JP2006214348A - Pump device, cooling system, and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump device to switch a flow path by a simple guide mechanism. <P>SOLUTION: The single suction volute pump device is provided with a power source to rotate an impeller, sucks a predetermined liquid from one suction part installed in the rotation axis direction of the impeller, flows into the rotation circumferential direction of the impeller, and discharges from a discharge part. In the pump device, a plurality of discharge ports are bored in a row in the discharge part in the rotation axial direction of the impeller as part of a pump casing storing the impeller. The impeller is movably assembled in the rotation axial direction. The impeller is moved to one discharge port out of plurality of the discharge ports corresponding to the increase and decrease in rotational speed by the power source so that plurality of the discharge ports are switched. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a centrifugal pump provided with a single suction impeller, and a cooling system provided with the centrifugal pump.

  Conventionally, a single suction centrifugal pump is known as a centrifugal pump. The single suction centrifugal pump is a pump that includes an impeller called an impeller and a motor, and gives energy to a sucked fluid by rotating the impeller by a driving force of the motor. This pump sucks fluid from one suction port and discharges it in an in-plane direction perpendicular to the suction direction. Such a pump is used, for example, in a cooling system such as a fuel cell or an internal combustion engine, and circulates cooling water in piping of the cooling system.

  In many cases, a switching valve for switching the flow path is provided on a flow path such as a cooling system equipped with such a pump. For example, in the above cooling system for a fuel cell, a main flow path provided with a radiator for cooling the fuel cell and a bypass flow path for avoiding a flow to the radiator to prevent overcooling are provided. As a result, the flow path is appropriately switched. By doing so, the cooling system functions sufficiently, but the cooling system occupies a large space. In order to cope with this, there is a technology for saving space by combining functions of two devices into one. For example, Patent Documents 1 and 2 below disclose a variable flow path pump that performs a fluid circulation function by a pump and a flow path switching function by a switching valve in one device. In such a pump, a guide mechanism (such as an on-off valve) that switches an internal flow path is driven, and a liquid can be flowed by appropriately switching the flow path. In addition, although the following patent document 3 is not an integrated mechanism, the switching valve which switches a flow path with the discharge pressure of a pump is disclosed.

JP-A-8-142647 Japanese Patent Laid-Open No. 10-77837 JP-A-63-158369

  However, such a variable flow channel pump requires a complicated guide mechanism for switching a plurality of flow channels provided in the same plane, and also requires an external drive source for driving the guide mechanism. For example, when the valve is opened and closed by external power such as a motor, it is necessary to control the valve motor in addition to the rotation speed control of the pump itself, which involves complicated control.

  In view of these problems, an object of the present invention is to provide a pump device that switches a flow path with a simple guide mechanism.

  In view of the above problems, the first pump device of the present invention employs the following method. That is, a piece provided with a power source for rotating the impeller, sucking a predetermined liquid from one suction portion provided in the rotation axis direction of the impeller, flowing in the circumferential direction of the impeller, and discharging from the discharge portion A suction spiral pump device, wherein the discharge unit is provided with a plurality of discharge ports arranged in a direction of a rotation axis of the impeller, which is a part of a pump casing that houses the impeller. Movably assembled in the direction of the rotation axis, and by moving the impeller to the position of one of the plurality of discharge ports by increasing or decreasing the number of rotations by the power source, the plurality of discharge ports The gist is to switch.

  According to the first pump device of the present invention, the pump casing itself includes a plurality of discharge ports, and the flow path is directly switched by moving the impeller to a position corresponding to each discharge port. This movement of the impeller is generated when the impeller receives an axial thrust force that increases as the rotational speed increases. That is, the movement of the impeller becomes a driving source for switching the flow path, and the movement of the impeller can be adjusted by increasing or decreasing the rotation speed. Therefore, it is possible to switch the flow path with a relatively simple structure without requiring another member for switching the flow path, and to mechanically switch the flow path depending on the rotation speed of the impeller. .

  The pump device having the above-described configuration further includes an initial position setting unit that returns the impeller that moves in the direction of the suction unit as the rotational speed increases to an initial position at a rotational speed lower than a predetermined value. can do.

  According to such a pump device, the impeller moved in the direction of the suction portion by the axial thrust force due to rotation returns to the initial position by the action of the initial position setting portion under a predetermined condition. Therefore, the adjustment of the position of the impeller according to the number of rotations can be facilitated.

  The initial position setting unit of the pump apparatus having the above-described configuration may include an elastic body that returns the impeller to the initial position with a restoring force.

  According to such a pump device, for example, the initial position of the impeller is set using the restoring force of an elastic body such as a spring or rubber, and the moved impeller is returned to the initial position. That is, the initial position of the impeller can be set using simple parts.

  The initial position setting unit of the pump apparatus having the above configuration may include an electromagnet that returns the impeller to the initial position by magnetic force.

  According to such a pump device, the initial position of the impeller is set using the magnetic force of the electromagnet, and the moved impeller is returned to the initial position. The position of the impeller can be adjusted by exciting the electromagnet as necessary.

  The second pump device of the present invention includes a power source for rotating the impeller, and sucks a predetermined liquid from one suction portion provided in the rotation axis direction of the impeller to rotate the impeller A single-suction spiral pump device that discharges in a direction and discharges from a discharge unit, wherein a plurality of flow paths into which the liquid from one discharge port flows into the discharge unit, and the flow of the liquid A direction switching valve for switching to one of the flow paths, and assembling the impeller so as to be movable in the direction of the rotational axis, transmitting the movement of the impeller in the rotational axis direction, and switching the direction The gist is to provide a transmission unit that drives the valve, and to drive the direction switching valve and switch the plurality of flow paths by increasing or decreasing the number of revolutions by the power source.

