JP2017089492A - Turbo compressor and turbo refrigerator having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance compression efficiency by improving a support structure of a turbine shaft in a radial direction, and to prevent an increase of rotation resistance of the turbine shaft and damage of a bearing by restraining a clearance in a bearing of the turbine shaft from becoming excessively small during a period from an operation start of a turbo compressor till a start of its normal operation.SOLUTION: A turbo compressor comprises: a driven gear 12 which is arranged at an intermediate part of a turbine shaft 26, and engaged with a drive gear of a drive shaft; turbine blades 13A, 13B which are arranged at one end of the turbine shaft 26, and constitute a refrigerant compression part 13; a first pivotally supporting part 34 which pivotally supports a portion between the driven gear 12b at the turbine shaft 26 and the turbine blades 13A, 13B; and a second pivotally supporting part 35 which pivotally supports the other end of the turbine shaft 26. At least one cylindrical roller bearing 36 is arranged at the first pivotally supporting part 34 and the second pivotally supporting part 35, respectively, and a four-point contact ball bearing 37 is arranged at least at one of the first pivotally supporting part 34 and the second pivotally supporting part 35.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a turbo compressor that compresses a refrigerant and a turbo refrigeration apparatus including the same.

  In a turbo compressor incorporated in a turbo refrigeration system used as a heat source for district heating and cooling, for example, as disclosed in Patent Documents 1 and 2, the rotation of the motor is increased by a speed increasing gear. Some drive the turbine shaft. That is, the drive gear (large gear) provided on the drive shaft of the electric motor and the driven gear (small gear) provided on the turbine shaft are meshed, and the rotation of the drive shaft is increased and transmitted to the turbine shaft. Is.

  In this case, in the turbine shaft, the positions on both sides of the driven gear are pivotally supported by the rolling bearing, and the radial load applied from the drive gear is supported. Further, since the drive gear and the driven gear are helical gears (helical gears) for reducing meshing noise, an axial load (thrust load) is applied to the turbine shaft during the meshing.

  In the turbo compressor described in Patent Document 1, the radial load of the turbine shaft is supported by a deep groove ball bearing, a cylindrical roller bearing, a tapered roller bearing, or a combination thereof, and the axial load is supported by the deep groove ball described above. It is supported by bearings or tapered roller bearings. That is, both the radial load and the axial load are supported by the deep groove ball bearing and the tapered roller bearing.

  In the turbo compressor described in Patent Document 2, the turbine shaft is supported by a plurality of angular ball bearings, and both the radial load and the axial load of the turbine shaft are supported by these angular ball bearings.

JP 2006-207471 A JP 2002-303298 A

  Deep groove ball bearings and angular contact ball bearings are in steady operating conditions, that is, with the turbine shaft warmed by the heat input of frictional heat generated in the speed increasing gear, and the temperature of the inner ring, outer ring, and balls of the bearing are raised uniformly, The bearing internal clearance is set in advance so that the clearance between the inner and outer rings and the ball, that is, the bearing internal clearance is substantially zero.

  Thus, if the bearing internal clearance under steady operating conditions is made zero, the support rigidity in the radial direction of the turbine shaft can be increased. As a result, the radial vibration of the turbine shaft is reduced, so that the gap between the turbine blade provided on the turbine shaft and the compression passage formed in the casing is set to a minimum, and the leakage of the compressed refrigerant is prevented. High efficiency can be achieved by minimizing.

  However, under the operating conditions in which the turbo compressor in the room temperature state is started without preheating and the speed is increased to the steady operation, as shown in FIG. First, the inner ring of the bearing rises in temperature due to heat input from, and the outer ring rises in temperature with a delay.

  For this reason, the temperature of the inner ring temporarily becomes higher than the temperature of the outer ring, and only the inner ring thermally expands, so that the bearing internal clearance becomes less than zero. At this time, when the balls are crushed (deformed), they generate heat and thermally expand, so that the inner clearance of the bearing becomes tighter, the rotational resistance increases, and eventually the bearing may be damaged.

  The present invention has been made in view of the above circumstances, and enhances the radial support structure of the turbine shaft to increase the compression efficiency. It is an object of the present invention to provide a turbo compressor that can prevent an increase in rotational resistance of a turbine shaft and damage to a bearing by suppressing the gap from becoming too small, and a turbo refrigeration apparatus including the turbo compressor.

