JP2008069681A - Side channel pump and fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To narrow a gap between an impeller and a case, and to improve a pump characteristic. <P>SOLUTION: In a side channel pump 10 provided with pump blades 19a, 19b on both front and reverse surfaces of the impeller 17, a first dynamic bearing part 38 is provided between an outer peripheral face 17a of the impeller 17 and an inner peripheral face 16a of an impeller housing part 16 facing the outer peripheral face 17a, a second dynamic bearing part 40 is provided between a flat part 17b of an upper face of the impeller 17 and an inner face 14b of a first case part 14 facing the flat part 17b, and a third dynamic bearing part 44 is provided between a flat part 17c of an lower face of the impeller 17 and an upper face 42a of a cylindrical part 42 of a second case part 15 facing the flat part 17c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a side channel pump having a configuration in which pump blades are provided on at least one surface in the axial direction of a disc-shaped impeller, and a fuel cell using the side channel pump.

Many types of pumps are known, such as centrifugal pumps and axial flow pumps, and constant displacement pumps such as gear pumps, vane pumps, and roots pumps.
A side channel pump as shown in FIG. 8 is known as an air supply pump having a certain pressure. The impeller 1 of the pump has a disk shape and has a plurality of pump blades 2a and 2b on both front and back surfaces in the axial direction. In the case 3 that accommodates the impeller 1, two fluid flow paths 4 a and 4 b are formed corresponding to the pump blades 2 a and 2 b on the front and back surfaces of the impeller 1. Although not shown, each fluid flow path 4a, 4b is provided with a suction port and a discharge port communicating with each other. The impeller 1 is rotationally driven by a motor 5 via a rotating shaft 6.

Here, when the impeller 1 is rotated, fluid, for example, air is sucked into the fluid flow paths 4a and 4b from the suction ports of the fluid flow paths 4a and 4b, and the air in the fluid flow paths 4a and 4b is discharged from the discharge ports. It is discharged from. In this case, the two fluid channels 4a and 4b can be configured in series by connecting the discharge port of one fluid channel 4a and the suction port of the other fluid channel 4b.
In the pump having such a configuration, the gap between the case 3 and the impeller 1 affects the pump characteristics (pressure-flow characteristics, particularly pressure), and the pressure can be increased by reducing the gap. It is known to improve.
Further, in this type of side channel pump, there is also known a configuration in which a plurality of impellers are provided in the axial direction and two adjacent fluid flow paths are connected in series or in parallel (for example, Patent Document 1). reference).
JP-T-2001-514361

  In the side channel pump having the above-described configuration, the impeller 1 has a central portion connected to the rotating shaft 6 of the motor 5 and is supported by the cylindrical bearing 7 of the motor 5 via the rotating shaft 6. In this case, the impeller 1 having a large diameter is supported by the bearing 7 having a small diameter, and the impeller 1 is likely to be shaken. There is also a swing of the impeller 1, and when trying to reduce the gap between the impeller 1 and the case 3, the impeller 1 may come into contact with the case 3, and may be rubbed or locked. Therefore, there is a problem that the gap between the impeller 1 and the case 3 cannot be reduced, and the pump characteristics cannot be improved.

  On the other hand, in recent years, fuel cells have attracted attention as power sources for portable devices. Direct methanol fuel cell (DMFC) that uses methanol as a hydrogen supply source: Although a methanol direct fuel cell is known, a side-channel pump is one of the options for pumping air or fuel to the DMFC. ing. Side channel pumps are considered promising because they have no mechanical contact like vane pumps and have suitable pump characteristics. However, the conventional configuration has a problem that the shape of the pump is large and the entire product (fuel cell) becomes large.

  The present invention has been made in view of the above-described circumstances, and a first object thereof is to provide a side channel pump that can reduce a gap between an impeller and a case and improve pump characteristics. There is to do. A second object is to provide a fuel cell that can be miniaturized.

