a pair of front and rear annular clearance seals 36 are formed on the cylindrical hub portion 23 except for spaces 35 which are low pressure spaces respectively outside the front and rear oil seals 33 in the axial direction. Are mounted on both front and rear end faces in the axial direction. The inner surface of the circular opening 37 at the center of the clearance seal 36 is not in close contact with the surface of the cylindrical eccentric shaft portion 17 of the shaft 16, and a minute clearance 38 is provided between the cylindrical surfaces over the entire circumference. Formed so that there is no friction or interlock between their surfaces. However, since there is only a small clearance 38 between the front and rear low pressure spaces 35 and the discharge spaces 30 and 31 in the hub portion 23 and there is almost no air permeability,
When the compressor 1 operates, a pressure difference occurs before and after the clearance seal 36.

The two low-pressure spaces 35 formed before and after the needle bearing 21 communicate with each other through one or more first communication holes 39 formed in the hub 23 in the axial direction. Further, an intermediate portion of the first communication hole 39 is connected to one or more second communication holes 40 formed in the disk 24 of the rotor 22 in the radial direction as shown in FIG. Thus, the low pressure is introduced into the left and right low pressure spaces 35 by communicating with the suction space 29 in the housing 2. Reference numeral 41 denotes a crescent-shaped notch formed in the hub portion 23 to expand a part of the low-pressure space 35 in the radial direction to communicate with the first communication hole 39.

A double-tooth scroll compressor 1 according to a first embodiment.
Has such a structure, the high-pressure fluid discharged from the working chambers 27 and 28 fills the discharge spaces 30 and 31 by performing the above-described fluid compression action as the scroll compressor during operation. However, the minute clearance 38 formed between the clearance seal 36 and the eccentric shaft portion 17 of the shaft 16 prevents the high pressure from directly acting on the oil seal 33 of the needle bearing 21.

The low-pressure space 35 before and after the pair of oil seals 33 is suctioned at a low pressure by a notch 41 having a sufficiently larger cross-sectional area than the clearance 38 and a passage including the first communication hole 39 and the second communication hole 40. Since the inside of the low pressure space 35 is always at a low pressure even during operation since it communicates with the space 29, a large pressure difference does not act between both surfaces of the oil seal 33. Therefore, the oil seal 33 does not wear out early, and high reliability can be maintained. Therefore, it is ensured that the lubricant sealed in the needle bearing 21 leaks out and foreign matter enters the inside. Is prevented. Although the clearance seal 36 is attached to the hub portion 23, the clearance seal 36 is modified so as to be fixed to the eccentric shaft portion 17, and a minute space is formed between the surface of the clearance seal 36 and the axial end surface of the hub portion 23. Similar effects can be obtained by forming a clearance.

Next, FIGS. 4 and 5 show a main part of a second embodiment of the present invention. The scroll type compressor of the second embodiment, not shown, has substantially the same general configuration as the double-toothed scroll type compressor 1 of the first embodiment, except that a circular opening 37 of an annular clearance seal 36 is formed. On the surface of the eccentric shaft portion 17 facing the inner surface, a plurality of minute circumferential grooves 42 are formed, and a labyrinth seal 43 that is not in contact with the clearance seal 36 is formed. I have.

The labyrinth seal 43, which is a feature of the second embodiment, has stronger sealing performance than the case of only the annular clearance seal 36 as in the first embodiment.
The degree of the high-pressure fluid in the discharge spaces 30 and 31 passing through the clearance 38 and affecting the low-pressure space 35 is further reduced as compared with the case of the first embodiment.
5 can be brought closer to the low pressure of the suction space 29.

FIG. 6 shows the overall structure of a double-tooth scroll compressor 44 according to a third embodiment of the present invention.
Portions of the compressor 44 having the same structure as the compressor 1 of the above-described first embodiment shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. The feature of the third embodiment is that the technical idea of the present invention is applied not only to the sealing device for the needle bearing 21 but also to the sealing device for the front bearing 14 and the rear bearing 15 which are the main bearings of the shaft 16. Since these bearings are also filled with a lubricant such as grease, the first lubricant is used to prevent the lubricant from leaking out and to prevent foreign substances from entering the bearing. It is desirable to take the same means as in the embodiment and the second embodiment.

As shown in FIG. 6, the compressor 4 of the third embodiment
In FIG. 4, lip seal type oil seals 45 and 46 are provided before and after the front bearing 14 in the axial direction. The front oil seal 45 seals the space between the atmosphere and the internal space of the front bearing 14. Since no high pressure acts before and after that, no special measures are required. The rear oil seal 46 seals the space between the discharge space 30 where high pressure acts and the internal space of the low pressure front bearing 14.
A large pressure difference occurs before and after 6. Therefore, an annular clearance seal 48 is mounted inside the bearing support 9 of the housing 3 with a low-pressure space 47 behind the oil seal 46.

A minute clearance 49 formed by the clearance seal 48 is formed between the inner surface of the circular opening 50 at the center of the annular clearance seal 48 and the surface of the shaft 16. Further, since the low-pressure space 47 communicates with the atmosphere through the communication hole 51 formed in the bearing support portion 9, the clearance 49 is very small even during the operation of the compressor 44 due to the minute clearance 49. ing.
Accordingly, there is no possibility that the oil seal 46 will be worn out at an early stage, and there is no risk that the lubricant sealed in the front bearing 14 leaks out or foreign matter enters. Needless to say, the circular opening 50 of the clearance seal 48
A labyrinth seal may be formed by providing an annular groove or the like on the surface of the shaft 16 facing the shaft.

