JPS5929793A - Rotary compressor - Google Patents

Abstract

PURPOSE:To improve the performance and reliability of a compressor while reducing rotor bending vibration by providing a vibrationproof mechanism against said rotor bending vibration on a thrust bearing for supporting axis load. CONSTITUTION:A vibrationproof mechanism 28 interposed between the outer peripheral parts of thrust bearing outer races 11a, 11b and the inner peripheral part of the cylindrical end part 15a of a thrust bearing retainer 15 comprises arbitrary number of ring-shaped spaces 29a-29c and O rings 30a, 30b respectively held between said adjacent spacers 29a, 29b and between said adjacent spacers 29b, 29c. The thrust bearing retainer 15 holds a thrust bearing 11, positions a female rotor 2 in its axial direction, permits the O rings 30a, 30b held among the spacers 29a-29c to be subjected to elastic deformation, and elastically holds a thrust bearing 11 in its radial direction. Thus, the O rings 30a, 30b adsorb the vibration energy of female rotor 2 to reduce its vibration amplitude and improve the reliability and performance of a compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rotary compressor, lp! Part i relates to the structure of the thrust bearing portion of the rotor.

A conventional rotary compressor, for example, an oil-free screw compressor, as shown in FIG.
It is configured to form a working chamber (not shown) between the two and compress the gas.

The rotors 1 and 2 are provided with suction side cylindrical roller bearings 6 and 7 provided in the casing 3 and suction cover 4, discharge side cylindrical roller bearings 8 and 10, and combination angular contact ball bearings 9,
It is rotatably supported by 11. Bearing holders 12 and 13 are provided on the suction cover 4 and the discharge side of the casing 3.
and 14.15 are installed respectively.

The radial load acting on the rotors 1 and 2 is supported by cylindrical roller bearings 6 to 8 and 10, and the thrust load is supported by angular contact ball bearings 9 and 11. The bearing outer ring is configured to be freely supported to prevent this.

In an oil-free screw compressor, oil drains 16.18, 20.2 are installed between the bearing and the working chamber to prevent lubricating oil from the bearing from flowing into the working chamber and contaminating the compressed gas.
2 and shaft seals 17.19, 21.23 are provided. Timing gears 24, 25 covered by a discharge cover 5 are attached to the discharge sides of the rotors 1, 2, and these timing gears 24, 25 prevent the rotors 1, 2, which are not lubricated, from coming into contact with each other. Adjusting the gap between the two. A pinion 26 is attached to the suction side of the male rotor l and is reversely driven by a speed increasing gear)' (not shown). Further, cooling water for the compressor is passed through a jacket 27 provided in the casing 3.

It is well known that a rotating body such as a screw rotor resonates when passing through its critical speed, and the bending motion amplitude becomes extremely large. When the bearing that supports the rotating body is a sliding bearing, vibration energy is largely absorbed by the bearing oil film, and it is possible to optimize the bearing characteristics for four-way damping.

On the other hand, in the case of a rolling bearing, since the bearing has high rigidity and absorbs little vibration energy, the vibration 1rb amplitude of the rotating body at critical speeds may increase significantly.

A screw compressor consists of a pair of intermeshing male, dFi
Since this is a mechanism that compresses gas by reducing the volume of the working chamber formed between the rotor and the casing, there is no leakage of gas from the gap formed between the two rotors or between the rotor and the casing. This is the biggest factor that reduces compressor performance. Therefore, in a screw compressor, it is important to make the gap as small as possible.

However, if the gap is made smaller, when the amplitude of the rotor's motion increases at the resonance point, contact between both rotors and contact between the rotor and the casing will cause p1 wear and seizure, reducing the reliability of the compressor. decreases significantly. For this reason, conventionally, the compressor operating speed (rotation speed) was designed so that it did not match the rotor's critical speed, and generally there was a difference of 15% or more between the compressor operating speed and the rotor's critical speed. is provided. This more advanced method has the following problems.

First, to create a series of compressors with different discharge flow rates, there is a method of using the same rotor and changing the discharge flow rate by changing its operating speed. in this case,
Since it is extremely difficult to design the rotor while avoiding several critical speeds such as primary, secondary, and tertiary speeds for each operating speed, the adjustment range of the discharge flow rate is inevitably limited.

On the other hand, as a capacity control method for screw compressors, there is a so-called rotation speed control method that changes the operating speed, but in this case as well, it is necessary to keep the rotor within the control range so that it does not pass through the critical speed. Therefore, it is extremely difficult to set a wide control range.

For a uniaxial rotating body such as a turbo compressor, a method has been proposed to reduce vibration by providing a squeeze film damper around the rolling bearing. However, screw compressors have two shafts, and the shaft center must be fixed in order to reduce the gap between the rotor and the casing. It cannot be supported elastically like a damper.

