JP3896278B2 - Fluid pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid pump of the motor built-in.
[0002]
[Problems to be solved by the invention]
In a relatively small electronic device such as a personal computer (hereinafter referred to as a personal computer), the amount of heat generated at the time of driving increases as the arithmetic unit (CPU) increases in speed. Therefore, the CPU is cooled by generating an air flow with a fan provided in the housing.
[0003]
However, if the amount of heat generated further increases as the CPU speed increases, the above-described so-called air cooling system cannot sufficiently cool the system, so a water cooling system cooling device that cools the CPU by circulating a refrigerant such as water by a fluid pump. Has been adopted. The cooling device includes a fluid pump, a heat radiating unit, and a heat receiving unit provided in the CPU, and connects the heat radiating unit and the heat receiving unit with a pipe to circulate the refrigerant. In this case, a fluid pump having a built-in motor as a driving source is generally used.
[0004]
However, the conventional fluid pump with a built-in motor has a large thickness because the inlet is provided at the top of the casing and the outlet is provided at the side. For this reason, in an electronic device having a very small thickness such as a notebook personal computer, it has been difficult to install the cooling device having the above-described configuration in the housing.
[0005]
The present invention has been made in view of the above circumstances, and its object is to provide a fluid pump which attained miniaturization of the thickness dimension of the casing.
[0006]
[Means for Solving the Problems]
The fluid pump according to claim 1 of the present invention has a casing having a refrigerant flow path through which liquid refrigerant flows, and a cup shape having a plurality of blades disposed on the outer periphery of the casing. A rotor, an annular stator disposed on the inner peripheral portion of the rotor with a gap between the rotor, a plain bearing disposed on the inner peripheral portion of the stator and rotatably supporting the rotating shaft of the rotor; A motor comprising a bearing assembly comprising a bearing holding portion for holding the slide bearing, an inlet provided in the casing and allowing the refrigerant to flow into the refrigerant flow path as the rotor rotates, and the rotor provided in the casing periphery from along with the rotation the coolant channel and a flow outlet for outflow of the coolant, the inlet and the outlet, both at the same height position as the blade, the blade Is arranged so as to face the end,
A portion where the rotation shaft at the center of the rotor is fixed is configured as a thick portion,
The rotor is provided with a vent hole for helping refrigerant flow into the gap between the rotor and the stator, and when the rotary shaft is inserted into the slide bearing in the bearing assembly, An escape hole is provided to allow air inside the slide bearing to escape.
[0008]
According to the said structure, the thickness dimension of a casing can be made still smaller. Further, a fluid refrigerant can be introduced into the gap between the rotor and the stator and used as a lubricant.
[0010]
In addition, if air remains in the inner part of the rotary shaft when the rotary shaft is inserted into the slide bearing, the air will expand due to a rise in temperature, etc., and the rotor will float, allowing the rotor to rotate with high precision. Disappear. According to the said structure, since the rotating shaft of a rotor can be reliably inserted to the back part in a slide bearing, a rotor can be rotated with sufficient precision.
[0011]
Further, in the case where a low-viscosity liquid refrigerant is circulated through the refrigerant flow path and includes a slide bearing that is provided in the refrigerant flow path and rotatably supports the rotating shaft of the rotor, the slide bearing is filled with an inorganic material. The inorganic filler has a thermal expansion coefficient of 4 × 10 −6 / ° C. or less, or a negative expansion coefficient, and at least an average particle size of 30 μm or less. Including a silicate compound and a carbon-based inorganic filler having an average particle size of 50 μm or more, the inorganic filler accounts for 50 to 80% of the molding material, and the carbon-based inorganic filler accounts for 20 to 50% of the molding material. It is preferable to configure as described above (invention of claim 2 ).
According to the said structure, the slidability of a plain bearing, wear resistance, and thermal stability can be improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment in which the present invention is applied to a notebook personal computer cooling apparatus will be described below with reference to FIGS. FIG. 3 is a perspective view schematically showing a notebook personal computer (hereinafter referred to as a personal computer) 1. The notebook computer 1 includes a computer main body 2 and a display unit 3 that is rotatably supported by the computer main body 2. The computer main body 2 has a flat rectangular box-shaped casing 4.