  According to the second pump device of the present invention, the movement of the impeller is transmitted to the direction switching valve, the direction switching valve is driven, and the flow path is switched. That is, the amount of movement of the impeller is taken out as a drive source and transmitted to the direction switching valve. Therefore, the valve can be driven without providing a special drive source.

  The transmission part of the pump device having the above-described configuration may be a link that connects the direction switching valve and the impeller.

  According to such a pump device, the movement amount of the impeller is taken out and transmitted to the direction switching valve using the link. The operating range of the direction switching valve and the moving range of the impeller can be determined by the link ratio. For example, the direction switching valve can be reliably driven even if the moving range of the impeller is reduced.

  The cooling system of the present invention is a cooling system that circulates cooling water to a predetermined device and cools the cooling water. The cooling water is sucked from one suction portion provided in the rotation axis direction of the impeller, and the impeller A single suction spiral pump device that flows in the circumferential direction of the rotation and discharges from the discharge unit, a heat exchanger that releases the heat absorbed by the cooling water by flowing through the predetermined device, and the pump device A heat exchanger side flow path for guiding the cooling water to the heat exchanger, a bypass flow path for supplying the cooling water from the pump device to the predetermined device without flowing to the heat exchanger, and A main flow path for returning the cooling water that has passed through the heat exchanger side flow path or the bypass flow path to the pump apparatus through the predetermined apparatus, and a controller that controls the rotation speed of the pump apparatus. The pump device includes the discharge unit Two flow paths are provided, one flow path of the two flow paths and the heat exchanger side flow path are connected to the other flow path and the bypass flow path, and the impeller is connected to the flow path. An initial position setting unit that is assembled so as to be movable in the direction of the rotation axis, and that returns the impeller that moves in the direction of the suction unit as the rotation speed increases to an initial position at a rotation speed lower than a predetermined value; The gist is to control the switching of the flow between the heat exchanger side flow path and the bypass flow path by adjusting the rotational speed and moving the impeller to a predetermined position.

  According to the cooling system of the present invention, switching between the heat exchanger side flow path and the bypass flow path is performed by moving the impeller of the pump device. Since the pump device circulates the cooling water and switches the flow channel, it is not necessary to separately provide a flow channel switching device such as a switching valve. Therefore, the number of parts can be reduced and the entire system can be made compact.

  The above cooling system can be applied to a fuel cell system. That is, the fuel cell system of the present invention includes the above-described cooling system, the fuel cell that generates electricity by an electrochemical reaction that is an exothermic reaction as the predetermined device, and the ions mixed in the cooling water in the cooling system. The initial position setting unit of the pump device, when the rotational speed is lower than a predetermined value, the impeller at the position of the flow path connected to the bypass flow path. And when starting the fuel cell after stopping for a predetermined period, prior to power generation of the fuel cell, the control unit increases the number of revolutions above the predetermined value to increase the heat exchanger. The gist is to perform switching control of the flow path by moving the impeller to the position of the flow path connected to the side flow path.

  According to the fuel cell system of the present invention, when the fuel cell system is started after stopping for a predetermined period, the impeller rotational speed of the pump device is increased to move the impeller and cool to the heat exchanger side flow path. Run water. The cooling water flowing on the heat exchanger side is subjected to ion removal by the ion exchanger, and circulates in the cooling system with low conductivity. That is, metal ions melted from the heat exchanger after a long-term stop, ions generated by deterioration of the cooling water, and the like are removed at an early stage, and power generation by the fuel cell is executed. Therefore, it is possible to construct a fuel cell system including a cooling system that can perform power generation by the fuel cell more safely.

Embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
A-1. Configuration of the cooling system in the fuel cell system:
A-2. Pump device structure:
A-3. Control of pump device:
B. Second embodiment:
B-1. Pump device structure:
B-2. Control of pump device:
C. Variations:

A. First embodiment:
A-1. Configuration of the cooling system in the fuel cell system:
FIG. 1 is a schematic configuration diagram showing a cooling system in an in-vehicle fuel cell system as a first embodiment of the present invention. The fuel cell 5 shown in the figure receives the supply of air from the air supply unit 6 and hydrogen gas from the fuel supply unit 7, and generates power by an electrochemical reaction. The generated electric power is taken out to the output unit 8 and used as a drive source for the vehicle. The fuel cell 5 in this embodiment has a stack structure in which a plurality of unit cells each having a hydrogen electrode, an oxygen electrode, and an electrolyte membrane are stacked, and a solid polymer electrolyte membrane is used as the electrolyte membrane. The electrochemical reaction that occurs through the electrolyte membrane is an exothermic reaction, and the temperature of the fuel cell increases with operation. Such a fuel cell 5 has an operating temperature range in which power generation is favorably performed.

  As shown in the figure, the cooling system 10 provided for suppressing the temperature rise of the fuel cell 5 includes a pump device 20 that circulates cooling water, a heat exchanger 25 that dissipates heat of the cooling water, and ions that remove ions. It comprises an exchanger 28, a main flow path 15 for connecting such devices and the fuel cell 5, a heat exchanger side flow path 16, a bypass flow path 17, and the like.

  The pump device 20 that pumps the cooling water in the cooling system 10 is a single suction spiral pump that discharges the sucked cooling water in an in-plane direction perpendicular to the suction direction. The pump device 20 includes one suction port 30 and two discharge ports 40 and 45, and discharges sucked cooling water from the discharge port 40 or the discharge port 45 under predetermined operating conditions. Circulate cooling water. That is, the pump device 20 is a device having a function of switching the discharge ports 40 and 45 (that is, a flow path) and a function of pumping cooling water. The structure of the pump device 20 will be described in detail later.

  The heat exchanger 25 connected to the pump device 20 via the heat exchanger side flow path 16 includes a core having a large heat radiation area, and dissipates heat into the atmosphere in the process of passing cooling water through the core. is doing. The heat exchanger 25 is provided with an electric fan 26, and the cooling water in the heat exchanger 25 is cooled by the fan 26 under a predetermined condition. The cooled cooling water is supplied to the fuel cell 5.