In view of the above, the present invention aims to reduce the bending vibration of the rotor and improve the performance and reliability of the compressor. It is characterized by the addition of a mechanism.

Embodiments of the present invention will be described below with reference to the drawings.

The symbol 9 in Figures 2 to 11, the symbol - in Figure 1.
Items that are the same as the numbers indicate the same or relevant parts.

In Fig. 2, 1 and 2 are the male rotor and female rotor, 11 is the thrust bearing of the female rotor 2, 11a and llb are the outer rings of the thrust bearing 11, 15 is the ring-shaped bearing holder of the thrust bearing 11, and 28 is the thrust bearing. This vibration damping mechanism 28 is a vibration allocation mechanism interposed between the outer periphery of the outer rings 11a and llb and the inner periphery of the cylindrical end 15a of the thrust bearing retainer 150.
An arbitrary number of ring-shaped spacers 29a to 29c, adjacent spacers 29a and 29b, and 29b and 29a.
It is composed of O-rings 30a and 30b held between them. The rest of the structure is the same as the conventional example shown in FIG. 1, so the drawings and explanation will be omitted.

The first embodiment has the above-mentioned configuration, in which the thrust bearing holder 15 holds down the thrust bearing 11 and positions the female rotor 2 in the axial direction, and the O-ring 30a is held between the spacers 293 to 29c.

30b is elastically deformed to elastically support the thrust bearing 11 in the radial direction. The above-mentioned blowfish 30a and 30b absorb the vibration energy of the bending vibration of the female rotor 2 to reduce the vibration amplitude.

FIG. 3 shows the characteristics of the first embodiment and the conventional example, that is, the relationship between the compressor rotation speed and the female rotor vibration amplitude.
Curves A and B in this figure show the characteristics of the first embodiment and the conventional example, respectively. In the same figure, the compressor rotation speed is 15,000 rpm.
At a nearby resonance point, the vibration amplitude of the female rotor is about 90 μI11 in the conventional example, whereas in the present example it is reduced to less than ⅓, and it is clear that this effect is significant.

In the first embodiment, since the shaft of the female rotor 2 has a small diameter and the bending vibration is large, the damping mechanism 27 was provided only on the female rotor side, but this damping mechanism 27 was attached to the male rotor 1 side. You can also get the same effect.

The second embodiment shown in FIG. 4 includes a thrust bearing outer ring 11a,
The first embodiment is characterized in that a ring-shaped elastic body 30 made of rubber or the like is used as a vibration damping mechanism interposed between the outer circumference of the thrust bearing holder 15 and the inner circumference of the end 15a of the thrust bearing holder 15. However, the other structures d are the same. With this configuration, the number of parts is reduced compared to the first embodiment,
It also has the advantage of being easy to assemble.

In the third embodiment shown in FIG. 5, a thrust bearing 15A is constructed of copper bodies 15A, 15A, such as a copper phase, and an elastic body 15Ab, such as rubber, and this thrust bearing 15A is allocated (also used as a surface structure). The second embodiment differs from the first embodiment in that it is configured as follows, and the other structures are the same.

With this configuration, when the thrust 1 pongee receiver 11 and the thrust bearing retainer 15A need to be fitted in a tight fit, the elastic body 15Ab can exert the p-vibration damping effect. can.

The fourth embodiment shown in FIG. 6 includes an outer ring 32a fitted into the thrust bearing 11, and an oil reservoir 32b filled with oil formed by the outer ring 32a and the end 15a of the thrust bearing holder 15. Vibration damper't: #3
The second embodiment is different from the first embodiment in that the second embodiment is configured with the second embodiment, and the other structures are the same. The oil may be the same as the bearing lubricating oil, and this oil is supplied from an oil supply hole (not shown). The present embodiment constructed in this manner is most suitable when the compressed gas is corrosive and rubber or the like cannot be used.

In addition, the vibration energy of the rotor is absorbed by the viscous damping effect in the oil sump, so there is an advantage that the distribution effect is even more effective.

In the fifth embodiment shown in FIG. 7, there is a
A plurality of thin rings 33a and these rings 33a
The difference from the first embodiment is that an allocation mechanism 33 made of an oil film formed by supplying oil between them is provided, but the other structures are the same. With this configuration, there is an advantage that the magnitude of viscosity reduction can be adjusted by changing the number of thin rings 33a and the thickness of the oil film formed between adjacent rings 33a.

The sixth embodiment shown in FIG.
This embodiment differs from the first embodiment in that the vibration damping mechanism 34, which consists of a thin wall portion 15b provided at the thrust bearing 11 and an oil film 35 formed between the bearing presser 15 and the casing 3, is formed into a thin film on the thrust bearing 11. Other structures are the same. With this configuration, the spring action of the thin portions 15b and the viscous action of the oil film 35 with respect to the radial displacement of the thrust bearing 110 can be combined to provide an optimal distribution effect.