  In order to achieve the first object described above, the side channel pump according to claim 1 is a disk-shaped impeller having a plurality of pump blades on one axial surface, housing the impeller, and the pump blades. A case in which a fluid flow path is formed in a corresponding portion, a suction port and a discharge port provided so as to communicate with the fluid flow path, and a motor that rotationally drives the impeller, and the impeller is rotated. Based on the above, in the configuration in which the fluid is sucked into the fluid flow path from the suction port by the action of the pump blade, and the fluid in the fluid flow path is discharged from the discharge port, the impeller and the case In the meantime, a dynamic pressure bearing portion is provided which generates dynamic pressure based on rotation of the impeller and supports the impeller.

  In order to achieve the second object described above, the fuel cell according to claim 6 uses the side channel pump according to any one of claims 1 to 5 as an air supply pump for supplying air to the power generation unit. It is characterized by.

  In the side channel pump according to the first aspect, the impeller can be supported by a dynamic pressure bearing portion that generates a dynamic pressure as the impeller rotates. For this reason, compared with the case where the impeller is only supported by the bearing through the center shaft, the swing of the impeller can be reduced and the rigidity of the impeller can be increased. The gap between the two can be narrowed, and the pump performance can be improved.

  According to the fuel cell of claim 6, if the same pumping performance is obtained by using a side channel pump capable of improving the pumping performance for the air supply pump that supplies air to the power generation unit, the conventional one is used. Therefore, the fuel cell can be downsized.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. First, in FIG. 1 to FIG. 3, a case 11 forming an outer shell of the side channel pump 10 of the present invention includes a rectangular case main body 12 and a cover 13 screwed to one side of the case main body 12. It is composed of The case body 12 is configured by screwing the upper first case portion 14 and the lower second case portion 15 in FIGS. 1 to 5. An impeller accommodating portion 16 is formed in the inner surface.

  A disc-shaped impeller 17 is accommodated in the impeller accommodating portion 16 inside the case body 12. A rotating shaft 18 is fixed to the center of the impeller 17. A plurality of pump blades 19a and 19b are provided at portions near the outer peripheral portions of the front and back surfaces in the axial direction of the impeller 17, respectively. In the upper first case portion 14, a first fluid flow path 20 is formed corresponding to a portion where the pump blade 19 a on the surface (the upper surface in FIGS. 4 and 5) side of the impeller 17 is formed. In the second case portion 15 on the side, a second fluid passage 21 is formed corresponding to a portion where the pump blade 19b on the back surface (lower surface in FIGS. 4 and 5) side of the impeller 17 is formed. .

  In the first case portion 14, a suction port 20 a and a discharge port 20 b are formed on the side surface 14 a on the side where the cover 13 is mounted. The suction port 20 a and the discharge port 20 b are connected to the first fluid flow. It communicates with the road 20. The first fluid channel 20 is partitioned by a partition portion 22 (see FIGS. 3 and 5) formed between the suction port 20a and the discharge port 20b. Further, in the second case portion 15, a suction port 21 a and a discharge port 21 b are also formed on the side surface 15 a on the side where the cover 13 is mounted. The suction port 21 a and the discharge port 21 b are connected to the second case portion 15. It communicates with the fluid flow path 21. The second fluid channel 21 is also partitioned by a partition 23 (see FIG. 5) formed between the suction port 21a and the discharge port 21b.

  A substantially cylindrical stator mounting convex portion 25 is provided at the center of the second case portion 15, and a stator 27 of the motor 26 is fixedly mounted on the outer peripheral portion of the stator mounting convex portion 25. . The stator 27 includes a stator core 28 and a stator coil 29 attached to the stator core 28. In FIG. 2, the stator coil 29 is omitted.

  A rotor 30 of the motor 26 is provided on the back surface (lower surface) of the impeller 17. The rotor 30 includes a cylindrical rotor yoke 31 provided so as to surround the stator 27, and a rotor magnet 32 attached to the inner peripheral surface of the rotor yoke 31, and the inner peripheral surface of the rotor magnet 32 is The stator core 28 faces the outer peripheral surface with a predetermined gap. Here, the stator 27 and the rotor 30 constitute an outer rotor type motor 26. The rotor 30 is configured integrally with the impeller 17.