The present invention relates to a rear bearing 1 of the compressor 44.
5 can also be applied to the oil seal 52. In this case, the rear bearing 15 is supported by a bottomed cylindrical bearing support, and the rear is closed by the bottom of the bearing support 13. Therefore, the oil seal 52 is provided only in front of the rear bearing 15. ing. In this case as well, the front of the oil seal 52 is the discharge space 31 where high pressure acts, so that the oil seal 5 does not adversely affect the rear bearing 15.
An annular clearance seal 54 is attached to the bearing support 13 with a low-pressure space 53 in front of 2.

The clearance 55 in the third embodiment is
Although formed between the surface of the shaft 16 and the circular opening at the center of the clearance seal 54, in some cases, by attaching the annular clearance seal 54 to the shaft 16, the bottomed cylindrical bearing support portion 13 is formed. A clearance may be formed between the inner surface and the outer peripheral surface of the clearance seal 54. Needless to say, such a modification can be made in each of the above-described embodiments. The low-pressure space 53 is connected to a low-pressure portion in the compressor 44 or to the atmosphere by a communication hole (not shown). The communication hole for this purpose is formed, for example, by penetrating the inside of the shaft 16 or piercing the inside of the wall of the rear housing 4. Alternatively, the other end of the thin tube whose one end is open to the atmosphere may be opened in the low-pressure space 47. In this manner, the third embodiment can also protect the oil seals of the main bearings 14 and 15 and maintain the reliability similarly to the above-described first embodiment and the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a scroll compressor according to the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a part of the scroll compressor shown in FIG.

FIG. 3 is an enlarged cross-sectional side view showing a part of the scroll compressor shown in FIG. 1;

FIG. 4 is an enlarged longitudinal sectional view showing only a main part of the second embodiment.

FIG. 5 is a longitudinal sectional view showing a part of FIG. 4 in a further enlarged manner.

FIG. 6 is a longitudinal sectional view showing a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Double-tooth scroll type compressor as 1st embodiment 2 ... Housing 5, 6 ... Fixed spiral blade 8 ... Suction port 9 ... Front side bearing support part (cylindrical member) 11 ... Discharge port DESCRIPTION OF SYMBOLS 13 ... Rear side bearing support part (cylindrical member) 14 ... Front bearing (bearing) 15 ... Rear bearing (bearing) 16 ... Shaft (rotating shaft) 17 ... Eccentric shaft part (rotating shaft) 21 ... Needle bearing (bearing) 22) rotor 23 ... hub (cylindrical member) 24 ... rotor disk 25, 26 ... movable spiral blade 29 ... suction space 30, 31 ... discharge space 33 ... oil seal 35 ... low pressure space 36 ... clearance Seal 38: Clearance 39, 40: Communication hole 42: Clearance seal 43: Labyrinth seal 44: Double tooth scroll compressor as the third embodiment 6 ... oil seal 47 ... low-pressure space 48 ... clearance seal 51 ... air vent 52 ... oil seal 53 ... low-pressure space 54 ... clearance seal

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16J 15/16 F16J 15/16 B 15/447 15/447 (72) Inventor Hiroshi Okada Showa, Kariya City, Aichi Prefecture 1-cho, Town 1 F-term in Denso Co., Ltd. (reference) 3H003 AA05 AB07 AC01 BC01 CA01 CA02 3H029 AA02 AA17 AB01 BB16 BB44 CC05 CC16 CC17 CC20 CC23 3H039 AA02 AA14 BB04 BB05 BB15 CC02 CC10 CC13 CC04 CC10 CC13 A04A DA10 3J043 AA16 BA06 CA02 CB13

Claims (7)

[Claims] 1. A substantially cylindrical member used in a compressor, a rotating shaft penetrating the inside of the cylindrical member and capable of rotating relative to the cylindrical member, A bearing mounted between the cylindrical member and the rotating shaft; and the cylindrical member being configured to close an internal space of the cylindrical member for the bearing in at least one of the axial directions of the bearing. An oil seal provided between a member and the rotary shaft, a low-pressure space having a predetermined size formed outside the oil seal when viewed in the axial direction from the bearing, and the cylindrical member and the rotary shaft Compression comprising: an annular clearance seal provided so as to form a minute radial clearance between the low pressure space and the low pressure portion. Bearings in machines Sealing device. 2. The device according to claim 1, wherein an annular groove is formed in at least one of the surface of the cylindrical member and the rotating shaft facing the clearance seal, and at least one of the surfaces of the clearance seal. A sealing device for a bearing in a compressor, wherein a labyrinth seal is constituted thereby. 3. The sealing device for a bearing in a compressor according to claim 1, wherein the compressor is a scroll compressor. 4. The compressor according to claim 3, wherein the bearing is a main bearing for supporting the rotating shaft, and the cylindrical member is a bearing support formed on a part of a housing of the compressor. The bearing sealing device in the compressor. 5. The bearing seal device according to claim 1, wherein the compressor is a double-tooth scroll compressor. 6. The compressor according to claim 5, wherein the rotary shaft is an eccentric shaft formed on a part of a drive shaft of the compressor, and the cylindrical member is a rotor of the double-tooth scroll compressor. A hub sealing part for a compressor, wherein the hub part is a center of a disk, and the bearing rotatably supports the hub part by the eccentric shaft part. 7. The method according to claim 1, wherein
A bearing sealing device for a compressor, wherein the low-pressure portion is one of a suction space of the compressor and an external atmospheric pressure space.