Drain Pump

Abstract: A drain pump 10 comprises a housing 20 of a pump body, and a rotary vane 30 placed inside the housing 20. A penetrating hole 24 is formed to the center of a lid 22 mounted to the upper portion of the housing 20, and a shaft 32 of the rotary vane 30 penetrates through the hole 24 and protrudes to the upper portion of the lid 22. A rotor 54 is equipped inside a bracket 52 of a motor 50, which rotates a driving shaft 60 of the motor. The driving shaft 60 is supported through bearings 70 and 80 to the motor bracket 52. The driving shaft 60 of the motor protrudes from the motor bracket 52, and is press-fitted to the hole 34 with a bottom formed to the shaft 32 of the rotary vane 30, so as to drive the rotary vane 30. The collar 100 comprises a cylindrical portion 105 and a disk-shaped flange 110, wherein the flange 110 positioned above the penetrating hole 24 prevents a deflector disk from moving upwards. The flange 110 also prevents the drain water leaking out from the hole 24 of the lid 22 from splashing on the motor. A lubricant oil collect area is formed between the upper surface 120 of the cylindrical portion 105 and the bearing 80.

Description: FIELD OF THE INVENTION The present invention relates to a drain pump, and specifically, to a drain pump equipped in an air conditioner. The GB-A-562907 discloses a fuel pump having a flared flinger member between the motor and the pump by which any leakage from the pump and through the seal of the pump is peripherally urged. The flinger member is associated with a flame barrier construction for preventing propagation of a flame from the motor to the pump. During a cooling operation in an interior unit of an air conditioner, the moisture in the air condenses and adheres to a heat exchanger of the unit, and the water drops into a drain pan placed below the heat exchanger. A drain pump is used to discharge the drain water collected in the drain pan. The drain pump comprises a housing having a suction opening formed to the lower area thereof, an opening formed to the upper area thereof, and a discharge opening formed to the side portion thereof, and a vane rotatably equipped inside the housing. The vane is rotated by a motor fixed through a cover to the upper area of the opening of the housing. The driving shaft of the motor is rotatably penetrated through a hole formed to the cover and connected to the shaft of the vane. When the motor is started and the vane is rotated, the drain water collected in the drain pan is sucked in from the lower end of the vane through the suction opening, and by centrifugal force, the water is pumped up along the inner surface of the housing, and discharged to the exterior through the discharge opening of the housing. According to the conventional drain pump explained above, there were cases where the drain water leaked out from the penetrating hole formed to the cover equipped to the upper portion of the housing opening and splashed on the motor, causing malfunction of the motor. Therefore, it is necessary to equip a disk-shaped deflector board on the driving shaft of the motor above the penetrating hole of the cover in the conventional drain pump, so as to prevent the drain water from splashing out from the penetrating hole. SUMMARY OF THE INVENTION In some cases, the deflector board of the conventional drain pump is moved towards the motor, and thereby, the deflector board comes into contact with the bracket of the motor, which causes the peripheral portion of the board to vibrate and generate noise. The present invention provides a drain pump with a deflector board which is prevented from contacting the motor, and also with a bearing of the driving shaft in the motor having improved lubrication. In order to achieve the above object, the present invention provides a drain pump comprising a rotary vane rotatably positioned inside a pump housing; a motor having a driving shaft for driving said rotary vane; and a deflector board mounted to said driving shaft; wherein said deflector board is placed between said rotary vane a collar pressfitted to said driving shaft comprising a disk-shaped flange and a cylindrical portion, the flange being at the end of the collar which is closest to the deflector board . According to an embodiment of the present invention, the drain pump characterizes in that an end surface of said cylindrical portion of said collar, on the other end of which is positioned said flange, forms a surface for receiving a lubricant oil for lubricating a bearing of said motor. According to the embodiment, the deflector disk of the pump is prevented from moving towards the motor, and at the same time, the structure enables to effectively lubricate the bearing of the driving shaft of the motor. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cross-sectional side view of the drain pump according to the present invention; and FIG. 2 is an explanatory view showing the main portion of FIG. 1. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 is a side view showing a portion of the drain pump according to the invention in cross-section, and FIG. 2 is an enlarged view of the main portion of FIG. 1. A pump body of the drain pump according to the present invention, which is denoted as a whole by reference number 10, comprises a pump housing constituted of a housing 20 and a lid 22, and a rotary vane 30 stored inside the pump housing. The housing 20 comprises a suction opening 21a and a discharge opening 21b of the drain water, which are communicated to a pump chamber 21c. A penetrating hole 24 is formed to the center of the lid 22 mounted to the upper portion of the housing 20. A driving shaft 60 of the motor penetrates through the hole 24, and the shaft is inserted to a hole 34 with a bottom formed to a shaft unit 32 equipped to a rotary vane 30. A motor 50 is equipped with a stator 51 mounted outside the motor. A rotor 54 is further equipped inside upper and lower brackets 52 of the motor 51, which rotates the driving shaft 60 of the motor. The driving shaft 60 is supported by two bearings 70 and 80 positioned in an upper area and a lower area of the upper and lower motor brackets 52. The bearings 70 and 80 are formed, for example, of a sintered alloy of the iron or copper system which has a porous structure, so that the bearing will have a good oil retaining character. Oil impregnated members 72 and 82 formed of felt and the like are inserted to the outside of the bearings 70 and 80, which are supported by ring-shaped springs 74 and 84 against the upper and lower brackets 52. The driving shaft 60 of the motor protrudes from the bracket 52 of the motor and is press-fitted to the hole 34 with a bottom formed to the shaft 32 of the rotary vane 30, and drives the rotary vane 30. The hole 34 with a bottom formed to the shaft 32 may also be formed as a penetrating hole. A deflector disk 40 formed of a thin plastic film is mounted to the upper surface of the shaft 32, through which the driving shaft 60 of the motor penetrates. In the drain pump of the present invention, a plastic collar 100 is press-fitted to the driving shaft 60 of the motor. The collar 100 is formed as one unit, so the mounting of the collar to the driving shaft 60 may be performed easily. As shown in FIG. 2, the collar 100 comprises a cylindrical portion 105 and a disk-shaped flange 110, and the flange 110 is positioned above the deflector disk 40. The deflector disk 40 prevents the drain water returning from the discharge pipe (not shown) and leaking out through the penetrating hole 24 of the lid 22 from splashing onto the motor. The flange 110 prevents the deflector disk 40 from being pushed up towards the motor, for example when the operation of the drain pump is stopped. In other words, even if the deflector disk 40 is moved, it will contact the flange 110, which prevents the disk 40 from moving any closer to the motor. Moreover, since the diameter of the deflector disk 40 is larger than that of the flange 110, only the center area of the deflector disk 40 will come into contact with the flange 110, and therefore, no vibration of the peripheral area of the disk 40 will occur. Further, since the flange 110 and the cylindrical portion 105 are formed as an integral unit, the flange is positioned so that it crosses the axis of the motor driving shaft 60 at right angles. Therefore, only minimum noise is generated when the vane is rotated, and the flange is prevented from contacting the lid 22 or the motor bracket 52. Further, an oil collect area 130 where the lubricant gathers is formed between the bearing 80 and the upper end surface 120 of the collar 100, which prevents the lubricant (lubricating oil) from leaking. The upper end surface 120 of the collar which functions as the oil receive surface is opposed to the bearing 80 in an approximate position, and the space between the surface and the bearing is set to approximately 0.5 mm. When the motor is started and the driving shaft 60 supported by the bearing 80 starts to rotate, the temperature of the oil is increased and the viscosity is decreased, which causes the oil to leak along the shaft. The oil having decreased viscosity travels to the upper end surface 120 of the cylindrical portion 105, but stays on the surface 120 by surface tension, and forms the oil collect area 130. When the motor is stopped, the bearing 80 formed of a porous material absorbs the oil collected to the upper end surface 120 of the cylindrical portion by capillary phenomenon, and the oil collect area 130 disappears. Such function of the cylindrical portion prevents the oil for lubricating the motor bearing from leaking. As explained, the drain pump according to the present invention characterizes in that a collar comprising a disk-shaped flange and a cylindrical portion is formed to the outer circumference of the driving shaft penetrating through the lid of the pump housing. The collar effectively prevents the deflector disk from being moved towards the motor, and also prevents water from splashing on the motor. Further, the upper end surface of the collar acts as a receive surface of the lubricant oil of the motor bearing, and forms an oil collect area between the surface and the bearing. The oil is held in position by the surface tension of the oil. The bearing is formed of a porous sintered alloy and the like, and the oil gathered on the oil receive surface is absorbed using the capillary phenomenon of the bearing.