In order to solve the above problems, the present invention employs the following means.
The turbo compressor according to the first aspect of the present invention includes a drive shaft provided with a drive gear, a turbine shaft supported in parallel with the drive shaft, and an intermediate portion of the turbine shaft provided with the drive. A driven gear that meshes with the gear, a turbine blade that is provided at one end of the turbine shaft and forms a refrigerant compression portion, and a first shaft support portion that pivotally supports between the driven gear and the turbine blade in the turbine shaft; A second shaft support portion that supports the other end of the turbine shaft, and each of the first shaft support portion and the second shaft support portion is provided with at least one cylindrical roller bearing, At least one of the shaft support portion and the second shaft support portion is provided with a four-point contact ball bearing.

  According to the turbo compressor having the above configuration, the first shaft support portion and the second shaft support portion provided with the driven gear of the turbine shaft interposed therebetween each include at least one cylindrical roller bearing. The rigidity of the turbine shaft in the radial direction can be increased as compared with the case where only ball bearings such as angular contact ball bearings are employed. In other words, in ball bearings, the balls make point contact with the inner and outer rings, but in the case of cylindrical roller bearings, the rollers bite into the inner and outer rings when a radial load is applied because the rollers make line contact with the inner and outer rings. Is significantly smaller than ball bearings, and the turbine shaft has higher support rigidity than ball bearings.

  For this reason, the cylindrical roller bearing can set a bearing internal clearance larger than that of the ball bearing at the time of steady operation in which the inner and outer rings are warmed. As a result, the inner ring of the cylindrical roller bearing is heated before the outer ring by heat input from the speed increasing gear under the operating condition in which the turbo compressor at room temperature is started without preheating and the speed is increased to the steady operation. Even if thermal expansion occurs, the bearing internal clearance of the cylindrical roller bearing does not become less than zero, and there is no concern of increasing the rotational resistance of the turbine shaft or damaging the bearing.

  Further, by supporting the turbine shaft with the cylindrical roller bearing, the support rigidity in the radial direction of the turbine shaft is increased, and the vibration of the turbine shaft in the radial direction is reduced. For this reason, the clearance between the turbine blade provided on the turbine shaft and the compression passage formed in the casing is set to a minimum, and the leakage of the compressed refrigerant is minimized, thereby improving the compression efficiency of the turbo compressor. it can.

  Further, since the four-point contact ball bearing provided together with the cylindrical roller bearing mainly bears the axial load of the turbine shaft, the bearing internal clearance in the radial direction can be increased. For this reason, as in the case of the cylindrical roller bearing, when the turbo compressor is accelerated from room temperature, the bearing internal clearance in the radial direction can be prevented from becoming less than zero, and the rotational resistance of the turbine shaft can be increased. Damage to the bearing can be avoided.

  A turbo compressor according to a second aspect of the present invention includes a drive shaft provided with a drive gear, a turbine shaft supported in parallel with the drive shaft, and an intermediate portion of the turbine shaft provided with the drive. A driven gear that meshes with the gear, a turbine blade that is provided at one end of the turbine shaft and forms a refrigerant compression unit, a bearing that supports the turbine shaft, and an outer ring heating unit that heats the outer ring of the bearing. It is characterized by that.

  According to the turbo compressor having the above-described configuration, under the operating conditions in which the turbo compressor in the room temperature state is started without preheating and the speed is increased to the steady operation, the outer ring of the bearing is first heated by the outer ring heating unit, The outer ring can be thermally expanded simultaneously with the inner ring or before the inner ring. As a result, it is possible to prevent the inner ring of the bearing from being heated and thermally expanded earlier than the outer ring due to heat input from the speed increasing gear, thereby avoiding an increase in rotational resistance of the turbine shaft and damage to the bearing.

  In the second aspect, the outer ring heating section may be an electric heater. Alternatively, the outer ring heating unit may be a refrigerant supply passage that supplies a part of the compressed refrigerant compressed in the refrigerant compression unit to the vicinity of the outer ring.

  By configuring the outer ring heating section as described above, the outer ring of the bearing can be heated with a simple structure, and the inner ring of the bearing rises in temperature before the outer ring due to heat input from the speed increasing gear during speed-up operation, so that the thermal expansion This can prevent the increase in rotational resistance of the turbine shaft and damage to the bearing.

