U.S. patent application number 16/502210 was filed with the patent office on 2020-01-30 for oil pump.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. The applicant listed for this patent is AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Hiroyuki KUROKAWA, Mitsuru TERADA, Yoshito UNO.
Application Number | 20200032789 16/502210 |
Document ID | / |
Family ID | 69149047 |
Filed Date | 2020-01-30 |
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United States Patent
Application |
20200032789 |
Kind Code |
A1 |
KUROKAWA; Hiroyuki ; et
al. |
January 30, 2020 |
OIL PUMP
Abstract
An oil pump includes: a pump housing having a rotor
accommodation space in an inner portion of the pump housing; a
rotor accommodated in the rotor accommodation space; a shaft
portion disposed inside the rotor; and a passage which is provided
to straddle at least one of the pump housing and the rotor and the
shaft portion and which communicates a pump chamber which is formed
by the rotor inside the pump housing with an outside of the pump
housing.
Inventors: |
KUROKAWA; Hiroyuki;
(Aichi-gun, JP) ; TERADA; Mitsuru; (Okazaki-shi,
JP) ; UNO; Yoshito; (Anjo-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AISIN SEIKI KABUSHIKI KAISHA |
Kariya-shi |
|
JP |
|
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi
JP
|
Family ID: |
69149047 |
Appl. No.: |
16/502210 |
Filed: |
July 3, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2210/206 20130101;
F04C 2/088 20130101; F04C 13/007 20130101; F04C 2/103 20130101;
F04C 2/102 20130101; F04C 2240/603 20130101 |
International
Class: |
F04C 2/08 20060101
F04C002/08; F04C 2/10 20060101 F04C002/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2018 |
JP |
2018-139395 |
Nov 19, 2018 |
JP |
2018-216210 |
Claims
1. An oil pump comprising: a pump housing having a rotor
accommodation space in an inner portion of the pump housing; a
rotor accommodated in the rotor accommodation space; a shaft
portion disposed inside the rotor; and a passage which is provided
to straddle at least one of the pump housing and the rotor and the
shaft portion and which communicates a pump chamber which is formed
by the rotor inside the pump housing with an outside of the pump
housing.
2. The oil pump according to claim 1, wherein the passage includes
a first passage portion which is provided to straddle at least one
of the pump housing and the rotor and the shaft portion and extends
in a direction intersecting an axial direction of the shaft
portion, and a second passage portion which is provided in the
shaft portion and extends in the axial direction.
3. The oil pump according to claim 1, wherein the shaft portion
includes an opening/closing mechanism which opens and closes the
passage.
4. The oil pump according to claim 2, wherein the shaft portion
includes a rotary shaft which rotationally drives the rotor, the
rotary shaft includes an opening/closing mechanism which opens and
closes the passage, the opening/closing mechanism includes an
opening/closing valve which includes a sealing wall and a
communication bore which is disposed at a position deviated in the
axial direction of the rotary shaft with respect to the sealing
wall and is capable of moving in the axial direction of the rotary
shaft, and the opening/closing mechanism is configured to close the
passage by moving to one side of the axial direction of the rotary
shaft to dispose the sealing wall between the first passage portion
and the second passage portion and to open the passage by moving to
the other side of the axial direction of the rotary shaft to
dispose, instead of the sealing wall, the communication bore
between the first passage portion and the second passage
portion.
5. The oil pump according to claim 4, wherein the opening/closing
mechanism is configured to move the opening/closing valve according
to an internal pressure of a discharging port and is configured to
close the passage by disposing the sealing wall between the first
passage portion and the second passage portion in a case in which
the internal pressure of the discharging port is low and to open
the passage by disposing, instead of the sealing wall, the
communication bore between the first passage portion and the second
passage portion in a case in which the internal pressure of the
discharging port is high.
6. The oil pump according to claim 5, wherein the opening/closing
mechanism includes a pressure chamber which is provided on one side
in the axial direction of the rotary shaft of the opening/closing
valve, communicates with the discharging port via a pressure
passage, and pressurizes the opening/closing valve to move the
opening/closing valve, a biasing member which is provided on the
other side in the axial direction of the rotary shaft of the
opening/closing valve and biases the opening/closing valve toward
the pressure chamber, and a restriction portion which restricts
movement of the opening/closing valve to the pressure chamber side,
and the opening/closing mechanism is configured to close the
passage by disposing the sealing wall between the first passage
portion and the second passage portion in a state in which the
opening/closing valve and the restriction portion are caused to
abut against each other by a biasing force of the biasing member in
a case in which the internal pressure of the discharging port and
the pressure chamber is low and to open the passage by disposing,
instead of the sealing wall, the communication bore between the
first passage portion and the second passage portion in a state in
which the opening/closing valve and the restriction portion are
separated from each other against the biasing force of the biasing
member by the internal pressure of the pressure chamber via the
opening/closing valve in a case in which the internal pressure of
the discharging port and the pressure chamber is high.
7. The oil pump according to claim 1, wherein the rotor is an
inscribed gear rotor which includes an outer rotor including a
plurality of internal teeth and an inner rotor including a
plurality of external teeth which mesh with the internal teeth of
the outer rotor, or the rotor is a vane rotor which includes a
rotor main body and a plurality of vanes which are provided to
protrude outward from the rotor main body and form the pump
chamber.
