JP2577204Y2 - Screw compressor - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an assembly structure of a rotor shaft support portion of a screw compressor, and more specifically, facilitates disassembly and assembly of a screw rotor without impairing the performance of the compressor. Screw compressor.

(Prior art and its problems) Generally, a screw compressor changes its volume while moving in the axial direction by the meshing rotation of a pair of male and female screw rotors, and achieves a desired compression.
Along with this volume change, a thrust load acting from the high pressure side toward the low pressure side and a radial load perpendicular to the axial direction of both rotors act on the pair of male and female screw rotors during operation.

As a result, the conventional screw compressor uses the roller bearings 43 and 43 'to apply a radial load to the low-pressure side LP of the male and female screw rotors 41 and 42, as shown in FIG. Angular ball bearings 44, 44 'made up of individual bearings are used to support both the radial load and the thrust load.

However, this structure requires a total of 6 bearings per bearing for both male and female screw rotors 41,42.
Since it is used individually, it has an expensive structure as a whole.

In order to improve this, Japanese Patent Publication No. Sho 62-48078 discloses that instead of the above-mentioned angular ball bearings 44, 44 ', the rolling surface of the screw rotor shaft on the high pressure side increases from the low pressure side to the high pressure side. There has been proposed a structure in which a tapered roller bearing having a diameter is provided, and the high-pressure side screw rotor shaft is supported by a single tapered roller bearing.

(Problem to be Solved by the Invention) Among the bearing structures of the screw rotor described above, the former is expensive because it has a large number of bearings and requires high precision.

On the other hand, the latter structure can reduce the total number of bearings that support the screw rotor. On the other hand, when disassembling the screw rotor from the casing, even if the high-pressure side end plate of the casing and the cylindrical body (cylinder part) are removed, the The roller bearing restricts the movement of the screw rotor from the high pressure side to the low pressure side, so that the screw rotor cannot be easily disassembled from the casing. In order to disassemble each from this state, it is necessary to use a special jig for detaching the tapered roller bearing from the screw rotor shaft, resulting in poor workability.

In addition, when the above-described tapered roller bearing is disposed on the low-pressure side screw rotor shaft, the rolling roller portion of the tapered roller bearing is integrated with the inner ring, and a shaft hole provided on the low-pressure side casing end wall. Since the diameter of the screw roller is smaller than the outer diameter of the rolling roller portion, when the screw rotor is disassembled from the casing, the rolling roller portion interferes with the shaft hole on the low-pressure side, and the screw rotor is removed from the casing. Cannot be disassembled. In order to disassemble each from this state, it is necessary to use a special jig for detaching the tapered roller bearing from the screw rotor shaft as described above, and thus there is a problem that workability is poor and skill is required.

Further, as a countermeasure against the interference between the rolling roller portion of the tapered roller bearing and the shaft hole provided in the casing end wall on the low pressure side, it is conceivable to make the shaft hole larger than the outer diameter of the rolling roller portion. When the diameter of the shaft hole becomes larger than the root diameter of the screw rotor, each working space formed between the groove of the pair of male / female screw rotors and the casing causes the low pressure of the screw rotor to decrease. It communicates via a gap formed between the tooth bottom at the side end and the shaft hole and a space formed between the outer peripheral surface of the screw rotor shaft on the low pressure side and the inner peripheral surface of the shaft hole. That is, there is a problem in that the suction space and the compression action space communicate with each other at the low pressure side end of the screw rotor, and the compressed air in the compression action space leaks into the suction space so that the original compression action cannot be performed.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an inexpensive screw compressor which solves the above-mentioned problems, has a simple structure, and has good workability in assembling and disassembling.

(Means for Solving the Problems) In order to solve the above problems, the present invention relates to a screw compressor in which a pair of screw rotors, which are male and female, are meshed with bearings and supported rotatably.
On the low-pressure side of the screw rotor shaft, a single tapered roller bearing is provided in which a bearing inner ring and a rolling roller portion are integrally assembled, and a rolling surface increases in diameter from the low-pressure side to the high-pressure side. The shaft hole provided in the casing end wall on the low pressure side is formed larger than the outer diameter of the rolling roller portion of the tapered roller bearing, and the diameter of the shaft hole on the low pressure side end surface of the screw rotor is smaller than the diameter of the shaft hole. Further, a sealing ring having a diameter larger than the tooth root diameter of the screw rotor is provided in close contact with the screw rotor.

(Operation) A taper roller bearing with a large rolling surface from the low-pressure side to the high-pressure side is installed on the low-pressure side of the screw rotor shaft, so that a single bearing supports both the thrust load and the radial load. And therefore the number of bearings can be reduced.

The shaft hole provided in the end wall of the casing on the low pressure side is formed larger than the outer diameter of the rolling roller portion of the tapered roller bearing, so that when the screw rotor is disassembled from the casing, the inner ring of the tapered roller bearing can be screwed down. There is no need to disconnect from the shaft. Further, the casing and the screw rotor can be disassembled simply by removing the fixing between the discharge end plate and the cylindrical body.

By providing a sealing ring having a diameter smaller than the diameter of the shaft hole and a diameter larger than the root diameter of the screw rotor in close contact with the low pressure side end surface of the screw rotor, a compression action space and a low pressure side are provided. The space formed between the outer peripheral surface of the screw rotor shaft and the inner peripheral surface of the shaft hole is substantially reduced by a narrow passage formed between the outer peripheral surface of the sealing ring and the inner peripheral surface of the shaft hole. Since the air is isolated and the compressed air in the compression working space does not leak to the suction space, the compression efficiency does not decrease.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIG.

