JP2017141782A - Blower and operation method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blower capable of continuing an operation even when misalignment occurs between a main shaft and a driving machine shaft during an operation, with a simple structure which does not cause increase in cost.SOLUTION: A blower includes: an impeller 14 on which a plurality of moving blades 12 are mounted; a main shaft 16 in which the impeller 14 is mounted on one end part; one bearing 30 for rotatably supporting the main shaft 16; an intermediate shaft 26 in which one end part is mounted with respect to the other end part of the main shaft 16; a driving machine shaft 18 mounted on the other end part of the intermediate shaft 26; and a driving machine 10 for rotating the driving machine shaft 18. During an operation, compared with before the operation, misalignment occurs between a center axis of the main shaft 16 and a center axis on the driving machine 18 side. The blower also includes: a fixed shaft coupling 28 for rigidly connecting the main shaft 16 and the intermediate shaft 26; and a flexible coupling 24 for connecting the intermediate shaft 26 and the driving machine shaft 18 by allowing misalignment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blower that blows a working fluid having a temperature different from room temperature, such as exhaust gas from a boiler, and an operation method thereof.

  For example, a blower is known as equipment for passing exhaust gas from a boiler (Patent Document 1 and Patent Document 2). Such a blower is, for example, an axial fan, and exhaust gas flows through a main channel formed between the outer cylinder and the inner cylinder.

JP 2003-278893 A Japanese Utility Model Publication No.59-62299

  As shown in FIG. 6, the blower that is an axial fan includes an outer cylinder 101 and an inner cylinder 102, and exhaust gas flows through a main flow path MF between the outer cylinder 101 and the inner cylinder 102 having a common axis. It is like that. The outer cylinder 101 and the inner cylinder 102 are installed so that the axial direction is substantially horizontal. In the inner cylinder 102, an impeller 103, a main shaft 104 to which the impeller 103 is attached at one end, two main bearings 105 a and 105 b that rotatably support the main shaft 104, and a counterweight fixed to the main shaft 104 106 and an intermediate shaft 107 are provided. Between the main shaft 104 and the intermediate shaft 107, there is provided a first flexible shaft coupling 108 that allows the deflection deformation between these shafts.

  The two main bearings 105a and 105b are accommodated in the bearing housing 118. The bearing box 118 is supported from below in the inner cylinder 102 by a bearing stand 119. The main bearings 105a and 105b are two in order to receive a moment that the impeller 103 supported in a cantilever manner falls vertically downward.

  The counterweight 106 is provided to counter a moment about the main bearings 105a and 105b of the impeller 103 that is cantilevered. The load direction of the counterweight 106 is indicated by an arrow C1.

  A motor shaft 109 is connected to the other end (right end in the figure) of the intermediate shaft 107 via a second flexible shaft coupling 110. The motor shaft 109 is rotationally driven by a motor 111 that is an electric motor. The motor shaft 109 is normally rotatably supported by two motor bearings 112a and 112b.

The motor 111 and the motor shaft 109 are not housed in the inner cylinder 102 and are installed in the atmosphere outside the inner cylinder 102 and the outer cylinder 101.
The motor 111 is installed on the foundation B. The outer cylinder 101 is installed on the foundation B through a plurality of legs 114. The inner cylinder 102 is fixed to the outer cylinder 101 via a plurality of support wings 113.

  Around the impeller 103, a plurality of moving blades 115 are provided. As the moving blade 115 rotates about the central axis CL1 of the main shaft 104, a flow of exhaust gas is formed. A stationary blade 116 is provided on the downstream side of the moving blade 115.

