JPH01130080A - Rotary pump - Google Patents

Abstract

PURPOSE:To perform a shut-off action positively by letting the radius of curvature of a rolling contact section to a section close to both an intake port and an exhaust port with respect to a rotor be larger than that of the other section. CONSTITUTION:A rotor 2 is not uniform in radius, that is, the radius of curvature R23 of a section rolling while coming in contact with the range A provided for the intake and exhaust ports 31 and 32 of a casing 3 is larger than the radius of curvature R2 of the other section, and is made equal to the inner radius R3 of the casing 3. Therefore, when the rotor 2 comes in contact with the casing between the exhaust port 32 and the intake port 31, a different radius section 23 set at the radius of curvature R23 positively shuts off both the intake port 31 and the exhaust port 32, reverse flow will never thereby be generated.

Description

[Detailed description of the invention] 【Technical field】

The present invention relates to a rotary pump of a type in which a circular rotor is rotated eccentrically within a casing to gradually shift the contact position between the inner circumferential surface of the casing and the outer circumferential surface of the rotor. τBackground Art An example of the above-mentioned type of rotary pump is shown in FIG. A circular rotor 2, which is freely rotatably attached to an eccentric shaft portion 10 of a drive shaft 1 via a bearing 11, is eccentrically rotated within a casing 3 by the rotation of the drive shaft 1, and the casing 3
A shutter 4, which is swingably attached to the rotor 2, is slidably fitted into a groove 20 provided on the outer peripheral surface of the rotor 2. As the rotor 2 eccentrically rotates, the contact position between the outer peripheral surface of the rotor 2 and the inner peripheral surface of the casing 3 gradually shifts, and at this time, the contact position between the outer peripheral surface of the rotor 2 and the inner peripheral surface of the casing 3 changes. As the suction pressurizing chamber 5 surrounded by the suction chamber 5 and the shaft 4 moves, its volume changes, and the fluid sucked from the suction port 31 is discharged to the discharge port 32. Here, in this type of rotary pump, the inner diameter of the casing 3 is larger than the outer diameter of the rotor 2, and for this reason, the drive shaft 1 rotates half a turn from the state shown in FIG. As shown in FIG. 10, when the rotor 2 contacts the open portion of the suction port 31 and the discharge port 32, the suction port 31 and the discharge port 32 communicate with each other through the suction pressurizing chamber 5. Although this situation only occurs for a brief moment, the high-pressure fluid transferred to the discharge port 32 flows back to the suction port 31 side, resulting in a decrease in flow rate and discharge pressure, reducing pump efficiency. is decreasing.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned α, and its object is to provide a rotary pump of this type that does not suffer from a decrease in efficiency due to backflow.

