JP2020125695A - Turbo type fluid machine - Google Patents

Abstract

To obtain a turbo type fluid machine, which is difficult to cause failures even when a member forming a seal structure and restraining increase of back face pressure comes in contact with an impeller back face part.SOLUTION: A turbo type fluid machine comprises: a housing 10 having a wall part 12a opposed on a back face part 31 of an impeller 30 at an interval, and forming an impeller back face region 32 between the wall part 12a and the back face part 31 in an axial direction; and a compartment member 40 forming an end face part 41 forming a gap 38 between it and the back face part 31 while one end is fixed to the wall part 12a and the other end is opposed to the back face part 31, and changing a position of the end face part 41 by being shrunk in the axial direction according to axial displacement of the impeller 30. In the impeller back face region 32, pressure on an inner diameter side than the compartment member 40 is made lower than pressure on an outer diameter side than the compartment member.SELECTED DRAWING: Figure 2

Description

This specification relates to a turbo fluid machine.

As disclosed in Patent Document 1, a turbo fluid machine including a housing, an impeller, and a shaft is known. The impeller is located within the impeller chamber of the housing. As the impeller rotates, the fluid is taken into the machine through the suction port and pumped downstream.

JP, 2011-169190, A

An impeller back surface region is formed on the back surface side of the impeller in the impeller chamber. The back pressure of the impeller increases as the fluid is pumped. The back pressure acts to displace the impeller toward the inlet side of the suction port. It is conceivable to form a non-contact type labyrinth seal structure in the back surface region in order to suppress an increase in back surface pressure. The back surface region is divided into an inner diameter side space and an outer diameter side space by a labyrinth. The space on the inner diameter side is connected to the atmospheric pressure via, for example, the space in the housing. The increase in back pressure is suppressed by the presence of the space on the inner diameter side.

In particular, when a seal structure is formed on the back surface of an impeller that rotates at high speed, a non-contact type seal structure can be adopted from the viewpoint of durability and the like. The member (protrusion, etc.) for forming the gap, that is, the member for forming the seal structure and suppressing the increase of the back pressure is provided as close as possible to the back surface of the impeller without contacting the back surface of the impeller. To be Thereby, the high pressure in the outer diameter side space and the low pressure in the inner diameter side space are more easily obtained, and it becomes possible to maintain or improve the pumping efficiency and suppress the increase of the back pressure. However, by bringing the member for forming the seal structure to suppress the increase of the back pressure and the impeller back surface portion close to each other, there is a high possibility that the member and the impeller back surface portion are in mutual contact or strong contact with each other.

An object of the present specification is to disclose a turbo type fluid machine having a structure in which a defect is unlikely to occur even if a member for forming a seal structure to suppress an increase in back pressure and the impeller back surface come into contact with each other. To do.

A turbo type fluid machine according to the present disclosure includes a shaft supported by bearings, a disc-shaped substrate, and a blade formed on the substrate to pump a fluid, and fixed to the shaft so as to be integrally rotatable. The impeller back surface is provided between the wall surface portion and the back surface portion in the axial direction, and the impeller surface of the substrate opposite to the blade is a back surface portion and the wall surface portion facing the back surface portion with a space. It has a tubular shape that surrounds the housing that defines the region and the shaft, and has one end fixed to the wall surface portion and the other end facing the back surface portion and forming a gap between the back surface portion and the back surface portion. And a partitioning member that expands and contracts in the axial direction to change the position of the end surface portion in accordance with the displacement of the impeller in the axial direction. The pressure on the inner diameter side of the partition member is set to be lower than the pressure on the outer diameter side of the partition member.

According to the above configuration, the partition member expands and contracts in the axial direction according to the displacement of the impeller in the axial direction, thereby changing the position of the end surface portion of the partition member in the axial direction. Even if the partition member comes into contact with the impeller back surface part, the contact pressure or impact generated between them can be made smaller than that in the case where the partition member is made of a rigid body, for example, a mere protrusion. The turbo fluid machine can be provided with a configuration that does not easily cause a problem.