  The main channel 15 is a channel through which mainly cooling water flows, and the fuel cell 5 is disposed on the channel. One end of the main flow path 15 is connected to the heat exchanger side flow path 16 and the bypass flow path 17 at the junction A, and the other end is connected to the suction port 30 of the pump device 20. The cooling water that has passed through the heat exchanger side flow path 16 or the bypass flow path 17 flows through the main flow path 15 and flows into the fuel cell 5. The inflowing coolant flows out of the fuel cell 5 and reaches the suction port 30 of the pump device 20 while taking heat from the fuel cell 5 whose temperature has risen due to an exothermic reaction. The reached cooling water is circulated by the action of the pump device 20.

  The heat exchanger side flow path 16 is a flow path for cooling the cooling water whose temperature has risen by passing through the fuel cell 5, and the heat exchanger 25 is disposed on the flow path. One end of the heat exchanger side flow path 16 is connected to the discharge port 40 of the pump device 20, and the other end is connected to the main flow path 15 at the junction A. The cooling water discharged from the discharge port 40 of the pump device 20 is cooled in the process of passing through the heat exchanger 25 and flows into the main flow path 15. That is, the fuel cell 5 can be efficiently cooled by flowing cooling water through the heat exchanger side flow path 16.

  The bypass channel 17 is a channel for preventing cooling water from being overcooled. One end of the bypass channel 17 is connected to the discharge port 45 of the pump device 20, and the other end is connected to the main channel 15 at the junction A. The cooling water discharged from the discharge port 45 of the pump device 20 flows into the main flow path 15 without passing through the heat exchanger 25. That is, it is possible to prevent the fuel cell 5 from being overcooled by flowing cooling water through the bypass channel 17. For example, at the initial start of the system in which the fuel cell 5 is in a cold state, cooling water is allowed to flow through the bypass channel 17 to quickly raise the temperature of the fuel cell 5.

  In addition to these three main flow paths, the cooling system 10 includes an ion exchanger flow path 18 in which an ion exchanger 28 is disposed. The ion exchanger flow path 18 is a flow path that connects the main flow path 15 on the inflow side of the cooling water of the fuel cell 5 and the main flow path 15 on the outflow side, and is disposed on the ion exchanger flow path 18. The ion exchanger 28 is arranged in parallel with the fuel cell 5. The ion exchanger 28 includes an ion exchange resin inside, and adsorbs and removes ions mixed in the cooling water with the ion exchange resin. In the cooling water circulating through the cooling system, metal ions dissolved from each flow path, the heat exchanger 25, and the like, ions generated due to deterioration of the cooling water, and the like are mixed. The ion exchanger 28 uses such cooling water as low-conductivity cooling water to improve the safety of the fuel cell 5. Such an ion exchanger 28 may be disposed downstream of the fuel cell 5, that is, in series with the fuel cell 5.

  The in-vehicle fuel cell system includes a control unit 100 that controls the entire system including the cooling system 10. The control unit 100 receives a signal from the temperature sensor 101 that detects the temperature of the coolant near the outlet of the fuel cell 5 and signals from various sensors such as an ammeter and a voltmeter (not shown) to determine the driving state of the vehicle. In addition to controlling the amount of air and hydrogen gas supplied to the fuel cell 5, the above-described pump device 20 and fan 26 are also controlled.

  In the cooling system 10 having the above-described configuration, the control unit 100 circulates the cooling water from the pump device 20 through the bypass passage 17 when the temperature of the fuel cell 5 is increased at the time of starting or at a low temperature. Let On the other hand, when the temperature of the fuel cell 5 is lowered during high output operation, the cooling water from the pump device 20 is circulated through the heat exchanger side flow path 16. A good output can be obtained by keeping the temperature of the fuel cell 5 within a predetermined range.

A-2. Pump device structure:
FIG. 2 is a cross-sectional view illustrating a schematic configuration of a cross section of the pump device 20 according to the first embodiment. As shown in the figure, the pump device 20 is mainly composed of a pump casing 50 having one suction port 30 and two discharge ports 40 and 45, and an impeller that is housed in the pump casing 50 and gives energy to cooling water. The impeller 55, the motor unit 70 that rotationally drives the impeller 55, and the like.

  The pump casing 50 has a space (a so-called spiral chamber) that functions to collect the flow that flows out from the outer periphery of the impeller 55 and send it to the discharge port 40 (or the discharge port 45). The discharge ports 40 and 45 of the pump casing 50 are formed side by side in a direction perpendicular to the direction of flow from the suction port 30 (hereinafter referred to as the suction direction or the rotation axis direction), and have a structure in which the thickness is increased in the suction direction. In other words, it is formed in a structure in which two spiral chambers are arranged in the suction direction. The impeller 55 moves in the suction direction under a predetermined condition in the pump casing 50 having these two spiral chambers. The vicinity of the suction port 30 of the pump casing 50 has a predetermined length in the suction direction, and the impeller 55 is movably fitted therein. In this embodiment, the two discharge ports 40 and 45 are provided at the same position when viewed from the rotation axis direction. However, if they are aligned in the rotation axis direction, they are shifted from the rotation axis direction. It may be prepared for. In other words, the discharge direction viewed from the rotation axis direction may be set from the arrangement of the flow paths to be connected.

  The impeller 55 includes a blade 55 a that changes the flow in the suction direction, a main plate 55 b that has a circular outer shape and a predetermined thickness, a side plate 55 c that is joined to the blade 55 a and forms a flow path in the impeller 55, and a cylindrical shape that engages with the motor unit 70. The shaft portion 55d and the like.