[0020]
The upper portion of the housing 4 is covered with a cover (not shown), and a keyboard or the like is disposed on the cover. A printed wiring board (not shown) on which the CPU 5 serving as a heating element is mounted is accommodated in the housing 4. The display unit 3 includes a flat rectangular box-shaped housing 6 and a liquid crystal display device (not shown) housed in the housing 6.
[0021]
A cooling device 11 including a fluid pump 7, a heat radiating unit 8, a heat receiving unit 9 and a tube 10 connecting the fluid pump 7, the heat radiating unit 8, and the heat receiving unit 9 is disposed in the notebook computer 1. ing. The tube 10 is composed of a flexible thin tube having an inner diameter of 2 to 3 mm. A fluid refrigerant having a low viscosity, such as water, circulates in a circulation cycle including the fluid pump 7, the heat radiating unit 8, the heat receiving unit 9, and the tube 10.
[0022]
Of the cooling device 11, the heat radiating portion 8 and the heat receiving portion 9 are disposed in the housing 4, and in particular, the heat receiving portion 9 is disposed on the CPU 5. Although not shown, a vent hole is provided in the housing 4 in the vicinity of the heat radiating portion 8. On the other hand, the fluid pump 7 is disposed in the housing 6 of the display unit 3. For this reason, the middle part of the tube 10 that connects the fluid pump 7 to the heat radiating part 8 and the heat receiving part 9 is configured to pass through a hinge part (not shown) that connects the computer main body 2 and the display unit 3. Yes.
[0023]
Next, the configuration of the fluid pump 7 will be described with reference to FIGS. The fluid pump 7 includes a flat rectangular box-shaped casing 14 including an upper case 12 and a lower case 13, and a partition wall 15 fitted in the lower case 13.
[0024]
A cylindrical portion 16 is provided on the lower surface of the upper portion of the upper case 12. The cylindrical portion 16 is provided with an inflow port 17 and an outflow port 18 at substantially the same height. In the inflow port 17 and the outflow port 18, an inflow pipe 19 and an outflow pipe 20 that extend through the side portion of the upper case 12 to the outside are provided integrally with the cylindrical portion 16. In the present embodiment, the inflow pipe 19 and the outflow pipe 20 extend along the opposite side portions of the upper case 12 and project outward from the same side portion.
[0025]
On the upper surface of the partition wall 15, an annular protrusion 21 that fits into the cylindrical portion 16 is provided. Further, a concave portion 23 for accommodating the packing 22 is provided on the inner side of the lower end portion of the cylindrical portion 16 over the entire circumference. With the above configuration, a water-tight refrigerant flow path 24 is formed between the cylindrical portion 16 of the upper case 12 and the annular protrusion 21 of the partition wall portion 15.
[0026]
A stator portion 25 that protrudes upward is provided at the central portion of the partition wall portion 15. A holding hole 27 for holding the slide bearing 26 is provided in the central portion of the stator portion 25. Therefore, in this embodiment, the partition wall portion 15 (stator portion 25) functions as a bearing holding portion, and the bearing assembly is configured by the slide bearing 26 and the partition wall portion 15. Further, a plurality of, for example, three notches 28 extending to the bottom of the holding hole 27 are provided around the holding hole 27 in the stator portion 25. On the other hand, three notches 29 extending in the radial direction are provided at the lower end of the slide bearing 26. The slide bearing 26 is inserted into the holding hole 27 so that the notch 29 coincides with the notch 28. As a result, the slide bearing 26 and the stator portion 25 are provided with relief holes that allow the holding holes 27 including the notches 28 and 29 to communicate with the refrigerant flow path 24.
[0027]
An annular recess 30 is provided around the lower portion of the stator portion 25. The recess 30 accommodates a stator 32 around which a coil 31 is wound. A substrate 33 on which a control circuit for controlling the drive voltage to the coil 31 is mounted is provided below the recess 30.
[0028]
On the other hand, a rotor 34 is accommodated in the refrigerant flow path 24. The rotor 34 has a shallow dish shape with an opening at the bottom, and a plurality of blades 35 projecting outward are provided at substantially equal intervals on the outer peripheral surface of the side portion. The blades 35 are configured to be at the same height as the inlet 17 and the outlet 18. The central portion of the upper surface portion of the rotor 34 is configured to be thick, and the rotary shaft 36 is fitted and fixed to the center of the thick portion 34a. The rotary shaft 36 extends downward from the upper surface portion of the rotor 34 and is rotatably supported by the slide bearing 26.
