JP2004060585A - Pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive, small-sized, thin, and lightweight pump capable of suppressing the dissipation of internal fluid through a synthetic resin thin-walled portion. <P>SOLUTION: In this pump, a wall portion having a thickness of less than a specified thickness causing the permeation of the internal fluid exceeding an allowable limit is formed in a portion formed of synthetic resin. Plating suppressing the permeation of the internal fluid is formed at least on the wall portions of a motor frame 2 and the casing 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a pump having a wall thickness less than a predetermined thickness at which permeation of an internal fluid exceeds an allowable limit, and particularly to a pump capable of preventing permeation of an internal fluid.
[0002]
[Prior art]
In recent years, in particular, pumps for assembling devices have been required to be smaller, lighter, and energy-saving in the trend of miniaturization, weight reduction, and energy saving of devices. As one of such pumps, there has been proposed a canned motor type pump in which a rotor sealed by a partition and a stator for driving the rotor are provided outside the partition, in which the motor is a DC brushless motor. FIG. 3 shows a structural diagram of a conventional pump.
[0003]
In FIG. 3, 101 is a casing, 102 is a suction port, 103 is an impeller, 104 is a discharge port, and 105 is a fixed shaft. The conventional pump incorporates a fixed shaft 105 which accommodates an impeller 103 for pressurizing fluid and is fixed so as not to rotate inside a casing 101 having a suction port 102 and a discharge port 104 as shown in FIG. Have been.
[0004]
In FIG. 3, reference numeral 106 denotes a bearing plate fixed to the casing 101, 107 denotes a rotatable bearing fixed to the impeller 103, 108 denotes a permanent magnet, 109 denotes a rotor having a permanent magnet 108 built therein, and 110 denotes a rotor. A stator that rotates the re-rotor 109 by energizing, 111 is a partition separating the rotor 109 and the stator 110, 112 is a control unit that controls a current supplied to the stator 110, 113 is a motor frame, and 114 is a power supply to the control unit 112. A lead wire for transmitting a control signal, 115 is an O-ring for sealing the motor frame 113 and the partition 111, 116 is an O-ring for sealing the casing 101 and the partition 111, 117 is a sealing member for sealing the lead 114 and the motor frame 113, 118 Is a drive element.
[0005]
As described above, in the conventional pump, the rotor 109 is disposed inside the stator 110 with the partition wall 111 interposed therebetween, and the rotor 109 and the impeller 103 are integrally formed and connected to the bearing 107 at the center of the rotor 109. The bearing 107 is rotatably mounted on a fixed shaft 105 which passes through the center of the rotor 109 and is fixed to the casing 101 and the partition 111 on both sides.
[0006]
In the conventional pump having the above structure, when a current is applied to the stator 110 from the control unit 112, a rotating magnetic field is generated in the stator 110 and the rotor 109 rotates. Since the impeller 103 is formed integrally with the rotor 109, when the rotor 109 rotates, the impeller 103 also rotates and pressurizes the fluid. The actual movement of the fluid flows through the suction port 102, is pressurized by the impeller 103, and is discharged from the discharge port 104. When the fluid is pressurized, a pressure difference occurs before and after the impeller 103, and a thrust load is applied to the rotor 109. In order to receive the thrust load, a bearing plate 106 is provided on the suction side of the bearing 107 to slide. The control unit 112 seals the motor frame 113 and the partition wall 111 with an O-ring 115 and seals the motor frame 113 and the lead wire 114 with a seal member 117 in order to prevent malfunction or destruction due to ingress of water from the outside. It has a sealed structure. With the above configuration, it is possible to obtain a small, lightweight, and energy-saving pump having excellent water resistance.
[0007]
[Problems to be solved by the invention]
However, in the case of a conventional pump having a closed structure, when it is used in a closed circulation system with a closed water channel when incorporated in a thin and lightweight device that requires further miniaturization and thinning, it is made of a synthetic resin to reduce the size and thickness. The thickness of the casing and motor frame must be considerably reduced, and the amount of internal circulating water is small due to the small closed circulation system used. Permeation) occurs, and when a long time elapses, there is a problem that the circulating water in the closed circulation system becomes insufficient and the function stops functioning.