As shown in FIG. 6, during the cold state before operation, the central axes of the motor shaft 109, the intermediate shaft 107, and the main shaft 104 coincide, and the central axis CL <b> 1 is parallel to the axial directions of the outer cylinder 101 and the inner cylinder 102. Assemble.
On the other hand, during operation, since high-temperature exhaust gas of 90 ° C. to 200 ° C. flows into the main flow path MF, thermal deformation occurs during the warm state as shown in FIG. Specifically, as shown in the figure, since the exhaust gas flows at a high temperature, the outer cylinder 101 and the inner cylinder 102 rise in temperature and thermally deform, and the whole is displaced vertically upward (upper side in FIG. 7). To do. On the other hand, since the motor 111 and the motor shaft 109 are exposed to the atmosphere outside the outer cylinder 101 and the inner cylinder 102, the temperature does not increase and does not thermally deform. Accordingly, the main bearings 105a and 105b accommodated in the bearing box 118 supported from the vertically lower side in the inner cylinder 102 are displaced upward in the vertical direction with the thermal deformation of the outer cylinder 101 and the inner cylinder 102. The motor shaft 109 that is not affected by thermal deformation is not displaced. That is, the central axis CL1 of the main shaft 104 is displaced vertically upward, while the central axis CL2 of the motor shaft 109 is not displaced. As a result, the center axis CL1 of the main shaft 104 and the center axis CL2 of the motor shaft 109 are misaligned, and misalignment (deflection angle) occurs before and after the axial direction of the intermediate shaft 107, which may hinder continued operation of the blower. . In FIG. 7, the misalignment between the central axes CL1 and CL2 is indicated by an angle θ.

  Even if misalignment occurs between the central axes CL1 and CL2 as shown in FIG. 7, the first flexible shaft coupling 108 and the second flexible shaft coupling 110 are provided at both ends of the intermediate shaft 107, so that the displacement due to thermal deformation is caused. The central axis CL1 of the main shaft 104 is kept horizontal. Thereby, even if a high-temperature exhaust gas flows through the main flow path MF, the operation can be continued by absorbing thermal deformation.

However, the following problems exist in the above configuration.
Since there are two main bearings 105a and 105b giving priority to securely supporting the impeller 103 to which the rotor blade 115 is attached so as not to cause displacement of the main shaft 104 attached to one end, the cost is reduced. Increases, the bearing box 118 increases in size, and the axial dimension increases.
Since it is necessary to install the counterweight 106, the cost increases and the axial dimension increases.
Since there are two flexible shaft couplings 108 and 110, the cost increases.

  The present invention has been made in view of such circumstances, and has a simple configuration that does not cause an increase in cost even if misalignment occurs between the main shaft and the motor shaft (drive shaft) during operation. It aims at providing the air blower which can continue driving | running, and its operating method.

In order to solve the above problems, the blower and the operation method thereof according to the present invention employ the following means.
That is, the blower according to the present invention includes an impeller to which a plurality of moving blades are attached, a main shaft to which the impeller is attached to one end, a single bearing that rotatably supports the main shaft, and the main shaft. An intermediate shaft having one end attached to the other end, a drive shaft attached to the other end of the intermediate shaft, and a drive device that rotates the drive shaft. Compared to the above, the blower in which misalignment occurs between the central axis of the main shaft and the central axis on the drive shaft side, the fixed shaft coupling rigidly connecting the main shaft and the intermediate shaft, and the intermediate shaft And a flexible shaft coupling that allows the misalignment to be connected.

As a result of various studies, the present inventors relaxed the condition of maintaining the central axis of the main shaft attached to one end of the impeller to which a plurality of moving blades are attached so as to be in the axial direction of the outer cylinder or the inner cylinder. I came back to the new idea of doing. Thus, by supporting the main shaft with a single bearing, the number of bearings can be minimized, the bearing box can be downsized, the axial length can be shortened, and the cost can be reduced.
As the main shaft is supported by one bearing, a moment due to the load of the impeller and the moving blade fixed to one end of the main shaft is generated around the bearing. In the present invention, the moment is received by using the load of the intermediate shaft as a mass body that generates a moment to counter this. Specifically, the intermediate shaft is added as a mass generating moment by connecting the intermediate shaft integrally with the main shaft by a fixed shaft joint that rigidly connects the main shaft and the intermediate shaft. Thereby, it is not necessary to provide the counterweight on the intermediate shaft side with respect to the bearing. Furthermore, since the counter weight can be omitted, the axial length can be shortened, and the cost can be reduced.
On the other hand, by adopting a flexible joint that connects the intermediate shaft and the drive shaft with allowance for misalignment, the drive shaft is not mainly considered as a mass generating moment. However, by adopting a flexible shaft coupling, during operation, the difference between the temperature on the main shaft side and the temperature on the driving machine shaft side between the main shaft and the central axis on the driving machine shaft side during operation is different. Even in a state where misalignment occurs in between, the misalignment is allowed and the operation can be continued.
Since the flexible shaft coupling can absorb the deviation of the central axis simply by providing it between the intermediate shaft and the drive shaft, a flexible shaft coupling is used instead of the fixed shaft coupling provided between the main shaft and the intermediate shaft. There is no need to do. Thereby, since the quantity of a flexible shaft coupling can be reduced, cost can be reduced.

