KR20170040075A - Gerotor oil pump - Google Patents

Abstract

The present invention relates to a gerotor oil pump, which comprises: an internal gear having a tooth shape on an outer circumferential surface; and an external gear having a tooth shape on an inner circumferential surface, wherein the internal gear is inscribed. Each tooth of the internal gear and the external gear is formed to have a reverse grade toward an opposite direction to reduce a gap between the internal gear and the external gear which are engaged with each other. Therefore, a leakage amount can be minimized, and a discharge flow rate amount can be increased.

Description

[0001] GERTER OIL PUMP [0002]

The present invention relates to a gerotor oil pump, and more particularly to a gerotor oil pump for supplying oil to an engine or a transmission of a vehicle.

The engine or the transmission of the vehicle is provided with an oil pump for supplying engine oil or transmission oil.

The oil pump is driven by a gear or a chain by a crankshaft or a camshaft, and can be classified into a rotary pump, a gear pump, a plunger pump, and a vane pump depending on the structure.

Generally, a gerotor oil pump which is one of the rotary pumps is widely used.

For example, FIG. 1 is a conceptual diagram of a conventional gerotor oil pump.

1, the conventional gerotor oil pump includes an internal gear 1 and an external gear 2 in which the internal gear 1 is in contact, and the internal gear 1 and the external gear 2 Is in contact with and rotates inside the housing (not shown) provided with the suction port 3 and the discharge port 4 facing each other, thereby supplying the oil of the hydraulic pressure source to the engine or the transmission side.

Here, the number of teeth of the internal gear 1 is set to be smaller than the number of teeth of the external gear 2 by one.

Such a Gerotor oil pump has a simple structure and is advantageous in downsizing because the discharge flow rate per one rotation is larger than other pumps of the same size.

Accordingly, the Gerotor oil pump is widely used not only as a supply source of engine lubricating oil for an automobile, a power transmission device, and a hydraulic pressure source of an automatic transmission, but also the application range thereof in various hydraulic systems is expanding due to development of processing technology.

The following Patent Document 1 discloses a gerotor oil pump construction.

Korean Patent Registration No. 10-0733520 (issued on June 28, 2007)

FIG. 2 is a cross-sectional view taken along the line A-A 'shown in FIG. 1, and FIG. 3 is a partially enlarged view of a portion B shown in FIG.

In the gerotor oil pump according to the prior art, the inner gear 1 and the outer gear 2 are generally manufactured in a perpendicular direction.

As shown in FIG. 2, however, the inner gear 1 and the outer gear 2 may have excessive angularity tolerances in the manufacturing process of the inner gear 1 and the outer gear 2, In order to eject ink in the same direction.

In this way, when the internal gear 1 and the external gear 2 have a gradient in the same direction, the gap between the internal gear 1 and the external gear 2 becomes larger, , There is a problem that the amount of leakage increases and the discharge flow rate decreases and noise and vibration are generated.

As shown in FIG. 3, the internal gear 1 of the conventional gerotor oil pump is provided with a key 5 for connecting to a rotary shaft of an apparatus for receiving power from an engine or a transmission, that is, a rotary shaft of a gerotor oil pump And key grooves 6 and 7 are formed on both sides of the key 5, respectively.

In the conventional gerotor oil pump, the key groove 7 formed on the rear side in the rotational direction about the key among the key groove portions 6, 7 on both sides rotates relative to the external gear 2, There has been a problem that, for example, as the stress is concentrated due to the torque acting on the contact with the torque converter, the torque is broken.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gerotor oil pump capable of minimizing a clearance by providing an internal gear and an external gear with a gradient in opposite directions to each other.

Another object of the present invention is to provide a zero-throttle oil pump capable of minimizing the gap between the intermeshing of the internal gear and the external gear, thereby reducing the leakage amount and increasing the discharge flow rate.

Still another object of the present invention is to provide a zero-throttle oil pump capable of preventing stress from acting on a key groove of an internal gear.

In order to achieve the above object, the present invention provides a zero-throttle oil pump comprising: an internal gear having a tooth shape on an outer peripheral surface; and an external gear having a tooth shape on an inner peripheral surface thereof, Are formed so as to have a reverse gradient toward opposite directions so as to decrease the leakage amount by increasing the area of contact with each other.

