KR101606815B1 - Method for Designing Outer Rotor Lobe Shape Using 2 Ellipses and Gerotor Pump Designed by the Method - Google Patents

Abstract

The present invention relates to a tooth form design method for a gerotor pump of designing the tooth form of an external rotor and an internal rotor by combining two ellipses and a gerotor pump designed through the same design method. The rotor tooth form for a gerotor designed by the present invention is named as ″SDICHOID III (product name)″, which is the dynamic and innovative tooth form curve, Samhan dynamic innovation choid III, developed by Samhan, the applicant of the present invention. According to a form of the present invention, the tooth form design method for a gerotor pump is a method for designing the tooth form of a gerotor pump for the lobe shape of an external rotor to have a shape where two ellipses are combined and includes: a step (S1) of, if the shape of a lobe (1a) of an external rotor (1) is a single shape of an ellipse, drawing a constitutive equation for the lobe shape of the external rotor; a step (S2) of drawing a shape function for the ellipse 1 by rotating and moving translationally the coordinate axis of the ellipse 1 obtained by the constitutive equation drawn in the step (S1) above and drawing a shape function for an ellipse 2 by moving the ellipse 1 symmetrically to the X-axis; a step (S3) of drawing contact point equations of the internal rotor and the external rotor for the ellipse 1 and 2 in the step (S2) above; and a step (S4) of calculating the shapes of the internal rotor and the external rotor from the contact point equations.

Description

[TECHNICAL FIELD] [0001] The present invention relates to a method of designing a tooth profile of a rotor pump in which two ellipses are combined and a method of designing the rotor pump using the same.

The present invention relates to a method of designing a geared rotor pump, and more particularly, to a geared design method of a geared rotor pump for designing a tooth profile of an outer rotor and an inner rotor by combining two ellipses, .

The rotor tooth profile of a ground rotor pump designed according to the present invention is referred to as " SDICHOID III (trade name) ", which means SAMHAN DYNAMIC INNOVATION CHOID III developed by Samhan who is Applicant.

The lubrication system of an automobile engine is an indispensable device for smooth engine operation and long life. An oil pump, which is one of the components of such a lubrication apparatus, is mainly used for an internal-type oil pump which is advantageous in terms of flow rate, durability, noise and miniaturization.

Such an oil pump is an essential functional part of an engine that is mounted on an engine of an automobile and converts mechanical energy supplied from the engine to pressure energy and speed energy of the engine oil so that lubricating oil To prevent abnormal wear, disconnection, and the like of the components. The components constituting the oil pump are composed of an electric motor, a key, an inner rotor, a rotor case, an O-ring, a screw, and the like . In addition to other standard products in the oil pump, the rotor case is manufactured by die casting according to the specifications of the oil pump, and the outer rotor and the inner rotor are produced by powder forging.

In order to improve the performance, vibration and efficiency of the oil pump, the parameters related to the tooth profile are analyzed to determine the geometry of the gear pump ), Computational fluid dynamics (CFD), and system simulation approaches.

There is a method for designing a ground rotor pump proposed by the present inventor and registered as a patent (Patent Registration No. 10-1269057) as a conventional technique for designing an outer rotor lobe shape of a rotor oil pump. 1, the lap 1a of the outer rotor 1 has a first elliptic curve (ellipse 1) from 0 ° to γ, an involute curve up to η, and a second round And an elliptic curve (ellipse 2). Wherein the involute curve is an involute curve derived from a circle.

However, the geothermal oil pump having the two-elliptic-poly-circle combination tooth type and the hypocyloid-poly-circle-epicycloid combination tooth type manufactured by the above-mentioned design method of the patent publication, It is true that it has a remarkable advantage in terms of flow rate, abrasion resistance, and noise compared to an oil pump. However, due to the trajectory of the involute curve, there is a limit to increase the flow rate and reduce the slip rate and the pressure angle.

In designing the tooth profile of the conventional rotor oil pump, when designing the tooth profile of the outer rotor lobe, it is designed to apply only the translation movement algorithm when inserting the involute curve between the first elliptic curve and the second elliptic curve. That is, in the design method using only the conventional translation movement algorithm, the coordinate axes of the involute are combined with the ellipse 1 and the ellipse 2 through the translational movement in the x and y axes.

In the method of applying only the translational movement algorithm, the design parameter of the curve is limited, so that the cusp and the loop of the combination shape appear, which adversely affects the slip rate and the pressure angle among the rotor performance factors.

Registration No. 10-1269057 (2013.05.23) Registration No. 10-0940980 (2010.01.29) Patent Publication No. 2010-0039523 (Apr. 16, 2010)

It is an object of the present invention to design an outer rotor lobe and an inner rotor shape in which two ellipses are combined using a rotation and translational motion algorithm, The present invention provides a ground rotor pump designed to increase the flow rate and reduce noise by reducing flow pulsation, slip rate and pressure angle.

