U.S. patent application number 10/848980 was filed with the patent office on 2004-11-25 for oil pump structure.
Invention is credited to Kim, Youn-Ho.
Application Number | 20040234393 10/848980 |
Document ID | / |
Family ID | 33448156 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040234393 |
Kind Code |
A1 |
Kim, Youn-Ho |
November 25, 2004 |
Oil pump structure
Abstract
An oil pump is adapted to pump oil by utilizing the variation of
a cavity formed between mutually inwardly engaging gear-teeth of a
drive gear and a driven gear. An oil pressure relief groove has a
certain shape and is disposed at an isolated portion of the oil
pump housing between an oil intake groove and an oil discharge
groove. The oil pressure relief groove is in fluid communication
with the oil discharge groove and relieves pressure of the oil as
it is compressed between the teeth of the gears.
Inventors: |
Kim, Youn-Ho;
(Hwaseong-city, KR) |
Correspondence
Address: |
MORGAN, LEWIS & BOCKIUS, LLP.
2 PALO ALTO SQUARE
3000 EL CAMINO REAL
PALO ALTO
CA
94306
US
|
Family ID: |
33448156 |
Appl. No.: |
10/848980 |
Filed: |
May 19, 2004 |
Current U.S.
Class: |
417/410.4 ;
417/410.3 |
Current CPC
Class: |
F04C 2/088 20130101;
F04C 2/101 20130101; F01C 21/108 20130101 |
Class at
Publication: |
417/410.4 ;
417/410.3 |
International
Class: |
F04B 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 2003 |
KR |
10-2003-0031573 |
Claims
What is claimed is:
1. An oil pump structure, comprising: an oil pressure relief groove
formed at an isolated portion of an oil housing, said oil pressure
relief groove communicating with an oil discharge groove and having
a start portion where a contact point between teeth of a drive gear
and teeth of a driven gear is projected onto said isolated portion,
and wherein said contact point is contact between gear-teeth at the
oil discharge groove side of the gear-teeth when the gear teeth
mutually and inwardly engage to form a maximum cavity, and said
isolated portion is configured and dimensioned for isolating an oil
intake groove from said oil discharge groove.
2. The structure as defined in claim 1, wherein the cross-section
of said oil pressure relief groove is configured to gradually
expand from said start portion to said oil discharge groove.
3. The structure as defined in claim 1, wherein the cross-section
of said oil pressure relief groove is configured to gradually
converge to zero from said oil discharge groove to said start
portion.
4. An oil pump structure, comprising: a housing defining an oil
intake groove and defining an oil discharge groove; an isolated
portion disposed between the oil intake groove and the oil
discharge groove, wherein said isolated portion maintains oil
discretely in the respective grooves; and wherein said isolated
portion defines an oil pressure relief groove, said oil pressure
relief groove configured and dimensioned in fluid communication
with said oil discharge groove.
5. The oil pump of claim 4, wherein said oil pressure relief groove
tapers to an end point with a zero cross-sectional diameter from
said oil discharge groove toward said oil intake groove.
6. The oil pump of claim 5, wherein said end point is positioned
toward said oil discharge groove from a position where a drive gear
and a driven gear form a cavity between respective teeth of the
gears.
7. The oil pump of claim 6, wherein said oil pressure relief groove
is configured in an arc that corresponds to an arc formed by
rotation of the cavity such that as the cavity rotates over the oil
pressure relief groove oil maintained within the cavity enters the
oil pressure relief groove.
8. An oil pump structure, comprising: a housing defining an intake
groove and a discharge groove, said intake groove and said
discharge groove being separated by an isolate portion of the
housing; and said isolate portion of the housing being configured
and dimensioned to define an oil pressure relief groove, said oil
pressure relief groove is in fluid communication with said oil
discharge groove and extends to an end point toward said oil intake
groove, wherein said end point is configured adjacent a position
where teeth of a drive gear and teeth of a driven gear mesh to form
an initial cavity.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of Korean Application No.
10-2003-0031573, filed on May 19, 2003, the disclosure of which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] Generally, the present invention relates to an oil pump with
a drive gear and a driven gear. More particularly the drive gear
and driven gear both comprise parachoid-shaped teeth that inwardly
engage each other without the aid of a crescent and an oil pump
housing that includes an oil pressure relief groove.
BACKGROUND OF THE INVENTION
[0003] In conventional oil pumps, an inner drive gear is typically
formed with one less gear-tooth than an outer driven gear. When the
drive gear and the driven gear engage each other and spin, the
drive gear rotates one gear-tooth faster than the driven gear per
cycle. During the execution of a single complete cycle or
revolution of the drive gear, a cavity is formed between the drive
gear-teeth and the driven gear-teeth. The cavity gradually and
consecutively expands and contracts as the drive gear and driven
gear rotate.
[0004] The typical oil pump also includes a housing that has an oil
intake groove, an oil discharge groove, and an isolated housing
portion. Theoretically, oil is taken up between teeth of the drive
gear and driven gear and compressed into a cavity between these
teeth. Initially the cavity is in an expended state, the cavity
between the drive gear and the driven gear then contracts as the
gears rotate and discharge the oil into the oil discharge groove.