  Furthermore, in the blower of the present invention, a moment centering on the bearing on the impeller side and a moment centering on the bearing on the intermediate shaft side are balanced within a predetermined range.

By balancing the moment centered on the bearing within a predetermined range, stable operation is possible without providing a counterweight. As a method of balancing moments, for example, it is preferable to adjust the mass by changing the diameter of the intermediate shaft. Here, the center of the bearing means more specifically the center in the axial direction of the bearing and the center of rotation of the main shaft supported by the bearing.
Note that the moment balance within the specified range does not mean that the moment is balanced in a strict sense. It means that it has only to be adjusted to become.

  Further, in the blower of the present invention, an outer cylinder that surrounds each of the moving blades to form a main flow path, and is provided in the outer cylinder, the impeller, the main shaft, the bearing, the intermediate shaft, and the fixed shaft A coupling and an inner cylinder that accommodates at least a part of the flexible shaft coupling, and the inner cylinder is formed with an opening for introducing outside air toward the flexible shaft coupling. .

A main flow path is formed in a region formed between the outer cylinder and the inner cylinder, and air is blown by the action of the moving blade.
An opening for introducing outside air toward the flexible shaft joint is formed in the inner cylinder. Thereby, the temperature rise by the windage loss of a flexible shaft coupling with the flow of outside air is suppressed, and strength can be maintained. Moreover, it is possible to prevent contaminants such as dust from adhering to the flexible shaft coupling.
The outside air that has passed through the flexible shaft joint is guided to the main flow path through the gap between the inner cylinder and the moving blade, for example. As a result, the intermediate shaft whose temperature rises due to the heat effect from the exhaust gas is cooled by the flow of outside air, so that the thermal expansion displacement is suppressed and the deformation load on the flexible shaft joint can be reduced.

  Further, in the blower of the present invention, a convex curved surface having the same radius as viewed from the center of the bearing is formed on the outer peripheral side tip surface of each of the moving blades, and the moving blade is provided on the inner periphery of the outer cylinder. A concave curved surface corresponding to the convex curved surface through a predetermined gap is formed at a position through which the outer peripheral side front end surface passes.

  Since the rotor blade is attached to an impeller that is cantilevered with the bearing as a support point, the outer peripheral end of the rotor blade is displaced about the center of the bearing as a center of rotation by a moment about the bearing. Therefore, a convex curved surface having the same radius as viewed from the center of the bearing is formed on the outer peripheral end surface of the rotor blade, and the convex curved surface is formed at a position where the outer peripheral end surface of the rotor blade passes on the inner periphery of the outer cylinder. A corresponding concave curved surface was formed. This eliminates the need to provide an interference prevention gap between the outer peripheral tip of the rotor blade and the inner periphery of the outer cylinder from the initial installation point, so that the impeller to which the rotor blade is attached is displaced around the center of the bearing. However, the gap between the inner periphery of the outer cylinder does not change greatly. As described above, since the fluid leaking from the gap between the outer peripheral tip of the rotor blade and the inner periphery of the outer cylinder can be reduced as much as possible, the efficiency of the blower is improved and the upper limit of the operable discharge pressure is also increased. Can keep.

  Further, the blower operating method of the present invention includes an impeller to which a plurality of moving blades are attached, a main shaft to which the impeller is attached at one end, a single bearing that rotatably supports the main shaft, A fan operating method comprising an intermediate shaft having one end attached to the other end of the main shaft, a drive shaft attached to the other end of the intermediate shaft, and a drive for rotating the drive shaft. When misalignment occurs between the central axis of the main shaft and the central axis on the drive shaft side during operation, compared to before operation, the main shaft and the intermediate shaft are connected by a fixed shaft joint. After the rigid connection, the intermediate shaft and the drive shaft are operated in a state where the misalignment is allowed by a flexible shaft joint.

  In order to allow misalignment between the main shaft and the drive shaft by providing a single shaft joint on the drive side of the intermediate shaft by using an intermediate shaft as the counterweight of the impeller with a single bearing. Therefore, the axial dimension can be reduced with a simple configuration, and the cost can be reduced.