In the turbo type fluid machine, the partition member includes an elastically deformable portion that is provided between the end surface portion and the wall surface portion and that is capable of elastically deforming to change the position of the end surface portion in the axial direction. The elastically deformable portion includes a tubular portion that extends along the axial direction and a folded portion that projects radially inward or radially outward of the tubular portion, and the axial direction of the folded portion. The position of the end surface portion in the axial direction may be changed by elastic deformation in.

According to the above configuration, the elastically deformable portion has a so-called bellows structure, and the partition member can be easily manufactured by, for example, resin molding.

In the turbo fluid machine, the tubular portion includes a first tubular portion and a second tubular portion, and the tubular portion is provided between the first tubular portion and the second tubular portion in the axial direction. A folded-back portion may be provided.

According to the above configuration, the first tubular portion can be easily joined to the wall surface portion by vulcanization adhesion, for example. Since the end surface of the second tubular portion constitutes, for example, a flat end surface portion, it is easy to design or set the gap between the back surface portion and the end surface portion.

In the turbo type fluid machine, the folded-back portion includes a first folded-back portion that projects radially outward with respect to the tubular portion and a second folded-back portion that projects radially inward with respect to the tubular portion. Parts, and may be included.

According to the above configuration, the high pressure on the outer diameter side of the partition member acts on the first folded portion so that the dimension of the first folded portion in the axial direction becomes shorter. On the other hand, the high pressure on the outer diameter side of the partition member acts on the second folded portion so that the axial dimension of the second folded portion becomes longer. With this configuration, it is possible to suppress the overall axial dimension of the partition member from being changed by the influence of high pressure and low pressure.

In the turbo type fluid machine, the partition member may include a main body made of rubber and a reinforcing member having higher rigidity than the main body.

According to the above configuration, when the main body is elastically deformed, the presence of the reinforcing member suppresses the main body from elastically deforming so as to fall inward or outward in the radial direction.

In the turbo type fluid machine, the partition member includes an elastically deformable portion that is provided between the end surface portion and the wall surface portion and that is capable of elastically deforming to change the position of the end surface portion in the axial direction. The elastically deformable portion includes a moving body that forms the end surface portion and one or more springs provided between the moving body and the wall surface portion, and the moving body is elastically deformed by the spring. You may change the position in the said axial direction.

According to the above configuration, it is possible to design or create the moving body and the spring independently of each other, and it is easy to design or set the gap between the back surface portion and the end surface portion.

In the turbo fluid machine, a guide member for guiding the movement of the moving body in the axial direction may be provided upright on the wall surface portion.

According to the above configuration, even if a high pressure acts from the outer diameter side of the partition member, the moving body can easily move stably in the axial direction.

In the turbo type fluid machine, the guide member may have a top surface portion facing the back surface portion, and the movable body may project from the top surface portion toward the back surface portion.

According to the above configuration, the presence of the top surface portion suppresses the high pressure on the outer diameter side of the partition member from acting on the moving body.

According to the turbo fluid machine disclosed in the present specification, even if the member for forming the seal structure to suppress the increase of the back pressure and the impeller back surface come into contact with each other, it is possible to prevent the trouble from occurring easily.

1 is a sectional view showing a turbo fluid machine 100 according to Embodiment 1. FIG. FIG. 3 is an enlarged cross-sectional view showing a partition member 40 and the like included in the turbo fluid machine 100 according to the first embodiment. FIG. 11 is a cross-sectional perspective view showing a partition member 40A in the first modification of the first embodiment. FIG. 9 is a cross-sectional perspective view showing a partition member 40B according to Modification 2 of Embodiment 1. FIG. 9 is a cross-sectional view showing a partition member 40C in the second embodiment. FIG. 6 is a sectional view taken along line VI-VI in FIG. FIG. 9 is a cross-sectional view showing a turbo fluid machine 100M according to a third embodiment.