Thus, the oil is taken in from the oil intake groove, compressed
between the teeth of the drive gear and driven gear and delivered
to the oil discharge groove.
[0005] Typically, the end portion of the oil intake groove and the
start portion of the oil exhaust groove are configured to be
separated by approximately 12 degrees. An isolated housing portion
is disposed between the oil intake and oil discharge grooves across
this 12 degree span. A drawback in the typical oil pump design is
that this approximately 12 degree angle the cavity between the
gear-teeth contracts and the oil between the gear-teeth becomes
extremely compressed thereby, lowering the durability of the
housing and increasing oil leakage through clearance between the
meshing gear-teeth.
SUMMARY OF THE INVENTION
[0006] An embodiment of the oil pump structure of the present
invention is provided to prevent deterioration of the durability of
the oil pump. Oil pump durability is deteriorated while the
gear-teeth of the drive gear and driven gear pass through the
isolated portion of a housing and the oil between the gear-teeth
becomes extremely compressed. The present invention also assists in
reducing oil leakage through clearance between the gear-teeth.
[0007] In an preferred embodiment of the present invention, the oil
pump structure comprises an oil pressure relief groove formed in
the isolated portion to communicate with the oil discharge groove.
The oil pressure relief groove has a start portion positioned where
a contact point of the gear-teeth is projected onto the isolated
portion. The contact point is where the gear-teeth make contact at
the oil discharge groove side thereby forming the maximum cavity
between the gear-teeth mutually and inwardly engaging. The isolated
portion is formed at a housing for isolating the oil intake groove
and the oil discharge groove.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For a better understanding of the nature and objects of the
present invention, reference should be made to the following
detailed description with the accompanying drawings, in which:
[0009] FIG. 1 illustrates an inside of an oil pump showing a drive
gear and a driven gear according to an embodiment of the present
invention;
[0010] FIG. 2 illustrates an inner side of an oil pump housing with
the drive gear and the driven gear of FIG. 1 removed; and
[0011] FIG. 3 illustrates the components of FIGS. 1 and 2 enlarged
in a working relationship according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0012] Referring to FIG. 1, a driven gear 3 is installed inside a
housing 1, and a drive gear 5 is mounted at an inner side of the
driven gear 3. The driven gear 3 and drive gear 5 engage each other
at a lower side of the drawing. In operation, when the drive gear 5
rotates, the driven gear 3 correspondingly rotates in a
counter-clockwise direction. In reference to the drawing, as the
drive gear 5 and driven gear 3 rotate, the drive gear 5 and driven
gear 3 change their dispositions from the state represented by the
alternating long and short dash lines to the position represented
by the solid lines of FIG. 1.
[0013] In the position represented by the letter "A" in FIG. 1, two
gear-teeth of the drive gear 5 and two gear-teeth of the driven
gear 3 are symmetrically placed and a cavity (S) is formed between
the four gear-teeth. At this position, the cavity (S) is at a
maximum volume. As the drive gear 5 and driven gear 3 spin in the
counterclockwise direction, the gears and respective cavity formed
there-between change from state "A" to state "B", as shown in FIG.
1 by the solid lines. In the position B, the oil in the cavity
starts to become compressed as the volume of the cavity
decreases.
[0014] FIG. 2 illustrates an inside of the housing 1 with the drive
gear 5 and the driven gear 3 removed. An oil intake groove 7 is
shown at the right side of the figure, while an oil discharge
groove 9 is shown at the left side of the figure. An isolated
portion 11 separates the oil intake groove 7 and oil discharge
groove 9 by being disposed therebetween. The isolated portion 11 is
formed with an oil pressure relief groove 13.
[0015] According to FIG. 3, a start portion 15 of the oil pressure
relief groove 13 is situated where a contact point (P) of the
gear-teeth is projected onto the isolated portion 11. The contact
point (P) is adjacent the oil discharge groove side of the
gear-teeth when the gear-teeth form a maximal cavity, such as at
state "A" of FIG. 1. The cross-section of the oil pressure relief
groove 13 is configured to gradually expand from the start portion
15 to the oil discharge groove 9. In other words, the cross-section
of the oil pressure relief groove 13 is configured to gradually
converge to zero from the oil discharge groove 9 toward the oil
intake groove 7 at the start portion 15. Therefore, when the
gear-teeth form a maximum cavity, such as in state "A", the oil
cannot flow through the oil pressure relief groove 13. However,
once the gear-teeth rotate beyond state "A", the cavity formed
there between becomes in fluid communication with the oil pressure
relief groove 13 and oil starts to flow into the oil discharge
groove 9 via the oil pressure relief groove 13.
[0016] As a result, when the gear-teeth of the drive gear 5 and
driven gear 3 pass through the isolated portion 11 of the housing 1
and the cavity between the gear-teeth starts to reduce immediately
after forming a maximum cavity, the oil from the cavity between the
gear-teeth may begin to be released into the oil discharge groove 9
via the oil pressure relief groove 13. The oil pressure relief
groove 13, thus, contributing to a prevention of the deterioration
of the durability of the oil pump, which occurs when an excessive
pressure is applied onto the housing 1, and a prevention of oil
leakage through the clearance between the gear-teeth.
* * * * *