8. The oil pump according to claim 1, wherein the shaft portion
includes a rotary shaft which includes a recessed portion having a
circular cross-section that is orthogonal to an axial direction of
the shaft portion and extending in the axial direction and which
rotates together with the rotor, and a fixed shaft which includes a
first member which is fixed to the pump housing and a second member
which is inserted into the recessed portion and is connected to the
first member in a state of being capable of moving in a direction
orthogonal to the axial direction.
9. The oil pump according to claim 8, wherein the fixed shaft
includes a turn-stopping portion which connects the first member
and the second member to each other in a state in which the second
member is capable of moving in the direction orthogonal to the
axial direction relative to the first member.
10. The oil pump according to claim 7, wherein the passage includes
a first passage portion which is provided to straddle at least one
of the pump housing and the inner rotor and the shaft portion and
extending in a direction intersecting an axial direction of the
shaft portion, and a second passage portion which is provided in
the shaft portion and extends in the axial direction, the shaft
portion includes a rotary shaft which includes a recessed portion
having a circular cross-section that is orthogonal to the axial
direction of the shaft portion and extends in the axial direction
and which rotates together with the inner rotor, and a fixed shaft
which includes a first member which is fixed to the pump housing
and a second member which is inserted into the recessed portion and
is connected to the first member in a state of being capable of
moving in a direction orthogonal to the axial direction, and the
first passage portion includes an outer passage portion which is
provided to straddle the rotary shaft and the inner rotor and an
inner passage portion which is provided in the fixed shaft and
communicates with the outer passage portion at a predetermined
rotational position of the rotary shaft.
11. The oil pump according to claim 7, wherein a tooth bottom of
the inner rotor is provided with a bubble introduction portion
which is disposed between the pump chamber and the passage,
collects the bubbles inside the pump chamber and introduces the
collected bubbles into the passage.
12. The oil pump according to claim 7, wherein the passage includes
a first passage portion which is provided to straddle at least one
of the pump housing and the inner rotor and the shaft portion and
extends in a direction intersecting the axial direction of the
shaft portion, and a second passage portion which is provided in
the shaft portion and extends in the axial direction, and one end
of the first passage portion is connected to a tooth bottom of the
inner rotor.
13. The oil pump according to claim 2, wherein the passage is
provided to straddle the pump housing and the shaft portion and the
passage on the pump housing side is formed in a groove shape which
communicates the pump chamber and the passage on the shaft portion
side with each other.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Japanese Patent Applications 2018-139395 and
2018-216210, filed on Jul. 25, 2018 and Nov. 19, 2018,
respectively, the entire contents of which are incorporated herein
by reference.
TECHNICAL FIELD
[0002] This disclosure relates to an oil pump, in particular, to an
oil pump which is provided with a rotor.
BACKGROUND DISCUSSION
[0003] In the related art, an oil pump which is provided with a
rotor is known (for example, refer to JP 2008-308991A (Reference
1)).
[0004] Reference 1 discloses an oil pump which is provided with an
inner rotor, an outer rotor, a pump housing, a rotary shaft, and a
passage for discharging bubbles. The inner rotor includes a
plurality of external teeth. The outer rotor includes a plurality
of internal teeth which mesh with the external teeth of the inner
rotor. The pump housing houses the inner rotor and the outer rotor.
The rotary shaft is disposed (inserted) in the inside of the inner
rotor, the outer rotor, and the pump housing and is configured to
rotate together with the inner rotor.
[0005] The passage for discharging the bubbles communicates a pump
chamber between the internal teeth and the external teeth with an
outside of the pump housing. The passage is provided in the pump
housing at a position in the vicinity of the rotary shaft. The
passage is configured to discharge the bubbles which are contained
in an oil inside the pump chamber to the outside of the pump
housing to remove the bubbles. The oil has a much greater specific
weight than the bubbles (air). Therefore, during the driving of the
oil pump, in the pump chamber, the oil is moved to the outside in a
radial direction of the rotary shaft by a centrifugal force. As a
result, the bubbles are gathered (moved relatively) on the inside
in the radial direction of the rotary shaft (on the rotary shaft
side). In other words, the bubbles are gathered on the passage
side.
[0006] However, in the oil pump of Reference 1, since the passage
for discharging the bubbles is provided in the pump housing at a
position on the outside in the radial direction of the rotary shaft
and the passage is disposed at a position which is distanced from a
central axis line of rotation of the rotary shaft, even when
discharging the bubbles which are gathered on the inside in the
radial direction of the rotary shaft via the passage, there is an
inconvenience in that a centrifugal force acts on the bubbles which
are separated from the oil. As a result, there is a problem in that
the bubbles (the bubbles which are contained in the oil) which are
separated from the oil may not be efficiently removed.
[0007] Thus, a need exists for an oil pump which is not susceptible
to the drawback mentioned above.
SUMMARY
[0008] An oil pump according to an aspect of this disclosure
includes a pump housing having a rotor accommodation space in an
inner portion of the pump housing, a rotor accommodated in the
rotor accommodation space, a shaft portion disposed inside the
rotor, and a passage which is provided to straddle at least one of
the pump housing and the rotor and the shaft portion and which
communicates a pump chamber which is formed by the rotor inside the
pump housing with an outside of the pump housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and additional features and characteristics of
this disclosure will become more apparent from the following
detailed description considered with the reference to the
accompanying drawings, wherein:
[0010] FIG. 1 is a view of an inscribed gear pump according to a
first embodiment of the disclosure as viewed from an axial
direction of a shaft portion;
[0011] FIG. 2 is a sectional diagram of the inscribed gear pump
according to the first embodiment of the disclosure as viewed from
an axial direction of the shaft portion;
[0012] FIG. 3 is a perspective view illustrating the shaft portion
and a body of the inscribed gear pump according to the first
embodiment of the disclosure;
[0013] FIG. 4 is a view illustrating the shaft portion, an inner
rotor, and an outer rotor of the inscribed gear pump according to
the first embodiment of the disclosure;
[0014] FIG. 5 is a sectional diagram taken along a V-V line of FIG.