  A cylindrical bearing cylinder 35 is disposed at the center of the stator mounting projection 25, and a plate-like thrust bearing 36 is disposed below the bearing cylinder 35. The rotary shaft 18 is inserted into the bearing cylinder 35 and its lower end is received by the thrust bearing 36. Accordingly, the impeller 17 and the rotor portion 30 are provided in the case body 12 so as to be rotatable around the rotation shaft 18. The rotary shaft 18 is supported in the radial direction by the bearing cylinder 35 and is supported in the axial direction by the thrust bearing 36.

  In the impeller 17, a large number of V-shaped dynamic pressure generating grooves 37 are formed on the outer peripheral surface 17 a that is on the outer peripheral side from the portion where the pump blades 19 a and 19 b are formed. The dynamic pressure generating groove 37 and the inner peripheral surface 16a of the impeller accommodating portion 16 facing the outer peripheral surface 17a of the impeller 17 constitute a first dynamic pressure bearing portion 38 (dynamic pressure bearing portion). The inner peripheral surface 16a of the impeller accommodating portion 16 is a smooth surface. In this case, the shape of each dynamic pressure generating groove 37 is set such that the length of the lower groove 37a is longer than that of the upper groove 37b, as shown in FIGS.

  On the upper surface (surface) of the impeller 17, a large number of slanting dynamic pressure generating grooves 39 are formed in an annular shape in the flat portion 17 b on the inner peripheral side from the portion where the pump blade 19 a is formed. The dynamic pressure generating groove 39 and the inner surface 14b of the first case portion 14 facing the flat portion 17b constitute a second dynamic pressure bearing portion 40 (dynamic pressure bearing portion). The inner surface 14b of the first case portion 14 is also a smooth surface.

  In the second case portion 15, a cylindrical portion 42 is provided so as to be positioned outside the rotor yoke 31 and surround the rotor yoke 31. A large number of slanting dynamic pressure generating grooves 43 are also formed in an annular shape in the flat portion 17 c on the lower surface of the impeller 17 facing the upper surface 42 a of the cylindrical portion 42. The dynamic pressure generating groove 43 and the upper surface 42a of the cylindrical portion 42 facing the flat portion 17c constitute a third dynamic pressure bearing portion 44 (dynamic pressure bearing portion). The upper surface 42a of the cylindrical part 42 is also a smooth surface.

  The cover 13 is provided with a main suction port 45 and a main discharge port 46 having a cylindrical shape. Among these, the main suction port 45 is connected to the suction port 21 a of the lower second fluid flow path 21, and the main discharge port 46 is connected to the discharge port 20 b of the upper first fluid flow path 20. Yes. Further, the cover 13 is formed with a connection passage 47 (see FIG. 5) that connects the discharge port 21a of the second fluid channel 21 and the suction port 20b of the first fluid channel 20.

  In the above configuration, when the rotor 30 of the motor 26 and thus the impeller 17 are stationary, the impeller 17 is supported in the axial direction by the thrust bearing 36 via the rotating shaft 18 and is supported in the radial direction by the bearing cylinder 35.

  When the stator coil 29 of the motor 26 is energized and a rotational force is generated in the rotor 30, the impeller 17 is rotated integrally with the rotor 30. The rotation direction at this time is the arrow A direction in FIGS. When the impeller 17 is rotated in the direction of arrow A, a fluid, for example, air is sucked from the main suction port 45 into the lower second fluid flow path 21 by the action of the lower pump blade 19b, and Air in the second fluid flow path 21 is discharged from the discharge port 21b to the connection passage 47 side. Further, due to the action of the upper pump blade 19 a accompanying the rotation of the impeller 17, the air in the connection passage 47 is sucked into the first fluid flow path 20 from the suction port 20 a of the upper first fluid flow path 20. At the same time, the air in the first fluid flow path 20 passes through the discharge port 20b and is discharged from the main discharge port 46.