It is a longitudinal cross-sectional view of the air blower which showed one Embodiment of this invention. It is a cross section of the air blower of FIG. 1, (a) shows the time of the cold state before a driving | operation, (b) shows the time of a hot state during a driving | operation. FIG. 2 is a longitudinal sectional view corresponding to FIG. 1 and showing a warm state during operation. The shape of the blade tip of the blower of FIG. 1 is specifically shown, (a) is a longitudinal sectional view showing a cold state before operation, and (b) is a longitudinal cross section showing a warm state during operation. FIG. It is the longitudinal cross-sectional view which showed the comparative example of FIG. It is the longitudinal cross-sectional view which showed the air blower as a reference example. FIG. 7 is a longitudinal sectional view corresponding to FIG. 6 and showing a warm state during operation.

Embodiments according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the blower 1 is a one-stage axial flow gas fan including a single-stage moving blade 12 that is an axial flow that blows exhaust gas from a boiler that is set to 90 ° C. to 200 ° C., for example. .

  The blower 1 includes an outer cylinder 3 and an inner cylinder 5. In the present embodiment, an example in which the axial direction of the outer cylinder 3 and the inner cylinder 5 is installed in a horizontal direction will be described as an example, but the axial direction may be inclined with respect to the horizontal direction. The same effect can be obtained with such a configuration.

  The outer cylinder 3 is fixed on the base B via a plurality of support legs 7. The outer cylinder 3 is substantially L-shaped when viewed from the side as shown in FIG. One end of the outer cylinder 3 is provided with an inlet portion 3a that opens toward the vertical upper side, and the other end of the outer cylinder 3 is provided with an outlet portion 3b that opens in the horizontal direction. Therefore, the exhaust gas flowing in from the inlet portion 3a flows toward the vertically lower side as indicated by the arrow A1, and then changes its direction in the horizontal direction and flows out from the outlet portion 3b.

Most of the inner cylinder 5 is accommodated in the outer cylinder 3 in a state of extending in the horizontal direction. The inner cylinder 5 is disposed so as to be the same as the central axis of the outer cylinder 3. The region between the inner cylinder 5 and the outer cylinder 3 becomes the main flow path MF, and the exhaust gas at a high temperature flows. The inner cylinder 5 is supported by a plurality of support blades 9 provided between the inner cylinder 5 and the outer cylinder 3. In the present embodiment, support wings 9 are provided at two locations separated in the axial direction (horizontal direction in the figure). Further, as shown in FIG. 2, a plurality of support wings 9 (eight in FIG. 2) are provided to extend in the radial direction at equal angular intervals.
One end 5a of the inner cylinder 5 located on the upstream side of the exhaust gas flow protrudes outward from the outer cylinder 3. Thereby, rotational power can be obtained from the motor (driving machine) 10 disposed outside the outer cylinder 3 (atmosphere side).

  The motor 10 is an electric motor and is installed on the foundation B. The motor 10 rotationally drives a motor shaft (driving machine shaft) 18 with electric power supplied from a power system (not shown). The motor shaft 18 is rotatably supported by two motor bearings 20 a and 20 b provided in the motor 10. The motor 10 can support the motor shaft even by the motor 10 alone, and the two motor bearings 20 a and 20 b are provided with an interval in the axial direction of the motor shaft 18. During the cold state, the central axis CL2 of the motor shaft 18 coincides with the axial battle direction of the outer cylinder 3.

  A connecting shaft 22 having a diameter larger than that of the motor shaft 18 is fixed to the tip of the motor shaft 18. The connecting shaft 22 is inserted into a hole formed in the one end wall 5b of the inner cylinder 5, and the motor 10 side (the right side in FIG. 1) becomes the outside of the inner cylinder 5 with the connecting shaft 22 as a boundary. The 14 side (left side in FIG. 1) is the inside of the inner cylinder 5.

The connecting shaft 22 is connected to the intermediate shaft 26 via the flexible shaft joint 24.
The flexible shaft coupling 24 allows the misalignment even when the center axis CL1 of the intermediate shaft 26 and the center axis CL2 of the connecting shaft 22 and the motor shaft 18 are relatively inclined to cause misalignment. It is a shaft coupling that can transmit rotation. As the flexible shaft coupling 24, a flange-type flexible element in which a plurality of thin plates are laminated and connected between the flanges is used, and for example, a flexing coupling available as a commercial product is used.