  A portion of the side plate 55c on the suction port 30 side (referred to herein as a tip portion of the impeller 55) has a cylindrical shape having a predetermined length and substantially the same diameter as the suction port 30, and the impeller 55 is disposed inside the pump casing 50. Even when going back and forth between the two spiral chambers, the tip end portion engages in the vicinity of the suction port 30 of the pump casing 50. Therefore, even if the impeller 55 moves, the cooling water inside the pump casing 50 does not flow backward and is sucked in, and the cooling water can be reliably sucked from the outside. The cooling water sucked into the impeller 55 passes through a flow passage surrounded by the blades 55a, the main plate 55b, and the side plates 55c, and receives the centrifugal force generated by the rotation of the impeller 55, so that the outer periphery of the impeller 55 (that is, the spiral chamber). ).

  The shaft portion 55d includes convex teeth that form splines at three positions on the outer periphery of the columnar shape. That is, the impeller 55 is connected to the motor unit 70 by a spline and can be rotated, and is supported so as to be slidable in the suction direction.

  The motor unit 70 mainly includes a motor casing 70a having a coil that generates electromagnetic force, a rotor 70b having a permanent magnet, a shaft 70c that rotatably supports the rotor 70b with respect to the motor casing 70a, and the like. Yes.

  The rotor 70b is formed in a substantially cylindrical outer shape, and a cylindrical groove concentric with the center of the column is formed in the height direction. The groove is an engagement portion with the shaft portion 55d of the impeller 55, and a concave groove corresponding to the convex tooth is formed.

  The motor casing 70a houses therein a rotor 70b that is a rotor, receives an excitation signal to the coil by the control unit 100, generates a magnetic force, and rotates the rotor 70b. The shaft 70c of the present embodiment is fixed to the motor casing 70a by press fitting, and is supported so as to be able to rotate and slide with respect to the rotor 70b. It is supported by.

  The pump device 20 including such devices is assembled by inserting the impeller 55 into the rotor 70b of the motor unit 70 and fastening the pump casing 50 to the motor unit 70 with bolts. During assembly, a spring 60 that sets an initial position of the impeller 55 is attached between the rotor 70 b and the impeller 55. The spring 60 is a tension spring and pulls the impeller 55 toward the discharge port 45 (the rotor 70b) to set a default position.

  The pump device 20 having the above configuration rotates the impeller 55 by transmitting the rotational power from the motor unit 70 through a spline. In the single suction spiral pump device 20, the pressure on the suction side and the pressure on the discharge side are not balanced, and the pressure on the discharge side is high. The pressure difference between the two increases as the rotational speed of the impeller 55 increases, and an axial thrust force is generated in the impeller 55 by this pressure difference. Therefore, when the rotation speed of the impeller 55 exceeds a predetermined rotation, the axial thrust force overcomes the restoring force of the spring 60, and the impeller 55 moves toward the suction port 30. That is, the impeller 55 that has discharged the cooling water from the discharge port 45 to a predetermined number of revolutions starts to move when exceeding the predetermined number of rotations, and further increases the number of rotations, and eventually discharges the cooling water from the discharge ports 40. Conversely, when the rotational speed is decreased from this state, the restoring force of the spring 60 overcomes the axial thrust force, the impeller 55 returns to the initial position, and the cooling water is discharged from the discharge port 45.

  FIG. 3 is an explanatory view showing a state of flow path switching by the impeller 55. 3A shows the state of the flow path when the rotation speed of the impeller 55 is lower than the predetermined rotation speed. FIG. 3B shows the state of the flow path of the impeller 55 higher than the predetermined rotation speed. Each state of the flow path in the case of rotation is shown.

  As shown in FIG. 3A, at the time of low rotation, the impeller 55 does not move in the suction direction, and the cooling water circulates from the discharge port 45 through the bypass channel 17. On the other hand, as shown in FIG. 3B, during high rotation, the impeller 55 moves in the suction direction, and the cooling water circulates from the discharge port 40 via the heat exchanger side flow path 16. Thus, the discharge port (flow path) can be switched depending on the rotation speed of the impeller 55.

A-3. Control of pump device:
FIG. 4 is a flowchart showing a flow of the flow path switching process as an example of the control of the pump device 20. This process is executed by the CPU in the control unit 100 at a predetermined timing after the fuel cell 5 is started.

  When the process is started, the control unit 100 inputs the temperature T of the fuel cell 5 (step S400). Specifically, the detection signal from the temperature sensor 101 is input, and the temperature of the cooling water at the outlet of the fuel cell 5 is detected as the temperature T of the fuel cell 5.

  Subsequently, it is determined whether or not the temperature T of the fuel cell 5 is higher than a predetermined value α (step S410). If it is determined in step S410 that the temperature T is higher than the predetermined value α (Yes), the rotational speed R of the impeller 55 is controlled in a range higher than the predetermined value β (step S420), and the process returns to NEXT. A series of processing is repeated at a predetermined timing. That is, by maintaining the rotation speed R in the high rotation range, the impeller 55 is moved in the suction direction, and the cooling water is caused to flow to the heat exchanger side flow path 16.

  On the other hand, if it is determined in step S410 that the temperature T is equal to or lower than the predetermined value α (No), the rotational speed R of the impeller 55 is controlled to a range equal to or lower than the predetermined value β (step S430), and the process returns to NEXT. Then, a series of processing is repeated at a predetermined timing. That is, by keeping the rotation speed R in the low rotation range, the cooling water is allowed to flow to the bypass flow path 17 without moving the impeller 55 in the suction direction.

  In such flow path switching processing, when the temperature T of the fuel cell 5 is high, increasing the circulating flow rate of the cooling water flowing through the fuel cell 5 per unit time (that is, increasing the rotational speed R of the impeller 55). Cooling water from the pump device 20 flows through the heat exchanger side flow path 16. As a result, the cooling water cooled by the heat exchanger 25 can be circulated, and the fuel cell 5 can be efficiently cooled.