4;
[0015] FIG. 6 is a diagram for explaining, in order, a discharging
process (A) to (C) of bubbles by the inscribed gear pump according
to the first embodiment of the disclosure;
[0016] FIG. 7 is a view of an inscribed gear pump according to a
second embodiment of the disclosure as viewed from an axial
direction of a shaft portion;
[0017] (A) in FIG. 8 is a sectional diagram of a state in which an
internal pressure of a pressure chamber is low, taken along a
VIIIA-VIIIA line, and (B) in FIG. 8 is a sectional diagram of a
state in which the internal pressure of the pressure chamber is
low, taken along a VIIIB-VIIIB line;
[0018] (A) in FIG. 9 is a sectional diagram of a state in which the
internal pressure of the pressure chamber is high, taken along a
VIIIA-VIIIA line, and (B) in FIG. 9 is a sectional diagram of a
state in which the internal pressure of the pressure chamber is
low, taken along a VIIIB-VIIIB line;
[0019] FIG. 10 is a side view illustrating an opening/closing valve
of the inscribed gear pump according to the second embodiment of
the disclosure;
[0020] FIG. 11 is a sectional diagram which enlarges an
opening/closing mechanism of the shaft portion of the inscribed
gear pump according to the second embodiment of the disclosure;
[0021] FIG. 12 is a perspective view illustrating the shaft portion
and a body of the inscribed gear pump according to the second
embodiment of the disclosure;
[0022] FIG. 13 is a diagram illustrating a graph for explaining the
relationship between a rotation frequency of an engine and a main
gallery oil pressure inside the engine;
[0023] FIG. 14 is a diagram for explaining, in order, a discharging
process (A) to (E) of bubbles by the inscribed gear pump according
to the second embodiment of the disclosure;
[0024] FIG. 15 is a view of a vane pump according to a third
embodiment of the disclosure as viewed from an axial direction of a
shaft portion;
[0025] FIG. 16 is a sectional diagram illustrating the inscribed
gear pump according to a fourth embodiment of the disclosure;
[0026] FIG. 17 is an exploded perspective view illustrating a fixed
shaft of the inscribed gear pump according to the fourth embodiment
of the disclosure; and
[0027] FIG. 18 is a schematic diagram for explaining restriction of
pivoting of a first member by a second member of the inscribed gear
pump of the fourth embodiment of the disclosure.
DETAILED DESCRIPTION
[0028] Hereinafter, a description will be given of an embodiment of
the disclosure based on the drawings.
First Embodiment
[0029] A description will be given of a configuration of an
inscribed gear pump (an oil pump) 100 according to the first
embodiment of the disclosure, with reference to FIGS. 1 to 6.
Configuration of Internally Connected Gear Pump
[0030] The inscribed gear pump 100 illustrated in FIG. 1 according
to the first embodiment of the disclosure is installed in an
automobile (not illustrated) which is provided with an engine. The
inscribed gear pump 100 is configured to draw an oil (a lubricating
oil) inside an oil pan and supply (pump) the oil to movable parts
(sliding parts) such as around pistons of the engine or a
crankshaft. The inscribed gear pump 100 is a trochoid pump.
[0031] The inscribed gear pump 100 is provided with a pump housing
1, an inscribed gear rotor 2 containing an inner rotor 21 including
a plurality of external teeth 21a and an outer rotor 22 including a
plurality of internal teeth 22a, a shaft portion 3, and a passage
4.
[0032] The inner rotor 21 and the outer rotor 22 are disposed
inside the pump housing 1 in a state in which the shaft portion 3
is inserted through the inner rotor 21 and the outer rotor 22. The
inner rotor 21 is configured to rotate inside the pump housing 1
according to the shaft portion 3. The outer rotor 22 is configured
to rotate inside the pump housing 1 according to the shaft portion
3 via the inner rotor 21.
[0033] As illustrated in FIG. 2, in the first embodiment, the
passage 4 (the configuration including a first passage portion 41
which is described later and a second passage portion 42 which is
described later) is provided to span the inner rotor 21 and the
shaft portion 3. The passage 4 communicates a pump chamber S1
between the internal teeth 22a (refer to FIG. 1) and the external
teeth 21a (refer to FIG. 1) with the outside of the pump housing 1.
The inscribed gear pump 100 is configured to discharge bubbles K
(refer to FIG. 6(A)) contained in the oil inside the pump chamber
S1 to the outside of the pump housing 1 via the passage 4. A
detailed description will be given later.
[0034] Hereinafter, a description will be given of the detailed
configuration of the parts of the inscribed gear pump 100.
Configuration of Pump Housing
[0035] As illustrated in FIG. 2, the pump housing 1 includes a body
11 and a cover 12. The body 11 and the cover 12 are positioned at
one side and the other side of the axial directions of the shaft
portion 3, respectively.