A turbo fluid machine according to an embodiment will be described below with reference to the drawings. In the following description, the same parts and corresponding parts are designated by the same reference numerals, and duplicate description may not be repeated.

[Embodiment 1]
As shown in FIG. 1, the turbo fluid machine 100 includes a housing 10, a shaft 20, an impeller 30, and a partition member 40 (FIG. 2 ). The housing 10 includes a front housing 11, a support plate 12, a center housing 13, a cylinder 14 and a rear housing 15. These members forming the housing 10 are sequentially coupled in the axial direction (the direction in which the central axis 20c of the shaft 20 extends).

The housing 10 has an intake port 11a, an impeller chamber 11b, a diffuser passage 11c, a discharge chamber 11d, a discharge port 11e, and a motor chamber 14a. The motor 16 (stator 17 and rotor 18) and the shaft 20 are arranged in the motor chamber 14a. The shaft 20 has a large diameter portion 21 and an inner ring 22, and is arranged so as to pass through the shaft hole 12 b of the support plate 12. An impeller 30 is provided on one end side of the shaft 20 (in the impeller chamber 11b), and an inner ring 23 is provided on the other end side of the shaft 20.

Inside the housing 10, a thrust foil bearing 24 and radial foil bearings 25, 26 are provided. The radial foil bearings 25 and 26 are provided on the outer peripheral sides of the inner rings 22 and 23, respectively. The shaft 20 is supported by these bearings and rotates with the rotor 18 and the impeller 30.

The impeller 30 has a disk-shaped substrate 30a and a blade 30b formed on the substrate 30a to pump a fluid. The impeller 30 is integrally rotatably fixed to the shaft 20, and a side of the substrate 30a opposite to the blade 30b is a rear surface portion 31 (impeller rear surface portion).

As shown in FIGS. 1 and 2, the housing 10 (here, the support plate 12) has wall surface portions 12 a that face the back surface portion 31 of the impeller 30 with a space therebetween. By placing the impeller 30 in the impeller chamber 11b, a back surface region 32 (impeller back surface region) is formed between the wall surface portion 12a and the back surface portion 31 in the axial direction. The impeller chamber 11b communicates with the motor chamber 14a via the back surface region 32 and the shaft hole 12b.

In the present embodiment, partition member 40 is provided on wall surface portion 12a. The partition member 40 has a tubular shape surrounding the periphery of the shaft 20. One end of the partition member 40 in the axial direction is fixed to the wall surface portion 12a. The other end of the partition member 40 in the axial direction forms an end surface portion 41 that faces the back surface portion 31 and forms a gap 38 between the back surface portion 31 and the back surface portion 31.

In the back surface region 32, the pressure on the inner diameter side of the partition member 40 is set to be lower than the pressure on the outer diameter side of the partition member 40. That is, the presence of the partition member 40 divides (partitions) the back surface region 32 into the inner diameter side space 33 and the outer diameter side space 34. The cylinder 14 is provided with an opening 14b. The inner diameter side space 33 is connected to the outer space S via the shaft hole 12b, the motor chamber 14a, and the opening 14b. The inner diameter side space 33 communicates with the outer space S, which is a space other than the outer diameter side space 34, without interposing the outer diameter side space 34. The external space S is at atmospheric pressure. On the other hand, the inner diameter side space 33 and the outer diameter side space 34 are communicated with each other through a gap 38, and the fluid passes through this gap as a throttle, so that the pressure of the inner diameter side space 33 is released when the fluid is pumped. It becomes lower than the pressure in the radial space 34.

As shown in FIG. 2, the partition member 40 includes an elastically deformable portion 42. The end surface portion 41 forms a gap 38 between the end surface portion 41 and the back surface portion 31. The elastically deformable portion 42 is provided between the end surface portion 41 and the wall surface portion 12a, and expands and contracts in the axial direction according to the axial displacement of the impeller 30 to change the position of the end surface portion 41. The elastically deformable portion 42 may be formed of resin such as rubber.

