JPS58155288A - Improved-type queen-bee pump - Google Patents

Abstract

PURPOSE:To obtain a pump whose efficiency is higher than that of a publicly- known Queen-bee pump and whose rotor is easier in manufacturing than that of the improved Queen-bee pump by constituting both rotors as crossed helical gears which have no trocoidal tooth-profile parts but a single-pointed, continuously touching tooth-profile part. CONSTITUTION:A main shaft rotor 1 and a driven rotor 2 are different in their turning directions but identical with each other in their tooth-profile curves and other tooth-profile particulars. Of a tooth-profile curve ABCDEFG, region AB is a circular arc whose center and a radius coincide with those of tip circle Co having a radius Ro, region BC is a circular arc having a radius r whose center is point P on a pitch circle Cp, region FG is a circular arc whose center and radius are same as those of a bottom circle Cs having a radius Rs, region DF is a circular arc having a radius r whose center is point Q on a pitch circle Cp, region DE is a straight line smoothly connected to the circulate arc FD, and region CD is a cycloid drawn by a straight line part CD of a mating gear. On the other hand, tooth profile curve g f e d c b a is also identical with the tooth profile curve ABCDEFG.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of the Finby pump, which is widely used as a birotor type axial flow screw pump, and in particular,
This invention relates to an improvement of the improved FinBee pump previously disclosed by the inventor in Japanese Patent Application No. 144302/1982.

Compared to other screw pumps, the casing structure of the Finby pump is simple, the rotor is easy to machine, and only two rotors are required.The structure is simple, the force is well balanced, and there is no risk of failure. In addition, compared to other bi-rotor type gear pumps, a large flow rate can be obtained for its size, there is no fluctuation in discharge pressure, the rotor rotation speed can be increased, and the rotor can be used for a long time. It is widely used because it has the advantage of being able to obtain a fairly high head just by doing so.

The pair of screw gears that make up Finby pumps, which have been widely used in the past, both have a right-hand thread and a left-hand thread of the same diameter. It is configured to rotate in opposite directions via a pilot gear while meshing with the left-hand threaded portion and the right-hand threaded portion.

Therefore, the axis-perpendicular tooth profile curve of this kind of known screw gear is:
It is a closed curve formed by a part of the arc of the tip circle and the root circle, and a trochoid drawn by both ends of the tip arc of the mating helical gear.

However, since this tooth profile is a tooth profile of the second tooth profile system and the driven gear cannot be directly driven via the tooth surface, there is a problem in that a pilot gear is required for rotation transmission.

In addition, it is known that this tooth profile cannot form a completely continuous fluid seal line, resulting in so-called pipe omission between the suction side and the discharge side. If it is not equivalent to 4 to 6 pitches or more, the head and volumetric efficiency required for normal use cannot be obtained, and even if the meshing part is combed in this way, the head and volumetric efficiency will not necessarily be at a sufficient level. There was also the problem that the suction was poor.

For this reason, the inventor has previously filed a patent application for patent application No. 55-144302.
In this issue, we proposed an improved Finby pump in which only one tooth surface of one drawing rack had a trochoidal tooth profile, and all other tooth surfaces had one-point continuous contact tooth profiles.

This improved Finby pump has a perfect seal, resulting in high volumetric efficiency, a well-balanced rotor, and no vibration even when rotating at high speed, and the single-point continuous contact tooth section can be used directly as a pilot gear. Therefore, there is no need to provide a special pilot gear, and the advantage is that rotation can be directly transmitted to the driven rotor regardless of whether the driving rotor is rotated in the forward or reverse direction.

However, there is a problem in that two types of cutters are required to process this rotor, and the gear cutting process also requires two steps.

Further, although this improved Finby pump provides a very high volumetric efficiency, there are many cases where such a high volumetric efficiency is not required depending on the application.

The present invention has been made based on the above-mentioned viewpoints, and although the volumetric efficiency is not as high as the above-mentioned improved Finby pump, it is vague compared to the conventionally known Finby pump. The object of the present invention is to provide a new improved Finbee pump that is more efficient and easier to process than the rotor of the improved Finbee pump described above and can be manufactured at a lower cost.

The gist of this method is to configure both rotors as screw gears consisting only of one-point continuous contact tooth profile without any trochoidal tooth profile.

Hereinafter, the details of the present invention will be specifically explained with reference to the drawings.

