JPH0727428Y2 - Bearing structure of screw rotating machine - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure of a screw rotary machine used for a compressor, an expander, a vacuum pump and the like.

[0002]

2. Description of the Related Art In general, a screw rotary machine is one in which a working space of the screw rotating mechanism is axially moved by a meshing rotation of a pair of male and female screw rotors to change a volume thereof to perform a desired compression or expansion action. Accordingly, during operation, a thrust load acting from the high pressure end toward the low pressure end and a radial load perpendicular to the axes of the both rotors act on the pair of male and female screw rotors during operation. At the same time, since the radial load is larger on the high pressure end side than on the low pressure end side, a single row angular ball bearing 52 and a flanged roller bearing 54 are generally provided on the high pressure end 51 of the screw rotor 58 as shown in FIG. The angular load is applied in combination with the angular ball bearing to the screw rotor in the direction from the high pressure end 51 to the low pressure end 53 during operation. The movement of the screw rotor shaft with respect to the direction is regulated so that the gap between both end walls of the rotor is appropriately maintained.

[0003]

The conventional one described above has a structure in which at least two different bearings are arranged on the high-pressure end 51 side of the screw rotor 58, so that the entire screw rotating machine is long. In addition, in order to secure a proper gap between both end walls of the screw rotor, the bearing must also have a high precision, which is expensive and the cost of the entire device is high.

As a countermeasure for the above, Japanese Patent Laid-Open No. 53-995.
A rotor bearing assembly for a rotating gas machine, as disclosed in Japanese Patent No. 11, has been proposed. In this assembly, a single taper roller bearing is arranged on the high-pressure end side and an axial floating type roller bearing is arranged on the low-pressure end side. Thrust load acting from the high-pressure end direction to the low-pressure end direction by the taper roller bearing. And the radial load is supported by the roller bearing on the low pressure end side, and the radial load is supported by the roller bearing. The structure is simple, but the above structure is driven when the rotary machine is started or stopped. In case of reverse rotation of the prime mover, or against reverse thrust load generated by the reverse rotation phenomenon of the rotor caused by the gas pressure that flows backward from the outlet opening (discharge side) to the inlet opening (intake unit) immediately after the compressor stops, Since there is no means for restricting the movement of the shaft in the direction of the high pressure end of the rotor, there is a serious defect that the outlet end plate of the high pressure end comes into contact with the rotor end face, causing seizure. It is inherent.

As a countermeasure, it may be possible to use a combination of slidable materials for the outlet end plate and the rotor, but this is not a practical measure because of lack of practicality.

Therefore, the present invention simplifies the above-mentioned bearing structure to make it inexpensive, and restricts the movement of the screw rotor shaft in either the low-pressure end direction or the high-pressure end direction to thereby reduce the above-mentioned screw. (EN) It is intended to provide a bearing structure for a screw rotating machine which can always maintain a proper gap between both end walls of the rotor and can safely operate the screw rotating machine.

[0007]

In order to solve the above-mentioned problems, the present invention provides a screw rotating machine in which the working space volume changes while moving in the axial direction by the meshing rotation of a pair of male and female screw rotors. A taper roller bearing is arranged on the low-pressure end side of each female rotor shaft so that the rolling surface of the roller has a large diameter toward the high-pressure end side.
The inner end of the inner race of the tapered roller bearing is brought into contact with a step portion provided on the rotor shaft, the outer end of the inner race is fixed to the rotor shaft by a fastener, and the outer race is fitted into the bearing box, and the outer end of the outer race is fixed. While fixing by the spigot part of the bearing cover via the adjusting plate, a roller bearing with a collar is arranged in the bearing box on the rotor shaft on the high pressure end side, and the outer race and the inner race of the roller bearing with the collar are arranged. The outer race is fitted into the bearing box with the collar ring locked by a collar ring through the roller of the bearing against the movement from the low pressure end direction to the high pressure end direction, and the outer end of the outer race is inserted through the adjustment plate into the bearing cover inlay. And the inner end of the inner race is brought into contact with a step provided on the rotor shaft, and the outer end of the inner race is fixed to the rotor shaft by a retainer.

[0008]