At this time, the impeller 17 is supported in the radial direction by the bearing cylinder 35 via the rotating shaft 18, and the first, second, and third hydrodynamic bearings provided between the impeller 17 and the case body 12. Also supported by the portions 38, 40, 44.
Among these, in the first dynamic pressure bearing portion 38, the dynamic pressure generating groove 37 on the outer peripheral surface 17 a of the impeller 17 and the inner peripheral surface 16 a of the impeller accommodating portion 16 facing each other as the impeller 17 rotates. Due to the generated dynamic pressure, the impeller 17 is supported in the radial direction without contact with the inner peripheral surface 16a of the impeller accommodating portion 16.

Further, in the second dynamic pressure bearing portion 40, the dynamic pressure generated between the dynamic pressure generating groove 39 of the flat portion 17b on the upper surface side of the impeller 17 and the lower surface 14b of the first case portion 14 facing this. Thus, the impeller 17 is supported in the axial direction without contact with the lower surface 14b of the first case portion 14.
Further, in the third dynamic pressure bearing portion 44, the impeller is generated by the dynamic pressure generated between the dynamic pressure generating groove 43 of the flat portion 17 c on the lower surface side of the impeller 17 and the upper surface 42 a of the cylindrical portion 42 facing this. 17 is supported in the axial direction without contact with the upper surface 42 a of the cylindrical portion 42.

  Thus, since the impeller 17 is supported not only in the radial direction by the bearing cylinder 35 via the rotating shaft 18 but also in the radial direction by the first dynamic pressure bearing portion 38, the vibration of the impeller 17 can be reduced. In addition, the rigidity of the impeller 17 can be increased, and in particular, the gap between the outer peripheral surface 17a of the impeller 17 and the inner peripheral surface 16a of the impeller accommodating portion 16 in the case main body 12 can be narrowed, and the pump performance It becomes possible to improve.

  Further, since the second and third dynamic pressure bearing portions 40 and 44 that support the impeller 17 in the axial direction in a non-contact manner are also provided between the impeller 17 and the case main body 12, the impeller 17 can be further shaken. Thus, the gap in the axial direction between the impeller 17 and the case body 12 can be reduced. During the rotation of the impeller 17, the axial bearing in the second dynamic pressure bearing portion 40 and the third dynamic pressure bearing portion 44 are caused by the dynamic pressure bearing action of the second and third dynamic pressure bearing portions 40 and 44. Can be positioned at a position where the axial gap is substantially equal.

  Incidentally, in the case of the configuration in which the first to third dynamic pressure bearing portions 38, 40, and 44 are not provided as described above, the gap between the impeller and the case is not set to a large value of 100 μm or 200 μm. There was a risk of contact. On the other hand, when the first to third dynamic pressure bearing portions 38, 40, 44 are provided between the impeller 17 and the case body 12 as in the present embodiment, the impeller 17 and the case The gap between the main body 12 can be set to several tens of μm or less. Therefore, since the gap between the impeller 17 and the case body 12 can be reduced, the characteristics of the pump and the pressure-flow rate characteristics can be improved, and a large flow rate can flow at a high pressure.

  In the above-described embodiment, the pump blades 19a and 19b are provided on both front and back surfaces of the impeller 17, and the first and second fluid flow paths 20 and 21 are provided on both front and back surfaces of the impeller 17. The second fluid flow paths 20 and 21 are connected in series. By setting it as such a structure, a pressure can be made high. However, in this case, the pressure is different between the first fluid channel 20 on the front side of the impeller 17 and the second fluid channel 21 on the back side. Specifically, the pressure is higher in the first fluid channel 20 on the discharge side than on the second fluid channel 21 on the suction side. For this reason, there is a possibility that fluid (air) leaks from the first fluid channel 20 having a high pressure to the second fluid channel 21 having a low pressure.