  In the second aspect, it is preferable that the bearing holding member for holding the outer ring is made of a material having better thermal conductivity than the material of the outer ring. Thereby, the heat which an outer ring | wheel heating part brings is favorably transmitted to the outer ring | wheel of a bearing with a bearing holding member. Therefore, the outer ring can be thermally expanded well to avoid an increase in the rotational resistance of the turbine shaft and damage to the bearing.

  A turbo compressor according to a third aspect of the present invention includes a drive shaft provided with a drive gear, a turbine shaft supported in parallel with the drive shaft, and an intermediate portion of the turbine shaft provided with the drive. A driven gear that meshes with the gear, a turbine blade that is provided at one end of the turbine shaft and forms a refrigerant compression unit, a bearing that supports the turbine shaft, and an inner ring cooling unit that cools the inner ring of the bearing. It is characterized by that.

  According to the turbo compressor having the above-described configuration, under the operating conditions in which the turbo compressor in the room temperature state is started without preheating and the speed is increased to the steady operation, the inner ring of the bearing is cooled by the inner ring cooling unit. Thermal expansion can be delayed more than the outer ring. As a result, it is possible to prevent the inner ring of the bearing from being heated and thermally expanded earlier than the outer ring due to heat input from the speed increasing gear, thereby avoiding an increase in rotational resistance of the turbine shaft and damage to the bearing.

  In the third aspect, the inner ring cooling section includes a cooling liquid supply passage formed inside the turbine shaft, and a cooling liquid supply section that supplies the cooling liquid to the cooling liquid supply passage. It is good also as a structure.

  By configuring the inner ring cooling section as described above, the inner ring of the bearing can be cooled with a simple structure, and the inner ring of the bearing is heated before the outer ring due to heat input from the speed increasing gear during the speed-up operation, so that the thermal expansion This can prevent the increase in rotational resistance of the turbine shaft and damage to the bearing.

  A turbo refrigeration apparatus according to a third aspect of the present invention includes any one of the above turbo compressors, a condenser that condenses the refrigerant compressed by the turbo compressor, and an evaporator that evaporates the expanded refrigerant. It is characterized by comprising.

  According to the above configuration, the radial support structure of the turbine shaft in the turbo compressor is enhanced to increase the compression efficiency, and the bearing internal clearance of the turbine shaft becomes too small from the start of operation to the start of steady operation. This can be suppressed to prevent an increase in rotational resistance of the turbine shaft and damage to the bearing, so that a turbo refrigeration apparatus with high performance and high reliability can be obtained.

  As described above, according to the turbo compressor according to the present invention and the turbo refrigeration apparatus provided with the turbo compressor, the support structure in the radial direction of the turbine shaft is increased to increase the compression efficiency, and from the start of operation to the start of steady operation. It is possible to prevent the turbine shaft bearing internal clearance from becoming too small in the meantime and to prevent the turbine shaft rotation resistance from increasing and the bearing from being damaged.

1 is a schematic configuration diagram of a turbo refrigeration apparatus according to an embodiment of the present invention. It is a cross-sectional view showing one structural example of a turbo compressor. FIG. 3 is an enlarged view of the vicinity of a turbine shaft showing a first embodiment of the present invention by enlarging a part III in FIG. 2. FIG. 4 is an enlarged view of the vicinity of a first shaft support portion showing a second embodiment of the present invention by enlarging the IV portion of FIG. 2. It is an enlarged view near the 1st axial support part which shows 3rd Embodiment of this invention. It is an enlarged view of the turbine shaft vicinity which shows 4th Embodiment of this invention. (A), (B) is a longitudinal cross-sectional view of the turbine shaft which follows the VII-VII line of FIG. It is a diagram which shows the correlation with the operating time of the turbo compressor which shows the conventional problem, an operating speed, and the temperature of an inner and outer ring | wheel.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a turbo refrigeration apparatus according to an embodiment of the present invention. The turbo refrigeration apparatus 1 includes a turbo compressor 2 that compresses refrigerant, an oil mist separation tank 3, a condenser 4, an economizer 5, an evaporator 6, a lubricating oil tank 7, a main expansion valve 8, The auxiliary expansion valve 9 is provided. As shown in FIG. 2, the turbo compressor 2 is a unit in which an electric motor 11, a speed increasing unit 12, a centrifugal turbine type refrigerant compressing unit 13, and a plurality of bearings described later are combined into one unit. is there. The lubricating oil tank 7 has a pump 7 a inside and stores the lubricating oil supplied to the speed increasing portion 12 and the bearing of the turbo compressor 2.