1 and 2 are right-angled tooth profile diagrams of the rotor in one embodiment of the improved Finby pump according to the present invention, and the diagrams are diagrams showing the rotor at different phase angles (i.e., in the axial direction). This shows the engaged state (at positions separated by 1). Moreover, FIG. 3 is an explanatory diagram of the seal line.

5- Thus, in the figure, ■ is the driving rotor, 2 is the driven rotor, 3 is a part of the casing that houses these ceramic rotors, and A
BCDEFG and gf edcba are part of the axis-perpendicular tooth profile of both rotors.

Note that the tooth profile curve is symmetrical with respect to its major and minor axes, so in order to simplify the diagram, only the x is marked with a symbol, and the symbols are omitted in other parts to correspond to the above points. The points are shown with black circles.

Thus, both rotors form helical gears when twisted along their respective axis center lines, and mesh with each other.
Both rotors are mirror symmetrical with respect to a cross section perpendicular to the axis at the center of the threaded portion. In other words, if one rotor, for example, the driving rotor 1, has a right-handed screw in the front half of the drawing, the half facing away from the sheet has a left-handed screw, and the driven rotor 2 is the opposite. It is.

Further, the casing 3 has a rotor chamber 3a having a cocoon-shaped cross section defined by a cylindrical inner wall having substantially the same diameter as the cylindrical surfaces of the tooth tips of both rotors, which are indicated by a closed curve 5TUVS in the figure,
Both rotors are housed here in an engaged state, and when the driving rotor l connected to the motor rotates in the direction of the arrow in the figure (counterclockwise), the driven rotor 2 rotates in the opposite direction (clockwise). ).

The casing has an inlet that communicates with the end faces of both rotors, and an outlet that communicates with the center portions of both rotors.

A seal line is formed by the contact between the tooth surfaces of the driving rotor 1 and the driven rotor 2 that mesh with each other, and by the extremely small gap provided between the tips of the teeth of both rotors and the rotor interior wall 3a. Fluid is sent to the rotor by moving from both ends of the rotor to the center as the rotor rotates.

The tooth profile curves and seal lines of both rotors 1 will be explained below.

Although the driving rotor 1 and the driven rotor 2 have different torsional directions, the shapes and specifications of their tooth profile curves are all the same. That is,
The tooth-shaped curves ABCDEFG and g[edcba are the same shape and the same size, and the points A, B, and C.

D, E, F, and G are points g 1f-, a-dlcm, respectively.
.

This corresponds to b and a.

Therefore, of the tooth profile ABCDEFG, the section AB is half a g! Ro is an arc that is concentric and has the same diameter as the tip circle Co. Section BC is a semicircular arc that is centered at point P on the pitch circle Cp and is half 4JI=r.Section FG is an arc that is concentric and the same diameter as the root circle Cs and has radius Rs. , section DF is an arc with radius r centered on point Q on pitch circle cp, section DB is a straight line smoothly connected to arc FD, and section CD is a cycloid drawn by straight line section cd of the mating gear.

On the other hand, in the tooth profile curve gfedcba, the section fg is an arc having a radius Ro and is concentric and the same diameter as the tip circle Co', and the section ef is an arc having a radius r centered at a point p on the pitch circle CpZ.
Section ab is a circular arc concentric with the root circle Cs' with radius Rs, and section bc is a radius r centered on point q on pitch circle Cp.
The section 1111cd is a straight line smoothly connected to the arc bc, and the section do is a cycloid drawn by the straight line DE of the mating gear.

The locus of the contact point between the two rotors, ie, the seal line, is a figure-eight (Reno-Niscate) curve indicated by HIJKL'MJNH in FIG.

The contact point between the state shown in FIG. 1 and the state shown in FIG. In the state shown in FIG. 2, the arc BC (which coincides with the arc be) in the same figure, that is, the arc H1 in FIG. 3 is obtained.

As the phase advances further, a line of contact is formed by the straight line cd of the driven rotor 2 sliding on the cycloid CD of the driving rotor l, so the contact point locus follows the arc I in Fig. 3.
It becomes J.

As the phase advances further, a contact line is formed by the straight line DB of the driving rotor 1 sliding on the cycloid CD of the driven rotor 2, and the contact point locus shifts to the arc JK in FIG. 3.

Therefore, when points E and e coincide, arcs EF and ef coincide to form a contact line, which is the arc KL in Fig. 3, and the phase advances further, causing the driven rotor to During the period when the tip of the tooth 2 is in contact with the bottom of the tooth of the driving rotor 1, the contact point remains at the point of contact between the bottom circle of the tooth 9 of the driving rotor 1 and the tip circle of the driven rotor 2.