[0036] Hereinafter, the axial directions of the shaft portion 3
will be referred to as A directions, and of the A directions, the
direction facing the cover 12 side from the body 11 side will be
referred to as an A1 direction and the opposite direction will be
referred to as an A2 direction.
[0037] The body 11 and the cover 12 are assembled in a state in
which an abutting surface 11a and an abutting surface 12a which
extend in directions orthogonal to the A directions abut against
each other. The body 11 and the cover 12 include through holes 11b
and 12b, respectively, on the same axis which extends in the A
directions. The shaft portion 3 is inserted through the through
holes 11b and 12b.
[0038] An inner portion of the pump housing 1 includes a rotor
accommodation space S2 which accommodates the inner rotor 21 and
the outer rotor 22. In detail, the body 11 includes a recessed
portion which is recessed in the A2 direction from the abutting
surface 11a. The body 11 and the cover 12 form the rotor
accommodation space S2 by blocking the recessed portion of the body
11 with the cover 12.
[0039] The thickness directions of the rotor accommodation space S2
are the A directions, and the rotor accommodation space S2 has a
circular column shape corresponding to the external shape of the
outer rotor 22. The inner rotor 21 and the outer rotor 22 have
approximately the same thickness in the A directions.
[0040] Therefore, the inner rotor 21 and the outer rotor 22 are
configured to cause the A2 direction end surfaces thereof to slide
on the body 11 and to cause the A1 direction end surfaces to slide
on the cover 12. In other words, the body 11 includes a sliding
surface 11c on a bottom portion of the recessed portion (the A2
direction side of the rotor accommodation space S2). The cover 12
includes a sliding surface on the A1 direction side of the rotor
accommodation space S2. The sliding surface of the cover 12 is
positioned on the same plane as the abutting surface 12a and is a
surface which continues from the abutting surface 12a (that is, the
sliding surface of the cover 12 and the abutting surface 12a are
the same surface).
[0041] As illustrated in FIG. 1, a suction port 51 and a
discharging port 52 are formed in the pump housing 1.
[0042] The suction port 51 functions as an introduction path which
guides the oil which is sucked into the apparatus to the pump
chamber S1. The discharging port 52 functions as an outlet path
which guides the oil inside the pump chamber S1 to the outside of
the apparatus. The suction port 51 and the discharging port 52 are
provided to span the body 11 and the cover 12 together. The suction
port 51 and the discharging port 52 are provided together to be
adjacent to the pump chamber S1. The suction port 51 and the
discharging port 52 are not directly continuous with each other and
are provided at angular positions in the circumferential direction
(the rotation direction) of the shaft portion 3 so as not to
overlap each other.
[0043] As illustrated in FIG. 3, the suction port 51 and the
discharging port 52 of the body 11 side are both formed in a
recessed shape which is more depressed to the A2 direction side
than the sliding surface 11c. The suction port 51 and the
discharging port 52 of the cover 12 side are both formed in a
recessed shape which is more depressed to the A1 direction side
than the abutting surface 12a.
[0044] As illustrated in FIG. 1, the suction port 51 is connected
to the oil pan (not illustrated) which is positioned on the
upstream side of the suction port 51 and is a supply source of the
oil. The suction port 51 includes an opening 51a which communicates
with the pump chamber S1 in a portion of the suction port 51 at
which the pump chamber S1 expands. The opening 51a functions as an
inflow port in which the oil flows into the pump chamber S1 from
inside the suction port 51.
[0045] The discharging port 52 is connected to engine parts (not
illustrated) which are positioned on the downstream side of the
discharging port 52 and are the oil supply destination. The
discharging port 52 includes an opening 52a which communicates with
the pump chamber S1 in a portion of the discharging port 52 at
which the pump chamber S1 contracts. The opening 52a functions as
an outflow port in which the oil flows out from the pump chamber S1
into the discharging port 52.
Configuration of Inner Rotor and Outer Rotor
[0046] As illustrated in FIG. 1, the external teeth 21a of the
inner rotor 21 are disposed on the inside of the outer rotor 22 to
mesh, from the inside, with the internal teeth 22a of the outer
rotor 22. The outer rotor 22 is accommodated in the rotor
accommodation space S2. The number of the external teeth 21a of the
inner rotor 21 is one tooth less than the number of the internal
teeth 22a of the outer rotor 22.
[0047] The inner rotor 21 is configured to be rotated by the shaft
portion 3 (a rotary shaft 31 which is described later) which is
disposed on the inside. The inner rotor 21 (the shaft portion 3) is
configured to rotate around a central axis line of rotation .alpha.
which is eccentric with respect to the central axis line of
rotation of the outer rotor 22.
[0048] When the inner rotor 21 is rotated in an arrow R direction,
the outer rotor 22 is rotated in the same direction. During the
rotation, the external teeth 21a of the inner rotor 21 and the
internal teeth 22a of the outer rotor 22 mesh with each other on
the side at which the distance between the inner rotor 21 and the
outer rotor 22 is small, and since the external teeth 21a are fewer
by one tooth than the internal teeth 22a on the side at which the
distance is great, the external teeth 21a and the internal teeth
22a do not mesh with each other and a gap (the pump chamber S1)
between the external teeth 21a and the internal teeth 22a is
formed.
[0049] The inner rotor 21 and the outer rotor 22 produce a pump
function by causing the pump chamber S1 to rotationally move in the
arrow R direction to expand and contract the pump chamber S1.