In the turbo refrigeration apparatus 1, when the refrigerant compression unit 13 is driven at an increased speed by the electric motor 11 of the turbo compressor 2, the vaporized refrigerant is sucked into the refrigerant compression unit 13 from the evaporator 6 and compressed, and the compressed refrigerant is converted into oil. The oil component is separated in the mist separation tank 3 and then fed to the condenser 4.
Inside the condenser 4, the hot compressed refrigerant compressed by the turbo compressor 2 exchanges heat with the cooling water, thereby cooling the condensation heat and condensing it into a liquid. The condensed refrigerant that has become a liquid phase in the condenser 4 is fed to the evaporator 6 through the economizer 5 and the main expansion valve 8.
A part of the condensed refrigerant passes through the sub-expansion valve 9 and is decompressed to adiabatically expand (vaporize) and flow to the economizer 5. The refrigerant is returned to the middle stage of the second refrigerant compression section 13.

  The condensed refrigerant passes through the main expansion valve 8 and is adiabatically expanded by being depressurized, and flows into the evaporator 6 in a low-temperature gas-liquid two-phase state. Inside the evaporator 6, the low-temperature refrigerant and the heat source water exchange heat, and the heat source water is cooled. The cooled heat source water is used as a cooling medium for air conditioning, industrial cooling water, or the like. The refrigerant vaporized by heat exchange with the heat source water is again sucked into the refrigerant compressor 13 of the turbo compressor 2 and compressed, and this cycle is repeated thereafter.

FIG. 2 is a cross-sectional view showing one structural example of the turbo compressor 2.
In the turbo compressor 2, an electric motor 11, a speed increasing unit 12, a refrigerant compressing unit 13, a drive shaft 25, and a turbine shaft 26 are enclosed in a casing 21 that forms an outer shell thereof. The drive shaft 25 is also a main shaft of the electric motor 11, and a turbine shaft 26 is supported in parallel with the drive shaft 25.

  The speed increasing portion 12 includes a drive gear 12a provided at a tip portion of the drive shaft 25 and a driven gear 12b provided at an intermediate portion of the turbine shaft 26 and meshing with the drive gear 12a. The drive gear 12a has more teeth than the driven gear 12b, so that the rotation of the drive shaft 25 is increased several times and transmitted to the turbine shaft 26. At that time, frictional heat is generated and the turbine shaft 26 is heated. These gears 12a and 12b are helical gears (helical gears) to reduce the meshing noise.

  The refrigerant compressor 13 includes, for example, two stages of turbine blades 13A and 13B fixed to the end of the turbine shaft 26 far from the motor 11 and a compression passage 13C formed in the casing 21. However, if it is a centrifugal turbine type, it is not made into this aspect.

  The drive shaft 25 is pivotally supported by bearings 31 and 32 provided on both sides of the electric motor 11. As these bearings 31 and 32, for example, deep groove ball bearings are employed. On the other hand, the turbine shaft 26 supports the first shaft support portion 34 that supports between the driven gear 12b and the turbine blades 13A and 13B, and the other end of the turbine shaft 26, that is, the end portion on the motor 11 side. The two shaft support portions 35 are pivotally supported.

[First Embodiment]
FIG. 3 is an enlarged view of the vicinity of the turbine shaft showing the first embodiment of the present invention by enlarging the III part of FIG. 2.
The first shaft support portion 34 that supports between the driven gear 12b and the turbine blades 13A and 13B in the turbine shaft 26 includes, for example, one cylindrical roller bearing 36 and one four-point contact ball bearing 37. An annular spacer 38 is interposed between them. Here, the cylindrical roller bearing 36 is disposed on the turbine blades 13A and 13B side, but the positional relationship between the cylindrical roller bearing 36 and the four-point contact ball bearing 37 may be reversed.

  On the other hand, the second shaft support portion 35 that supports the other end of the turbine shaft 26 (the end portion on the electric motor 11 side) is provided with, for example, two cylindrical roller bearings 36 adjacent in the axial direction. These two cylindrical roller bearings 36 may be single and wide cylindrical roller bearings. Each cylindrical roller bearing 36 includes an inner ring 36a, an outer ring 36b, and a roller 36c. The four-point contact ball bearing 37 includes an inner ring 37a, an outer ring 37b, and a ball 37c. The inner ring 37a is divided into two in the axial direction, and the ball 37c contacts the inner ring 37a and the outer ring 37b at two points.