[0029]
As described above, the slide bearing 26 and the stator portion 25 are provided with the cutouts 28 and 29, and the holding hole 27 and the refrigerant flow path 24 communicate with each other through the cutouts 28 and 29. For this reason, when the rotary shaft 36 is inserted into the slide bearing 26, the air in the holding hole 27 can be released to the refrigerant flow path 24 through the notches 28 and 29, and as a result, the rotary shaft 36 is moved to the back of the slide bearing 26. Can be inserted.
[0030]
In addition, a plurality of, for example, four holes 37 penetrating vertically are provided around the thick portion 34 a in the upper surface portion of the rotor 34. Further, a plurality of permanent magnets 38 for forming magnetic poles are fixed inside the lower part of the side portion of the rotor 34. The permanent magnet 38 faces the stator 32 in the radial direction with the partition wall 15 interposed therebetween. A motor 39 is composed of the rotor 34 and the stator 32.
[0031]
The stator portion 25 of the partition wall portion 15 enters the rotor 34 from below, and the side surface portion of the rotor 34 and the permanent magnet 38 enter between the annular protrusion 21 of the partition wall portion 15 and the stator portion 25 from above. With such a configuration, the space between the rotor 34 and the partition wall 15 is set to be very narrow, and the thickness dimension of the casing 14 is kept small.
[0032]
In the fluid pump 7 configured as described above, when the rotor 34 rotates in the direction of arrow A, the refrigerant in the refrigerant flow path 24 receives centrifugal force and is sent out from the outlet 18, while the inlet 17 enters the refrigerant flow path 24. The refrigerant flows in. Thereby, a refrigerant | coolant circulates through the circulation cycle which consists of the fluid pump 7, the thermal radiation part 8, the heat receiving part 9, and the tube 10, and CPU5 can be cooled.
[0033]
A part of the refrigerant flowing through the refrigerant flow path 24 flows into the gap between the rotor 34 and the partition wall portion 15. At this time, the hole 34 was provided in the rotor 34 so that the gas in the gap between the rotor 34 and the partition wall 15 was released. For this reason, even if the said clearance gap is very narrow, a refrigerant | coolant can be passed to the slide bearing 26 part, and a refrigerant | coolant can be utilized as a lubricant of the slide bearing 26. FIG.
[0034]
Here, the configuration of the slide bearing 26 will be described in detail. The slide bearing 26 is made of spherical amorphous carbon (corresponding to a carbon-based inorganic filler) having an average particle diameter of 30 μm, leucite which is a silicate compound having an average particle diameter of 20 μm, and clay mineral having an average particle diameter of 15 μm. It is obtained by mixing an inorganic filler, a PPS resin, and zinc stearate, heating and kneading, and molding the pelletized molding material with an injection molding machine.
[0035]
In this example, the proportion (weight ratio) of amorphous carbon, leucite, clay mineral, PPS resin, and zinc stearate in the molding material is 20%, 30%, 4%, 45%, and 1%, respectively. It is configured as follows. Therefore, the proportion of the inorganic filler in the entire molding material is 54%, and the proportion of the carbon-based inorganic filler is 20%.
[0036]
According to the experiments by the inventors, the proportion of the inorganic filler in the molding material is 50% or more, and the thermal expansion coefficient is 4 × 10 ⁻⁶ / ° C. or less, or has a negative expansion coefficient, and the average particle diameter It was found that by adding a silicate compound having a particle size of 30 μm or less to the inorganic filler, it becomes easy to pack finely, and the thermal expansion coefficient of the molding material is 1.4 × 10 ⁻⁵ / ° C. or less. Thus, when the thermal expansion coefficient is small, the thermal stability of the slide bearing is excellent, and therefore the rotor 34 can be stably rotated without being affected by the temperature change. Note that if the proportion of the inorganic filler in the molding material exceeds 85%, it is not possible to give appropriate fluidity and bonding property to the molding material.
[0037]
In addition, by using a carbon-based inorganic filler having an average particle size of 50 μm or more as the inorganic filler and making the proportion of the carbon-based inorganic filler in the molding material 20% or more, slidability and wear resistance can be obtained. It turns out that it improves. This is because the carbon-based inorganic filler protrudes from the surface of the molded product and makes point contact with the counterpart material. Therefore, in this embodiment, the sliding bearing and the shaft are in point contact, and the slidability and wear resistance are improved. If the proportion of the carbon-based inorganic filler in the molding material exceeds 50%, the molding material cannot be provided with appropriate fluidity and binding properties.