[0008]
An object of the present invention is to provide an inexpensive, small, thin, and lightweight pump that suppresses the permeation and dissipation of an internal fluid from a thin portion of a synthetic resin.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a pump according to the present invention is a pump in which a portion formed of a synthetic resin is provided with a thick portion having a predetermined thickness or less which causes internal fluid permeation to exceed an allowable limit, and a motor. At least the thick part of the frame and the casing is formed with plating for suppressing the permeation of the internal fluid.
[0010]
Thereby, plating is formed on the thin portion of the synthetic resin casing or the motor frame to suppress the amount of permeation of water, so that an inexpensive, small, and lightweight pump can be obtained.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the invention described in claim 1 of the present invention, an impeller is housed by a motor frame and a casing, and at least a part of the motor frame and the casing are formed of a synthetic resin. A pump provided with a thick portion having a thickness not more than a predetermined thickness that causes internal fluid permeation to exceed an allowable limit, and at least a thick portion of a motor frame and a casing is formed with plating that suppresses internal fluid permeation. The pump is characterized by forming a plating on the thin wall of the synthetic resin casing and motor frame to suppress the amount of fluid permeation, and to prevent the internal fluid from evaporating and permeating after being permeated. This has the effect that an inexpensive, compact and lightweight pump can be obtained.
[0012]
The invention according to claim 2 of the present invention is the pump according to claim 1 disposed in a closed circulation system, wherein the allowable limit is the elapsed time since the circulating fluid was sealed and the fluid in the closed circulation system. 2. The pump according to claim 1, wherein the amount is determined based on the amount of decrease in the amount of fluid decreased from the closed circulatory system and the elapsed time since the circulating fluid was sealed in the closed circulatory system. Since the allowable limit is set, it is practical and easy to set.
[0013]
The invention according to claim 3 of the present invention is characterized in that a stator is arranged in an annular recess of a motor frame, and a rotor driven by the stator is provided in a pump chamber on an outer periphery of the annular recess. Item 1. The pump according to Item 1 or 2, wherein a small-sized pump can be realized by the configuration of the stator, the rotor, and the annular concave portion, and the motor frame has a large surface area and many thin portions can be prevented from being permeated by plating. .
[0014]
The invention according to claim 4 of the present invention is the pump according to claim 1, wherein the plating is Ni plating, and uses Ni plating which is a very common and inexpensive method among plating. This has the effect of suppressing the amount of water transmission.
[0015]
The invention according to claim 5 of the present invention is the pump according to any one of claims 1 to 3, wherein the plating is composed of two layers of Ni plating and Cu plating. By doing so, it has the effect of enhancing the suppression of moisture permeation while suppressing plating unevenness and maintaining the bonding strength to the material to be plated made of resin.
[0016]
The invention according to claim 6 of the present invention is the pump according to any one of claims 1 to 3, characterized in that Cu plating is used as a base in a two-layer structure, and the pump is physically flexible. Forming a second plating layer such as Ni plating while maintaining the bonding strength with the material to be plated by improving the effect of preventing peeling from the material to be plated by using the rich Cu plating as a base. And has the effect of enhancing the suppression of the amount of water permeation.
[0017]
The invention according to claim 7 of the present invention is the pump according to any one of claims 1 to 4, wherein the thickness of the plating film is 5 to 20 µm, and the pump is peeled off when the plating film is too thick. When the thickness is too small, the effect of preventing moisture permeation is reduced. Therefore, the thickness of the plating film in a predetermined range of 5 to 20 μm has an effect of surely suppressing the amount of moisture permeation.
[0018]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0019]
(Embodiment 1)
FIG. 1A is a front view of the suction side of the pump according to the first embodiment of the present invention, FIG. 1B is a sectional view of the pump of FIG. 1A, and FIG. It is a graph which shows transition of the amount of transmission. Note that the same reference numerals are given to the same components as those in the related art, and the description will be omitted.