A pair of keys are formed at positions opposing each other in the internal gear, a key groove is formed on both sides of each key, and a key groove formed on the rear side in the rotational direction about the key has a stress And is formed with a curvature larger than a predetermined reference curvature so as to distribute the concentration.

The inner gear is provided with a pair of keys at positions opposing to each other, and key grooves are formed on both sides of the keys, respectively. The key grooves are formed so as to distribute stress concentration due to torque and vertical load. And is formed with a large curvature.

As described above, according to the present invention, since the internal gear and the external gear are formed so as to have a reverse gradient in the direction opposite to each other, the gap between the internal gear and the external gear meshed with each other The leakage amount can be minimized, and the discharge flow rate can be increased.

According to the present invention, since the key groove portion formed on the rear side in the rotational direction about the key formed on the internal gear is formed to have a curvature larger than a predetermined reference curvature, the torque acts upon contact with the counterpart rotating the external gear It is possible to prevent the internal gear from being broken by dispersing the stress concentration caused by the stress.

According to the present invention, since the key groove portions formed on both sides of the key formed on the inner gear are formed to have the same curvature larger than the predetermined reference curvature, torque and vertical It is possible to distribute the stress concentration due to the load and to prevent the internal gear from being broken.

Thus, according to the present invention, it is possible to obtain an effect that the rigidity of the key and the internal gear can be increased by reducing the torque acting on the internal gear and the stress due to the vertical load.

FIG. 1 is a conceptual diagram of a conventional gerotor oil pump.
2 is a sectional view taken along the line AA 'shown in FIG. 1,
Fig. 3 is a partially enlarged view of part B shown in Fig. 1,
4 is a perspective view of a gerotor oil pump according to a preferred embodiment of the present invention,
5 is a cross-sectional view taken along line CC 'shown in FIG. 4,
Fig. 6 is a partially enlarged view of part D shown in Fig. 4,
7 and 8 are graphs of measurement results of the two products shown in Table 1,
Figs. 9 and 10 are graphs of noise vibration measurements for the same gradient and reverse gradient of two products,

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a gerotor oil pump according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a perspective view of a gerotor oil pump according to a first embodiment of the present invention.

Hereinafter, terms indicating directions such as 'left', 'right', 'forward', 'rearward', 'upward' and 'downward' are defined as indicating respective directions based on the states shown in the respective drawings do.

As shown in FIG. 4, the gerotor oil pump 10 according to the first embodiment of the present invention includes an internal gear 20 having a tooth shape on its outer circumferential surface, an outer gear 20 having a tooth shape on an inner circumferential surface thereof, And a gear (30).

Here, the teeth of the internal gear 20 and the external gear 30 may be formed in an arc shape or a trochoid shape.

The internal gear 20 and the external gear 30 are installed in a housing (not shown), and the suction port and the discharge port may be provided so as to face each other inside the housing.

Thus, the oil is sucked through the suction port, and is moved to the discharge port and pumped to the engine or the transmission in accordance with interlocking of the internal gear (20) and the external gear (30).

The inner gear 20 rotates about the imaginary first rotation axis C1 and the outer gear 30 rotates about the virtual second rotation axis C2 spaced apart from the first rotation axis C1 by a certain distance do.

Thus, the inner gear 20 is rotated by the rotation of the outer gear 30 to rotate the outer gear 30 at one side, the second teeth 31 formed at the inner peripheral surface of the lower left end as viewed in FIG. 4, And the first teeth 21 formed on the second shaft 21 rotate while being engaged with each other to pump the oil.

5 is a cross-sectional view taken along the line C-C 'shown in FIG.

5, the first teeth 21 and the second teeth 31 formed on the inner gear 20 and the outer gear 30 may be formed to have a reverse gradient toward the opposite direction.

For example, the first teeth 21 and the second teeth 31 may be formed to be inclined by about 0.1 degrees about the baseline and have a reverse gradient toward the opposite directions.

