KR100733520B1 - Structure of gerotor oil pump - Google Patents

Abstract

The present invention relates to a structure of a gerotor oil pump, and more particularly, to a structure of a gerotor oil pump to reduce pressure pulsation during movement of a working fluid in a housing by interlocking an internal gear and an external gear.

The present invention includes an inner gear connected to an axis rotatably installed in a housing in which arc-shaped suction ports and discharge ports each of which a working fluid moves are opposed to each other, and an external gear that interlocks with the internal gears. In the structure of the zero rotor oil pump in which the gear rotates with the shaft about a rotation axis away from the external gear by a predetermined distance, the suction relief groove and the discharge relief groove are provided at one end of each of the mutually opposite suction and discharge ports. Is extended so that the pressure pulsation when the working fluid passes through the suction port and enters the discharge port is reduced, but the shape of the extended suction and discharge relief groove portion is such that the working fluid enters the discharge port through the suction port. Characterized by matching the teeth of the external gear located at the moment just before do.

Gerotor, oil pump, relief groove, housing, internal gear, external gear, suction port, discharge port, pressure pulsation

Description

Structure of gerotor oil pump

1 is a conceptual diagram showing the structure of a conventional gerotor oil pump

Figure 2 is a graph showing the pressure change in the housing of the conventional gerotor oil pump

3 is a conceptual diagram showing the structure of the gerotor oil pump according to the present invention;

4 is a conceptual diagram showing the structure of the suction relief groove which is the main part of the present invention;

5 is a conceptual diagram showing the structure of the discharge relief groove which is the main part of the present invention;

Figure 6 is a graph showing the pressure change in the housing of the gerotor oil pump according to the present invention

* Description of the symbols for the main parts of the drawings *

10 ... internal gear 20 ... outer gear

40 ... Suction port 50 ... Discharge port

60 ... axis 70 ... housing

The present invention relates to a structure of a gerotor oil pump, and more particularly, to a gutter oil pump in which a pressure pulsation in a housing is reduced according to an interlock between an internal gear and an external gear of a gerotor oil pump used for automobile engine oil supply. It is about the structure.

In general, the Gerotor oil pump has a simple structure and has a large discharge flow rate per revolution compared to other pumps of the same size, which is advantageous for miniaturization.It is a source of engine lubricating oil of a vehicle and a hydraulic source of a power transmission device and an automatic transmission. Not only is it widely used, but the development of processing technology is expanding the range of applications in various hydraulic systems.

1 is a conceptual diagram showing the overall configuration of a conventional gerotor oil pump.

As shown, the gerotor oil pump has an internal gear 1 having a trochoid tooth on an external gear 2 having an arc-shaped tooth as an internal gear mechanism, and a suction port 4 and a discharge port ( It is characterized in that 5) rotates inwardly in the housing 7 provided opposite to each other, and the number of teeth of the inner gear 1 is one smaller than this number of the outer gear 2, have.

However, in the conventional gerotor oil pump, the housing fluid in the process of moving the working fluid in the housing 7 from the suction port 4 to the discharge port 5 according to the interlocking of the inner and outer gears 1 and 2. 7) Cavitation and sudden pressure pulsation occur.

Figure 2 is a graph showing the pressure change in the housing of the conventional gerotor oil pump.

As shown, the X axis of FIG. 2 represents the position of the internal and external gears (see FIGS. 1 and 2) in the housing 7 (see FIG. 1), and the Y axis represents the pressure within the housing 7.

In the position of the suction port 4 on the X-axis of FIG. 2, a sudden pressure drop occurs when the suction port 4 (see FIG. 1) is closed by interlocking of the internal and external gears 1 and 2.

In addition, when the discharge port 5 (see FIG. 1) is opened at the position of the X-axis discharge port 5, a sudden pressure increase occurs.

Noise and vibration due to rapid pressure pulsation at the suction and discharge ports 4 and 5 will seriously impede the operation of the gerotor oil pump, causing problems such as failure or shortened life. .

In order to solve the above problems, most of the studies conducted so far have focused on tooth design of internal and external gears, and have focused on research on abrasion and contact stress occurring in contact portions of each tooth.

However, since the shape of the suction and discharge ports in the housing into which the working fluid is sucked and discharged is not taken into consideration, the effect of the working fluid behavior inside the gerotor oil pump, especially the pressure pulsation, on the dynamic characteristics of the pump cannot be accurately known. There is this.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, of the gerotor oil pump to reduce the sudden pressure pulsation of the working fluid sucked and discharged by the interlocking of the internal and external gears in the housing of the gerotor oil pump The purpose is to provide a structure.

