JP2002070781A - Impeller for bath water sele-priming pump for washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve cavitations occurring at the rotation of an impeller, to prevent intake air, to shorten an initial bath water suction time and to increase the volume of discharge water. SOLUTION: A closed type impeller equipped with a shroud ring at a suction pipe side 20 and a shroud ring 25 at a motor side is changed to the semi-open type impeller 10 which opens the shroud ring 25 at the motor side, and curved surface shape is provided in the inner face of a water intake 29 which is not equipped with a prominent cylindrical wall at the center of the shroud ring at the suction pipe side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bath water self-priming pump for a DC motor driven type washing machine, and more particularly to alleviation of cavitation occurring when an impeller rotates, shortening of initial bath water suction time, The present invention relates to an impeller for a bath water self-priming pump for a washing machine, which has an improved water discharge amount and the like.

[0002]

2. Description of the Related Art Conventionally, a self-priming (negative pressure) type pump (hereinafter, bath water self-priming for a washing machine) mounted on a substantially upper part (for example, a top cover, a top panel) of a washing machine for absorbing bath water. A DC power supply (for example, 100 V AC ground voltage, DC low voltage obtained by full-wave rectification of a frequency of 50 Hz or 60 Hz, or DC voltage 12 V) is applied to the DC pump to drive the DC motor to rotate the impeller. Type and general-purpose low-voltage single-phase AC power supply (for example, AC ground voltage 100 V, frequency 50 Hz or 60 Hz AC low voltage)
Is applied to drive an AC motor such as a bipolar reversible motor or a bipolar shaded motor (skeleton motor) to rotate the impeller.

[0003] The DC motor drive type can employ a small impeller having curved blades, which is ideal for water absorption, and rotates the small impeller at a high speed (for example, 6000 to 12000 rpm).
m) to absorb water at a high flow rate, so that the water absorption noise (noise or vibration sound, cavitation) is high, but the bath water self-priming pump for a washing machine can be made compact. As of the filing date of the patent application of the present invention, the mainstream of the bath water self-priming pump for a washing machine is a DC motor driven type. For example, Japanese Patent Application Laid-Open Nos.
JP-A-262395, JP-A-10-57683, and JP-A-10-196582 disclose pumps. Further, there is a technique related to improvement of water absorption noise disclosed in, for example, JP-A-10-225592.

In the AC motor drive type, since the direction of the circular motion of the impeller itself is difficult to regulate, for example, a medium-sized impeller of a cruciform blade is adopted, and the medium-sized impeller is rotated at a low speed (for example, 3000 to 3600 rpm). ) To absorb water at a low flow rate, so that the water absorption sound is low, but the bath water self-priming pump for a washing machine itself tends to be large. For example, JP-A-10-24194, JP-A-10-3
0586, JP-A-10-47289, JP-A-1
There are pumps disclosed in Japanese Patent Application Laid-Open Nos. 0-103290 and 10-274195.

For reference, when using household appliances or the like which can be driven at a low voltage in a place where water is used, attention should be paid particularly to electric shock. The danger is determined by the current flowing through the human body, and the magnitude of the voltage is secondary. However, the lower the voltage (the contact voltage applied to the human body), the smaller the current flowing in the human body (equivalent resistance: 500Ω). Therefore, the following allowable contact voltage (as per the Japan Electric Association, Low Piezoelectric Ground Fault Protection Guidelines) is preferred. .) Should be adhered to. In the first type contact state (the state where most of the human body is in water), it is 2.5 V or less. In the second type contact state (the state where the human body is extremely wet), 25 V or less.
V or less, 50 in the third type contact state (other than the above)
V or less. In addition, a material having high insulation properties (for example, ABS resin) may be used to avoid exposure of metal parts to the external part (for example, casing), or watertightness (such as insulation treatment) may be improved. Taking these into consideration, an AC motor drive type that can adopt a brushless structure is advantageous. However, if the applied DC voltage is 25 V or less, safety can be easily ensured even with a DC motor drive type. Hereinafter, a DC motor and an AC motor are simply referred to as an electric motor without distinction.

The impeller used in the bath water self-priming pump for a washing machine includes a closed impeller, a semi-open impeller, an open impeller, and the like. The closed-type impeller 13 is externally fitted to an electric motor shaft or an impeller shaft in a bath water self-priming pump for a washing machine, and is made of a synthetic resin and includes a water absorbing pipe side shroud (side plate) 20 and a motor side shroud (side plate) 25. Impeller (see FIG. 6),
One having no cylindrical protruding wall at the water inlet at substantially the center of the water pipe side shroud (for example, one having a shape as disclosed in JP-A-10-225592 [particularly, see FIG. 5 of the publication]) ), Those having the cylindrical projecting wall (for example, Japanese Patent Application Laid-Open No. 10-227291 [in particular, FIG.
reference. And the like). The semi-open type impeller includes an impeller which is externally fitted to an electric motor shaft or an impeller shaft in a bath water self-priming pump for a washing machine, is made of synthetic resin and has a water-absorbing pipe side shroud opened (for example, Japanese Patent Application Laid-Open No. 7-243398). There is a gazette having a shape as disclosed in a gazette [in particular, see FIG. 3 of the gazette].