While the screw rotating machine is in operation, the radial load is axially supported by the roller bearing with a flange on one shaft end (high pressure end side) of the male / female screw rotor, and the rotor is moved from the low pressure end side to the high pressure end direction. Even if the rotor is reversely rotated at the time of starting or stopping the rotating machine and a reverse thrust load acts from the low pressure end side to the high pressure end direction, the outer race and the inner race of the flanged roller bearing are respectively bearings. It is fixed to the box or rotor shaft, and the outer race and the inner race are locked against movement from the low pressure end direction to the high pressure end direction by the collar ring via the roller of the bearing, so that Movement is regulated. Further, the taper roller bearing at the other shaft end (low pressure end side) axially supports both the thrust load and the radial load, and restricts the movement of the rotor in the low pressure end direction. Keep the gap between the walls properly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 denotes a screw rotary machine of the present invention, which accommodates a male rotor 3 and a female rotor 4 in a cylinder casing 2 and a single taper roller bearing 1 on the low pressure end 5 side.
6 is arranged, and a roller bearing 8 with a collar is arranged on the high pressure end 14 side. The assembly structure is such that the tapered roller bearing 16 is arranged such that the rolling surface of the roller 15 has a large diameter toward the high pressure end side 14 direction, and the inner end of the inner race 20 is provided on the rotor shaft side. While directly contacting the stepped portion 10 and fixing the outer end with a lock nut 11 as a fastener, the inner end of the outer race 21 is provided with a proper gap with respect to the rear end of the bearing box 7, and The outer end is pressed and fixed by the spigot portion of the bearing box cover 13 attached to the low-pressure casing 6 via the adjusting plate 35, and the movement of the male / female rotor from the high-pressure end 14 side to the low-pressure end 5 direction is restricted. At the same time, it axially supports the thrust load and the radial load in that direction.

On the other hand, the flanged roller bearing 8 on the high pressure end 14 side has the inner end of the inner race 9 on the step portion 18 on the rotor shaft side.
The outer race 1 is abutted directly on the rotor race, and its outer end is fixed to the rotor shaft with a bolt 25 via a retainer 19.
The outer end of the bearing 2 is pressed against the spigot portion of the bearing cover 23 through the adjustment plate 35 to securely fix the bearing to the bearing housing. The movement of the roller 36 in the direction of the high-pressure end 14 of the rotor is restricted by a collar ring 37 provided on both ends of the inner race 9 and a collar ring 38 of the outer race 12, whereby the movement of the female and female rotors is suppressed. The axial position is set accurately. So low with the rotor,
The gap between the end walls of the high pressure casing is properly maintained.

In the above structure, the collar rings 37 and 38 of the roller bearing 8 with collars are the male and female rotors 3,
The arrangement position and structure are not particularly limited as long as it is a structure that restricts the movement of 4 in the high pressure end direction. Further, the adjustment plate 35 for fixing the outer races of the taper roller bearing 16 and the flanged roller bearing 8 includes the cover 1
The structure may be provided not only on the spigot portions 3 and 23 but also on the cover and the flange portion of the casing. Also,
The step portions 10 and 18 of the male / female rotor may be integrated with the rotor, or may have a structure in which a ring-shaped member such as a collar is fitted. In addition, 27 is a low pressure port of gas, 28 is a high pressure port of gas, and 29 is a shaft sealing device.

[0012]

As described above, according to the present invention, the taper roller bearing is arranged at the low pressure end side and the roller roller bearings at the high pressure end side are arranged one by one, respectively. , Low voltage side,
Axial movement of the screw rotor is restricted in any direction on the high pressure end side, so that the clearance between the low and high pressure end walls of the rotor is accurately maintained regardless of whether the rotor is in operation or stopped. Therefore, even if a reverse thrust load is applied to the screw rotor, the rotor and the end wall of the casing will not be seized. Also, when adjusting the clearance between the rotor and the end wall of the casing, the thickness of the adjustment plate can be easily changed by simply removing the bearing cover, so there is no need to disassemble and adjust each bearing as in the past. Easy to assemble.

[Brief description of drawings]

FIG. 1 is a detailed view of a first embodiment of the present invention.

FIG. 2 is a detailed view of a conventional example.

[Sign code]

 1 Screw Rotating Machine 3 Male Rotor 4 Female Rotor 5 Low Pressure End 8 Roller Bearing with Collar 10 Step 14 High Pressure End 16 Tapered Roller Bearing 18 Step 35 Adjustment Plate 37 Collar Ring 38 Collar Ring

Claims (1)

[Scope of utility model registration request] 1. A screw rotating machine in which the working space volume changes while moving in the axial direction due to the meshing rotation of a pair of male and female screw rotors. A tapered roller bearing is arranged so that the rolling surface of the roller has a large diameter, and the inner end of the inner race of the tapered roller bearing is brought into contact with the stepped portion provided on the rotor shaft and the outer end thereof is fastened. The outer race is fitted into the bearing box by the tool and the outer end is fixed by the spigot part of the bearing cover via the adjusting plate, while the rotor shaft on the high pressure end side is fixed in the bearing box. A roller bearing with a collar is arranged, and the outer race and the inner race of the roller bearing with a collar are connected to the roller ring of the bearing by a collar ring so that the low pressure end direction The outer race is fitted into the bearing housing, the outer end of which is fixed by the spigot of the bearing cover via the adjustment plate, and the inner end of the inner race is fixed by the rotor shaft. A bearing structure for a screw rotating machine, characterized in that it abuts on a step portion provided on a rotor shaft, and an outer end thereof is fixed to a rotor shaft by a retainer.