Therefore, during the Z rotation of both rotors from the state shown in Fig. 1 to the state shown in Fig. 2, or during the length corresponding to the A lead of both rotors, the A contact point locus HI JKL is formed, and a contact point locus LMJNI (is formed in the next χ rotation or A lead).

The original rotor of the Finby pump, which has been widely used in the past, consists of semicircular arcs of the tip circle and tooth root circle that face each other across one diameter of the tip circle, and both ends of the semicircular arc of the tip circle of the mating gear. It is a closed curve made up of points and trochoids, but with this tooth profile, it is impossible to form a completely continuous fluid seal line, and a so-called tube gap occurs between the suction side and the discharge side. It is publicly known.

Further, the tooth profile is a second tooth profile system, which cannot directly drive the mating gear via the south face, and requires a pilot gear for rotation transmission.

As mentioned above, the present inventor proposed in Japanese Patent Application No. 10-144302 that if a FinBee pump is constructed using a rotor having a composite tooth profile that is a combination of the trochoidal tooth profile and the one-point continuous contact tooth profile, It has been disclosed that a complete fluid seal line can be formed, not only eliminating the problem of tube omission, but also eliminating the need for a pilot gear.

In the case of the Finby pump connected to this gear, as mentioned above (
, a rotor is used that has no trochoidal tooth profile and consists of only one point continuous contact tooth profile. This rotor has no second tooth profile and consists only of the first tooth profile.

In this rotor, although a lemniscate contact point locus HIJKLMJNH is formed between both rotors, the seal line formed on the rotor surface due to this does not form a complete closed curve on the surface of both rotors, and therefore, Theory - Although upper liquid leakage occurs, this seal imperfection is extremely mild compared to the known original Finby pump, and the leakage of the tube is also extremely small.

Therefore, when using the Finby pump according to the present invention for a fluid with a high sealing effect, it is necessary to use a rotor in which the left and right threaded parts each have a fully threaded part with one lead or more, or the length of the left and right threaded parts is By using a rotor of 1, 21J or more, it is possible to construct a Finbee pump that can be operated at high efficiency over a long period of time without any practical problems.

In addition, since the rotor of the Finby pump according to the present invention has a single point continuous contact tooth profile of the first tooth profile system, the pyro
It does not require a throat gear and can be operated in either forward or reverse direction.

Further, since this rotor has a high tooth profile strength, it can be operated at high speed and high head, and therefore the pump can be made small and lightweight.

Furthermore, since this rotor can be geared in one step with a single tool, it can be provided at an extremely low cost.

In the explanation below, a well-known circular arc buikroid composite tooth profile is shown as an example of a single point continuous contact tooth profile, but the configuration of the present invention is not limited to this example, and any Of course, the design can be changed by adopting widely known one-point continuous contact tooth profiles such as circular arc tooth profiles and cycloid tooth profiles, and the present invention encompasses all of them.

Since the present invention is constructed as described above, it is possible to provide FinBee pumps in large quantities at extremely low cost and with high practical value.

[Brief explanation of the drawing]

1 and 2 are right-angled tooth profile diagrams of the rotor in one embodiment of the improved Finby pump according to the present invention, and the diagrams are diagrams showing the rotor at different phase angles (i.e., in the axial direction). This shows the engaged state (at positions separated by 1). Moreover, FIG. 3 is an explanatory diagram of the seal line. 1. Main rotor 2. Driven rotor 3. Casing patent applicant Chief 1) Outside Chongqing - Principal representative (7524 ) Mogami Shotabe 13-

Claims (1)

[Scope of Claims] (11) In a Finby pump configured using a pair of screw gear type rotors each having a right-handed threaded portion and a left-handed threaded portion, the threaded portions of both rotors have the same shape and the same tooth profile in the cross section perpendicular to the axis. The above-mentioned Finby pump characterized in that it has a large two-lobed one-point continuous contact tooth profile. (2) The Finby pump according to claim 1, in which an arcuate tooth profile is used as the single-point continuous contact tooth profile. (3) The finby pump according to claim 1, which uses a cycloidal tooth profile as the one-point continuous contact tooth profile. (4) The fin according to claim 1, which uses a composite tooth profile of an arc and a cycloid as the one-point continuous contact tooth profile. Bee pump. (5) Both the axial length of the right-hand threaded part and the left-hand threaded part are
The FinBee pump according to any one of claims 1 to 4, which has a lead of 1.2 or more.