There are two types of impellers, which are fixed directly to the motor shaft (shaft) and those which are fixed to the impeller shaft (shaft). The impeller shaft is a shaft for fixing an impeller extended from the motor shaft. Specifically, the impeller shaft and the motor shaft are connected (joint, coupling) with an electric insulating material such as a resin molded member (for example, polyacetal resin). It was made. The purpose is to improve the electrical insulation and transfer the heat generated by the motor to the impeller (for example, when the temperature of the bath water is low, if the temperature of the impeller is higher than the water temperature, cavitation occurs around the impeller. Water absorption sound becomes higher). Here, it should be noted that if the motor runs for a long time, it will overheat (for example, 1
20 ° C.), and in such a case, the heat may melt the resin molded member, loosening the connection with the motor shaft, and causing the motor to run idle. The temperature of the bath water to be absorbed is about 50 ° C. or lower. However, if the motor housed in the pump casing is a closed type, it is necessary to take measures such as cooling the motor to prevent overheating.

Usually, an oil seal inner ring of a housing fixed type comprising at least a metal ring and rubber is attached to a motor shaft or an impeller shaft for watertightness. In addition to oil seals, O-rings, lip packings (U-packing, V-packing), mechanical seals, gland packings, etc. are used, but oil seals are typically used for shaft parts of electric motors and the like. It is a seal.

Now, a description will be given of a case where a bath water self-priming pump for a washing machine, which is constituted by the above-described element parts (electric motor, oil seal inner ring type, impeller) and the like, is operated. When the impeller rotates by driving the motor, the pump chamber (the chamber surrounding the impeller) becomes negative pressure and the bath water is absorbed, but at the same time, the air in the motor chamber (the chamber surrounding the motor) is also sucked. You. In other words, since the oil seal inner ring is attached to the motor shaft or the impeller shaft with the lip tip facing the impeller, a reed valve-like operation occurs, and the air is sucked in from the shaft.

[0010]

However, if such air intake is repeated, the watertightness of the inner ring of the oil seal decreases, the initial suction time of bath water increases, and the amount of water discharged decreases. There is a point. In addition, due to the cavitation that occurs when the impeller rotates, there is a problem that the initial suction time of bath water cannot be reduced and the amount of water discharged cannot be increased.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to alleviate cavitation occurring at the time of rotation of an impeller, to prevent atmospheric air intake, and to improve the initial state of bath water. An object of the present invention is to provide an impeller for a bath water self-priming pump for a washing machine, which has an improved suction time, an increased water discharge amount, and the like.

[0012]

In order to achieve the above object, an impeller for a bath water self-priming pump for a washing machine according to the present invention comprises an electric motor shaft or an impeller in a bath water self-priming pump for a washing machine. A semi-open type impeller which is externally fitted to a shaft and made of synthetic resin and has an electric motor-side shroud (side plate) opened, and has an inner surface of a water-absorbing opening which does not have a cylindrical projecting wall substantially at the center of a water-absorbing-tube-side shroud (side plate). Is provided with a curved surface shape (for example, a simple chamfer, a streamlined shape, a curved shape, etc.).

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view including a partially cutaway view of an impeller 10 according to a first embodiment of the present invention, and FIG. 2 is a rear view of the impeller 10 according to the first embodiment of the present invention. FIG. 6 is a sectional view of a bath water self-priming pump 50 for a washing machine according to an embodiment in which the conventional impeller 13 is mounted.

FIG. 3 shows an impeller 10 according to a first embodiment of the present invention.
FIG. In the impeller 10, it is externally fitted to the motor shaft 52 or the impeller shaft 54 in the bath water self-priming pump 50 for a washing machine, and may be made of synthetic resin (for example, polypropylene resin, polyacetal resin, etc. The motor-side shroud 25 is made of a polyacetal resin containing carbon fiber, which is resistant to abrasion in water, and may be a polypropylene resin containing carbon fiber, a nylon resin containing carbon fiber, or a polyether ether ether ketone resin containing carbon fiber. An open semi-open type impeller, in which a simple chamfered portion 21 is formed on an inner surface of a water inlet 29 which does not have a cylindrical protruding wall at a substantially central portion of the water absorbing tube side shroud 20.
Alternatively, a curved surface portion 22 (which may be streamlined or curved) is provided. As a result, cavitation noise generated when the impeller 10 rotates is reduced. Also, the initial wicking time of bath water was reduced by 10 to 30%. Water discharge increased by 7-25%. (The above data is not a variation, but is based on a test result due to a difference in test conditions such as a head and the number of revolutions of an impeller.) Further, a negative pressure generation (atmospheric intake) due to the presence of the motor-side shroud 25 is reduced. Since the amount of water is reduced, the water tightness of the inner ring of the oil seal is hardly reduced, so that the initial suction time of bath water is extended and the amount of water discharged is reduced.