  On the other hand, if the circulating flow rate of the cooling water flowing through the fuel cell 5 per unit time is decreased when the temperature T of the fuel cell 5 is low (that is, the rotational speed R of the impeller 55 is decreased), the cooling from the pump device 20 is performed. Water flows through the bypass channel 17. As a result, since it is not cooled by the heat exchanger 25, the temperature of the fuel cell 5 can be efficiently increased or overcooling can be prevented. Since the detected temperature T of the fuel cell 5 is controlled with a predetermined hysteresis, the rotation speed R region of the impeller 55 is not frequently switched.

  According to the above pump device 20, the cooling system 10 including the pump device 20, and the flow path switching process of the pump device 20, the flow path is switched by moving the impeller 55, and the timing of the movement is performed by controlling the rotational speed. be able to. Therefore, the flow path can be switched without providing a special drive source, and the control in the control unit 100 can be simplified. Further, since the pump device 20 itself has a flow path switching function, for example, it is not necessary to separately provide a flow path switching valve such as a three-way valve in the cooling system. Therefore, the number of parts in the entire cooling system can be reduced, and the entire system can be made compact. By applying such a cooling system 10 to a fuel cell system, it is possible to increase the degree of freedom of arrangement of peripheral devices in the fuel cell system. In particular, the effect is large in the case of a fuel cell system in which a fuel cell is arranged in a narrow space of a vehicle.

  Generally, in a single suction spiral pump device, it is desirable in terms of structure to reduce the axial thrust force acting on the impeller by rotation. Therefore, on the back side of the impeller blades, a member that reduces the pressure acting on the main plate of the impeller called back blades and a through-hole in the rotating shaft direction called a counter hole are provided on the impeller, and a device for reducing the axial thrust force has been made. Yes. On the other hand, in the pump apparatus 20 in the present embodiment, the axial thrust force acting on the impeller 55 is positively used. Therefore, it is not necessary to provide a back blade, a countersink, or the like on the impeller.

  Moreover, in the pump apparatus 20 of 1st Example, although demonstrated as what sets the default position of the impeller 55 using the restoring force by the tension spring 60, it is good also as what uses a compression spring. FIG. 5 is a cross-sectional view showing a schematic configuration of a cross section of the pump device 200 using a compression spring. The pump device 200 shown in the drawing is different from the pump device 20 of the first embodiment shown in FIG. Therefore, the other parts are denoted by the same reference numerals and description thereof is omitted.

  As shown in the figure, the pump device 200 is in contact with the tip of the impeller 55 and is fixed to the compression spring 190 that presses the impeller 55 toward the motor unit 70, and the suction port 30 of the pump casing 50, and holds the compression spring 190. And a stopper 191. The stopper 191 rotatably holds the compression spring 190, and the rotor 70b, the impeller 55, and the compression spring 190 rotate integrally.

  In such a pump device 200, when the rotation speed of the impeller 55 is a low value up to a predetermined value, the compression spring 190 overcomes the axial thrust force in the suction direction, and the impeller 55 does not move in the suction direction. When the rotation speed of the impeller 55 is higher than a predetermined value, the axial thrust force overcomes the compression spring 190 and the impeller 55 moves in the suction direction. Even if the pump device 200 having such a structure is used, the same effect as the pump device 20 of the first embodiment is obtained.

  The setting of the default position of the impeller 55 is not limited to the springs such as the tension spring 60 and the compression spring 190. For example, the default position may be set using an elastic body other than a spring such as a disc spring or rubber.

B. Second embodiment:
B-1. Pump device structure:
FIG. 6 is a cross-sectional view showing a schematic configuration of a cross section of the pump device 300 of the second embodiment. As shown in the figure, the pump device 300 mainly includes a pump casing 50, an impeller 56, a motor unit 71, and the like. The pump casing 50 has the same structure as the pump device 20 of the first embodiment, and includes two discharge ports 40 and 45.

  The cooling system according to the second embodiment is a system including the pump device 300 according to the second embodiment instead of the pump device 20 in the cooling system 10 of FIG. The channel 16 and the discharge port 45 are connected to the bypass channel 17, respectively. Since the cooling system of the second embodiment is different only in the pump device 300, detailed description is omitted.

  The impeller 56 shown in FIG. 6 is mainly made of iron, which is a magnetic material on the motor unit 71 side, in addition to the blades 55a, side plates 55c, and shaft portions 55d similar to those of the first embodiment, and has a circular outer shape and a predetermined thickness. The main plate 56b is provided with an annular member 56e. That is, only the structure of the main plate 56b is different from the first embodiment.

  The motor unit 71 mainly includes a rotor 71b having permanent magnets and coils 71d arranged at equal intervals on the end surface on the impeller 56 side in addition to the same motor casing 70a as in the first embodiment, The rotor 71b is rotatably supported, and includes a shaft 71c having a brush (not shown) for energizing the coil 71d. That is, the structure of the rotor 71b and the shaft 71c is different from the first embodiment.

  The pump device 300 provided with such devices is assembled by inserting the impeller 56 into the rotor 71b of the motor unit 71 and fastening the pump casing 50 with the motor unit 71 with bolts. However, the tension spring as in the first embodiment is used. 60 is not mounted. In the pump device 300 of the second embodiment, the initial position of the impeller 56 is set by pulling the annular member 56e (that is, the impeller 56) using electromagnetic induction by energization of the coil 71d. That is, the pump device 300 of the second embodiment sets the default position of the impeller 56 by magnetic force (electromagnet). The energization of the coil 71d is executed by the control unit 100.