  In the present embodiment, the four-point contact ball bearing 37 is provided on the first shaft support portion 34, but the four-point contact ball bearing 37 is provided on the second shaft support portion 35, or the first shaft support portion 34 and the second shaft support portion 34. You may provide in both of the axial support parts 35 of this. In short, one or more cylindrical roller bearings 36 are provided on both the first shaft support portion 34 and the second shaft support portion 35, respectively, and at least one of the first shaft support portion 34 and the second shaft support portion 35 is provided. A four-point contact ball bearing 37 may be provided.

  In the above configuration, the radial load of the turbine shaft 26 is supported by the cylindrical roller bearings 36 of the first shaft support portion 34 and the second shaft support portion 35, and the turbine shaft 26 is supported by the four-point contact ball bearing 37 of the first shaft support portion 34. Axial load (thrust load) is supported.

  As described above, since at least one cylindrical roller bearing 36 is provided on each of the first shaft support portion 34 and the second shaft support portion 35 that are provided across the driven gear 12b of the turbine shaft 26, a deep groove ball bearing or an angular ball bearing is provided. The rigidity of the turbine shaft 26 in the radial direction can be increased as compared with the case where the turbine shaft 26 is supported only by such ball bearings.

  That is, in the ball bearing, the balls are in point contact with the inner and outer rings, but in the cylindrical roller bearing 36, the roller 36a is in line contact with the inner ring 36a and the outer ring 36b, so that when the radial load is applied, the roller 36a The size of the inner and outer rings 36a, 36b is much smaller than that of the ball bearing, and the support rigidity of the turbine shaft 26 is higher than that of the ball bearing.

  For this reason, the cylindrical roller bearing 36 can set a bearing internal clearance larger than that of the ball bearing during the steady operation in which the inner and outer rings 36a and 36b are warmed. Accordingly, the inner ring 36a of the cylindrical roller bearing 36 is moved by the heat input from the speed increasing gear 12 (driven gear 12b) under the operating condition in which the turbo compressor 2 in the room temperature state is started without preheating and the speed is increased to the steady operation. Even if the temperature is increased before 36 b and the thermal expansion is performed, the bearing internal clearance of the cylindrical roller bearing 36 does not become less than zero, and there is no concern that the rotational resistance of the turbine shaft 26 increases or the bearing is damaged.

  Further, since the four-point contact ball bearing 37 provided together with the cylindrical roller bearing 36 mainly bears the axial load of the turbine shaft 26, the bearing internal clearance in the radial direction can be increased in advance. For this reason, as in the cylindrical roller bearing 36, when the turbo compressor 2 is operated at an ascending speed from the room temperature, the bearing internal clearance in the radial direction can be prevented from becoming less than zero, and the rotational resistance of the turbine shaft 26 can be reduced. Increase and bearing damage can be avoided.

  Since the turbine shaft 26 is supported by the cylindrical roller bearing 36, the support rigidity in the radial direction of the turbine shaft 26 is increased, and the vibration of the turbine shaft 26 in the radial direction is reduced. The clearance between the turbine blades 13A and 13B and the compression passage 13C formed in the casing 21 can be set to a minimum, and the compression efficiency of the turbo compressor 2 can be increased by minimizing the leakage of the compressed refrigerant.

[Second Embodiment]
FIG. 4 is an enlarged view of the vicinity of the first shaft support portion 35 showing the second embodiment of the present invention by enlarging the IV portion of FIG. 2. The casing 21, the turbine shaft 26, the turbine blades 13 </ b> A and 13 </ b> B constituting the refrigerant compressor 13, the compression passage 13 </ b> C, the cylindrical roller bearing 36 constituting the first shaft support 35, the four-point contact ball bearing 37, and the spacer 38 shown here. The shape, positional relationship, etc. are the same as in the configuration of the first embodiment. The bearing types of the cylindrical roller bearing 36 and the four-point contact ball bearing 37 may be replaced with other types, for example, a deep groove ball bearing or an angular ball bearing.