The flexible shaft joint 24 is disposed in a seal box 36 formed in the inner cylinder 5. On the side wall of the motor 10 of the seal box 36, that is, the one end wall 5 b of the inner cylinder 5, a seal hole (opening) 38 for introducing seal air, which is external air, from the outside is formed. Seal air is introduced into the seal box 36 from the sealing hole 38 (see arrow A2). Seal air is also introduced into the seal box 36 from the gap between the connecting shaft 22 and the one end wall 5b of the inner cylinder 5 (see arrow A3).
By introducing the seal air in this way, the temperature rise due to the windage loss caused by the rotation of the flexible shaft coupling 24 in the seal box 36 is suppressed, the strength and life of the flexible shaft coupling 24 are maintained, and the decrease is suppressed. This is preferable. In addition, introduction of the seal air is preferable because it prevents the contaminants such as dust accumulated in the seal box 36 from adhering to the flexible shaft joint 24 and maintains the performance of the flexible shaft joint 24.

  A cooling hole 42 is formed in the side wall 40 of the impeller 14 of the seal box 36. The air in the seal box 36 (seal air) flows to the intermediate shaft 26 side (left side in the figure) through the cooling hole 42. The intermediate shaft 26 is cooled by the flow of this air (seal air). As a result, the intermediate shaft 26 whose temperature rises due to the heat effect from the exhaust gas is cooled, so that the thermal expansion displacement is suppressed and the deformation load on the flexible shaft coupling 24 can be reduced. It is preferable because strength and life are maintained and a decrease is suppressed.

  The main shaft 16 is connected to one end portion (left end portion in the figure) of the intermediate shaft 26 via a fixed shaft joint 28. The fixed shaft joint 28 is configured to be rigidly connected between the flanges using bolts or reamer bolts and nuts, and fixes the intermediate shaft 26 and the main shaft 16. Therefore, the central axis CL1 of the intermediate shaft 26 and the main shaft 16 coincides even in the cold state before operation and in the warm state during operation.

The main shaft 16 is rotatably supported by one main bearing 30. As shown in FIG. 4A, the main bearing 30 is a slide bearing provided with a bearing metal 30a that is in sliding contact with the main shaft 16 via a lubricant. However, a rolling bearing such as a ball bearing may be employed instead of the sliding bearing. A spherical seat 31 is provided on the outer peripheral side of the bearing metal 30a. The spherical seat 31 allows the central axis CL1 extending in the longitudinal axis direction of the main bearing 30 to rotate about the center O. In addition, it is good also as a self-aligning type ball bearing, without using a spherical surface seat.
As shown in FIG. 1, the main bearing 30 is disposed in a bearing box 32. Although not shown, the inside of the bearing box 32 may be cooled by cooling air introduced from the outside of the outer cylinder 3. The bearing box 32 is supported by a bearing stand 34 from the vertically lower side. The bearing stand 34 is fixed to the inner peripheral surface of the inner cylinder 5.

An impeller 14 is fixed to the tip of one end side (left end side in the figure) of the main shaft 16. The impeller 14 has a substantially disk shape, and a plurality of moving blades 12 extending in the radial direction are attached to the outer periphery of the impeller 14. The rotation center of the impeller 14 coincides with the central axis line CL1 of the main shaft 16.
The impeller 14 is disposed in the inner cylinder 5, and the moving blade 12 is disposed in the main flow path MF between the inner cylinder 5 and the outer cylinder 3. A predetermined gap is formed between the impeller 14 and the inner cylinder 5, and the air in the inner cylinder 5 is drawn into the main flow path MF through the gap due to a pressure difference.
A plurality of stationary blades 13 extending in the radial direction are provided on the downstream side (left side in the drawing) of the moving blade 12. The stationary blade 13 is fixed between the inner cylinder 5 and the outer cylinder 3.

In the present embodiment, the impeller 14 is attached to the tip of one end side of the main shaft 16 in a cantilever state, so that a moment around the main bearing 30 is applied by the load of the impeller 14 and the moving blade 12. Since there is only one main bearing 30, a moment is generated around the center O of the main bearing 30. Therefore, a load from the intermediate shaft 26 that is rigidly connected to the main shaft 16 via the fixed shaft joint 28 is applied to the moment about the main bearing 30 so as to receive the moment against the moment by the impeller 14. It is like that. The direction of load applied by the intermediate shaft 26 is indicated by an arrow C2 in FIG. Further, the mass of the intermediate shaft 26 is adjusted so that moments about the main bearing 30 are balanced within a predetermined range. Specifically, the mass of the intermediate shaft 26 is adjusted by adjusting the outer diameter without changing the axial dimension of the intermediate shaft 26.
Here, strict mass adjustment of the intermediate shaft 26 for balancing and balancing the moment about the main bearing 30 is not required. The balance of moments means that the load applied to the flexible shaft coupling 24 when the flexible shaft coupling 24 is deformed may be adjusted so as to be within the allowable load.