  In the pump device 300 having the above-described configuration, the coil 71d is energized continuously before the impeller 56 is rotationally driven, and the impeller 56 is held on the discharge port 45 side by electromagnetic force. As a result, the impeller 56 rotates. When the rotation speed of the impeller 56 exceeds a predetermined rotation, the axial thrust force overcomes the electromagnetic force, and the impeller 56 moves toward the suction port 30. That is, the impeller 56 that has discharged the cooling water from the discharge port 45 to the predetermined number of revolutions starts to move when exceeding the predetermined number of revolutions, and further increases the number of rotations, and eventually discharges the cooling water from the discharge ports 40. Conversely, when the rotational speed is decreased from this state, the electromagnetic force overcomes the axial thrust force, the impeller 56 returns to the initial position, and the cooling water is discharged from the discharge port 45. Thus, the discharge port (flow path) can be switched depending on the rotation speed of the impeller 56.

B-2. Control of pump device:
Such control of the pump device 300 is executed by the CPU in the control unit 100 at a predetermined timing after the start of the fuel cell 5 as in the first embodiment. In the control of the pump device 300 according to the second embodiment, the energization process for the coil 71d is performed after the fuel cell 5 is started and before the impeller 56 is rotationally driven. This energization process is continuously performed until the fuel cell 5 is stopped, during which the flow path switching process shown in FIG. 4 is performed. That is, the process is controlled by substantially the same processing as in the first embodiment. Therefore, the description of the flow path switching process is omitted.

  As described above, according to the pump device 300, the cooling system, and the flow path switching process of the second embodiment, the number of components in the cooling system can be reduced as in the first embodiment. In addition, compared with the first embodiment, an energization process to the coil 71d is added, but this is a process that only energizes constantly. Therefore, the control in the control unit 100 can be simplified as compared with a system including a flow path switching valve such as a motor-driven three-way valve.

  The control of the pump device 300 of the second embodiment may be such that the coil 71d is energized at a predetermined timing instead of the process of always energizing. FIG. 7 is a flowchart showing a flow of the flow path switching process as an example of the control of the pump device 300.

  When the process is started, the control unit 100 inputs the temperature T of the fuel cell 5 (step S700), and determines whether or not the temperature T of the fuel cell 5 is higher than a predetermined value α (step S710). The processing so far is the same processing as steps S400 and S410 of the flow path switching processing shown in FIG.

  If it is determined in step S710 that the temperature T is higher than the predetermined value α (Yes), the current to the coil 71d is turned off (step S720). Specifically, when the coil 71d is not energized, the state is left as it is, and when the coil 71d is energized, the coil 71d is deenergized. With this process, no electromagnetic force acts on the impeller 56, and the impeller 56 is in a state of being freely movable in the direction of the rotation axis. Subsequently, the rotational speed R of the impeller 56 is controlled within a range higher than the predetermined value β (step S730), the process returns to NEXT, and a series of processing is repeated at a predetermined timing. That is, by maintaining the rotation speed R in the high rotation range, the impeller 56 is moved in the suction direction, and the cooling water flows into the heat exchanger side flow path 16.

  On the other hand, if it is determined in step S710 that the temperature T is equal to or lower than the predetermined value α (No), the current to the coil 71d is turned on (step S740). Specifically, when the coil 71d is not energized, the coil 71d is energized, and when the coil 71d is energized, it is left as it is. In this process, an electromagnetic force acts on the impeller 56, and the impeller 56 is constrained to the discharge port 45 side (motor unit 71 side). Subsequently, the rotational speed R of the impeller 56 is controlled to a range equal to or less than the predetermined value β (step S750), the process returns to NEXT, and a series of processing is repeated at a predetermined timing. That is, by maintaining the rotation speed R in the low rotation range, the impeller 56 is held on the discharge port 45 side, and the cooling water is allowed to flow to the bypass channel 17.

  Even when such a flow path switching process is performed, a cooling system that efficiently maintains the fuel cell 5 at a temperature within a predetermined range and does not require complicated control can be constructed as in the first embodiment.

  In the pump device 300 of the second embodiment, the coil 71d provided on the rotor 71b and the annular member 56e provided on the impeller 56 have been described as rotating together, but the coil is fixed to the shaft side. Also good.

  FIG. 8 is a cross-sectional view showing a schematic configuration of a cross section of a pump device as a modification of the second embodiment. The pump device 400 includes a pump casing 50, an impeller 57, a motor unit 72, and the like. The pump device 400 differs from the pump device 300 only in a main plate 57b of the impeller 57, a rotor 72b, and a shaft 72c of the motor unit 72. Accordingly, parts having the same structure are denoted by the same reference numerals and description thereof is omitted.

  As shown in the figure, the impeller 57 is formed by using a main plate 57b having a steel member 57e on the motor part 72 side near the center of the rotating shaft, and as in the second embodiment, the motor part is formed by a spline. 72 is engaged with the rotor 72b. The motor unit 72 includes a rotor 72b having a through hole at the center of rotation, and a shaft 72c is engaged with the through hole. The shaft 72c has a coil 72d at its tip, is formed in a length protruding from the through hole of the rotor 72b, and rotatably supports the rotor 72b. Inside the shaft 72c, electrical wiring (not shown) to the coil 72d is provided, and a current according to a command from the control unit 100 reaches the coil 72d.

  In the pump device 400 having such a structure, the coil 72d is excited by the current from the control unit 100, and the impeller 57 is pulled toward the shaft 72c by the magnetic force. In this structure, since the coil 72d is provided on the shaft 72c which is a fixed portion, the electrical wiring can be handled relatively easily.

C. Variations:
In the present embodiment, a pump device having a structure in which two discharge ports (flow passages) are provided in the pump casing has been described. However, the pump casing has one discharge port, and a branch pipe is connected to the pump device, so that the pump as a whole The apparatus may be configured. In this case, a valve for switching the flow path may be provided inside the branched pipe.

  FIG. 9 is a schematic configuration diagram illustrating a configuration of a pump device including a flow path switching valve. As shown in the figure, the pump device 500 mainly includes a pump casing 51, an impeller 58, a motor part 73, a branch pipe 80, a link part 95, and the like.