[0020]
In FIGS. 1 (a) and 1 (b), reference numeral 1 denotes a casing which is Ni-plated after being degreased on the surface of a portion having a thickness less than a predetermined thickness, and 2 denotes a surface of a portion having a thickness less than a predetermined thickness. This is a motor frame that is Ni-plated after being degreased and formed integrally with the partition wall 111. The casing 1 and the motor frame 2 are at least partially formed of a synthetic resin such as PPE. In the first embodiment, all of the casing 1 and the motor frame 2 are formed of a synthetic resin for weight reduction. The motor frame 2 is provided with an annular recess toward the side outward, and the stator 110 is disposed in the annular recess. A rotor 109 driven by the stator 110 is provided in a pump chamber on the outer periphery of the stator 110 (outer periphery of the annular concave portion). That is, it is a canned motor type pump. Reference numerals 3 and 4 denote ultrasonic welding ribs provided on the casing 1 and the motor frame 2, respectively, so that the casing and the motor frame are welded and sealed during assembly. Reference numeral 5 denotes an O-ring that is disposed between the casing 1 and the motor frame 2 to prevent welding scum from entering inside during welding and to function as a seal, 6 denotes a sealing member made of urethane resin or the like, 7 denotes Ni plating or It is a film composed of two layers such as Ni plating and Cu plating.
[0021]
With the above structure, when the control unit 112 supplies electricity to the stator 110, a rotating magnetic field is generated in the stator 110 and the rotor 109 rotates. Since the impeller 103 is formed integrally with the rotor 109, when the rotor 109 rotates, the impeller 103 also rotates and pressurizes the fluid. The actual movement of the fluid flows through the suction port 102, is pressurized by the impeller 103, and is discharged from the discharge port 104. When the fluid is pressurized, a pressure difference occurs before and after the impeller 103, and a thrust load is applied to the rotor 109. In order to receive this thrust load, a bearing plate 106 is provided on the suction side of the bearing 107 and is slid. The control unit 112 seals the motor frame 2 and the lead wires 114 with the sealing member 6 made of urethane resin in order to prevent malfunction or destruction due to the intrusion of fluid from the outside and to suppress fluid permeation from the motor frame 2. It is a structure that is hermetically sealed.
[0022]
Next, FIG. 2 is a graph showing a change in weight when the pump is assembled and filled with circulating water and the suction port 102 and the discharge port 104 are sealed and left in an atmosphere at 70 ° C. The circulating water here is water. It is considered that this weight change (reduction amount in the present invention) was caused by a decrease in circulating water due to moisture permeation. Further, since the maximum temperature of the circulating water in Embodiment 1 of the present invention was 55 ° C., the effect of leaving at 70 ° C. at which the steam pressure doubled was converted by an acceleration factor of 2. That is, since it is assumed that the time to saturation takes twice as long as the water vapor pressure is twice, the elapsed time is halved when obtaining the elapsed time.
[0023]
Graph 1 is a graph when the casing 1 and the motor frame 2 are made of synthetic resin PPE, and the thickness of the thin portion is 1.2 mm. The thin portion is usually a water-contact portion of the casing 1 and the motor frame 2. However, in the case of a thin and small pump, the top surface portion 119, the suction port 102, and the discharge port 104 of the casing 1 are also thin portions. In the motor frame 2, the partition wall 111 is a thin portion. Although it is necessary to prevent the internal fluid from permeating through the thin portion, the permissible limit of permeation is set based on the time and the amount of change in weight in the graph 1 in the first embodiment. Further, the predetermined thickness in the first embodiment is determined by the thickness indicating the allowable limit. For example, if a change in weight of 0.12 g in 40 hours is an allowable limit, the thickness 1.2 mm at this time is a predetermined thickness indicating the allowable limit.
[0024]
Graph 2 is a graph when Ni plating is applied to the resin conditions of Graph 1 and the plating film thickness is about 10 μm. Note that the thickness of the Ni plating film 7 is proportional to the amount of current applied during plating, and can be freely controlled by adjusting the current application time. In the pump according to the first embodiment, the amount of moisture permeation from the synthetic resin material can be suppressed by the Ni plating film 7.
