JPH0649780U - Vane pump - Google Patents

Abstract

(57) [Abstract] [Purpose] A small gap is formed between the pump chamber 11 and the rotor 12 without cutting, and a high self-sufficiency is maintained for a long time. A flexible plate 22 arranged so as to close the open end of the pump chamber 11, a packing 25 for sealing a gap between the outer peripheral edge of the flexible plate 22 and the open end, and fastening and fixing to the casing 10. The packing 25 and the flexible plate 22.
And a spring member 30 for bending the flexible plate 22 toward the pump chamber 11 side.
A small hole 31 is opened in the flexible plate 22.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a small vane pump built in, for example, an electric device as a water supply means.

[0002]

[Prior art]

 The vane pump is generally used when a large discharge pressure or self-sufficiency (a force that allows a pump to be installed at a position higher than the liquid surface and suck up the liquid from a dry state inside the pump chamber) is used. As shown in FIGS. 9 and 10, a rotor 12 is rotatably arranged at an eccentric position inside a pump chamber 11 formed by a casing 10 and a cover 19 sealed to the casing 10. A vane 14 is disposed in each of a plurality of radially formed vane grooves 13 so as to be capable of projecting and retracting in the radial direction. The rotor 12 is inserted into the pump chamber 11 while being axially sealed by a shaft seal 20. It has a structure connected to the output shaft of the motor 18.

[0003]

[Problems to be solved by the device]

 In this type of vane pump, when the rotor 12 is rotationally driven in the X direction of FIG. 10, each vane 14 is brought into sliding contact with the peripheral wall of the pump chamber 11 by the centrifugal force, and the crescent moon between the peripheral wall and the rotor 12 is eccentric to each other. By moving the vane 14 in the space 15, the fluid is sucked from the suction port 16 while the fluid is discharged from the discharge port 17. In the above configuration, in order to improve the discharge pressure and the self-sufficiency, the surfaces of the pump chamber 11 and the rotor 12 are machined with a tolerance of μm with high precision, and the space between the facing end faces of the rotor 12 and the pump chamber 11 is increased. It is necessary to make the gap δ of the product as small as possible, but if highly accurate processing is performed by cutting a metal material, the manufacturing cost will rise, so for example, a water supply step to the steam generation part of an electric iron, etc. However, it was difficult to apply it as a small vane pump to be built into electrical equipment.

Therefore, as shown in FIGS. 7 and 8, the present inventors formed an expansion chamber 21 in the casing 10 which is expanded stepwise from the open end of the pump chamber 11, and the expansion chamber 2 A flexible plate 22 made of metal arranged so as to close the open end, and a second flexible plate arranged inside the expansion chamber 21 outside the flexible plate 22 and having an opening 23a in the center thereof. 23, a cover 24 having a convex portion 24a fixed to the outer end surface of the casing 10 by a screw member 27 and fitted in the expansion chamber 21, and between the flexible plates 22 and 23 and the flexible plate on the outer side. A small vane pump having a pair of O-rings 25 and 26 which is interposed between the projection 23a and the convex portion 24a and seals the gap between the wall surface of the expansion chamber 21 has been developed. That is, in this vane pump, as shown in FIG. 8, when the cover 24 is completely tightened with the screw member 27, the O-rings 25 and 26 are compressed, and the O-rings 25 and 26 and the flexible plate 22 are compressed. By pressing the closed space S surrounded by the convex portion 24a of the cover 24 and the convex portion 24a of the cover 24, the flexible plate 22 forming the wall surface at one end of the pump chamber 11 flexes toward the inside of the pump chamber 11. The self-sufficiency is improved by reducing the gaps existing on both sides of the motor 12 in the axial direction. Therefore, according to this configuration, the dimensional accuracy of the casing 10, the rotor 12, and the like can be made rough, so that the casing can be manufactured by molding a synthetic resin material, and the cost can be reduced. is there.

However, according to this structure, although the initial self-sufficiency is improved, the self-sufficiency is decreased with the passage of time, and it was found from the subsequent experiments. The present invention was made by investigating the cause of such a decrease in self-sufficiency, and the technical problem is that the gap between the pump chamber and the rotor is not affected by cutting. It is to provide a vane pump that can be formed in a long time and can maintain a high self-sufficiency for a long time.

[0006]

[Means for Solving the Problems]

 The above technical problems can be effectively solved by the present invention. That is, the vane pump according to the present invention is arranged so as to close the open end of the pump chamber and the casing having the pump chamber in which the rotor in which the vane is slidably engaged is disposed, and one end in the axial direction is opened. A flexible plate, a packing that seals a gap between the outer peripheral edge of the flexible plate and the open end, and a packing that is fastened and fixed to the casing from the outside of the open end to secure the packing to the outer peripheral edge of the flexible plate. And a spring member interposed between the flexible plate and the cover for bending the flexible plate toward the pump chamber. In this case, more preferably, the flexible plate is provided with a small hole at a position substantially corresponding to the axial center of the rotor.