(Action and effect)
The turbo fluid machine 100 is used in a fuel cell system as an air compressor, for example. The rotation of the rotor 18 causes the impeller 30 to rotate in the impeller chamber 11b. Air as an external fluid is sucked in through the suction port 11a, kinetic energy of the air is converted into pressure energy in the diffuser passage 11c and compressed, and the compressed air is sent under pressure to the discharge chamber 11d. High-pressure air in the discharge chamber 11d is supplied to the stack of the fuel cell system.

The pressure in the back surface region 32 (impeller back surface pressure) increases as the fluid is pumped. The back pressure acts to displace the impeller 30 toward the inlet side of the suction port 11a. In the present embodiment, the back surface region 32 is divided into a low pressure inner diameter side space 33 and a high pressure outer diameter side space 34, and these spaces are communicated with each other via a gap 38. The increase of the back pressure is suppressed by the existence of the inner diameter side space 33, and thus the displacement of the impeller 30 toward the inlet side of the suction port 11a is also suppressed. It is also suppressed that the thrust foil bearing 24 receives an excessive force from the large diameter portion 21 of the shaft 20.

An increase in fluid leakage from the outer diameter side space 34 to the inner diameter side space 33 may lead to a reduction in compression efficiency. The partitioning member 40 for forming the non-contact type seal structure (gap 38) is provided as close to the back surface portion 31 as possible within a range not in contact with the back surface portion 31 of the impeller 30 in order to reduce leakage. By bringing the partitioning member 40 and the back surface portion 31 close to each other, the possibility that the partitioning member 40 and the back surface portion 31 contact each other increases.

On the other hand, in the present embodiment, the partition member 40 expands and contracts in the axial direction according to the axial displacement of the impeller 30, whereby the position of the end surface portion 41 of the partition member 40 in the axial direction is changed. A gap 38 is set between the partition member 40 and the back surface portion 31 in accordance with the range in which the impeller 30 can be displaced. Even if the end surface portion 41 of the partition member 40 and the back surface portion 31 come into contact with each other, contact is made. At some time, the elastic deformation portion 42 elastically deforms. The contact pressure and impact generated between them can be made smaller than in the case where the partition member is made of a rigid body, for example, a mere protrusion. can do.

(Other Configuration 1 for Embodiment 1)
As shown in FIG. 2, in the present embodiment, the elastically deformable portion 42 includes a tubular portion 43 extending along the axial direction and a folded back portion that projects outward in the U direction in the radial direction with respect to the tubular portion 43. Section 44. Due to the elastic deformation of the folded-back portion 44 in the axial direction, the position of the end surface portion 41 in the axial direction is changed.

The elastically deformable portion 42 has a so-called bellows structure, and the partitioning member 40 can be easily manufactured by, for example, resin molding. The folded-back portion 44 may protrude radially inward with respect to the tubular portion 43, and the folded-back portion 44 may have an arbitrary protruding shape such as a V-shape.

(Other Configuration 2 of First Embodiment)
In the present embodiment, the tubular portion 43 of the partition member 40 includes a first tubular portion 43a and a second tubular portion 43b. The folding|returning part 44 is provided between the 1st cylindrical part 43a and the 2nd cylindrical part 43b in an axial direction. The first tubular portion 43a can be easily joined to the wall surface portion 12a by, for example, vulcanization adhesion. Since the end surface of the second tubular portion 43b constitutes the flat end surface portion 41, for example, the design or setting of the gap 38 between the back surface portion 31 and the end surface portion 41 becomes easy.

[Modification 1 of Embodiment 1]
FIG. 3 is a cross-sectional perspective view showing a partition member 40A in the first modification of the first embodiment. In the partition member 40A, the folded back portion 44 includes a first folded back portion 44a and a second folded back portion 44b. The first folded-back portion 44 a projects radially outward (that is, the outer diameter side space 34 side) with respect to the tubular portion 43, and the second folded-back portion 44 b radially inner (ie, the inner diameter) with respect to the tubular portion 43. It projects to the side space 33 side).