Therefore, as the volume of the pump chamber S1 expands, the oil
flows from the suction port 51 into the pump chamber S1. As the
volume of the pump chamber S1 contracts, the oil flows out from the
pump chamber S1 to the discharging port 52.
[0050] A bubble introduction portion 21c is provided in each of the
plurality of (six) tooth bottoms 21b of the inner rotor 21. The
bubble introduction portion 21c has a recessed shape which is
depressed to the inside in the radial direction of the shaft
portion 3. The passage 4 (an outer passage portion 41a of the first
passage portion 41 which is described later) is connected to the
bubble introduction portion 21c from the inside in the radial
direction of the shaft portion 3. The bubble introduction portion
21c is disposed between the pump chamber S1 and the passage 4. The
bubble introduction portion 21c is configured to collect the
bubbles K of the pump chamber S1 and introduce the collected
bubbles K into the passage 4.
Configuration of Shaft Portion
[0051] As illustrated in FIG. 2, the shaft portion 3 includes the
rotary shaft 31 and a fixed shaft 32. The rotary shaft 31 is
attached to the pump housing 1 from the A2 direction side to be
capable of rotating. Meanwhile, the fixed shaft 32 is attached in a
fixed manner to the pump housing 1 (the cover 12) from the A1
direction side.
[0052] The rotary shaft 31 has a circular column shape,
substantially extending in the A directions. The rotary shaft 31
includes a belt attaching portion 31a to which a belt B is attached
at an end portion in the A2 direction. The rotary shaft 31 is
configured to rotationally drive the inner rotor 21 by receiving a
rotational driving force (torque) from a crankshaft or the like via
the belt B and rotationally driving. The rotary shaft 31 is
inserted through (fitted into) the inner rotor 21 by press-fitting
and rotates in synchronization with the inner rotor 21.
[0053] The rotary shaft 31 includes a positioning surface 31b which
abuts against the A2 direction end surface of the inner rotor 21 to
position the rotary shaft 31 in the A directions. The positioning
surface 31b is positioned on substantially the same plane as the
sliding surface 11c of the body 11. The positioning surface 31b is
formed by a level difference which reduces the size of the inner
diameter of the rotary shaft 31 on the A1 direction side.
[0054] The rotary shaft 31 is also inserted through the through
hole 12b such that the end portion of the rotary shaft 31 on the A1
direction side is disposed inside the through hole 12b of the cover
12. The rotary shaft 31 extends from the body 11 side in the A1
direction to a middle position in the thickness directions (the A
directions) of the cover 12. A recessed portion 31c which is
depressed in the A2 direction is formed in the end surface of the
rotary shaft 31 on the A1 direction side. The recessed portion 31c
has a circular column shape in a cross-section orthogonal to the A
directions. The central axis line of the recessed portion 31c is
positioned on substantially the same axis as the central axis line
of rotation .alpha. of the rotary shaft 31. A bottom portion 31d of
the recessed portion 31c on the A2 direction side is positioned
closer to the A2 direction side than the inner rotor 21.
[0055] The fixed shaft 32 is disposed inside the rotary shaft 31
excluding a portion of the fixed shaft 32 on the A1 direction side.
The fixed shaft 32 is provided with an inner passage portion 41b of
the first passage portion 41 (described later) of the passage 4 and
the second passage portion 42 (described later) of the passage
4.
[0056] The fixed shaft 32 includes a fixed shaft main body 32a and
a fixed shaft attaching portion 32b.
[0057] The fixed shaft main body 32a has a circular column shape (a
cylindrical shape) extending in the A directions. The fixed shaft
main body 32a is inserted into the recessed portion 31c of the
fixed shaft main body 32a (is fitted into the recessed portion 31c)
from the A1 direction side. Therefore, the central axis line of the
fixed shaft main body 32a is positioned on substantially the same
axis as the central axis line of rotation .alpha. of the rotary
shaft 31. The fixed shaft main body 32a extends from the cover 12
side in the A2 direction to a position in the vicinity of the A2
direction side end surface (the sliding surface 11c of the body 11)
of the inner rotor 21.
[0058] As illustrated in FIG. 4, the fixed shaft attaching portion
32b has a flat plate shape which extends along the outer surface of
the A1 direction side of the cover 12 (refer to FIG. 1). The fixed
shaft attaching portion 32b includes a pin mounting hole 320a and a
bolt mounting hole 320b. A positioning pin for restricting the
rotation of the fixed shaft 32 with respect to the cover 12 is
mounted to the pin mounting hole 320a and a bolt for fixing the
fixed shaft 32 to the cover 12 is mounted to the bolt mounting hole
320b.
[0059] As illustrated in FIG. 2, the fixed shaft attaching portion
32b is provided with a protruding portion 323 which protrudes in
the A2 direction and is fitted into the through hole 12b of the
cover 12.
[0060] A lubrication chamber 33 is formed between an end surface of
the fixed shaft main body 32a on the A2 direction side and the
bottom portion 31d of the recessed portion 31c of the rotary shaft
31. The lubrication chamber 33 is adjacent to the inner surface of
the recessed portion 31c of the rotary shaft 31 and the outer
surface of the fixed shaft main body 32a which slide against each
other during the rotation of the rotary shaft 31, and the
lubrication chamber 33 is configured to supply the oil inside the
lubrication chamber 33 to the surfaces which slide against each
other.