According to an aspect of the present invention, there is provided a method of designing a tooth profile of a ground rotor pump such that a lobe shape of an outer rotor has a shape in which two ellipses are combined, (S1) deriving a constitutive equation of the lobe shape of the outer rotor in the case where the shape of the lobe (1a) of the outer rotor (1) is a single shape of an ellipse; (S2) The shape function for the ellipse 1 is derived by rotating and translating the coordinate axes of the ellipse 1 obtained by the constitutive equation derived in the step S1, and the shape function of the ellipse 2 is derived by symmetry of the ellipse 1 with respect to the X axis step; (S3) deriving a contact point equation between the inner rotor and the outer rotor for the ellipse 1 and the ellipse 2 obtained in the step S2; (S4) calculating the shapes of the inner rotor and the outer rotor from the contact point equations.

According to the present invention, since the tooth profile of the outer rotor and the inner rotor of the geared pump has a tooth shape in which two ellipses are combined by the rotation and translation movement algorithm, the flow rate is increased more than the conventional one, and the flow rate pulsation, It is confirmed that the effect of reducing the noise can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plan view schematically illustrating a ground rotor pump having a tooth profile of a conventional elliptical 1-involute-elliptic 2 combination.
FIG. 2 is a view sequentially illustrating a process of designing a geopower pump according to the present invention.
3 is a diagram for deriving a constitutive equation of an ellipse.
4 is a view showing a combination shape of an elliptical 1-ellipse 2 using a rotation movement and translation movement algorithm.
5 is a diagram for deriving a contact point equation between an inner rotor and an outer rotor for a single ellipse and involute shape.
6 is a diagram for deriving a contact point equation between the inner rotor and the outer rotor for the ellipse 1 and the ellipse 2.
7 is a view showing a process of designing a tooth profile of an outer rotor using a contact point.
8 is a view showing a process of designing a tooth profile of an inner rotor using a contact point.
9 is a diagram showing an example in which design variables are inputted through an input module of a tooth type design system of a ground rotor pump.
10 is a diagram showing an example in which the outer rotor and the inner rotor generated by the creation module are output through the output module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a ground rotor pump according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a diagram illustrating a process of designing a geopower pump according to an embodiment of the present invention. First, a pitch circle for an inner rotor and an outer rotor is designed (step 1), and a configuration for an ellipse 1 and an ellipse 2 The lobe shape of the outer rotor combined with two ellipses is designed through the equation (step 2-1, 2-2). Then, the contact point equations of the inner rotor and the outer rotor are derived (step 3), and the shapes of the inner rotor and the outer rotor are calculated from the contact point equations (steps 4 and 5).

This design method will be described in more detail as follows.

● Parameter equation of elliptic shape

The parameter equation for the shape of the outer rotor lobe in the case where the shape of the lobe 1a of the outer rotor 1 is a single ellipse is obtained. At this time, the elliptical shape can be obtained by enlarging or reducing the circle (Equation 1) in one axial direction. As shown in Fig. 3, the distance (rho) between the arbitrary point F on the ellipse and the center point of the intersection A of the intersection point of the waterline drawn from F is the same as the equation ( ₂ ) with the radius of the circle (rl ₂ ). Since the ellipse is obtained by reducing and enlarging the circle in one axial direction, the parameter equation of the circle and the ellipse is expressed by Equation (4).

● Ellipse 1 - Ellipse 2 Combining shape function

As shown in FIG. 4, the lobe shape of the outer rotor combined with the 2-ellipse using the rotation and translational motion algorithm of the present invention is composed of two parts of the ellipse 1-ellipse 2. Then, the shape function for the ellipse 1 is obtained as shown in Equation (5) by translating the first shape ellipse 1 by 侶 in the counterclockwise direction with reference to the coordinate axis, translating the second shape in the -y direction by b, In the case of the ellipse 2, the ellipse 1 is symmetrically formed with respect to the x-axis, expressed by Equation 6, and the rotation and translation movement algorithm is shown in FIG. In this case, b is a value for making y _{1 in} Equation (5) and y ₂ in Equation (6) equal, and O1 and O2 are centers of the inner rotor and the outer rotor, respectively. where d is the distance between the center of the outer rotor and the center of curvature of the outer rotor lobe, rl ₂ is the radius of the outer rotor lobe, and k is the longitudinal short axis ratio of the ellipse.

● Contact Point Equation of 2-elliptic Combined Shape

As shown in FIG. 6 and (8) to (11), an angle at which a direction vector (V ₁ ) and a tangent vector (V ₂ ) from the pitch point P ₂ at one point of the outer rotor lobe are perpendicular to each other θ is found by using the Newton-Rahpson method and the contact point is obtained. Where α is the angle between P ₂ and the center O ₂ of the outer rotor.

The contact point equations (C _e1 , C _e2 ) of the ellipse 1 and ellipse 2 of the combination type for the 2-ellipse can be expressed by Equations (12) and (13) using the shape function and the kinematic conditions of each ellipse.

● Rotor creation equation using contact points

Next, the shape of the lobe of the outer rotor is designed using the curvature shape of the inner rotor.