Reference numeral 1 denotes a screw compressor main body, in which a male and female screw rotor is housed in a casing, and both low-pressure LPs are tapered roller bearings 5,5 ', and high-pressure HP
Are rotatably supported by meshed roller bearings 6, 6 '.

The tapered roller bearings 5, 5 'have an inner ring 7, 7' and a rolling roller unit integrated with each other, and are configured to be separable from the outer ring 9, 9 'to be fitted. It has a large diameter toward the side, and supports a thrust load acting on the screw rotors 3 and 4 in operation from the high pressure side HP to the low pressure side LP direction and a radial load perpendicular to the axial direction.

On the other hand, the flanged roller bearings 6, 6 'are configured such that the rolling roller portions 10, 10' and the outer races 11, 11 'are integral with each other and are separable from the inner races 12, 12'. ′ For low pressure side LP
And receives a thrust load and a radial load acting in the direction of the high pressure side HP.

A sealing ring 15 is attached to the low-pressure side end 14 of the male rotor 3 with a retaining ring 16 in close contact therewith, and its outer diameter is provided on an end wall 17 of a casing in which the tapered roller bearing 5 is fitted. The diameter is smaller than the diameter of the shaft hole 18 and larger than the diameter of the tooth bottom 19 of the male rotor 3.

At the same time, the shaft hole 18 is formed to have a diameter larger than the outer diameter of the rolling roller portion 8 of the tapered roller bearing, and is opened, so that the shaft hole 18 can be inserted even while being fitted into the rotor shaft 3 passing through the inner ring 7 of the bearing. Has become.

Reference numerals 21 and 22 denote bearing covers, which are tapered roller bearings 5, 5 'and outer rings 9, 6 of flanged roller bearings 6, 6'.
11 is restricted in the axial direction, whereby the lower end 14 and 14 'of the screw rotor 3 and the casing 2,
An appropriate clearance between the end walls 17, 17 'of the 2' is maintained.

On the other hand, the screw rotor 4 is supported on the low-pressure side of the female rotor 4 by a tapered roller bearing 5 'similarly to the male rotor, but in this embodiment, the screw rotor side end is sealed at the screw rotor side end like the male rotor. No stop ring is provided.

This is because the radial load is smaller than the male rotor side,
Therefore, since its outer diameter is smaller than the root diameter of the female rotor, at the meshing portion at the male / female rotor side end,
This is because there is no space for blowing compressed air from a compression action space (not shown) to the suction space 24, and whether or not to provide the sealing ring is appropriately selected in design according to the dimensional conditions described above.

(Other Embodiment) FIG. 2 shows a mounting structure of a sealing ring on a low pressure side of a male rotor, in which a sealing ring 31 having a substantially L-shaped cross section is connected to a side end portion 14 of a rotor 3 and a tapered roller. It is sandwiched between bearings 5. Thereby, the fixing structure of the sealing ring 31 can be simplified as compared with the structure shown in FIG.

(Effects of the Invention) As described above, the present invention has a single tapered roller bearing in which the rolling surface has a large diameter from the low pressure side to the high pressure side on the low pressure side of the screw rotor shaft. Since both the thrust load and the radial load are supported by the bearing, the number of bearings can be reduced, and an inexpensive screw compressor as a whole can be provided.

Further, by forming the shaft hole provided in the end wall of the casing on the low pressure side larger than the outer diameter of the rolling roller portion of the tapered roller bearing, when disassembling the screw rotor from the casing, the inner ring of the tapered roller bearing is formed. There is no need to remove from the screw rotor shaft, eliminating the hassle of inserting and removing the inner ring from the rotor shaft each time.
No special tools are required, and the casing and screw rotor can be easily disassembled simply by removing the fixing between the discharge end plate and the cylindrical body, so that no skill is required and workability is greatly improved.

By providing a sealing ring having a diameter smaller than the diameter of the shaft hole and a diameter larger than the root diameter of the screw rotor in close contact with the low pressure side end surface of the screw rotor, a compression action space and a low pressure side are provided. The space formed between the outer peripheral surface of the screw rotor shaft and the inner peripheral surface of the shaft hole is substantially reduced by the narrow passage formed between the outer peripheral surface of the sealing ring and the inner peripheral surface of the shaft hole. Since the air is isolated and the compressed air in the compression working space does not leak to the suction space, the compression efficiency does not decrease.

[Brief description of the drawings]

1 is a detailed view of a screw compressor according to the present invention, FIG. 2 is another embodiment of a fixing structure of a sealing ring, and FIG. 3 is a detailed view of a conventional screw compressor. 2 ... casing, 3 ... male rotor 4 ... female rotor, 15 ... sealing ring 18 ... shaft hole, 23 ... working space 24 ... suction space

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F04C 18/16 F04C 29/00

Claims (1)

(57) [Scope of request for utility model registration] 1. A screw compressor in which a pair of female and female screw rotors are rotatably supported by bearings in a casing, and a bearing inner ring and a rolling roller portion are integrally formed on a low-pressure side of the screw rotor shaft. A single tapered roller bearing having a large diameter rolling surface from the low-pressure side to the high-pressure side is provided, and the shaft hole provided in the casing end wall on the low-pressure side is used for rolling the tapered roller bearing. A sealing ring having a diameter smaller than the diameter of the shaft hole and a diameter larger than the root diameter of the screw rotor is brought into close contact with the low-pressure side end face of the screw rotor while being formed larger than the outer diameter of the roller portion. A screw compressor characterized by being provided.