  The cylindrical roller bearing 36, the four-point contact ball bearing 37, and the spacer 38 constituting the first shaft support portion 35 are lightly press-fitted into a cylindrical bearing holding member 41, and the bearing holding member 41 is tightly fitted to the casing 21. It is inserted. The metal material forming the bearing holding member 41 is formed of a material having better thermal conductivity than the metal material (steel material) forming the outer ring 36 b of the cylindrical roller bearing 36 and the outer ring 37 b of the four-point contact ball bearing 37. For example, the metal material of the bearing holding member 41 includes aluminum, brass (brass), copper, and the like. The bearing holding member 41 may be integrated with the casing 21 and the entire casing 21 may be formed of a material having good thermal conductivity.

  For example, a cylindrical electric heater 43 (outer ring heating portion) is provided on the outer peripheral portion of the bearing holding member 41. In the present embodiment, the electric heater 43 is mounted on the casing 21 side in contact with the outer periphery of the bearing holding member 41, but the electric heater 43 may be mounted on the bearing holding member 41 side. The electric heater 43 can uniformly heat the outer ring 36b of the cylindrical roller bearing 36 and the outer ring 37b of the four-point contact ball bearing 37 via the bearing holding member 41 having good thermal conductivity.

  By providing such an electric heater 43, under the operating conditions in which the turbo compressor 2 in a room temperature state is started without preheating and the speed is increased to a steady operation, the electric heater 43 is started first, and the heat H By heating the outer rings 36b and 37b of the bearings 36 and 37, the outer rings 36b and 37b can be thermally expanded simultaneously with the inner rings 36a and 37a or before the inner rings 36a and 37a. This prevents the inner rings 36a and 37a of the bearings 36 and 37 from being heated and thermally expanded earlier than the outer rings 36b and 37b due to heat input from the driven gear 12b, and prevents the rotation of the turbine shaft 26. Increase in resistance and damage to the bearing can be avoided.

  In addition, the bearing holding member 41 that holds the bearings 36 and 37 is formed of a material having better thermal conductivity than the material of the outer rings 36b and 37b of the bearings 36 and 37, so that the heat of the electric heater 43 that is the outer ring heating unit is obtained. Can be transmitted to the outer rings 36b and 37b in a good and even manner by the bearing holding member 41. Therefore, the outer rings 36b and 37b can be thermally expanded well to avoid an increase in rotational resistance of the turbine shaft 26 and damage to the bearings. The electric heater 43 is stopped when the expansion of the bearings 36 and 37 is completed.

[Third Embodiment]
FIG. 5 is an enlarged view of the vicinity of the first shaft support portion showing the third embodiment of the present invention. This embodiment is the same as the configuration of the second embodiment except that a refrigerant supply passage 46 is provided as an outer ring heating unit in place of the electric heater 43 of the second embodiment, and therefore the same components are the same. The reference numerals are attached and the description is omitted.

  Also in the present embodiment, as in the second embodiment, the cylindrical roller bearing 36 and the four-point contact ball bearing 37 constituting the first shaft support portion 35 may be changed to other types of bearings. The metal material of the bearing holding member 41 that holds these bearings 36 and 37 is formed of a material having better thermal conductivity than the metal material that forms the outer rings 36b and 37b of the bearings 36 and 37, as in the second embodiment. To do.

  In the present embodiment, as the outer ring heating section that heats the outer rings 36b and 37b of the bearings 36 and 37, a refrigerant that extracts a part of the compressed refrigerant R compressed in the refrigerant compression section 13 and supplies it to the vicinity of the outer rings 36b and 37b. A supply passage 46 is provided. The refrigerant supply passage 46 includes a refrigerant extraction passage 46a, a refrigerant inlet passage 46b, and a refrigerant outlet passage 46c.

  The refrigerant extraction passage 46a is formed as a torus-like (cylindrical) passage or a plurality of parallel straight hole passages in the bearing holding member 41 along the axial direction of the turbine shaft 26, for example. In addition, the refrigerant inlet passage 46b is a slanted hole-like passage that extends from the vicinity of the labyrinth seal 48 provided between the turbine blade 13b and the casing 21 to one end of the refrigerant extraction passage 46a, and the refrigerant outlet passage 46c is a refrigerant extraction passage. This is a slanted hole-shaped passage extending from the other end of the passage 46 a to the rear end portion of the bearing holding member 41.

