JPH0242187A - Bearing device - Google Patents

Abstract

PURPOSE:To keep the fastening load between bearings constant regardless of the temperature difference between shafts and spacers by forming the spacers with a shape memory alloy in a bearing device provided with the spacers in a oil feed space between bearings arranged in parallel in the axial direction. CONSTITUTION:An oil-free screw compressor has male and female rotors 6 and 7 stored in a casing 1, the rotors 6 and 7 are fitted to rotor shafts 8 and 9 respectively. Cylinder roller bearings 16-19, angular ball bearings 20 and 21, bearing outer wheel fixing plates 22-25, shaft seal devices 26-29, bearing oil feed nozzle inner wheel spacers 30 and 31 to secure an oil feed space, and oil feed nozzles 32 and 33 are provided as a bearing device rotatably supporting the shafts 8 and 9. In this case, the spacers 30 and 31 are formed with a shape memory alloy, the spacers 30 and 31 are set to maintain the integral shape and size at the operating temperature of a machine.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to bearing devices such as oil-free screw compressors and mabo pumps. The present invention relates to a bearing device suitable for preventing a phenomenon of wear caused by repetitive micro-slips between a shaft and a shaft (hereinafter, this phenomenon is referred to as "7-lettering").

[Conventional technology]

In conventional bearing devices, for example, cylindrical roller bearings and
A lubrication space was provided between the ball bearing and the bearing lubrication nozzle, and a carbon steel spacer for groove passages was interposed in this lubrication space.

[Problem to be solved by the invention]

In the above-mentioned prior art 1, a spacer made of structural carbon fA is interposed between the bearings.

Therefore, for example, if the machine is an oil-free screw compressor, and the spacer is connected to the inner ring of the cylindrical roller bearing,
When the inner ring of the cylindrical roller bearing is interposed between the inner rings of the cylindrical roller bearing, when a temperature difference occurs between the male and female rotor shafts and the spacer during operation of the oil-free screw compressor, the inner ring of the cylindrical roller bearing This reduces the tightening load on the inner rings of angular bearings, loosens the inner rings of these bearings, and may create gaps between the inner rings of these bearings and the spacer. As mentioned above, when a gap is created between the inner ring of the bearing and the spacer, retching occurs between the inner ring of the bearing and the m and i rotor shafts, and the male and S rotors are relatively displaced in the shaft direction and come into contact. The purpose of the present invention is to solve the problem of the prior art, and to solve the problem of the prior art, and to solve the problem of the reduction in the clamping load of the bearing due to the spacer due to the temperature difference between the shaft and the spacer during machine operation. Prevents gaps between the bearing and spacer,
It is an object of the present invention to provide a bearing device that can prevent 7-retension between a shaft and a bearing.

[Means to solve the problem]

The purpose is to construct a spacer made of a shape memory alloy to provide a lubrication space between the bearings, and to set the spacer to maintain a constant shape and dimensions under the operating temperature of the machine. This is achieved by:

[Effect]

In the present invention, the spacer is made of a shape memory alloy and is set to have a constant shape and dimensions at -F temperature during machine operation, so that the spacer is formed between the shaft and the spacer f' during machine operation. Even if a temperature difference occurs, it is possible to maintain a constant tightening load between the bearings. Therefore, it is possible to prevent the occurrence of a gap between the bearing and the spacer, and to prevent the shaft and the bearing from collapsing, thereby eliminating troubles caused by relative displacement in the axial direction between the shaft and the bearing.

〔Example〕

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

FIG. 1 is a vertical sectional view of an embodiment in which the present invention is applied to an oil-free screw compressor, and FIG. 2 is an enlarged vertical vR side view of a male rotor shaft and a bearing device portion on the discharge side thereof.

As shown in FIG. 1, the oil-free screw compressor of the embodiment shown in these figures includes a casing l, a bearing housing 4, an end cover 5, male and female rotors 0 and 7, and a male rotor and a rotor R. Rotor shaft 8.9, speed increasing gear 10, timing gear 12°13, and lubricating oil injection nozzle 14.1
5 and a bearing device.

The casing 1 is provided with a jacket 2, which is a cooling passage, and a cover 8.

The bearing hatch 4 is fixed to the suction side end of the casing l.

The end cover 5 is fixed to the end of the casing 1 on the discharge side.

The male 1*0 and 6 and 7 are housed in the casing 1 and are engaged with each other.

The male rotor shaft 8.9 is rotatably supported on a bearing device.

The speed increasing gear IO is attached to a portion of the salt rotor shaft 8. This speed increasing gear 10 is connected to a rotation GM source (not shown) via a drive gear 11.