[0061] A lubrication chamber 34 is formed between the end surface
of the rotary shaft 31 on the A1 direction side and the protruding
portion 323 of the fixed shaft 32. The lubrication chamber 34 is
adjacent to the outer surface of the rotary shaft 31 and the inner
surface of the through hole 12b of the cover 12 which slide against
each other during the rotation of the rotary shaft 31, and the
lubrication chamber 34 is configured to supply the oil inside the
lubrication chamber 34 to the surfaces which slide against each
other.
Configuration of Passage
[0062] The passage 4 is provided to span the inner rotor 21 and the
shaft portion 3 as described above. The passage 4 includes the
first passage portion 41 and the second passage portion 42.
[0063] As illustrated in FIG. 5, the first passage portion 41
extends in directions which intersect (directions which are
orthogonal to) the axial directions (the A directions) of the shaft
portion 3. FIG. 5 illustrates a cross-section which is orthogonal
to the A directions at a middle position of the inner rotor 21 in
the A directions. In detail, the first passage portion 41 extends
in the radial direction of the shaft portion 3. The first passage
portion 41 is disposed at a middle position of the inner rotor 21
in the thickness directions. The first passage portion 41 includes
a plurality of (six) outer passage portion 41a and the single inner
passage portion 41b.
[0064] The outer passage portion 41a is formed by a through hole
which is provided in the inner rotor 21. The outer passage portion
41a is disposed closer to the outside than the inner passage
portion 41b in the radial direction of the shaft portion 3. The
outer passage portion 41a is provided to span the inner rotor 21
and the rotary shaft 31. Therefore, the outer passage portion 41a
rotates in synchronization with the inner rotor 21 and the rotary
shaft 31.
[0065] One end on the outside of the outer passage portion 41a is
connected to the tooth bottoms 21b (the pump chamber S1) of the
inner rotor 21 via the bubble introduction portion 21c. The other
end on the inside of the outer passage portion 41a is connected to
the recessed portion 31c of the rotary shaft 31. Therefore, the
outer passage portion 41a communicates the pump chamber S1 with the
inside of the recessed portion 31c of the rotary shaft 31.
[0066] The plurality of outer passage portions 41a are disposed at
the same position from each other in the A directions. The
plurality of outer passage portions 41a are disposed at an equal
angular interval in the circumferential direction (the rotation
direction) of the shaft portion 3. The plurality of outer passage
portions 41a extend both linearly and radially in the radial
direction of the shaft portion 3.
[0067] The inner passage portion 41b is formed using a through hole
which is provided in the fixed shaft 32. Therefore, even if the
inner rotor 21 and the shaft portion 3 rotate, the inner passage
portion 41b does not rotate. One end on the outside of the inner
passage portion 41b is connected to the outside surface of the
fixed shaft 32. The other end on the inside of the inner passage
portion 41b is connected to the second passage portion 42 on the
inside of the fixed shaft 32. The inner passage portion 41b has a
smaller diameter (the diameter in a cross-section orthogonal to the
directions in which the inner passage portion 41b extends) than the
outer passage portion 41a.
[0068] The inner passage portion 41b extends linearly in the radial
direction of the shaft portion 3. The inner passage portion 41b is
disposed at a position (refer to FIG. 2) corresponding to the outer
passage portion 41a in the A directions so as to communicate with
the outer passage portion 41a at a predetermined rotational
position of the rotary shaft 31 during the rotation of the inner
rotor 21 and the rotary shaft 31 (during the rotation of the outer
passage portion 41a).
[0069] As illustrated in FIG. 1, the inner passage portion 41b
faces the discharging port 52 side more than the suction port 51
side. In detail, the inner passage portion 41b is disposed closer
to the discharging port 52 side than a middle position (the
dot-dash line of FIG. 1) between the end portion of the suction
port 51 (the opening 51a) and the end portion of the discharging
port 52 (the opening 52a) on the side at which the distance between
the inner rotor 21 and the outer rotor 22 increases. In other
words, the inner passage portion 41b is configured to communicate
with the pump chamber S1 via the outer passage portion 41a at a
later point than the timing at which the volume of the pump chamber
S1 reaches the maximum. The discharging port 52 (the opening 52a)
is also configured to communicate with the pump chamber S1 at a
later point than the timing at which the volume of the pump chamber
S1 reaches the maximum.
[0070] The second passage portion 42 is formed using a through hole
which is provided in the fixed shaft 32 of the shaft portion 3. The
second passage portion 42 extends in the axial directions (the A
directions) along the central axis line of rotation .alpha. of the
rotary shaft 31 of the shaft portion 3. The central axis line of
the second passage portion 42 is positioned on substantially the
same axis as the central axis line of rotation .alpha. of the
rotary shaft 31.
[0071] One end of the second passage portion 42 on the A1 direction
side is connected to the outer surface (the outside) of the pump
housing 1. In other words, one end of the second passage portion 42
on the A1 direction side is connected to the atmosphere. The other
end of the second passage portion 42 on the A2 direction side is
connected to the lubrication chamber 33. The second passage portion
42 is provided with a lateral hole 42a which is connected to the
lubrication chamber 34 and extends in a direction which intersects
the A directions. Therefore, the passage 4 is configured to supply
the oil which flows out in tiny amounts from the pump chamber S1 to
the lubrication chamber 33 and the lubrication chamber 34 during
the discharging of the bubbles K.