As described above, in the present embodiment, since the first and second teeth 21 and 31 of the internal gear 20 and the external gear 30 are formed to have a reverse gradient in the direction opposite to each other, It is possible to increase the contact area between these portions 21 and 31.

Accordingly, the present invention can minimize the leakage amount and increase the discharge flow rate by reducing the gap between the intermeshing of the internal gear and the external gear.

6 is a partially enlarged view of part D shown in Fig.

6, the inner gear 20 is provided with a pair of keys 22 at positions opposed to each other so as to be connected to the drive shaft of the gerotor oil pump 10 that receives power from the engine or the transmission And the first and second key groove portions 23 and 24 may be formed on the left and right sides of the keys 22, respectively.

6, when the external gear 30 and the internal gear 20 are rotated counterclockwise, the second key groove 24 formed on the right side of the key 22 is provided with the external gear 30, The stress is concentrated as the torque acts upon contact with the mating member 30, for example, the torque converter.

In order to prevent breakage due to stress concentration in the present embodiment, the second key groove portion 24 has a radius of curvature of reference, in which the key groove portions 6 and 7 according to the related art are formed, As shown in FIG.

Here, the first key groove 23 may be formed in a substantially rectangular shape in cross section so as to avoid interference with the counterpart, and each vertex portion may be formed into a curved surface having a radius of curvature smaller than the reference radius of curvature.

As described above, according to the present invention, since the key groove portion formed on the rear side in the rotational direction about the key is formed to have a curvature larger than a predetermined reference curvature, the stress concentration due to the torque action upon contact with the counterpart rotating the external gear It is possible to prevent breakage of the internal gear.

For example, Table 1 is a table of discharge flow rates and torque deviations measured using two products manufactured to have the same gradient and reverse gradient.

7 and 8 are graphs of measurement results of the two products shown in Table 1.

division Experiment 1 Deviation (%) Experiment 2 Deviation (%) rpm Flow Torque Flow Torque 600 3.2 -0.7 3.3 2.6 1000 2.3 -3.1 2.0 1.6 1500 1.0 -4.7 -0.5 -2.2 2000 0.6 -1.5 0.3 -2.7 2500 0.0 -2.8 0.2 -1.9 3000 0.0 4.4 -0.2 -0.9 3500 0.4 7.2 0.2 -0.6 4000 -0.5 10.2 0.1 1.4 4500 -0.4 8.6 0.8 2.8 5000 -0.3 6.7 1.1 2.1 5500 0.4 4.8 -1.3 1.3 6000 0.9 4.1 -0.5 0.2 6500 -0.2 2.4 -0.1 -0.7

As a result of measuring the discharge flow rate and torque using the two products, as shown in Table 1 and Figs. 7 and 8, the internal gear 20 and the external gear 30 have a reverse gradient toward the opposite direction It can be confirmed that the discharge flow rate increases by about 3.3% at about 600 to 1000 rpm as compared with the case where the discharge flow rate has the same gradient toward the same direction.

On the other hand, it can be confirmed that there is almost no difference in the discharge flow rate in the range of about 1500 to 6500 rpm.

Figs. 9 and 10 are graphs of noise vibration measurements for the same gradient and reverse gradient of two products.

As shown in Figs. 9 and 10, in the case of the same gradient and the reverse gradient in the first and second products, the measured values of the noise vibration exhibit a similar tendency at a low rotation of about 2000 rpm or less.

On the other hand, in the section of about 2500 rpm or more, it is confirmed that the measurement value of the noise vibration is significantly reduced as compared with the case where the internal gear 20 and the external gear 20 having the reverse gradient have the same gradient.

According to the above-described process, the internal gear and the external gear are formed so as to have a reverse gradient in the direction opposite to each other, whereby the gap between the internal gear and the external gear meshed with each other is reduced to minimize the leakage amount And the discharge flow rate can be increased.

Further, according to the present invention, since the key groove portion formed on the rear side in the rotational direction around the key formed on the internal gear is formed to have a curvature larger than a predetermined reference curvature, The stress concentration can be dispersed to prevent the internal gear from being broken.

Meanwhile, in the present embodiment, the key groove portion formed on the rear side in the rotational direction about the key formed on the internal gear is formed to have a curvature larger than a preset reference curvature, but the present invention is not limited thereto.