The timing gear 12.1B is attached to the other end of the female rotor shaft 8, 9 and the male rotor shaft.

The female rotors 6 and 7 are rotated at the same speed. This oil-free screw compressor uses pigeon, female rotor 6
．． During operation of 7, the male and female rotors 6°7
and the male and female rotors 6.7, and between the rotor rope end face and the casing 1.
For example, the backward plane gap and the forward plane gap between about 1
It is set to a constant amount of 0 to 80 μm. Therefore, the timing gears 12 and 18 are timed so that the R rotor 6.7 can rotate while maintaining the above-determined reverse gap and forward face gap.

The lubricating oil injection nozzle 14.15 is attached to the end cover 5. These lubricating oil injection nozzles 14, 15
The tip of the rotor shaft 8.9 is inserted into a recess formed in the other end of the female rotor shaft 8.9. By the way, in an oil-free screw compressor, since the discharge pressure rises to, for example, kgf/cImg in a single stage, the discharge air temperature rises to 820 to 880° C. due to heat generated by adiabatic compression of the air. It is necessary to prevent that heat from being transmitted to the male salt rotor 6.7. Therefore, the lubricating oil injection nozzle 1
Starting from 4.15, lubricating oil is injected into the other end of the #s rotor shaft 8.9, and the lubricating oil is used to cool the rotor shaft.

The bearing device includes cylindrical roller bearings 16, 17; 18.19
, angular contact ball bearing 20.21, bearing outer ring fixing plate 22.28; 24.25, and shaft sealing device 26.27
; 28.29 and the bearing lubrication nozzle inner ring space, which is a long length to ensure lubrication space. 30.31 and bearing oil supply nozzles 32.33.

The cylindrical roller bearing 16.17 is fixed to the bearing/S housing 4 by the bearing outer ring fixing plate 2, 2.23, and supports one end of the male, M rotor shaft 8.9.

Between the cylindrical roller bearing 18 and the angular contact ball bearing 20,
A bearing lubrication nozzle inner race spacer 30 is interposed to secure a space for the bearing lubrication nozzle, and a bearing lubrication nozzle inner race spacer 81 is interposed between the cylindrical roller bearing 19 and the angular contact ball bearing 21 to secure a space for the bearing lubrication nozzle. space is secured.

the cylindrical roller bearing 18 and the angular contact ball bearings 20 and 1;
It is fixed to the end cover 5 by a bearing outer ring fixing plate 24, and supports the other end of the male rotor shaft 8. The cylindrical roller bearing 19 and the angular contact ball bearing 21 are
It is fixed to the end cover 5 by a bearing outer ring fixing plate 25, and supports the other end of the female rotor shaft 9.

Said bearing outer ring fixing plate? Reference numerals 22 and 28 tighten the cylindrical roller bearings 16 and 17 with a constant torque using bolts (not shown). The bearing outer ring fixing plate 24 is
The cylindrical roller bearing 18 and 200 pairs of angular contact ball bearings are tightened to a constant torque through bolts (not shown). 19 and angular ball bearing 2
10 sets are tightened to a constant torque.

Further, the bearing devices on the discharge side of the front male and female rotor shafts 8 and 9, that is, the inner rings of the cylindrical roller bearings 18 and 19, and the bearing oil supply nozzle inner ring spacer 30. f31 and the inner ring of the angular ball bearing 20.21 is connected to the timing gear 12.
It is maintained and fixed by the press-fitting load of 1B and the mounting allowance between the inner diameter of the tying gears 1B and li3 and the male and female rotor shafts 8.9.

The shaft sealing device 26.27 is arranged inside the cylindrical roller bearing 16.17 and is mounted on the bearing nozzle 4. The shaft sealing device 28.29 is a cylindrical roller bearing 18.
19, and is attached to the discharge side of the casing l. These shaft seal devices 26, 27; 28, 2
9 prevents bearing lubricating oil from entering the compression working chamber.

Is the bearing oil supply nozzle inner ring flat? 30.31 is constructed of shape memory alloy. In addition, the bearing oil supply nozzle inner race spaces T30 and 81 are preset under the operating temperature of the oil-free screen compressor, that is, for example, when the temperature of the male and female rotor shafts 8.9 is about 110'C, the bearing oil supply nozzle inner race spacer The temperature of 80.81 itself is about 80°C, and the temperature of the male and R rotor shafts 8.9 and the bearing oil supply nozzle inner race space? It is set to maintain constant shape and dimensions at a temperature difference of approximately 80'C from a temperature of 30.31°C.