FIG. 4 shows the tip shape of the outer peripheral side of each rotor blade 12 and the inner peripheral surface shape of the outer cylinder 3 at a position corresponding to the tip of the rotor blade 12.
A convex curved surface 12a having the same radius R1 (in the cold state) as viewed from the center O of the main bearing 30 is formed on the front end surface on the outer peripheral side of each rotor blade 12 by curved surface processing. Here, the center O of the main bearing 30 specifically means the center in the axial direction of the main bearing 30 and the center of rotation of the main shaft 16 supported by the main bearing 30.
A concave curved surface 3c corresponding to the convex curved surface 12a with a predetermined gap is formed on the inner peripheral surface of the outer cylinder 3 at a position where the tip of the moving blade 12 passes by curved surface processing. That is, the concave curved surface 3c is formed so as to have the same radius R2 (>R1; when cold) when viewed from the center O of the main bearing 30. The distance between the convex curved surface 12a and the concave curved surface 3c is substantially constant in the axial direction (left-right direction in the figure). Thereby, even if the impeller 14 to which the moving blade 12 is attached is displaced around the center O of the main bearing 30, the distance between the convex curved surface 12a and the concave curved surface 3c does not change greatly.
In this way, it is not necessary to provide an interference preventing gap between the outer peripheral side tip of the rotor blade 12 and the inner periphery of the outer cylinder 3 from the initial installation time. Therefore, the fluid leaking from the gap between the outer peripheral tip of the rotor blade 12 and the concave curved surface 3c on the inner periphery of the outer cylinder 3 can be reduced as much as possible. The upper limit of can be kept high.

Next, operation | movement of the air blower 1 of the said structure is demonstrated.
During the cold state before operation, the entire blower 1 substantially matches the environmental temperature such as the outside air temperature, and the outer cylinder 3 and the inner cylinder 5 are not thermally deformed. Therefore, as shown in FIG. 1, the central axis CL1 of the main shaft 16 and the central axis CL2 of the motor shaft 18 coincide with each other.
In this state, the motor 10 is driven, the motor shaft 18 is rotated, and the intermediate shaft 26 and the main shaft 16 connected to the motor shaft 18 are rotated, thereby rotating the impeller 14 around the central axis CL1. Thereby, each rotor blade 12 rotates around the central axis CL1 in the main flow path MF, and exhaust gas from the boiler (not shown) is drawn into the main flow path MF and flows in the direction of the arrow A1. When the high-temperature exhaust gas at 90 ° C. to 200 ° C. flows in the main flow path MF, the outer cylinder 3 and the inner cylinder 5 are heated, and thermal elongation occurs. When the thermal expansion of the outer cylinder 3 and the inner cylinder 5 occurs, the inner diameter of the outer cylinder 3 increases from φD to φD ′ as shown in the cold state of FIG. 2A and the warm state of FIG. 2B (D <D ′), the inner diameter of the inner cylinder 5 increases from φd to φd ′ (d <d ′). As a result, the outer cylinder 3 and the inner cylinder 5 are displaced vertically upward by thermal expansion.

Thus, when the inner cylinder 5 is displaced vertically upward, as shown in FIG. 3, the bearing box 32 supported by the bearing stand 34 fixed to the inner cylinder 5 is displaced vertically upward, and the bearing box The main bearing 30 in 32 is also displaced vertically upward. As a result, the main shaft 16 and the intermediate shaft 26 connected by the fixed shaft joint 28 are displaced integrally. On the other hand, the motor shaft 18 does not rise in temperature even during operation and does not cause the displacement of the center axis CL2. However, since the intermediate shaft 26 and the motor shaft 18 are connected by the flexible shaft coupling 24, the motor shaft 18 It is not affected by the displacement of the shaft 26. Therefore, the center axis CL1 of the main shaft 16 and the intermediate shaft 26 is inclined and misaligned (declination) vertically upward by an angle θ with respect to the center axis CL2 of the motor shaft 18 that is not affected by the heating by the exhaust gas. The impeller 14 attached to the tip of one end side of the main shaft 16 and each moving blade 12 attached thereto are rotated at an angle θ from a direction perpendicular to the central axis CL2 (vertical vertical direction in the present embodiment). To do.
In the present embodiment, since the intermediate shaft 26 has a predetermined length in the axial direction, the angle θ, which is the misalignment deviation angle, is reduced, and is actually suppressed to about a few tenths of a degree. Thus, the displacement angle of the flexible shaft coupling 24 is sufficiently acceptable. In other words, the axial length of the intermediate shaft 26 has a predetermined length that is within an allowable displacement angle of the flexible shaft coupling 24.
The blower 1 of the present embodiment can continue the operation while allowing such a misalignment state.