  By providing such a refrigerant supply passage 46, low-speed operation is performed so that the bearings 36 and 37 do not overheat under the operating conditions in which the turbo compressor 2 in the room temperature state is started without preheating and the speed is increased to steady operation. By performing for a while, a part of the compressed warm refrigerant R can be extracted and passed through the refrigerant supply passage 46 to thermally expand the outer rings 36b and 37b of the bearings 36 and 37.

  That is, a small amount of the compressed refrigerant R leaking from the labyrinth seal 48 flows from the refrigerant inlet passage 46b into the refrigerant extraction passage 46a, flows backward while warming the bearing holding member 41, and flows out from the refrigerant outlet passage 46c. Since the bearing holding member 41 is formed of a material having good thermal conductivity, the heat of the compressed refrigerant R flowing through the refrigerant extraction passage 46a is well transmitted to the outer rings 36b and 37b of the bearings 36 and 37, and the outer rings 36b and 37b are When heated, it expands.

  Thus, the outer rings 36b, 37b of the bearings 36, 37 can be thermally expanded simultaneously with the inner rings 36a, 37a or before the inner rings 36a, 37a. For this reason, the inner ring 36a, 37a of the bearings 36, 37 is prevented from being heated and thermally expanded earlier than the outer rings 36b, 37b due to heat input from the driven gear 12b with a simple structure, and the rotation of the turbine shaft 26 is prevented. Increase in resistance and damage to the bearing can be avoided.

  Instead of forming the refrigerant supply passage 46 (46a, 46b, 46c) inside the bearing holding member 41 as described above, a groove-like refrigerant supply passage (not shown) is formed between the casing 21 and the bearing holding member 41. ), And the compressed refrigerant R leaking from the labyrinth seal 48 may flow to the outer peripheral side of the bearing holding member 41.

[Fourth Embodiment]
6 is an enlarged view of the vicinity of a turbine shaft showing a fourth embodiment of the present invention, and FIGS. 7A and 7B are longitudinal sectional views of the turbine shaft taken along line VII-VII in FIG. . This embodiment is the same as the configuration of the first embodiment shown in FIG. 3 except that an inner ring cooling section 52 that cools the inner rings 36a and 37a of the bearings 36 and 37 is provided. The description is omitted. The bearing types of the cylindrical roller bearing 36 and the four-point contact ball bearing 37 may be replaced with other types, for example, a deep groove ball bearing or an angular ball bearing.

  The inner ring cooling unit 52 includes a cooling liquid supply passage 53 formed in the turbine shaft 26 and a cooling liquid supply unit 54 that supplies the cooling liquid to the cooling liquid supply passage 53. The coolant supply passage 53 includes, for example, a coolant forward path 53a formed at the axial center of the turbine shaft 26, a coolant return path 53b formed so as to surround the periphery of the coolant forward path 53a, and the interior of the turbine shaft 26. And a communication passage 53c that allows the tips of both passages 53a and 53b to communicate with each other. The cross-sectional shape of the coolant return path 53b is a cross section that concentrically surrounds the periphery of the coolant forward path 53a as shown in FIG. 7A, or surrounds the periphery of the coolant forward path 53a as shown in FIG. 7B. A plurality of linear passages can be formed.

  The coolant supply section 54 is formed in a pipe shape capable of supplying the coolant to the coolant forward path 53 a of the coolant supply passage 53. The other end of the coolant supply unit 54 is connected to a coolant supply pump (not shown). As the coolant, it is conceivable to extract and use a part of the heat source water cooled by exchanging heat with a low-temperature refrigerant in the evaporator 6 shown in FIG. Alternatively, it is conceivable to extract and use the low-pressure liquid refrigerant portion supplied to the evaporator 6.

  By providing the inner ring cooling section 52 configured as described above, the bearings 36 and 37 are supported by the inner ring cooling section 52 under the operating conditions in which the turbo compressor 2 in a room temperature state is started without preheating and is accelerated to a steady operation. The inner rings 36a and 37a can be cooled in advance, and the thermal expansion of the inner rings 36a and 37a can be delayed more than that of the outer rings 36b and 37b. That is, the refrigerant liquid fed from the coolant feeding section 54 to the coolant forward path 53a flows through the communication path 53c to the coolant return path 53b, and thereby the turbine shaft 26 is cooled. , 37 are transmitted to the inner rings 36a, 37a, and the inner rings 36a, 37a are cooled to delay thermal expansion.