[0007]

[Action]

 In the vane pump having the structure shown in FIG. 8 described above, the fact that the initial self-sufficiency decreases with time means that the cover 24 is tightened to pressurize the closed space S to give the initial force to the flexible plate 22. This is because the amount of flexure of the is decreased over time, and it is considered that the cause is as follows. (1) Creep theory; The casing 10 and the cover 24 molded from a synthetic resin material are subjected to strain as shown in an exaggerated manner in Fig. 8 when tightened, but the initial reaction force caused by this is the creep phenomenon ( As a result of the permanent strain), the pressure applied to the closed space S is reduced, and as a result, the bending of the bending plate 22 is reduced. (2) Air cushion theory: The air existing in the closed space S slightly leaks to the outside due to the temperature cycle caused by repeated driving and stopping of the pump, or the deformed state of the O-rings 25 and 26 changes. As a result, the volume of the closed space S increases, and the air pressure in the closed space S decreases. As a result, the bending of the bending plate 22 decreases. Among them, especially regarding the air cushion theory, when the cover 24 is removed from the pump once the self-sufficiency is once reduced and the same parts are reassembled as it is, the self-sufficiency is restored to the same level as the initial level. It has been confirmed by experiments that self-sufficiency is the same as when fully assembled when a small hole that has almost no effect on the bending calculation formula of material mechanics is opened in the center of the bending plate 22. It was

The present invention suppresses such a decrease in the bending of the bending plate by the biasing force of the spring member. By forming a small hole in the flexible plate at a position that roughly corresponds to the axis of the rotor, the flexure of the flexible plate toward the pump chamber does not depend on the air pressure, but is applied only by the biasing force of the spring member. It is a thing. In this case, since the opening of the small hole in the flexible plate is in a state of being extremely close to the end surface of the rotor due to the biasing force of the spring member, the decrease in self-sufficiency due to the existence of the small hole is negligible. is there.

[0009]

【Example】

 As a first embodiment of the present invention, FIG. 1 shows a vane pump having a structure shown in FIGS. 7 and 8 which is incorporated as a means for supplying water to a steam generating portion of an electric iron, for example, a convex portion 24a of a cover 24 and a flexible plate 22. And the coil spring 30 in an appropriately compressed state through the opening 23a of the second flexible plate 23, thereby pressing the central portion of the flexible plate 22 toward the inside of the pump chamber 11. .

FIG. 2 shows a second embodiment of the present invention in which a small hole 31 is formed in the bending plate 22 of the vane pump of the first embodiment at a position substantially corresponding to the axial center of the rotor 12.

As a third embodiment of the present invention, FIG. 3 shows an O-ring which abuts on the flexible plate 22 by removing the second flexible plate 23 and the O-ring 26 on the outside thereof in the vane pump of the second embodiment. 25 is tightened by the convex portion 24a of the cover 24 with only the minimum crushing margin required for sealing, and when the cover 24 is tightened by the screw member 27, the cover 24 and the casing 10 are not deformed (initial stress) as much as possible. It is the one.

[0012] Fig. 4 schematically shows the situation of the change over time of the self-sufficiency in the vane pumps according to the above-described embodiments and the vane pumps according to the structures of Figs. 7 and 8. As is apparent from this figure, in the structure of the first embodiment, the decrease in the bending of the bending plate 22 is compensated by the biasing force of the coil spring 30, so that the decrease in the self-sufficiency is suppressed, but the casing 10 and the In contrast to the passive countermeasure that does not deal with the decrease of the initial stress of the cover 24 (creep theory) and the decrease of the air pressure due to the expansion of the closed space S (air cushion theory), the second embodiment In this case, the above-mentioned air cushion theory is considered, and since the structure in which the bending of the bending plate 22 does not depend on the air pressure and is given only by the biasing force of the coil spring 30, the amount of bending of the bending plate 22 does not decrease. It is only due to the decrease in the initial stress of the casing 10 and the cover 24, and the decrease in the self-sufficiency can be suppressed significantly. Further, in the case of the third embodiment, both the air cushion theory and the creep theory are taken into consideration, that is, since the initial stress due to the tightening of the cover 24 and the casing 10 is made as small as possible, only a small self-sufficiency can be obtained only in the very initial stage. Although a decrease was observed, the stable state was immediately obtained, and the best effect in each Example was obtained.