As described above, a low pressure is formed in the inner diameter side space 33, and a high pressure is formed in the outer diameter side space 34. The high pressure in the outer diameter side space 34 acts on the first folded portion 44a so that the dimension of the first folded portion 44a in the axial direction becomes shorter (arrows AR1, AR2). On the other hand, the high pressure in the outer diameter side space 34 acts on the second folded-back portion 44b so that the axial dimension of the second folded-back portion 44b becomes longer (arrows AR3 and AR4). With this configuration, it is possible to suppress the overall dimension of the partition member 40A in the axial direction from varying (compared to the partition member 40 of the above-described first embodiment) due to the effects of high pressure and low pressure.

[Modification 2 of Embodiment 1]
FIG. 4 is a cross-sectional perspective view showing a partition member 40B according to the second modification of the first embodiment. In the partition member 40B, the elastically deformable portion 42 includes a main body portion 42a, a head portion 42b, and a reinforcing member 42c. Unlike the case of the partition members 40 and 40A, the folded portion 44 may not be provided in the main body portion 42a. The main body 42a is made of rubber, and the main body 42a itself is elastically deformable in the axial direction.

For convenience of forming the gap, the head portion 42b may be made of a member having higher rigidity than the main body portion 42a with higher accuracy. The reinforcing member 42c is composed of, for example, a circular coil, and is embedded inside the main body portion 42a. When the body portion 42a elastically deforms, the presence of the reinforcing member 42c prevents the body portion 42a from elastically deforming so as to fall inward or outward in the radial direction.

[Second Embodiment]
FIG. 5 is a sectional view showing a partition member 40C according to the second embodiment. FIG. 6 is a sectional view taken along line VI-VI in FIG. In the partitioning member 40C, the elastically deformable portion 42 includes one or more (six in the present embodiment) moving body 45 forming the end surface portion 41 and one provided between the moving body 45 and the wall surface portion 12a. The spring 46 is included, and the position of the moving body 45 in the axial direction, and thus the position of the end surface portion 41 in the axial direction, is changed by elastic deformation of the spring 46. The moving body 45 and the spring 46 can be independently designed or created, and the design or setting of the gap 38 between the back surface portion 31 and the end surface portion 41 becomes easy.

Preferably, a guide member 47 for guiding the movement of the moving body 45 in the axial direction may be provided upright on the wall surface portion 12a. Even if the high pressure acts from the outer diameter side space 34 side, the spring 46 can be stably elastically deformed in the axial direction. Here, the guide member 47 includes an inner wall portion 47a and an outer wall portion 47b. A top surface portion 47t facing the back surface portion 31 is formed on the outer wall portion 47b. The moving body 45 projects from the top surface portion 47t to the back surface portion 31 side. The presence of the top surface portion 47t suppresses the high pressure of the outer diameter side space 34 from acting on the moving body 45.

The step 45a may be provided on the moving body 45 so that the step 45a contacts the top surface portion 47t. For example, the spring 46 biases the moving body 45 so that the step 45a contacts the top surface portion 47t. Based on the position of the moving body 45 forming the contact state, the design or setting of the gap 38 between the back surface portion 31 and the end surface portion 41 becomes easy.

[Third Embodiment]
FIG. 7 is a sectional view showing a turbo fluid machine 100M according to the third embodiment. In the turbo fluid machine 100M, communication passages 11h and 12h are formed in the front housing 11 and the support plate 12. The inner diameter side space 33 is connected to the suction port 11a via the shaft hole 12b and the communication passages 11h and 12h. Also in this configuration, the inner diameter side space 33 is in communication with the space (suction port 11a) that is a space other than the outer diameter side space 34 without the outer diameter side space 34, and when the fluid is pumped, The pressure in the inner diameter side space 33 becomes lower than the pressure in the outer diameter side space 34.