DISCLOSURE OF THE INVENTION Accordingly, the present invention includes a casing and a rotor that is eccentrically driven and rolls into contact with the inner circumferential surface of the casing. In a rotary pump that changes the volume of the suction area J surrounded by the outer peripheral surface of the rotor and the inner peripheral surface of the casing by shifting the contact position, one of the inner peripheral surface of the casing and the outer peripheral surface of the rotor is made of an elastic material. At the same time, a different diameter portion is provided in the casing or the rotor so that the radius of curvature is approximately equal between a portion of the casing near the suction port and the discharge port that are provided close to each other, and a portion of the rotor that connects to the adjacent portion. This is characterized by the fact that the suction port and the discharge port are reliably closed off at different diameter portions. The present invention will be described in detail below based on illustrated embodiments.
FIG. It is formed by inserting a ring-shaped metal fitting 22 into the inner peripheral surface of a ring-shaped elastic body 21 made of rubber or the like, and a groove 20 is provided on the outer peripheral surface thereof. On the other hand, as is clear from FIG. 2, the casing 3 provided with the circular sill 30 for housing the rotor 2 is composed of a main body 33 and a cover 34, and has an inlet 31 and a cover 34 provided close to each other. The drive shaft 1 is supported by bearings 12, 12. *In addition, one end of the shutter 4 protruding into the casing 3 is swingably supported between the suction port 31 and the discharge port 32. The shutter 4 has its leading end slidably fitted into the groove 20 of the rotor 2. 15 in Figure 2 is a retaining ring, 2
Reference numeral 4 denotes an O-ring holder that holds O-rings 25 and 26 between the metal fitting 22 and the inner surface of the casing 3. Now, in this rotary pump, when the rotor 2 is in the position shown in FIG. The suction pressurization chamber 5 is in a state where there are two connected to the suction port 31 and the discharge port 32, respectively, and from this state, the rotation of the drive shaft 1 causes the rotor 2 to eccentrically rotate in the direction shown by the arrow in the figure. If so, the eccentric shaft portion 10
Since the rotor 2 can freely rotate relative to the shutter 4 and its rotation is restricted by fitting with the shutter 4, the rotor 2 gradually shifts the point of contact with the inner circumferential surface of the casing 3. As shown in FIG. 5(d), the volume of the suction pressurized chamber 5 connected to the discharge port 32 is reduced to discharge to the discharge port 32, and at the same time, the suction pressurized chamber 5 connected to the suction port 31 is discharged. The volume of the pressurized chamber 5 is increased to perform suction from the suction port 31. As the rotation of the rotor 2 further progresses, as shown in FIG.
As shown in FIG.
A new suction pressurization chamber 31 connected to 1 is created,
Then, the state returns to the state shown in FIGS. 1 and 5(c). During this time, the shutter 4 slides within the groove 20 of the rotor 2 and at the same time swings in proportion to the amount of eccentricity of the rotor 2. Here, the radius of the rotor 2 is not uniform (as is clear from FIG. , is larger than the radius of curvature R2 of other parts and is equal to the inner diameter R3 of the casing 3. For this reason, as shown in FIGS. 3, R54, and FIG. When contact is made between the rotor 2 and the suction port 31, the suction port 31 and the discharge port 32 will communicate through the suction pressurizing chamber 5 due to the difference between the outer diameter of the rotor 2 and the inner diameter of the casing 3. However, in this case, the different diameter portion 23 of the rotor 2 whose radius of curvature is set to R2 reliably closes both the suction port 31 and the discharge port 32, so no backflow occurs. In the eccentric rotation of the rotor 2, before and after the above state, the amount of pressure contact between the rotor 2 and the casing 3 increases due to the different diameter portion 23, but as described above, the amount of pressure contact between the rotor 2 and the casing 3 increases. Since the outer peripheral part is formed of the elastic body 21, the rotor 2
Since the outer periphery of the rotor 2 is formed of the elastic body 21, the outer diameter of the rotor 2, the inner diameter of the casing 3, or the eccentric shaft portion 10 will not cause problems. Even if the dimensional accuracy of the eccentricity is rough, the deflection of the elastic body 21 absorbs the roughness of the accuracy and ensures the contact between the outer circumferential surface of the rotor 2 and the inner curved surface of the casing 3, and also the sliding fitting part with the shutter 4. Other embodiments are shown in FIGS. tpa to 8. In this embodiment, the rotor 2 has a constant radius of curvature R2, and the inlet 31 in the casing 3 The radius of curvature RjS near the discharge port 32 is made equal to the radius of curvature R2 of the rotor 2 and smaller than the radius of curvature R1 of other parts, and the different diameter portion 35 provided on the casing 3 side ,
This allows the discharge port 32 and the suction port 31 to be closed at the same time. In addition to the above embodiments, the radius of curvature of the rotor 2 and the casing 3 in the vicinity of the inlet 31 and the outlet 32 is the same as the radius of curvature R2 of other parts of the rotor 2 and the casing 3.
? The different diameter portion 23.3 is approximately the middle value of R3.
5 may be formed on both the rotor 2 and the casing 3. In addition, as a countermeasure against the increase in the amount of pressure contact due to the provision of the different diameter portions 23.35, the outer peripheral portion of the rotor 2 is made of an elastic body 21, but at least the above-mentioned vicinity of the inner peripheral portion of the casing 3 is shown. The portion may be made of an elastic body. [Effects of the Invention] As described above, in the present invention, when the rotor contacts the part between the suction port and the discharge port, the different diameter portion provided in the rotor or the casing allows the suction port and the discharge port to pressurize the suction. This prevents communication through the chamber, thereby preventing backflow and achieving high pump efficiency with no drop in flow rate or discharge pressure. Since the surface is made of an elastic material, the increase in the amount of pressure contact caused by providing the different diameter portion does not cause problems with the rotation of the rotor, and the dimensional accuracy of the rotor and casing and the rotor Although the accuracy of the amount of eccentricity is a little rough, the deflection of the elastic body absorbs this and keeps the suction pressurization chamber sealed, so the discharge pressure and efficiency are increased in this respect as well.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of one embodiment of the present invention, Figure 2 is a vertical cross-sectional view of the same, Figure 3 is an enlarged cross-sectional view of the same, tiS4 is a cross-sectional view of the same, and Figure 5 (a). ~(d) are cross-sectional views showing the same operation as above, FIGS. 6 and 7 are cross-sectional views of other embodiments, FIG. 8 is an enlarged cross-sectional view of the same, and fjS9 and 10.
The figure is a cross-sectional view of a conventional example, with reference numeral 2 a rotor, 3 a casing, 5 a suction pressurizing chamber, 21 an elastic body, 23 a different diameter section, 31 an inlet, and 32 an outlet. Agent Patent Attorney Ishi 1) Ai 72 Law! 3 Casing 3 % Diameter 31 Suction [J 32 Outlet Fig. 1 Fig. 2 Fig. 4

Claims (3)

[Claims] (1) It is equipped with a casing and a rotor that is driven to rotate eccentrically and rolls into contact with the inner circumferential surface of the casing, and the outer circumferential surface of the rotor is In a rotary pump that changes the volume of a suction pressurized chamber surrounded by a casing inner circumferential surface and a casing inner circumferential surface, one of the casing inner circumferential surface and the rotor outer circumferential surface is formed of an elastic body, and the rotor is adjacent to each other in the casing. A rotor characterized in that the casing or the rotor is provided with a portion of different diameter that makes the radius of curvature of a portion near the suction port and the discharge port provided substantially equal to a portion of the rotor that is in contact with the portion near the said portion. pump. (2) The rotary pump according to claim 1, characterized in that a different diameter portion is provided on the rotor side. (3) The rotary pump according to claim 1, characterized in that a different diameter portion is provided on the casing side.