According to this embodiment, there exist the following effects.
In the present embodiment, the main shaft 104 is not supported by the two main bearings 105a and 105b as shown in FIG. 6, but the main shaft 16 is supported by the single main bearing 30, so that the number of bearings is minimized. The bearing box 32 can be reduced in size to the limit, the axial length can be shortened, and the cost can be reduced.

  As the main shaft is supported by one main bearing 30, a moment is generated around the main bearing 30 due to the load of the impeller 14 and the moving blade 12 fixed to the tip of the main shaft 16. For this reason, the moment is received by using the load of the intermediate shaft 26 as a mass body that generates a moment that opposes the moment generated by the impeller 14 and the moving blade 12. Thereby, it is not necessary to provide the counterweight 106 as shown in FIG. Furthermore, since the counterweight can be omitted, the axial length can be shortened and the cost can be reduced.

  By adopting a flexible shaft coupling 24 between the intermediate shaft 26 and the motor shaft 18, the center axis CL 1 of the main shaft 16 and the motor shaft 18 can be connected to each other due to the thermal expansion of the outer cylinder 3 and the inner cylinder 5 during a warm condition during operation. Even if misalignment occurs with the central axis CL2 (see FIG. 3), the operation can be continued.

  Since the deflection shaft coupling 24 can absorb the deviation of the central axis only by being provided between the intermediate shaft 26 and the motor shaft 18, the deflection between the main shaft 16 and the intermediate shaft 26 as shown in FIG. There is no need to use shaft couplings. Thereby, since the quantity of a flexible shaft coupling can be reduced, cost can be reduced. In the present embodiment, the angle θ, which is the amount of deviation of misalignment, is reduced by the length of the intermediate shaft 26, so that even a single flexible shaft coupling 24 is an allowable misalignment amount.

A sealing hole 38 (see FIG. 1) for introducing outside air (air) toward the flexible shaft joint 24 is formed in the one end wall 5 b of the inner cylinder 5. Thereby, the temperature rise by the windage loss of the flexible shaft coupling 24 in the seal box 36 due to the flow of the outside air is suppressed, and the strength and life of the flexible shaft coupling 24 are prevented from being reduced. Further, it is possible to prevent contaminants such as dust derived from exhaust gas from adhering to the flexible shaft joint 24 due to the flow of outside air.
The outside air (air) that has passed through the flexible shaft coupling 24 is guided to the main flow path through the gap between the inner cylinder 5 and the rotor blade 12, for example. As a result, the intermediate shaft 26, which rises in temperature due to the heat effect from the exhaust gas, is cooled by the flow of outside air, so that displacement due to thermal expansion is suppressed, and the deformation load on the flexible shaft coupling 24 can be reduced. The strength and life of the shaft coupling 24 can be suppressed from decreasing.

As shown in FIG. 4, the convex curved surface 12a is formed at the tip of the moving blade 12, and the concave curved surface 3c is formed on the inner periphery of the outer cylinder 3, so that in the cold state of FIG. 4 (b), the outer cylinder 3 and the inner cylinder 5 are changed in the warm state, and even if the rotor blade 12 rotates around the center 0 of the main bearing 30, the tip of the rotor blade 12 and the outer The gap with the cylinder 3 is kept substantially constant.
On the other hand, as shown in FIG. 5, when the tip of the rotor blade 12 and the inner peripheral surface of the outer cylinder 3 are both cylindrical surfaces centered on the central axis CL1, as shown in FIG. When the thermal expansion occurs during the warm state, the tip of the moving blade 12 and the inner peripheral surface of the outer cylinder 3 may come into contact with each other. Therefore, the tip of the moving blade 12 during the cold state shown in FIG. In order to prevent interference between the inner peripheral surface of the outer cylinder 3 from the initial stage, a large gap must be taken. By increasing the gap, gas leaking from the gap increases, which causes a decrease in blower efficiency and a decrease in the range of discharge pressure that can be operated.
In the present embodiment shown in FIG. 4, the convex curved surface 12a and the concave curved surface 3c allow the gaps to be substantially the same even when thermally expanded, so that the gaps can be set small. Thereby, the fluid which leaks from a clearance gap can be decreased as much as possible, and the efficiency of the blower 1 can be improved.