  The pump casing 51 has a suction port 31 and a discharge port 35 and includes a space for storing the impeller 58 therein. The impeller 58 and the motor unit 73 are structured to support the impeller 58 so as to be movable in the direction of the rotation axis, almost the same as in the first embodiment shown in FIG. 2, but the movement amount (stroke) is the same as that of the first embodiment. It is set small compared to.

  The branch pipe 80 is a pipe having an inlet portion 83 and two outlet portions 81 and 82, and the inlet portion 83 is connected to the discharge port 35 of the pump casing 51. The branch pipe 80 includes a valve portion 90 that guides cooling water flowing from the inlet portion 83 to either the outlet portion 81 or the outlet portion 82. The valve portion 90 and the tip of the impeller 58 are connected by a link portion 95, and the valve portion 90 is driven according to the stroke of the impeller 58 in the rotation axis direction. That is, the pump device 500 drives the valve unit 90 in conjunction with the movement of the impeller 58 due to the axial thrust force generated by the rotation.

  By setting it as the pump apparatus of such a structure, special motive power is not required for the drive of the valve part 90 which switches the two exit parts 81 and 82 (flow path). Therefore, the switching of the flow path can be controlled by the amount of movement of the impeller 58, that is, the rotational speed of the impeller 58.

  The amount of movement of the impeller 55 described in the present embodiment is about 20 to 30 mm. However, since the mechanism for extracting the amount of movement is a link mechanism, the valve can be switched even if the amount of movement of the impeller 58 is small. it can. Therefore, the structure of the entire pump device can be configured in a compact manner, and it is relatively easy to configure from a pump having a conventional structure. Furthermore, by providing the branch pipe 80 on the suction port 31 side, the degree of freedom of equipment arrangement in the cooling system can be improved.

  In this modification, the movement of the impeller is used for the driving power of the valve, and the stroke is taken out by the link. However, for example, the stroke may be taken out using a cable or the like. Alternatively, the axial thrust force acting on the impeller may be indirectly extracted and used as the driving power for the valve. For example, the axial thrust force is taken out as a pressure difference (differential pressure) between the suction side and the discharge side, and a predetermined stroke is created by the differential pressure. The valve may be driven by this stroke.

  In the control of the pump device of this embodiment, after the fuel cell is started, only the temperature of the fuel cell is detected and controlled. However, the pump device is controlled in consideration of the period during which the fuel cell is stopped. It is good as a thing.

  FIG. 10 is a flowchart of control of the pump device in consideration of the stop period of the fuel cell. This process is executed by the CPU in the control unit 100 at a predetermined timing prior to the start of the fuel cell 5. A cooling system that controls the pump device described below is the same as the cooling system 10 shown in FIG.

  When the process is started, the control unit 100 inputs the stop period L of the fuel cell 5 (step S900). The control unit 100 is provided with a counter and counts elapsed time as the vehicle stops. The control unit 100 recognizes this elapsed time as the stop period L.

  Subsequently, it is determined whether or not the stop period L is longer than the predetermined value γ (step S910). The predetermined value γ is set to a time corresponding to about one month. If it is determined in step S910 that the stop period L is longer than the predetermined value γ (Yes), the rotational speed R of the impeller 55 is set to a predetermined value ω, and the impeller 55 is rotated for a predetermined time. (Step S920). The predetermined value ω is a rotational speed larger than the predetermined value β shown in FIG. 4, and in this process, the impeller 55 moves in the suction direction, and the cooling water flows into the heat exchanger side flow path 16 (that is, the heat exchanger 25). ) Surely flows.

  Thus, after the cooling water is circulated in the heat exchanger 25 and the fuel cell 5 for a predetermined time, the electrochemical reaction in the fuel cell 5 starts. That is, the control unit 100 issues a supply command to the air supply unit 6 and the fuel supply unit 7. Along with this supply command, the control unit 100 executes a flow path switching process in the pump device 20 (step S930) and ends a series of processes. The flow path switching process is the process shown in FIG.

  On the other hand, when it is determined in step S910 that the stop period L is equal to or less than the predetermined value γ (No), the flow path switching process is executed together with the supply command to the air supply unit 6 and the fuel supply unit 7 (step S910). S930), a series of processing ends.

  According to the above control of the pump device, when the fuel cell 5 is started after a long-term stop (period exceeding the predetermined value γ), the cooling water is placed on the heat exchanger 25 side for a while before the start. Shed. In particular, the conductivity of the cooling water supplied to the fuel cell 5 can be reduced by flowing the cooling water to the heat exchanger 25 side where ions are expected to be dissolved and removing the ions by the ion exchanger 28. . Therefore, the fuel cell 5 can be cooled more safely.

  In this embodiment, the pump device is described as having two discharge ports (flow channels), but a plurality of discharge ports (flow channels) may be formed to switch the flow channels. Further, although the description has been made on the assumption that the impeller is moved by increasing or decreasing the number of revolutions by the motor unit, the present invention is not limited to this. For example, an actuator that forcibly moves the impeller from the outside in the direction of the rotation axis may be provided, and thereby the flow path may be switched. Even in this case, since the moving direction of the impeller by the actuator is the rotation axis direction, a complicated member is not required for switching the flow path, and the flow path variable pump device is formed with a relatively simple structure. be able to.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the spirit of the present invention. . In the present embodiment, the fuel cell cooling system has been described as an example of the pump device, but the same effect can be obtained even when the pump device of the present invention is used in the cooling system of the internal combustion engine.