Discharging Operation of Bubbles
[0072] Next a description will be given of the discharging
operation of the bubbles K from the pump chamber S1 via the passage
4 of the inscribed gear pump 100 with reference to FIG. 6(A) to
6(C).
[0073] First, as illustrated in FIG. 6(A), the communication
between the suction port 51 and the pump chamber S1 is shut off in
a state in which the oil is supplied into the pump chamber S1 via
the opening 51a of the suction port 51. In this state, the pump
chamber S1 does not communicate with any of the suction port 51,
the discharging port 52, and the passage 4.
[0074] When the pump chamber S1 rotates in the arrow R direction
from the state of FIG. 6(A), the pump chamber S1 becomes the
maximum volume and assumes the state of FIG. 6(B) while contracting
from the maximum volume. In the state of FIG. 6(B), the pump
chamber S1 communicates with the outside of the pump housing 1 via
the passage 4. In other words, the first passage portion 41 and the
second passage portion 42 communicate with each other and the
passage 4 assumes a state of being capable of discharging the
bubbles K.
[0075] When the pump chamber S1 rotates in the arrow R direction
from the state of FIG. 6(B), the pump chamber S1 assumes the state
of FIG. 6(C). In the state of FIG. 6(C), the pump chamber S1 and
the discharging port 52 communicate with each other and the
communication between the first passage portion 41 and the second
passage portion 42 is nullified. In other words, the inscribed gear
pump 100 assumes a state in which it is possible to discharge, to
the engine parts (not illustrated) via the discharging port 52, the
oil in which the discharging of the bubbles K from the pump chamber
S1 via the passage 4 is completed and which does not substantially
contain the bubbles K. Hereinabove, the series of operations for
discharging the bubbles K from the pump chamber S1 is
completed.
Effects of First Embodiment
[0076] In the first embodiment, it is possible to obtain the
following effects.
[0077] In the first embodiment, as described above, by providing
the passage 4 to straddle the shaft portion 3 which is disposed on
the inside of the inscribed gear rotor 2 (the inner rotor 21), it
is possible to dispose the passage 4 at a closer position to the
central axis line of rotation of the inscribed gear rotor 2 (the
inner rotor 21) as compared to a case in which the passage 4 is
provided in the pump housing 1. In other words, since it is
possible to ensure that a centrifugal force does not substantially
act on the bubbles which are separated from the oil by a
centrifugal force and gathered on the passage 4 side, it is
possible to efficiently discharge the bubbles which are separated
from the oil via the passage 4. As a result, it is possible to
efficiently remove the bubbles K contained in the oil via the
passage 4.
[0078] In the first embodiment, as described above, the passage 4
includes the first passage portion 41 which is provided to straddle
the inscribed gear rotor 2 (the inner rotor 21) and the shaft
portion 3 and extends in a direction intersecting the axial
directions of the shaft portion 3, and the second passage portion
42 which is provided in the shaft portion 3 and extends in the
axial directions. Accordingly, it is possible to easily move the
bubbles K to the shaft portion 3 side using the first passage
portion 41 and it is possible to easily discharge and remove the
bubbles K which are moved to the shaft portion 3 side by the first
passage portion 41 to the outside of the pump housing 1 using the
second passage portion 42.
[0079] In the first embodiment, as described above, the inscribed
gear rotor 2 which includes the outer rotor 22 and the inner rotor
21, the outer rotor 22 including the plurality of internal teeth
22a and the inner rotor 21 including the plurality of external
teeth 21a which engage with the internal teeth 22a of the outer
rotor 22 is used. Accordingly, it is possible to obtain a great
output using a comparatively small structure according to the
inscribed gear rotor 2.
Second Embodiment
[0080] Next, a description will be given of the second embodiment
with reference to FIGS. 7 to 14. In the second embodiment, unlike
the first embodiment in which the passage 4 for discharging the
bubbles is provided to straddle only the inner rotor 21 and the
shaft portion 3, a description will be given of an example in which
a passage 204 for discharging the bubbles is provided to straddle a
pump housing 201 in addition to an inner rotor 221 and a shaft
portion 203. In the second embodiment, a description will be given
of an example in which the shaft portion 203 includes an
opening/closing mechanism 6 of the passage 204 in addition to the
configuration of the first embodiment. In the figures,
configurations that are the same as those of the first embodiment
are depicted with the same reference numerals as in the first
embodiment.
[0081] As illustrated in FIG. 7, an inscribed gear pump (an oil
pump) 200 in the second embodiment of the disclosure includes the
pump housing 201, an inscribed gear rotor (the rotor) 202, the
shaft portion 203, and the passage 204. The inscribed gear rotor
202 contains the inner rotor 221 which includes the plurality of
external teeth 21a, and the outer rotor 22 which includes the
plurality of internal teeth 22a.
Configuration of Pump Housing
[0082] As illustrated in (A) and (B) in FIG. 8, the pump housing
201 includes a body 211 and the cover 12. (A) and (B) in FIG. 8
illustrate different states of the pump housing 201 from those of
(A) and (B) in FIG. 9. In detail, (A) and (B) in FIG. 8 illustrate
a state in which the passage 204 is closed by the opening/closing
mechanism 6 (described later), and (A) and (B) in FIG. 9 illustrate
a state in which the passage 204 is opened by the opening/closing
mechanism 6.
[0083] The body 211 includes a pressure passage 211a which supplies
the oil to a pressure chamber 62 which is provided on the inside of
a rotary shaft 231 (described later) from the discharging port 52.