The seventh embodiment shown in FIG. 9 has a ring 38 loosely fitted into the thrust bearing 11, an oil film 39 formed between the ring 38 and the thrust bearing 11, and an intervening space between the ring 38 and the casing 3. An arbitrary number of ring-shaped springs 40 (10th
This embodiment differs from the first embodiment in that a vibration damping mechanism 37 consisting of a vibration damping mechanism 37 (see figure) is provided, but the other structures are the same. With this configuration, the viscous action of the oil film 39 and the ring-shaped spring 40 can be reduced.
There is an advantage that the spring action of the ring springs 40 can be synchronized to obtain a distribution effect, and that the spring force can be adjusted by changing the wall thickness and number of the ring-shaped springs 40.

The eighth embodiment shown in FIG. 11 includes a wavy spring 42 having a shape shown in FIG.
This embodiment differs from the first embodiment in that an allocation mechanism 41 consisting of an oil film 43 formed between the thrust bearing 11 and the thrust bearing 11 is provided.
Other structures are the same. This configuration has the advantage of simplifying the structure, reducing the number of parts, and improving workability.

Although each of the above-mentioned embodiments has been described with respect to an oil-free screw compressor, the present invention is not limited thereto, and can also be applied to rotary positive displacement expansion compressors such as oil-cooled screw compressors and Roots compressors.

As explained above, according to the present invention, by attaching an allocation mechanism to the thrust bearing, bending vibration of the rotor can be reduced and the performance and reliability of the compressor can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional oil-free screw compressor, Fig. 2 is a sectional view of essential parts showing an embodiment of the rotary compressor of the present invention, and Fig. 3 is a comparison of characteristics between the same embodiment and a conventional example. 4 to 9 and 11 are sectional views of main parts showing other embodiments of the present invention, and FIG. 10 is a sectional view of the ring-shaped spring of the allocation mechanism in the embodiment of FIG. 9. , FIG. 12 is an explanatory diagram of the shape of the wavy spring of the allocation mechanism in the embodiment of FIG. 11. 1.2...Rotor, 3...Casing, 11...
Thrust bearing, 15... Thrust bearing holder, 15A,
2B. 31-34, 37.41... Vibration damping mechanism, 29a-29
C--Sveza, 15A, 30a, 30b-elastic body, 15A, 15Ab-rigid body, 32a, 33a. 38.42...Ring, 32b...Oil sump, 35°39.43...Oil film, 40.42...Spring. Sakae 1 Mouth Fang Z Sensai 3 Eyes Fang 4 Eyes Ri Otsu (+5 Kyousai Otsu Sen υ 2 O″7 Kousai 3 eyes’ J-

Claims (1)

[Claims] 1. A working chamber is formed by a casing and a rotor rotatably provided within the casing, and a radial bearing that supports the radial load acting on the rotor and a thrust bearing that supports the axial load are provided. 1. A rotary compressor, characterized in that the thrust bearing is provided with an allocation mechanism for bending vibration of the rotor. 2. The vibration damping mechanism consists of an arbitrary number of ring-shaped spacers and a ring-shaped elastic body sandwiched between these adjacent spacers, and this vibration damping mechanism is interposed between the thrust bearing and the thrust bearing valve valve. A rotary compressor according to claim 1, characterized in that: 3. The compressor according to claim 1, wherein the allocation mechanism is comprised of a cylindrical elastic body interposed between a thrust 411 holder and a thrust 411 holder. 4. The rotary compressor according to claim 1, wherein the vibration damping mechanism also serves as a thrust bearing valve plate made of a rigid body and an elastic body. 5. Claims characterized in that the vibration damping mechanism consists of an outer circumferential ring that fits into the thrust bearing, and an oil reservoir filled with oil formed by the outer circumferential ring and the thrust bearing valve cage. The rotary compressor according to item 1. 6. The allocation mechanism is comprised of a plurality of thin rings provided between the thrust bearing and the thrust 11 + retainer, and an oil film formed between these rings. rotary compressor. 7. The vibration control mechanism according to claim 1, wherein the vibration damping mechanism includes a thin wall portion provided on the thrust bearing valve valve and an oil film formed between the bearing valve valve and the casing. compressor. 8. The vibration damping mechanism includes a ring loosely fitted to the thrust bearing, an oil film formed between the ring and the thrust bearing, and an arbitrary number of ring-shaped springs provided between the ring and the casing. A rotary compressor according to claim 1, characterized in that: 9. The rotation according to claim 1, wherein the control dragon mechanism comprises a wavy spring loosely fitted into a thrust bearing, and an oil film formed between the spring and the thrust bearing. compressor.