  This prevents the inner rings 36a and 37a of the bearings 36 and 37 from being heated and thermally expanded earlier than the outer rings 36b and 37b due to heat input from the speed increasing gear 12 (driven gear 12b) with a simple structure. Further, an increase in the rotational resistance of the turbine shaft 26 and damage to the bearings 36 and 37 can be avoided. The supply of the cooling liquid is stopped when the expansion of the bearings 36 and 37 is completed.

  As described above, according to the turbo compressor 2 according to the present embodiment and the turbo refrigeration apparatus 1 including the turbo compressor 2, the radial shaft direction support structure of the turbine shaft 26 is enhanced to increase the compression efficiency of the turbo compressor 2. It is possible to increase the rotational resistance of the turbine shaft 26 and to prevent the bearing from being damaged by suppressing the bearing internal clearance of the turbine shaft 26 from becoming too small during the period from the start of operation to the start of steady operation.

  It should be noted that the present invention is not limited to the configuration of the embodiment described above, and can be modified or improved as appropriate, and such modified and improved embodiments are also included in the scope of the right of the present invention. To do. For example, the types of the bearings 36 and 37 in the second to fourth embodiments may be changed to other things. In addition, the configurations of the first to fourth embodiments can be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Turbo refrigeration apparatus 2 Turbo compressor 4 Condenser 6 Evaporator 8 Main expansion valve 12 Speed increasing part 12a Drive gear 12b Driven gear 13 Refrigerant compression part 13A, 13B Turbine blade 25 Drive shaft 26 Turbine shaft 34 First shaft support part 35 Second shaft support 36 Cylindrical roller bearing 36a Inner ring 36b Outer ring 36c Roller 37 Four-point contact ball bearing 37a Inner ring 37b Outer ring 37c Ball 41 Bearing holding member 43 Electric heater (outer ring heating part)
46 Refrigerant supply passage (outer ring heating section)
52 Inner ring cooling section 53 Coolant supply passage 54 Coolant supply section H Heat R Compressed refrigerant

Claims (8)

A drive shaft provided with a drive gear;
A turbine shaft supported in parallel to the drive shaft;
A driven gear provided at an intermediate portion of the turbine shaft and meshing with the drive gear;
A turbine blade provided at one end of the turbine shaft and constituting a refrigerant compression section;
A first shaft supporting portion that pivotally supports between the driven gear and the turbine blade in the turbine shaft;
A second shaft support portion that supports the other end of the turbine shaft,
Each of the first shaft support portion and the second shaft support portion is provided with at least one cylindrical roller bearing,
A turbo compressor, wherein at least one of the first shaft support portion and the second shaft support portion is provided with a four-point contact ball bearing. A drive shaft provided with a drive gear;
A turbine shaft supported in parallel to the drive shaft;
A driven gear provided at an intermediate portion of the turbine shaft and meshing with the drive gear;
A turbine blade provided at one end of the turbine shaft and constituting a refrigerant compression section;
A bearing for supporting the turbine shaft;
An outer ring heating section for heating the outer ring of the bearing;
A turbo compressor characterized by comprising:   The turbo compressor according to claim 2, wherein the outer ring heating unit is an electric heater.   The turbo compressor according to claim 2, wherein the outer ring heating unit is a refrigerant supply passage that supplies a part of the compressed refrigerant compressed in the refrigerant compression unit to the vicinity of the outer ring.   The turbo compressor according to any one of claims 2 to 4, wherein the bearing holding member that holds the outer ring is formed of a material having better thermal conductivity than the material of the outer ring. A drive shaft provided with a drive gear;
A turbine shaft supported in parallel to the drive shaft;
A driven gear provided at an intermediate portion of the turbine shaft and meshing with the drive gear;
A turbine blade provided at one end of the turbine shaft and constituting a refrigerant compression section;
A bearing for supporting the turbine shaft;
An inner ring cooling section for cooling the inner ring of the bearing;
A turbo compressor characterized by comprising: The inner ring cooling section is
A coolant supply passage formed inside the turbine shaft;
A coolant supply section for supplying the coolant to the coolant supply passage;
The turbo compressor according to claim 6, comprising: The turbo compressor according to any one of claims 1 to 7, which compresses the refrigerant;
A condenser for condensing the refrigerant compressed by the turbo compressor;
An evaporator for evaporating the expanded refrigerant;
A turbo refrigeration apparatus comprising:

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