In addition, although this embodiment demonstrated the air blower used as the axial flow fan as an example, this invention is not limited to this, It can apply also to the air blower used as the centrifugal fan.
Moreover, although the outer cylinder 3 and the inner cylinder 5 showed the example which heat-extends by high temperature waste gas, the case where heat elongation arises not only by waste gas but by another working fluid may be sufficient.
Further, although the main bearing 30 is raised by the thermal elongation, the present invention can be applied as long as the center axis CL1 of the main shaft 16 and the center axis CL2 of the motor shaft 18 are relatively inclined. For example, the motor shaft 18 may be thermally extended by the surrounding temperature environment and displaced vertically upward with respect to the main shaft 16 side. Further, the foundation B may be a case where the main shaft 16 side and the motor shaft 18 side relatively change.

DESCRIPTION OF SYMBOLS 1 Fan 3 Outer cylinder 3a Inlet part 3b Outlet part 3c Concave surface 5 Inner cylinder 5a One end 5b One end wall 7 Support leg 9 Support wing 10 Motor (drive machine)
12 Rotor blade 12a Convex curved surface 13 Stator blade 14 Impeller 16 Main shaft 18 Motor shaft (Driver shaft)
20a motor bearing 20b motor bearing 22 connecting shaft 24 flexible shaft coupling 26 intermediate shaft 28 fixed shaft coupling 30 main bearing 32 bearing box 34 bearing stand 36 seal box 38 sealing hole (opening)
40 Impeller side wall MF main flow path

Claims (5)

An impeller with a plurality of moving blades attached thereto;
A main shaft with the impeller attached to one end;
One bearing rotatably supporting the main shaft;
An intermediate shaft having one end attached to the other end of the main shaft;
A drive shaft attached to the other end of the intermediate shaft;
A drive for rotating the drive shaft;
With
During operation, compared to before operation, the blower in which misalignment occurs between the central axis of the main shaft and the central axis on the side of the drive shaft,
A fixed shaft coupling that rigidly connects the main shaft and the intermediate shaft;
A flexible shaft coupling that connects the intermediate shaft and the drive shaft while allowing the misalignment; and
A blower characterized by comprising:   The blower according to claim 1, wherein a moment centered on the bearing on the impeller side and a moment centered on the bearing on the intermediate shaft side are balanced within a predetermined range. An outer cylinder surrounding each of the moving blades to form a main flow path;
An inner cylinder provided in the outer cylinder and accommodating at least a part of the impeller, the main shaft, the bearing, the intermediate shaft, the fixed shaft coupling, and the flexible shaft coupling;
With
The blower according to claim 1 or 2, wherein an opening for introducing outside air toward the flexible shaft coupling is formed in the inner cylinder. A convex curved surface having the same radius as viewed from the center of the bearing is formed on the outer peripheral side tip surface of each of the blades,
The concave surface corresponding to the convex curved surface through a predetermined gap is formed in the inner periphery of the outer cylinder at a position where the outer peripheral side tip surface of the moving blade passes. 3. The blower according to 3. An impeller with a plurality of moving blades attached thereto;
A main shaft with the impeller attached to one end;
One bearing rotatably supporting the main shaft;
An intermediate shaft having one end attached to the other end of the main shaft;
A drive shaft attached to the other end of the intermediate shaft;
A drive for rotating the drive shaft;
A method of operating a blower comprising:
During operation, when misalignment occurs between the central axis of the main shaft and the central axis on the side of the driving machine shaft compared to before the operation,
An air blower characterized in that the main shaft and the intermediate shaft are rigidly connected by a fixed shaft joint, and the intermediate shaft and the drive shaft are operated in a state in which the misalignment is allowed by a flexible shaft joint. how to drive.

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