The structure of the gerotor oil pump according to the present invention for achieving the above object is an internal gear connected to the shaft rotatably installed in a housing provided with an inlet port and an outlet port of the arc shape in which the working fluid moves, respectively; And an external gear interlocked with the inner gear, wherein the inner gear rotates with the shaft about a rotation axis spaced apart from the outer gear by a predetermined distance. And an intake relief groove and an outlet relief groove are formed at one end of each of the discharge ports to reduce pressure pulsation when the working fluid passes through the suction port and enters the discharge port, and the extended suction and discharge relief grooves are formed. The shape is the moment just before the working fluid passes through the suction port and enters the discharge port. And characterized in that to match the teeth of the external gear is located.

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Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a conceptual diagram showing the structure of the gerotor oil pump according to the present invention, Figure 4 is a conceptual diagram showing the structure of the suction relief groove which is the main part of the present invention, Figure 5 is a structure of the discharge relief groove which is the main part of the present invention. The conceptual diagram shown.

As shown in FIG. 3, the present invention has a configuration in which suction and discharge relief grooves 41 and 51 are extended to one end of each of the suction and discharge ports 40 and 50 provided in the gerotor oil pump housing 70. to be.

The suction and discharge ports 40 and 50 are disposed at positions opposite to each other in an arc shape in which an area gradually increases from one side to the other side, and are formed through the housing 70 to form the suction and discharge ports 40 and 50. The movement of the working fluid is made through a pipe (not shown) connected to it.

Movement of the working fluid is achieved by rotation of the inner gear 10 in the housing 70 by sliding contact with the outer gear 20, and each tooth contacting the inner and outer gears 10 and 20. The working fluid moves as the space moves between the teeth.

When the working fluid introduced from the suction port 40 passes through the suction port 40 and enters the discharge port 50 side according to the interlock between the internal and external gears 10 and 20, the external gear 20 The volume between the internal gears 10 is the largest.

The largest volume between the inner gear 10 and the outer gear 20 is centered on the rotation axis C ′ in which the inner gear 10 is separated by a predetermined distance from the center C of the outer gear 20. This is due to the shape of the suction and discharge ports 40 and 50 whose area increases from one side to the other side with the geometrical characteristics of rotating together with the shaft 60.

The suction and discharge relief grooves 41 and 51 extend in a slit shape having a predetermined width and length at one end of each of the suction and discharge ports 40 and 50, and the suction and discharge ports 40 and 50. Similarly, it is formed through the housing 70.

Here, the suction and discharge relief grooves 41 and 51 are suctioned at the moment when the inner and outer gears 10 and 20 move and enter the discharge port 50 through the suction port 40 in the housing 70. And the discharge ports 40 and 50 play a role of reducing pressure pulsation due to a sudden reduction in an area of the inner gear 10 and the outer gear 20, that is, a communication area.

As shown in FIGS. 4 and 5, the lengths C'D 'and C "D" of the suction and discharge relief grooves 41 and 51 have a working fluid passing through the suction port 40 so that the discharge port ( To match the teeth of the external gear 20 located at the moment just before entering 50.

In addition, the widths B'C 'and A'D' of the suction relief groove 41 and the widths B "C" and A "D" of the discharge relief groove 51 allow the working fluid to be suction port 40. It is preferable that the height of the external gear 20 located at the moment just before entering the discharge port 50 through the) coincides with the height or is somewhat lower.

Lengths C'D 'and C "D" of the suction and discharge relief grooves 41 and 51 are larger than teeth of the external gear 20, or the widths B'C', A'D ', B "C", A "D") is greater than this height of the outer gear 20, the gap between the inner and outer gears 10, 20 and the suction and discharge ports 40, 50 of the housing 70 Excessive fluid leakage or pressure loss occurs.

The lengths C'D 'and C "D" of the suction and discharge relief grooves 41 and 51 are smaller than the teeth of the external gear 20, or the widths B'C' and A'D '. , B "C", A "D") is excessively lower than this height of the outer gear 20, the pressure pulsation due to the working fluid in the housing 70 will occur.

The positions of the suction and discharge relief grooves 41 and 51 according to the present invention are designed in more detail as follows.