[0038]
Therefore, in this example, the proportion of the inorganic filler in the molding material, the proportion of the carbon-based inorganic filler in the molding material, the average particle size, and the like were set as described above.
For example, FIG. 4 shows thermal expansion coefficients of a molded product sample (“Example”) according to the present example and a molded product sample (“Comparative Example”) in which PPS is highly filled with glass fibers as an inorganic filler. ing. As shown in FIG. 4, it is clear that the thermal expansion coefficient of the example is superior to that of the comparative example in both the flow direction and the perpendicular direction.
[0039]
In particular, the carbon-based inorganic filler (amorphous carbon) is superior in wear resistance when water is used as a lubricant compared to other bearing materials. For example, the friction coefficient when the fixed test piece was made of amorphous carbon, the rotating test piece was made of SUJ2 (bearing steel), and water was used as the lubricant was 0.005. On the other hand, the friction coefficient when the fixed test piece was made of WC (super steel), the rotating test piece was made of SUJ2, and water was used as the lubricant was 0.06.
[0040]
Thus, in this embodiment, the inlet 17 and the outlet 18 of the fluid pump 7 are both arranged at the same height as the blade 35 so as to face the outer peripheral side end of the blade 35 . The thickness dimension of the casing 14 can be reduced. In addition, since the stator 32 is configured to enter the rotor 34, the thickness dimension of the casing 14 can be further reduced. For this reason, even if the fluid pump 7 is built in the notebook computer 1, the notebook computer 1 is not increased in size. In particular, in the present embodiment, since the fluid pump 7 is disposed in the housing of the display unit 3 in which an empty space remains as compared with the computer main body 2, the computer main body 2 can be miniaturized.
[0041]
5 and 6 show a second embodiment of the present invention, and the differences from the first embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals. FIG. 5 schematically shows a cooling device 41 according to the second embodiment. The cooling device 41 includes a heat receiving portion 9, a heat radiating portion 8, a fluid pump 7, a tube 10 connecting them, and a fan device 42 disposed in the vicinity of the heat radiating portion. The cooling device 41 is built in the notebook computer 1 as in the first embodiment.
[0042]
The fan device 42 is for accelerating the heat radiation from the heat radiating portion 8, and has a function of discharging the air around the heat radiating portion 8 to the outside of the housing 4. The heat radiating section 8 and the heat receiving section 9 are provided with temperature sensors 43 and 44 for the heat radiating section and the heat receiving section, respectively. The temperature sensors 43 and 44 are composed of, for example, a thermistor.
[0043]
As shown in FIG. 6, the output signal of the temperature sensors 43 and 44 is given to the control circuit 45 as a control means. The control circuit 45 detects the temperatures of the heat radiating unit 8 and the heat receiving unit 9 based on output signals from the temperature sensors 43 and 44, and connects the fan motor 42 a of the fan device 42 and the motor 39 of the fluid pump 7 via the drive circuit 46. To drive.
[0044]
For example, the control circuit 45 starts driving the motor 39 of the fluid pump 7 when the temperature of the heat receiving unit 9 exceeds the set value t1, and the fan motor when the temperature of the heat radiating unit 8 exceeds the set value t2 (t1 ≦ t2). It can be configured to start driving 42a.
[0045]
According to such a configuration, the cooling device 41 and the fan device 42 can be efficiently driven according to the temperatures of the heat radiating unit 8 and the heat receiving unit 9, and excessive temperature rise of the CPU 5 can be prevented.
[0046]
FIG. 7 shows a third embodiment of the present invention, and the differences from the first embodiment will be described. In the third embodiment, the cooling device 51 includes a fluid pump 7 disposed on the upper side of the CPU 5, a heat radiating unit 8, and a tube 10 connecting the fluid pump 7 and the heat radiating unit 8. That is, in the present embodiment, the heat receiving part is constituted by the fluid pump 7.
[0047]
According to such a configuration, since the number of components of the cooling device 51 is reduced, further miniaturization can be achieved.
[0048]
The present invention is not limited to the above-described embodiments, and for example, the following modifications and expansions are possible.
If the ratio of the inorganic filler to the entire molding material of the slide bearing 26 is 50 to 85% and the ratio of the carbon-based inorganic filler is 20 to 50%, appropriate changes can be made.