FIG. 4 shows an impeller 11 according to a first embodiment of the present invention.
FIG. The impeller 10 is a semi-open type impeller that is externally fitted to the motor shaft 52 or the impeller shaft 54 in the bath water self-priming pump 50 for a washing machine, is made of synthetic resin, and has the motor-side shroud 25 opened. A curved portion 22 (or a chamfered portion 21) and / or a streamlined portion 23 (a curved shape may be provided) on the inner surface of a water inlet 29 having no cylindrical projecting wall at a substantially central portion of the tube side shroud 20.
Was provided. As a result, cavitation noise generated when the impeller 11 rotates is reduced. Also, the initial wicking time of bath water was reduced by 10 to 30%. Water discharge increased by 7-25%. (The above data is not a variation, but is based on a test result due to a difference in test conditions such as a head and the number of revolutions of an impeller.) Further, a negative pressure generation (atmospheric intake) due to the presence of the motor-side shroud 25 is reduced. Since the amount of water is reduced, the water tightness of the inner ring of the oil seal is hardly reduced, so that the initial suction time of bath water is extended and the amount of water discharged is reduced.

FIG. 5 shows an impeller 12 according to a first embodiment of the present invention.
FIG. The impeller 10 is a semi-open type impeller that is externally fitted to the motor shaft 52 or the impeller shaft 54 in the bath water self-priming pump 50 for a washing machine, is made of synthetic resin, and has the motor-side shroud 25 opened. A curved portion 22 (or a chamfered portion 21) and / or a streamlined portion 23 (a curved shape may be provided) on the inner surface of a water inlet 29 having no cylindrical projecting wall at a substantially central portion of the tube side shroud 20.
In addition, a curved surface portion or a streamlined portion 24 (a curved shape may be provided) is provided on the outer surface of the water absorption port 29 (on the water absorption pipe side). In other words, it is a wing shape of an airplane or the like. Thereby, the impeller 1
The noise of the cavitation occurring during the rotation of 2 was reduced. Also, the initial wicking time of bath water was reduced by 10 to 30%. Water discharge increased by 7-25%. (The above data is not a variation, but is based on a test result due to a difference in test conditions such as a head and the number of revolutions of an impeller.) Further, a negative pressure generation (atmospheric intake) due to the presence of the motor-side shroud 25 is reduced. Since the amount of water is reduced, the water tightness of the inner ring of the oil seal is hardly reduced, so that the initial suction time of bath water is extended and the amount of water discharged is reduced.

As described above, various combinations and the like of the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and a number of combinations are possible without departing from the spirit of the invention. Needless to say, combinations, modifications and the like can be made. For example, as disclosed in Japanese Patent Application Laid-Open No. 2000-130391, a water seal lip having a lip tip facing water to be sealed, and an air seal lip having a lip tip facing the atmosphere. The oil suction for a bath water self-priming pump for a washing machine may further improve the problem of air intake.

[0018]

According to the impeller for a bath water self-priming pump for a washing machine according to the present invention, cavitation occurring at the time of rotation of the impeller, shortening of the initial suction time of bath water, and increase in water discharge are improved. This has the effect.

[Brief description of the drawings]

FIG. 1 is a front view including a partially cutaway view of an impeller according to a first embodiment of the present invention.

FIG. 2 is a rear view of the impeller according to the first embodiment of the present invention.

FIG. 3 is a plan sectional view of the impeller according to the first embodiment of the present invention.

FIG. 4 is a plan sectional view of an impeller according to a second embodiment of the present invention.

FIG. 5 is a plan sectional view of an impeller according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a bath water self-priming pump for a washing machine of one embodiment equipped with a conventional impeller.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Impeller of 1st Example, 11 ... Impeller of 2nd Example, 12 ... Impeller of 3rd Example, 13 ... Conventional Impeller, 20 ... Shroud on water-absorbing pipe side, 21 ... Chamfered part (inner surface), 22 ... Curved surface (inner surface), 23: Streamlined portion (inner surface), 24: Curved surface or streamlined portion (water-absorbing pipe side), 25
... shroud on motor side, 29 ... water inlet, 30 ... blades, 4
0 ... substrate, 41 ... bearing, 50 ... bath water self-priming pump for washing machine of one embodiment, 51 ... oil seal inner ring type, 52 ...
Motor shaft, 53 joint, 54 impeller shaft, 55
... electric motor, 56 ... water absorption pipe, 57 ... discharge pipe, 58 ... check valve, 59 ... pump casing, 60 ... electric motor power supply wire,
61 ... Pump room

Claims (1)

[Claims] 1. A semi-open type impeller which is fitted around an electric motor shaft or an impeller shaft in a bath water self-priming pump for a washing machine and is made of synthetic resin and has an electric motor side shroud opened, wherein An impeller for a bath water self-priming pump for a washing machine, wherein a curved surface is provided on an inner surface of a water intake port which does not have a cylindrical projecting wall at a substantially central portion.