The bearing lubrication nozzles 32 and 33 provide jet lubrication between the cylindrical roller bearing 18 and the angular contact ball bearing 20 on the discharge side, and between the cylindrical roller bearing 19 and the angular contact ball bearing 21.
Even when the female rotor 7 shafts 8 and 9 rotate at high speeds of, for example, approximately 20,000 r, p, m, the lubrication conditions are satisfied.

The bearing device t of the above embodiment operates as follows: the radial load i applied to the male and 40 bearings 6 and 7 is received by the cylindrical roller bearings 18 and 19, and the axial load is received by the two ball bearings 20 and 20. Received at .21. Also, male, male rotor 6
．． 7 is supported by the angular ball bearings 20 + 21.

And the inner rings of the cylindrical roller bearings 18 and 19 of the bearing devices on the discharge side of the male and female rotor shafts 8.9, and the inner rings of the bearing oil supply nozzles. 30.31 and angular ball bearing 20.2
1 inner ring means, for example, about 1 of the timing gear 12.13.
It is fixed by a pressure load of 500#, the inner diameter of the timing gear 12.18, m, and the mounting allowance of the rotor shafts 8, 9, and the male and female rotor shafts 8, 9 and the cylindrical roller bearings 18.19. Inner ring and bearing oil supply nozzle Inner ring side 4'
Relative sliding between 80.31 and the inner ring of angular ball bearing 20.21 is prevented.

By the way, when an oil-free screw compressor is operating, for example, the temperature of the male rotor shaft is about 110
℃, and the temperature of the bearing oil supply nozzle circular ring sub-r30.31 is about 80'O. Therefore, male and female rotor shafts; 18, 9 and bearing oil supply nozzle inner race spacer 80.81
There is a temperature difference of about 30°C between the two. As a result, when the bearing oil supply nozzle inner race spacer is made of structural carbon steel as in the prior art, the bearing oil supply nozzle inner race spacer is relatively reduced due to the above-mentioned degree difference of approximately 30"C.
As a result, the initial tightening load could not be maintained.

In contrast, in this embodiment, the inner ring spacer 80.31 of the oil receiving nozzle is made of a shape memory alloy. Inner ring Subey i10.31
Since the setting is made to maintain a constant shape and size under the temperature difference of, for example, about 80° C., it is possible to maintain the initial tightening load.

Therefore, in this embodiment, even when the oil-free screw compressor is operating, the cylindrical roller bearings 18, 1'
The inner ring of cylindrical roller bearing 18, the bearing lubrication nozzle inner ring spacer 80, 81, and the angular contact ball bearing 20.2117) can be maintained at the initial tightening load. There is no gap between the inner rings of the cylindrical ζ roller bearing 190, the bearing oil supply nozzle inner ring groove t31, and the inner ring of the angular contact ball bearing 21. As a result, the male and female rotor shafts 8.9,
Inner ring of cylindrical roller bearing 18.19 and angular contact ball bearing 20
．． Since it is possible to eliminate relative displacement in the axial direction with 21 and prevent fretting,
It is possible to eliminate the trouble of contact and burnout caused by the relative movement of the cylinders 6 and 7 in the axial direction.

Note that the bearing device according to the present invention is applicable not only to oil-free screw compressors but also to vacuum pumps, for example.

〔Effect of the invention〕

In the present invention described above, the spacer is made of a shape memory alloy, and is set to have a constant shape and size under the operating temperature of the machine, so that there is no space between the shaft and the spacer during machine operation. Even if a temperature difference occurs, it is possible to maintain a constant tightening load between the bearings. therefore,
According to the present invention, it is possible to prevent the occurrence of a gap between the bearing and the spacer, and it is possible to prevent the shaft and the bearing from fretting or collapsing, thereby eliminating troubles caused by relative displacement in the axial direction between the shaft and the bearing. effective.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment in which the present invention is applied to an oil-free screen compressor, and FIG. 2 is an enlarged longitudinal sectional view of a male rotor shaft and a bearing device portion thereof on the discharge side. l...Casing 6.7...Pheasant, female rotor 8.
9...Male, female rotor shafts 16, 17; 18.
19...Cylindrical roller bearing that constitutes the bearing device
20. 22.23 p Fixed plate position 30° pacer 3 21...Same angular contact ball bearing 24.25...Same bearing outer ring 26.27; 28.29...Shaft seal 31...Same bearing oil supply nozzle inner ring S2.38... Also bearing oil supply nozzle.

Claims (1)

[Claims] 1. In a bearing device in which at least two bearings are arranged in parallel in the axial direction, a lubrication space is provided between both bearings, and a spacer is interposed between the lubrication spaces, the spacer is made of a shape memory alloy, and the spacer is made of a shape memory alloy. A bearing device characterized in that the spacer is set to maintain a constant shape and dimensions under the operating temperature of the machine.