In the above embodiment, the blades 35 are provided along the axial direction of the rotation axis of the rotor 34. However, the blades 35 may be inclined or curved in the rotation direction.
[0049]
A hole communicating with the notch 28 of the slide bearing 26 may be provided inside the slide bearing 26 as a relief hole, or a hole communicating with the outside may be provided inside the partition wall 15 as a relief hole.
The motor for driving the fluid pump is not limited to a radial gap type motor, but may be an axial gap type motor.
[0050]
In the second embodiment, the fan motor 42 a and the motor 39 of the fluid pump 7 are driven and controlled based on the temperatures of the heat radiating unit 8 and the heat receiving unit 9. The drive control may be performed based on one of the temperatures.
The cooling device according to the present invention may be mounted on another electronic device of a notebook personal computer.
[0051]
【The invention's effect】
As is clear from the above description, the fluid pump of the present invention has the inlet and outlet provided in the casing at the same height as the blade provided on the outer periphery of the rotor, and the outer peripheral side end portion of the blade. since was arranged so as to face a, it is possible to reduce the thickness of the casing.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view of a fluid pump according to a first embodiment of the present invention. FIG. 2 is a partial cross-sectional plan view of the fluid pump along line XX in FIG. FIG. 4 is a diagram showing the arrangement of a cooling device in a personal computer. FIG. 4 is a diagram showing a sample of a slide bearing molded product according to the present embodiment and a coefficient of thermal expansion of a comparative example. FIG. 5 is a second embodiment of the present invention. FIG. 6 is a block diagram showing a schematic electrical configuration of the cooling device. FIG. 7 is a diagram corresponding to FIG. 3 showing a third embodiment of the present invention.
In the figure, 1 is a notebook personal computer, 2 is a computer main body, 3 is a display unit, 5 is a CPU, 7 is a fluid pump, 8 is a heat radiating unit, 9 is a heat receiving unit, 11, 41 and 51 are cooling devices, and 14 is Casing, 15 is a partition wall (bearing holding part, bearing assembly), 17 is an inlet, 18 is an outlet, 24 is a refrigerant flow path, 26 is a slide bearing (bearing assembly), 28 and 29 are notches (relief holes), Reference numeral 32 denotes a stator, 34 denotes a rotor, 35 denotes blades, 39 denotes a motor, 42 denotes a fan device, and 45 denotes a control circuit (control means).

Claims (2)

A casing having a refrigerant flow path through which liquid refrigerant flows;
A cup-shaped rotor disposed in the refrigerant flow path in the casing and having a plurality of blades on the outer periphery; an annular stator disposed on the inner periphery of the rotor with a gap between the rotor; A motor comprising a bearing assembly including a slide bearing disposed on an inner peripheral portion of the stator and rotatably supporting a rotating shaft of the rotor, and a bearing holding portion for holding the slide bearing;
An inlet provided in the casing for allowing a refrigerant to flow into the refrigerant flow path as the rotor rotates;
An outlet that is provided in the casing and causes the refrigerant to flow out of the refrigerant flow path as the rotor rotates.
The inflow port and the outflow port are both disposed at the same height position as the blade, and are opposed to the outer peripheral side end of the blade ,
The rotating shaft is fixed to a thick portion at the center of the rotor,
The rotor is provided with a venting hole for helping the refrigerant flow into the gap between the rotor and the stator,
The fluid pump according to claim 1, wherein the bearing assembly is provided with an escape hole for allowing air inside the slide bearing to escape when the rotary shaft is inserted into the slide bearing. The refrigerant flow path is configured to allow a low-viscosity liquid refrigerant to circulate, and includes a slide bearing that is provided in the refrigerant flow path and rotatably supports the rotating shaft of the rotor,
The sliding bearing is composed of a molding material mainly composed of an inorganic filler and a synthetic resin,
The inorganic filler has a thermal expansion coefficient of 4 × 10 −6 / ° C. or less, or a negative expansion coefficient, a silicate compound having an average particle size of 30 μm or less, and a carbon-based compound having an average particle size of 50 μm or more. Including inorganic fillers,
The fluid pump according to claim 1, wherein the inorganic filler accounts for 50 to 80% of the molding material, and the carbon-based inorganic filler accounts for 20 to 50% of the molding material .

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