  In this regard, in the present embodiment, the first dynamic pressure bearing portion 38 is provided on the outer peripheral portion of the impeller 17, and a gap between the outer peripheral surface 17 a of the impeller 17 and the inner peripheral surface 16 a of the impeller accommodating portion 16 is provided. Since the size can be reduced, the occurrence of fluid leakage between the first fluid channel 20 and the second fluid channel 21 can be suppressed as much as possible. Moreover, the shape of the dynamic pressure generating groove 37 formed on the outer peripheral surface 17a of the impeller 17 is set so that the length of the lower groove 37a is longer than that of the upper groove 37b, and the lower first pressure is low. The fluid between the first and second fluid flow paths 20 and 21 is configured such that the dynamic pressure on the second fluid flow path 21 side is higher than that of the first fluid flow path 20 on the upper side where the pressure is high. Therefore, the occurrence of fluid leakage can be further reduced.

  Since the motor 26 that rotationally drives the impeller 17 is an outer rotor type, a large driving torque can be obtained. Further, since the rotor 30 and the impeller 17 of the motor 26 are integrally formed, the size can be reduced. Moreover, since the stator 27 of the motor 26 is housed in the case body 12, the entire pump can be further reduced in size.

  On the other hand, FIG. 6 shows a schematic configuration in which the above-described side channel pump 10 is used for the fuel cell 50. The fuel cell 50 is a portable DMFC that generates power using hydrogen and oxygen in the air as fuel, a fuel tank 52 that stores methanol serving as a hydrogen supply source, and the fuel tank 52 to the power generation unit 51. It includes a fuel supply pump 53 for supplying methanol and an air supply pump 54 for supplying air to the power generation unit 51. Here, the above-described side channel pump 10 is used as the air supply pump 54.

  The fuel tank 52 is connected to the suction port 56 of the fuel supply pump 53 via the connection tube 55, and the discharge port 57 of the fuel supply pump 53 is connected to the power generation unit 51 via the connection tube 58. The main discharge port 46 of the air supply pump 54 (side channel pump 10) is connected to the power generation unit 51 via the connection tube 59, and the main suction port 45 is open to the atmosphere as it is.

  In the above configuration, the methanol in the fuel tank 52 is supplied to the power generation unit 51 by the fuel supply pump 53, and air is supplied to the power generation unit 51 by the air supply pump 54, and the methanol and air are used in the power generation unit 51. Power generation.

In the above-described embodiment, by using the side channel pump 10 that is small, has a high pressure, and has a large fluid flow rate as the air supply pump 54, the overall shape of the fuel cell 50 can be reduced, and the product (fuel The value of the battery 50) can be increased.
Note that the above-described side channel pump 10 may also be used for the fuel supply pump 53.

(Second Embodiment)
FIG. 7 shows a second embodiment of the present invention. This second embodiment is different from the first embodiment described above in the following points. That is, the main suction port 61 of the cover 60 in the case 11 communicates with both the suction port 21a of the lower second fluid channel 21 and the suction port 20a of the upper first fluid channel 20. Is provided. The main discharge port 62 of the cover 60 is provided so as to communicate with both the discharge port 21b of the lower second fluid flow path 21 and the discharge port 20b of the upper first fluid flow path 20. ing. Thereby, the 1st fluid channel 20 and the 2nd fluid channel 21 have the parallel composition.

  In the above-described configuration, when the impeller 17 is rotationally driven by the motor 26, the air sucked from the main suction port 61 through the suction ports 20a and 21a by the action of the pump blades 19a and 19b on the front and back sides of the impeller 17 respectively. And the second fluid flow paths 20 and 21 are separated and sucked, and the air in the first and second fluid flow paths 20 and 21 is discharged from the discharge ports 20b and 21b to the main discharge port 62, At the main discharge port 62, they merge and are discharged from there.