[0025]
In the first embodiment of the present invention, a portion having a thickness equal to or less than a predetermined thickness, that is, the top surface portion 119 and the suction port 102 and the discharge port 104 in the casing 1, and the partition wall 111 in the motor frame 2 are coated with Ni plating. However, a method of coating the entire casing 1 and the motor frame 2 may be used in order to save time and labor due to masking or the like. Further, the thickness of the Ni plating film 7 is set to 10 μm. However, if the film thickness is too thick, the processing time is long and the cost increases, and the flexibility of the plating film is significantly reduced. It is easy to peel off, and the bonding strength decreases. Also, if the plating thickness is too thin, micropores (fine holes) may occur when plating unevenness occurs, or a portion where an extremely thin plating layer is formed may be formed. The suppression effect of is reduced. Therefore, it is appropriate that the thickness of the Ni plating is formed in the range of 5 to 20 μm.
[0026]
In addition, by using a flexible plating such as Cu plating as a base and forming a hard plating layer such as Ni plating on the upper layer, the plating is prevented from peeling from the resin material to be plated. , The bonding strength can be maintained, and the effect of suppressing the amount of water permeation can be further enhanced.
[0027]
【The invention's effect】
As is clear from the above description, according to the pump of the present invention, plating is formed on a thin-walled portion of a synthetic resin casing or a motor frame to suppress the amount of fluid permeation, and the internal fluid is vaporized after permeation. This has the effect that an inexpensive, compact and lightweight pump can be obtained. Since the permissible limit is set based on the elapsed time since the circulating fluid is sealed in the closed circulation system and the amount of decrease in the fluid decreased from the closed circulation system, the setting is practical and easy. A small pump can be realized by the configuration of the stator, the rotor, and the annular concave portion, and the point where the motor frame has a large surface area and many thin portions can be prevented from being transmitted by plating.
[0028]
Further, since the plating is Ni plating, the use of Ni plating, which is a very common and inexpensive plating method, has the effect of suppressing the amount of moisture transmission. Further, since the plating is composed of two layers of Ni plating and Cu plating, by adopting a two-layer constitution, the moisture permeation amount can be reduced while suppressing the plating unevenness and maintaining the bonding strength to the material to be plated made of resin. The suppression can be enhanced.
[0029]
In addition, since Cu plating is used as a base in a two-layer configuration, the effect of preventing peeling from the material to be plated is improved by using Cu plating as a base that is highly flexible in physical properties, and the bonding strength with the material to be plated is improved. By forming a second plating layer such as Ni plating in a state where is maintained, the suppression of the amount of moisture transmission can be enhanced. In addition, since the thickness of the plating film is 5 to 20 μm, it is possible to surely suppress the amount of permeated water.
[Brief description of the drawings]
FIG. 1 (a) is a front view of a suction side of a pump according to a first embodiment of the present invention. FIG. 1 (b) is a cross-sectional view of the pump of FIG. 2 (a). FIG. Graph showing transition [Fig. 3] Structure diagram of conventional pump [Explanation of reference numerals]
1, 101 Casing 2, 113 Motor frame 3, 4 Ultrasonic welding rib 5, 115, 116 O-ring 6, 117 Seal member 102 Suction port 103 Impeller 104 Discharge port 105 Fixed shaft 106 Bearing plate 107 Bearing 108 Permanent magnet 109 Rotor 110 Stator 111 Partition wall 112 Control unit 114 Lead wire 118 Drive element 119 Top surface

Claims (7)

A motor frame and a casing accommodate an impeller, at least a part of the motor frame and the casing are formed of synthetic resin, and a predetermined portion that causes internal fluid permeation to a portion formed of the synthetic resin to an allowable limit or more. A pump in which a thick portion less than the thickness is formed,
A pump wherein at least the thick portion of the motor frame and the casing is formed with plating for suppressing the permeation of an internal fluid. 2. The pump according to claim 1, wherein the pump is disposed in a closed circulation system, wherein the allowable limit is determined based on an elapsed time since the circulating fluid is sealed and a decrease amount of the fluid in the closed circulation system. The pump according to claim 1, wherein: The pump according to claim 1 or 2, wherein a stator is disposed in the annular recess of the motor frame, and a rotor driven by the stator is provided in a pump chamber on an outer periphery of the annular recess. The pump according to claim 1, wherein the plating is Ni plating. The pump according to any one of claims 1 to 3, wherein the plating includes two layers of Ni plating and Cu plating. The pump according to any one of claims 1 to 3, wherein in the two-layer structure, Cu plating is used as a base. The pump according to claim 1, wherein the plating film has a thickness of 5 to 20 μm.

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