It is a schematic block diagram which shows the cooling system in the vehicle-mounted fuel cell as 1st Example of this invention. It is sectional drawing which shows schematic structure of the cross section of the pump apparatus of 1st Example. It is explanatory drawing which shows the mode of the flow-path switching by an impeller. It is a flowchart which shows the flow of the flow-path switching process as an example of control of a pump apparatus. It is sectional drawing which shows schematic structure of the cross section of the pump apparatus using a compression spring. It is sectional drawing which shows schematic structure of the cross section of the pump apparatus of 2nd Example. It is a flowchart which shows the flow of the flow-path switching process as an example of control of a pump apparatus. It is sectional drawing which shows schematic structure of the cross section of the pump apparatus as a modification of 2nd Example. It is a schematic block diagram which shows the structure of the pump apparatus provided with the valve of flow path switching. It is a flowchart of control of the pump apparatus in consideration of the stop period of the fuel cell.

Explanation of symbols

5 ... Fuel cell 6 ... Air supply part 7 ... Fuel supply part 8 ... Output part 10 ... Cooling system 15 ... Main flow path 16 ... Heat exchanger side flow path 17. ..Bypass channel 18 ... Ion exchanger channel 20 ... Pump device 25 ... Heat exchanger 26 ... Fan 28 ... Ion exchanger 30 ... Suction port 31 ... Suction Port 35 ... Discharge port 40, 45 ... Discharge port 50 ... Pump casing 51 ... Pump casing 55 ... Impeller 55a ... Blade 55b ... Main plate 55c ... Side plate 55d ... .Shaft part 56 ... Impeller 56b ... Main plate 56e ... Ring member 57 ... Impeller 57b ... Main plate 57e ... Member 58 ... Impeller 60 ... Spring 70 ... Motor part 70a ... motor casing 70b ... rotor 70c ... shaft 71 ... motor part 71b ... rotor 71c ... shaft 71d ... coil 72 ... motor part 72b ... rotor 72c. .. Shaft 7 2d ... Coil 73 ... Motor part 80 ... Branch pipe 81, 82 ... Outlet part 83 ... Inlet part 90 ... Valve part 95 ... Link part 100 ... Control unit 101 ... Temperature sensor 190 ... Compression spring 191 ... Stopper 200 ... Pump device 300 ... Pump device 400 ... Pump device 500 ... Pump device

Claims (8)

A power source for rotating the impeller is provided, and a predetermined liquid is sucked from one suction portion provided in the rotational axis direction of the impeller, flows in the rotation circumferential direction of the impeller, and is discharged from the discharge portion. A spiral pump device,
The discharge unit is a part of a pump casing that houses the impeller, and is arranged in the direction of the rotation axis of the impeller to provide a plurality of discharge ports.
Assembling the impeller movably in the direction of the rotation axis,
A pump device that switches the plurality of discharge ports by moving the impeller to a position of one of the plurality of discharge ports by increasing or decreasing the number of rotations by the power source. The pump device according to claim 1, further comprising:
A pump device comprising an initial position setting unit that returns the impeller that moves in the direction of the suction unit as the rotational speed increases to an initial position at a rotational speed lower than a predetermined value. The pump device according to claim 2,
The said initial position setting part is a pump apparatus provided with the elastic body which returns the said impeller to an initial position with a restoring force. The pump device according to claim 2,
The said initial position setting part is a pump apparatus provided with the electromagnet which returns the said impeller to an initial position with magnetic force. A power source for rotating the impeller is provided, and a predetermined liquid is sucked from one suction portion provided in the rotational axis direction of the impeller, flows in the rotation circumferential direction of the impeller, and is discharged from the discharge portion. A spiral pump device,
The discharge unit is provided with a plurality of flow paths into which the liquid from one discharge port flows, and a direction switching valve for switching the flow of the liquid to one of the plurality of flow paths,
Assembling the impeller movably in the direction of the rotation axis,
A transmission unit that transmits movement of the impeller in the rotation axis direction and drives the direction switching valve;
A pump device that drives the direction switching valve and switches the plurality of flow paths by increasing or decreasing the number of rotations of the power source. The pump device according to claim 5,
The said transmission part is a pump apparatus which is a link which connects the said direction switching valve and the said impeller. A cooling system that circulates cooling water to a predetermined device and cools it,
A single suction spiral pump device that sucks the cooling water from one suction portion provided in the direction of the rotation axis of the impeller and flows it in the rotation circumferential direction of the impeller, and discharges it from the discharge portion;
A heat exchanger that releases heat absorbed by the cooling water by flowing through the predetermined device;
A heat exchanger side channel for guiding the cooling water from the pump device to the heat exchanger;
A bypass flow path for supplying the cooling water from the pump device to the predetermined device without flowing to the heat exchanger;
A main flow path for passing the cooling water through the heat exchanger side flow path or the bypass flow path through the predetermined device and returning it to the pump device again;
A control unit for controlling the rotational speed of the pump device,
The pump device is
Providing two flow paths in the discharge unit, connecting one flow path of the two flow paths and the heat exchanger side flow path, and connecting the other flow path and the bypass flow path;
Assembling the impeller so as to be movable in the direction of the rotation axis,
An initial position setting unit that returns the impeller that moves in the direction of the suction unit with an increase in the rotational speed to an initial position at a rotational speed lower than a predetermined value;
The said control part controls the switching of the flow of the said heat exchanger side flow path and the said bypass flow path by adjusting the said rotation speed and moving the said impeller to a predetermined position Cooling system. A fuel cell system,
A cooling system according to claim 7;
As the predetermined device, a fuel cell that generates electricity by an electrochemical reaction that is an exothermic reaction;
The cooling system further includes an ion exchanger that removes ions mixed in the cooling water,
The initial position setting unit of the pump device holds the impeller at a position of the flow path connected to the bypass flow path when the rotational speed is lower than a predetermined value,
When starting the fuel cell after stopping for a predetermined period, prior to power generation of the fuel cell, the control unit increases the number of rotations to be greater than the predetermined value and connects to the heat exchanger side flow path. A fuel cell system for controlling the switching of the flow path by moving the impeller to the position of the flow path.

Images