First, an analysis of pressure pulsation caused by the working fluid in the housing 70 is performed under the assumption that the working fluid has an infinite volume modulus and ignores leakage.

The above assumption is valid because the volume modulus of elasticity of the actual working fluid is approximately 1.62 × 10 ⁶ kPa and has little compressibility.

Considering the volume modulus of elasticity of the working fluid, the pressure change in the housing (see Fig. 1) changes rapidly as shown in Fig. 2 even in the case of minute volume changes, so that the distance between the suction port 40 and the discharge port 50 is reduced. Should be a space in which one chamber is completely filled.

Here, the chamber is defined as a space formed by the inner and outer gears 10 and 20 in the housing 70.

When the interval is narrowed so that the suction port 40 and the discharge port 50 is close to the overlap state, the discharge flow rate loss from the discharge port 50 to the suction port 40 occurs, and if the interval is large Due to the influence of the volume modulus of the working fluid, the pressure in the chamber increases rapidly, resulting in damage to the mechanism or operation of the pump.

Looking at the pressure change in the housing 70 by the suction and discharge relief grooves 41 and 51 of the present invention designed as described above are as follows.

6 is a graph showing the pressure change in the housing of the gerotor oil pump according to the present invention.

The X axis of FIG. 6 represents the positions of the inner and outer gears 10 and 20 (see FIG. 3) in the housing 70 (see FIG. 3), and the Y axis represents the pressure within the housing 70.

As shown, in the position of the suction port 40 on the X-axis of FIG. 6, the moment when the suction port 40 (see FIG. 3) is closed by interlocking of the internal and external gears 10 and 20, the pressure drops rapidly. It can be seen that undershoot is greatly reduced.

This is a clear improvement compared to FIG. 2 where a large pressure drop occurs at the distal side of the suction port 4 (see FIG. 1) of the prior art in the absence of a suction relief groove 41 (see FIG. 3) according to the invention. You can see that it was done.

In addition, as the discharge port 50 (see FIG. 3) is opened at the position of the discharge port 50 on the X-axis of FIG. 6, it can be seen that overshoot due to a sudden pressure increase is greatly reduced.

This is a significant improvement compared to Fig. 2, where a large pressure rise occurs on the inlet side of the prior art discharge port 5, see Fig. 1, in the absence of a discharge relief groove 51 (see Fig. 3) according to the present invention. You can see that it was done.

As such, the positions of the suction and discharge relief grooves 41 and 51 are positions at which the volume change rate of the chamber becomes zero according to the interlocking of the inner and outer gears 10 and 20, that is, the volume of the working fluid is maximum. The closer the position is, the greater the effect of reducing pressure pulsations.

And, as the widths B'C ', A'D', B "C", and A "D" of the suction and discharge relief grooves 41 and 51 increase, the working fluid comes out of the suction port 40. Or, as soon as it enters the discharge port 50, the opening area of the suction and discharge ports 40 and 50 is increased, thereby reducing the pressure pulsation.

As described above, according to the present invention, it is a basic technical idea to provide a structure of a gerotor oil pump in which a pressure pulsation is reduced during movement of a working fluid in a housing by interlocking an internal gear and an external gear. Able to know.

In addition, within the scope of the basic technical idea of the present invention, to those skilled in the art, many other modifications such as those applicable to not only automobile engine oil pumps but also construction machinery, machine tools and various hydraulic systems, etc. Of course this is possible.

According to the present invention, it is possible to reduce the sudden pressure drop and the pressure rise generated at one end of each of the suction and discharge ports by the working fluid in the housing of the gerotor oil pump by the suction and discharge relief grooves. By blocking noise and vibration, problems such as failure and shortening of life can be prevented in advance.

Claims (2)

An inner gear connected to an axis rotatably installed in a housing having an arc-shaped suction port and a discharge port each having a working fluid moved therebetween, and an external gear cooperating with the inner gear, wherein the inner gear is the external gear. In the structure of the gerotor oil pump that rotates with the shaft about a rotation axis away from the gear by a predetermined distance, At one end of each of the suction port and the discharge port facing each other, the suction relief groove and the discharge relief groove are extended so as to reduce the pressure pulsation when the working fluid passes through the suction port and enters the discharge port, And the shape of the suction and discharge relief grooves formed so as to match the teeth of the external gear located at the moment just before the working fluid passes through the suction port and enters the discharge port. delete

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