If the number of teeth of the outer rotor LA Z _2, a case where in each case the radius of curvature of the inner rotor becomes the maximum is the inner rotor, as shown in Fig. 7 is rotated from the center of the outer rotor have to be as shown in Equation 14 below.

In Fig. 7, the section (1) is a toothbrush portion, and the contact point A 'of the outer rotor is obtained by rotating the center of the outer rotor. This is shown in equation (15). The section (2) consists of a part of the internal rotor shape created by the tooth-turning part and rotated by the equation (14) with respect to the center of the external rotor. This is shown in Equation (16).

Referring to the process of designing the inner rotor from the contact point derived in FIG. 8, the inner rotor shape is created by rotating the contact point A 'by the angle?' In the clockwise direction of the inner rotor center point O ₁ as shown in Equation 17 below. Here, α 'is expressed by the following equation (18).

Here, α 'is expressed by the following equation (20).

Geothermal Design System

The method of designing the outer rotor and the inner rotor teeth of the ground rotor pump in which the ellipse 1-ellipse 2 of the present invention as described above is combined is implemented as a design program in the ground rotor pump design system.

The gear tooth designing system of the present invention includes an input module for inputting design parameters, a creation module for generating an elliptical 1-ellipse 2 combination tooth profile using the rotation and translation movement algorithm of the present invention Generating profile module, and an output module for outputting the performance factor calculation and the calculation result to the screen.

The geotechnical design system of the geothermal pump generates the trajectories of the external and internal rotors from the input design variables by the toothed equation and calculates the flow rate, flow rate pulsation, slip rate and pressure angle based on the generated trajectories.

FIG. 9 shows an example in which design variables are input through an input module of a tooth type design system of a ground rotor pump, and FIG. 10 shows an example in which an outer rotor and an inner rotor generated by a creation module are output through an output module.

As a result of the optimal design of the tooth profile having the 2-elliptical combination shape according to the present invention by inputting the design factors as shown in the following Table 1, the flow rate was 20.4710 cc / rev, the flow rate pulsation as the noise factor was 4.1424% Slip ratio of 1.0945 and a pressure angle of 22.5056 °. The flow rate was increased by 4.39% compared to the conventional circular rotor type lobe pump, and the flow rate was improved by 22.92%, slip rate by 52.62% and pressure angle by 18.07% .

D t tooth e d rl ₂ k ₁ gamma η 90 12.6 9/10 3.421 43.5 3.6 1.4 35 28

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. And it is to be understood that such modified embodiments belong to the scope of protection of the present invention defined by the appended claims.

1: outer rotor
1a: lobe
2: Internal rotor

Claims (7)

A method of designing a tooth profile of a ground rotor pump so that a lobe shape of an outer rotor has a shape in which two ellipses are combined,
(S1) deriving a constitutive equation of the lobe shape of the outer rotor in the case where the shape of the lobe (1a) of the outer rotor (1) is a single shape of an ellipse;
(S2) After rotating the ellipse 1 in the clockwise direction about the coordinate axis of the ellipse 1 obtained by the constitutive equation derived in the step S1 by 侶, the shape function for the ellipse 1 is derived by translating it by -y direction by b , Deriving a shape function of the ellipse 2 by symmetry of the ellipse 1 with respect to the X axis;
(S3) deriving a contact point equation between the inner rotor and the outer rotor for the ellipse 1 and the ellipse 2 obtained in the step S2;
(S4) calculating a shape of the inner rotor and the outer rotor from the contact point equations,
The shape function of the ellipse 1 derived in the step S2 is expressed by the following equation,

The shape function of the ellipse 2 is expressed by the following equation,

Here, b is a value to become a y ₂ of the shape function of the y _1, the shape function of the elliptical one with ellipse 2 I, O1 and O2 and the center of each of the inner rotor and the outer rotor, γ is the period to insert the oval D is the distance between the center of the outer rotor and the center of curvature of the outer rotor lobe, rl ₂ is the radius of the outer rotor lobe, k is the longitudinal short axis ratio of the ellipse,
In step S3, a point P 'obtained by rotating the pitch point P of the lobe of the outer rotor by an angle? In the clockwise direction is connected to a point on the elliptic shape, and then the point P'

Wherein the contact equation is derived from the contact equation. delete delete delete The method of claim 1, wherein the S4 step, looking at the angle θ is the pitch point P ₂ between the direction vector (V ₁₎ and a tangent vector (V ₂₎ at a point of the outer rotor lobes perpendicular using a Newton-Rahpson method contacts And the contact equation between the outer rotor and the inner rotor for the ellipse 1 and the ellipse 2 obtained in the step S3 is found. 6. The method of claim 5, wherein the contact point equation between the inner rotor and the outer rotor for the ellipse 1 derived in step S4 is expressed by the following equation,

The contact point equation between the inner rotor and the outer rotor for the ellipse 1 derived in the step S4 is expressed by the following equation,

Wherein said step (d) comprises the steps of: Characterized in that it is designed by the designing method according to any one of claims 1 to 6 and has a lobe tooth profile of an outer rotor of a shape in which two ellipses are combined by a rotational movement and translation movement algorithm Rotor pumps.

Images