Although not shown in FIG. 7, the first to third dynamic pressure bearing portions 38, 40, and 44 are provided between the impeller 17 and the case body 12, as in the first embodiment. Is provided.
(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
The pump blades 19a and 19b of the impeller 17 may be provided only on the front side or only on the back side instead of being provided on both the front and back sides. Two or more impellers 17 may be provided in the axial direction.
The fluid handled by the side channel pump 10 is not limited to air, and may be a gas other than air or a liquid.
In the impeller 17, when there are annular flat portions on the front and back surfaces on the outer peripheral side of the pump blades 19 a and 19 b, the second and third portions are arranged between the flat portion and the inner surface of the case facing the flat portion. The hydrodynamic bearings 40 and 44 can also be provided. In the case of such a configuration, fluid leakage between the first and second fluid flow paths 20 and 21 can be further suppressed by the second and third dynamic pressure bearing portions 40 and 44. become.

The perspective view of the side channel pump which shows the 1st Embodiment of this invention Exploded perspective view from above Exploded perspective view from below 1 is a longitudinal sectional view taken along line X1-X1 in FIG. Longitudinal sectional view along line X2-X2 in FIG. Schematic configuration diagram of fuel cell The perspective view of the side channel pump which shows the 2nd Embodiment of this invention. Broken side view of a conventional side channel pump

Explanation of symbols

  In the drawings, 10 is a side channel pump, 11 is a case, 17 is an impeller, 18 is a rotating shaft, 19a and 19b are pump blades, 20 is a first fluid flow path (fluid flow path), and 21 is a second fluid flow. Path (fluid flow path), 20a and 21a are suction ports, 20b and 21b are discharge ports, 26 is a motor, 27 is a stator, 30 is a rotor, 35 is a bearing cylinder, 36 is a thrust bearing, 37 is a dynamic pressure generating groove, 38 is a first dynamic pressure bearing portion (dynamic pressure bearing portion), 39 is a dynamic pressure generating groove, 40 is a second dynamic pressure bearing portion (dynamic pressure bearing portion), 43 is a dynamic pressure generating groove, and 44 is a third dynamic pressure generating groove. , 45 is a main suction port, 46 is a main discharge port, 50 is a fuel cell, 51 is a power generation unit, 54 is an air supply pump (side channel pump), 60 is a cover, 61 Indicates a main suction port, and 62 indicates a main discharge port.

Claims (6)

An impeller having a disk shape and having a plurality of pump blades on one surface in the axial direction, a case for accommodating the impeller and forming a fluid flow path in a portion corresponding to the pump blade, and communicating with the fluid flow path And a motor that drives the impeller to rotate, and based on rotating the impeller, fluid flows from the suction port into the fluid flow path by the action of the pump blades. In the side channel pump configured to inhale and discharge the fluid in the fluid flow path from the discharge port,
A side channel pump characterized in that a dynamic pressure bearing portion is provided between the impeller and the case to generate dynamic pressure based on rotation of the impeller and support the impeller.   The impeller has a plurality of pump blades on both front and back surfaces in the axial direction, and the case has fluid passages formed in portions corresponding to the pump blades on both the front and back surfaces of the impeller, and both sides of the impeller The two fluid channels are configured in series by connecting the discharge port of one of the two fluid channels and the suction port of the other fluid channel. The side channel pump according to claim 1.   3. The side channel pump according to claim 1, wherein the hydrodynamic bearing portion is provided on the outer peripheral side of a portion where the pump blade is formed in the impeller.   The dynamic pressure bearing portion has a dynamic pressure generating groove that generates a dynamic pressure based on the rotation of the impeller, and the dynamic pressure generating groove is formed on the outer peripheral surface of the impeller. The side channel pump according to claim 2, wherein the flow of fluid between the fluid flow paths existing on both sides of the front and back sides is blocked.   5. The side channel pump according to claim 1, wherein the motor has an outer rotor configuration, and the rotor and impeller of the motor are integrally formed.   6. A fuel cell using the side channel pump according to claim 1 as an air supply pump for supplying air to a power generation unit.

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