Claims: A drain pump comprising: a rotary vane (30) rotatably positioned inside a pump housing (20); a motor (50) having a driving shaft (60) for driving said rotary vane (30); and a deflector board (40) mounted to said driving shaft (60); wherein said deflector board (40) is placed between said rotary vane (30) and a collar (100) pressfitted to said driving shaft (60) comprising a disk-shaped flange (110) and a cylindrical portion (105), the flange (110) being at the end of the collar (100) which is closest to the deflector board (40). A drain pump defined in claim 1, wherein an end surface (120) of said cylindrical portion (105) of said collar (100), on the other end of which is positioned said flange (110), forms a surface for receiving a lubricant oil for lubricating a bearing (80) of said motor (50). A drain pump defined in claim 2, wherein the area between the bearing (80) and the end surface (120) of said cylindrical portion (105) of said collar (100) forms an oil collect area (130) for collecting the lubricant oil that leaks from the bearing (80) of said motor (50).

Inventors: IMAI MASAYUKI, NINOMIYA TATUSHI, IMAI, MASAYUKI, NINOMIYA, TATUSHI, Imai, Masayuki, c/o Fujikoki Corporation, Ninomiya, Tatushi, c/o Fujikoki COrporation
Applicants: FUJIKOKI CORP, FUJIKOKI CORPORATION
Application year: 1999
Main classification: F04D29
IPC codes: F04D1, F04D13, F04D29, F04D11