Although the embodiments have been described above, the above disclosure is illustrative in all points and not restrictive. The technical scope of the present invention is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

10 housing, 11 front housing, 11a suction port, 11b impeller chamber, 11c diffuser passage, 11d discharge chamber, 11e discharge port, 11h, 12h communication passage, 12 support plate, 12a wall surface portion, 12b shaft hole, 13 center housing, 14 Cylinder, 14a Motor chamber, 14b Opening, 15 Rear housing, 16 Motor, 17 Stator, 18 Rotor, 20 Shaft, 20c Central axis, 21 Large diameter part, 22,23 Inner ring, 24 Thrust foil bearing (bearing), 25, 26 Radial foil bearing (bearing), 30 impeller, 30a substrate, 30b blade, 31 back surface (impeller back surface), 32 back surface area (impeller back surface area), 33 inner diameter side space, 34 outer diameter side space, 38 gap, 40, 40A, 40B, 40C partitioning member, 41 end face part, 42 elastic deformation part, 42a main body part, 42b head part, 42c reinforcing member, 43 tubular part, 43a first tubular part, 43b second tubular part, 44 folded back Part, 44a first folded part, 44b second folded part, 45 moving body, 45a step, 46 spring, 47 guide member, 47a inner wall part, 47b outer wall part, 47t top surface part, 100, 100M turbo fluid machine, AR1, AR2, AR3, AR4 Arrows, S External space.

Claims (8)

A shaft supported by bearings,
A disc-shaped substrate, and a blade formed on the substrate for pumping fluid, fixed integrally rotatably to the shaft, the impeller on the side opposite to the blade of the substrate is a back surface part, and
A housing having wall surfaces facing each other with a space in the back surface, and forming an impeller back surface region between the wall surface and the back surface in the axial direction;
It has a cylindrical shape surrounding the periphery of the shaft, one end of which is fixed to the wall surface portion, and the other end of which forms an end face portion that faces the back face portion and forms a gap between the back face portion. And a partitioning member that expands and contracts in the axial direction to change the position of the end surface portion according to the displacement of the impeller in the axial direction,
In the impeller back surface region, the pressure on the inner diameter side of the partition member is lower than the pressure on the outer diameter side of the partition member,
Turbo fluid machine. The partitioning member is provided between the end surface portion and the wall surface portion, and includes an elastically deformable portion that is elastically deformable to change the position of the end surface portion in the axial direction,
The elastic deformation portion,
A tubular portion extending along the axial direction,
A folded portion that projects radially inward or radially outward with respect to the tubular portion,
By the elastic deformation of the folded portion in the axial direction, the position of the end surface portion in the axial direction is changed.
The turbo fluid machine according to claim 1. The tubular portion includes a first tubular portion and a second tubular portion,
The folded portion is provided between the first tubular portion and the second tubular portion in the axial direction,
The turbo fluid machine according to claim 2. The folded-back portion includes a first folded-back portion that projects outward in the radial direction with respect to the tubular portion, and a second folded-back portion that projects inward in the radial direction with respect to the tubular portion.
The turbo fluid machine according to claim 2 or 3. The partition member includes a main body made of rubber and a reinforcing member having a rigidity higher than that of the main body.
The turbo fluid machine according to claim 1. The partitioning member is provided between the end surface portion and the wall surface portion, and includes an elastically deformable portion that is elastically deformable to change the position of the end surface portion in the axial direction,
The elastically deformable portion includes a moving body that forms the end surface portion and one or more springs provided between the moving body and the wall surface portion, and elastically deforming the spring causes the moving body to move. Changing the position in the axial direction,
The turbo fluid machine according to claim 1. On the wall surface portion, a guide member for guiding the movement of the moving body in the axial direction is provided upright.
The turbo fluid machine according to claim 6. The guide member has a top surface portion facing the back surface portion,
The moving body projects from the top surface portion toward the back surface portion,
The turbo fluid machine according to claim 7.

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