FIG. 5 shows the results of additional tests as shown in FIGS. 6A, 6B, and 6C on the initial self-sufficiency of the vane pump. That is, (A) is a measurement of the difference in self-sufficiency for a plurality of samples in which the flexible plate 22 in the third embodiment of FIG. 3 is replaced with one having no holes and coil springs 30 having different loads are mounted. In (B), a hole 24b is formed in the cover 24, and the change in the self-sufficiency is measured while changing the pressure applied to the coil spring 30 that is placed therein and abuts against the bending plate 22. In (), the change in self-sufficiency is measured in the same manner as in (B) above using a flexible plate 22 having a small hole 31.

As is clear from the above test results, in all of (A), (B), and (C), the load of the coil spring 30 and the initial self-sufficiency are in a substantially proportional relationship, and only (A) has an inclination. It got bigger. It is considered that this is because the self-sufficiency increase x at the same spring load was given by the increase in the bending of the bending plate 22 due to the air cushion. That is, in the case of the structure of (A), since the closed space S is formed between the flexible plate 22 and the cover 24, when the cover 24 is fastened and fixed to the casing 10, the closed space S is compressed so that the air Although a cushioning action occurs, as described above, this air cushioning action decreases with time. On the other hand, in the cases of (B) and (C), since the space S ′ between the bending plate 22 and the cover 24 is open, there is no such unstable element, and The flexure is purely provided only by the load of the coil spring 30. Therefore, it was proved that the structures of the second and third embodiments were less likely to cause a decrease in self-sufficiency with time.

An additional effect of the present invention is that the self-sufficient force can be arbitrarily set by the load of the coil spring 30 to be inserted. Particularly, in the case of the third embodiment, the approaching state of the flexible plate 22 to the end face of the rotor 12 is given only by the load of the coil spring 30, and the unstable factors such as the initial stress of the air cushion and the cover 24 are generated. Since it hardly exists, the set initial self-sufficiency is maintained for a long time. Further, since the flexible plate 22 is elastically held, it is less likely that the rotor 12 and the vanes 14 come into contact with the flexible plate 22 to lock the rotation. Further, due to the presence of the flexible plate 22, a small amount of water is likely to remain in the pump chamber 11 even after the pump is stopped, and when the pump is driven again, the remaining water will remain in the pump chamber 11 including the flexible plate 22. The self-sufficiency is further improved because it acts as a sealing element against air between the wall surface and the rotor 12 and the vane 14.

The O-ring 25 or 26 in each of the above-described embodiments may be replaced with another packing, and the coil spring 30 may be another spring member such as a leaf spring.

[0017]

[Effect of device]

 As is clear from the above description, according to the present invention, the bending plate that forms the one end wall surface of the pump chamber is bent toward the pump chamber by the biasing force of the spring member, so that the clearance between the rotor and the bending plate becomes small, and the bending plate It is possible to maintain the initial self-sufficiency for a long period of time by suppressing the decrease in the amount of flexure of the. In particular, by providing a small hole in the flexible plate at a position corresponding to the end surface of the rotor, it is possible to more effectively prevent a decrease in self-sufficiency due to a decrease in the amount of flexure of the flexible plate, and yet to reduce the spring member The initial self-sufficiency can be set arbitrarily by the load.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a vane pump according to the present invention.

FIG. 2 is a sectional view showing a second embodiment of the vane pump according to the present invention.

FIG. 3 is a sectional view showing a third embodiment of the vane pump according to the present invention.

FIG. 4 is an explanatory diagram showing a change in self-sufficiency over time.

FIG. 5 is an explanatory diagram showing the relationship between spring load and self-sufficiency in the present invention.

FIG. 6 is an explanatory diagram of an experimental method for obtaining the relationship between the spring load and the self-sufficiency.

FIG. 7 is a cross-sectional view showing a vane pump from which a spring member for pressing a flexible plate is removed.

FIG. 8 is a cross-sectional view exaggeratingly showing an initial deformed state of the vane pump from which a spring member for pressing the flexible plate is removed.

FIG. 9 is a sectional view showing a basic structure of a conventional vane pump.

10 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 10 Casing 11 Pump Chamber 12 Rotor 14 Vanes 22 Bending Plate 23 Second Bending Plate 24 Cover 24a Convex 25, 26 O-ring (Packing) 30 Coil Spring (Spring Member) 31 Small Hole S Sealed Space

Claims (2)

[Scope of utility model registration request] 1. A casing having a pump chamber in which a rotor having a vane projectingly engaged therein is disposed and one end in the axial direction is opened; and a flexible plate arranged so as to close the open end of the pump chamber. A packing that seals a gap between the outer peripheral edge of the flexible plate and the open end, and a cover that is fastened and fixed to the casing from the outside of the open end to press the packing against the outer peripheral edge of the flexible plate, A vane pump, comprising: a spring member that is interposed between the flexible plate and the cover to bend the flexible plate toward the pump chamber. 2. The vane pump according to claim 1, wherein a small hole is formed in the flexible plate at a position substantially corresponding to the axis of the rotor.