11 and 12 are a perspective view and a plan view of an internal gear of a gerotor oil pump according to a second embodiment of the present invention.

The gerotor oil pump 10 according to the second embodiment of the present invention is similar to that of the gerotor oil pump 10 according to the first embodiment shown in Fig. 4, As shown in the figure, the third and fourth key groove portions 43 and 44 formed on the front side and the rear side, respectively, of the rotation direction about the key 42 formed on the inner gear 40 have the same curvatures larger than the reference curvature As shown in Fig.

In the first embodiment, the first key groove 23 is formed in a substantially rectangular shape in cross section so as to avoid interference with the object, and each vertex portion is formed into a curved surface having a curvature smaller than the reference curvature, And the second key trench 24 is formed into a curved surface having a curvature radius larger than the reference curvature.

However, even if only the second key groove 24 is formed with a curvature larger than the reference curvature as in the first embodiment, there is a limit to effectively disperse the torque acting on the internal gear 20 and the stress due to the vertical load.

Therefore, in the second embodiment of the present invention, the third and fourth key troughs 43 and 44 are formed to have the same curvature as that of the reference curvature larger than the reference curvature, and as shown in Figs. 11 and 12, 40 and the stress due to the torque.

Here, the setting curvature may be set to about 1 to 2 mm.

13 and 14 are graphs of stress measurement results for torque and vertical load acting on the internal gears of the first and second embodiments, and Table 2 shows stress measurement results for torque and vertical load shown in Figs. 13 and 14 Table.

Load condition Stress measurement result (MPa) Stress variation First Embodiment Second Embodiment Torque (3430 N.mm) 9.72 8.94 8 & Decrease Vertical load (1000N) 96.47 77.97 20% reduction

Figs. 13 (a) and 13 (b) show stress measurement results for torque and vertical load acting on the internal gear according to the first embodiment, and Figs. 14 (a) 2 shows stress measurement results for torque and vertical load acting on the internal gear according to the embodiment.

That is, as shown in Figs. 13 and 14 and Table 2, when the configuration of the second embodiment is applied, it can be seen that the stress due to the torque is reduced by about 8% as compared with the first embodiment.

In the case of applying the configuration of the second embodiment, it is understood that the stress due to the vertical load is reduced by about 20% as compared with the first embodiment.

As described above, according to the present invention, the key recesses formed on the front side and the rear side in the rotational direction around the key of the internal gear are formed to have the same curvature larger than the preset reference curvature, so that the stress concentration due to the torque and the vertical load can be dispersed have.

Thus, according to the present invention, the torque acting on the internal gear and the stress due to the vertical load are reduced to increase the rigidity, thereby preventing the key and the internal gear from being broken.

Although the invention made by the present inventors has been described concretely with the above embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

In the present invention, the inner gear and the outer gear are formed so as to have a reverse gradient in the direction opposite to each other so as to reduce the gap between the inner gear and the outer gear meshing with each other to minimize the leakage amount, Applies to oil pump technology.

10: Gerotor oil pump
20, 40: internal gear
21,41: No. 1
22, 42: key
23, 24: first and second key grooves
30: external gear
31: The second
43, 44: third and fourth key grooves
C1, C2: first and second rotation axes

Claims (3)

An inner gear having teeth on the outer circumferential surface thereof and
And an outer gear having a tooth shape on an inner peripheral surface thereof and in contact with the inner gear,
Wherein each of the internal gear and the external gear is formed to have a reverse gradient toward the opposite direction so as to increase an area in contact with each other and reduce a leakage amount. The method according to claim 1,
A pair of keys are formed at positions facing each other in the internal gear,
On both sides of each key, a key groove is recessed and formed,
Wherein the key groove portion formed on the rear side in the rotational direction about the key is formed with a curvature larger than a preset reference curvature so as to disperse stress concentration due to the torque action. The method according to claim 1,
A pair of keys are formed at positions facing each other in the internal gear,
On both sides of each key, a key groove is recessed and formed,
Wherein each of the key groove portions is formed with a curvature larger than a predetermined reference curvature so as to disperse stress concentration due to torque and vertical load.

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