In other words, the discharging port 52 and the pressure chamber 62
communicate with each other via the pressure passage 211a.
Therefore, the rotation frequency (the rotation speed) of the
rotary shaft 231 (described later) of the shaft portion 203
increases due to an increase in the rotation frequency of the
engine and the internal pressure of the pressure chamber 62 also
increases due to an increase in the internal pressure of the
discharging port 52.
Configuration of Inner Rotor
[0084] As illustrated in FIG. 7, the bubble introduction portion
21c and the through hole (the inner passage portion 41b) are not
provided in the inner rotor 221 as they are in the first
embodiment. The inner rotor 221 is provided with a groove-shaped
rotor-side passage portion 241b which forms a portion of the
passage 204 (a first passage portion 241 which is described later).
A detailed description will be given later.
Configuration of Shaft Portion
[0085] As illustrated in (A) and (B) in FIG. 8, the shaft portion
203 includes the rotary shaft 231, the opening/closing mechanism 6
which is provided on the rotary shaft 231 and opens and closes the
passage 204, and a plug 232 which is provided on the rotary shaft
231.
[0086] A recessed portion 231a which is depressed in the A2
direction is formed in the end surface of the rotary shaft 231 on
the A1 direction side. The recessed portion 231a has a circular
column shape in a cross-section orthogonal to the A directions. The
central axis line of the recessed portion 231a is positioned on
substantially the same axis as the central axis line of rotation
.alpha. of the rotary shaft 231. A bottom portion of the recessed
portion 231a on the A2 direction side is positioned closer to the
A2 direction side than the inner rotor 221 (the sliding surface 11c
of the body 211).
Configuration of Open-Close Mechanism of Shaft Portion
[0087] As illustrated in (A) and (B) in FIG. 8, the opening/closing
mechanism 6 is disposed inside the recessed portion 231a. The
opening/closing mechanism 6 includes an opening/closing valve 61,
the pressure chamber 62, a restriction portion 63, and a compressed
coil spring (a biasing member) 64.
[0088] The opening/closing valve 61 has a hollow shape in which the
A1 direction side is open. The opening/closing valve 61 has a
substantially circular column outside shape. In a state in which
the opening/closing valve 61 is disposed inside the recessed
portion 231a, the opening/closing valve 61 partitions the inside
space of the recessed portion 231a into two spaces, a space (the
pressure chamber 62) on the A2 direction side of the
opening/closing valve 61 and a space (a second passage portion 242
which is described later) on the A1 direction side of the
opening/closing valve 61. The opening/closing valve 61 performs the
partitioning of the two spaces such that there is no (substantially
no) exchanging of the oil between the two spaces.
[0089] The opening/closing valve 61 is configured to be capable of
moving in the axial directions (the A directions) of the rotary
shaft 231. In detail, the opening/closing valve 61 is configured to
be capable of reciprocal movement in a predetermined area in the A
directions within the rotary shaft 231 according to the internal
pressure of the pressure chamber 62 (the discharging port 52).
[0090] The pressure chamber 62 is provided adjacent to the rotary
shaft 231 of the opening/closing valve 61 on one side (the A2
direction side) of the axial directions of the rotary shaft 231. As
described above, the pressure chamber 62 communicates with the
discharging port 52 via the pressure passage 211a of the body 211.
The pressure chamber 62 is configured to pressurize the
opening/closing valve 61 in the A1 direction in accordance with a
fluctuation in the internal pressure of the pressure chamber 62 to
move the opening/closing valve 61 in the A1 direction against the
biasing force of the compressed coil spring 64. The opening/closing
valve 61 separates from the restriction portion 63 when the
opening/closing valve 61 moves in the A1 direction.
[0091] As illustrated in (A) in FIG. 8, the rotary shaft 231 is
provided with a pressure passage 231b which communicates the
pressure chamber 62 with the pressure passage 211a of the body 211.
The pressure passage 231b includes an annular groove which has an
annular shape extending along the outside surface of the rotary
shaft 231 to surround the rotary shaft 231, and a through hole
which extends from the annular groove to the inside of the shaft
portion 203 in the radial directions to communicate with the
pressure chamber 62.
[0092] The restriction portion 63 is formed on the inside surface
of the recessed portion 231a. In detail, the restriction portion 63
is formed by a level difference which reduces the size of the inner
diameter of the recessed portion 231a on the A2 direction side. The
restriction portion 63 is positioned closer to the A2 direction
side than the inner rotor 221 (the sliding surface 11c of the body
211). The restriction portion 63 is configured to restrict the
movement of the opening/closing valve 61 to the pressure chamber 62
side by abutting against the opening/closing valve 61. In other
words, the opening/closing valve 61 does not move further to the A2
direction side than a position at which the opening/closing valve
61 abuts against the restriction portion 63.
[0093] The compressed coil spring 64 is provided adjacent to the
rotary shaft 231 of the opening/closing valve 61 on the other side
(the A1 direction side) in the axial directions of the rotary shaft
231 and is configured to bias the opening/closing valve 61 toward
the pressure chamber 62 (the restriction portion 63).
[0094] The plug 232 supports the A1 direction end portion of the
compressed coil spring 64. The plug 232 is attached to the A2
direction end portion of the recessed portion 231a of the rotary
shaft 231 using fitting (including screwing). The plug 232 has a
through hole which penetrates the plug 232 in the A directions.
[0095] As illustrated in FIGS. 10 and 11, the opening/closing valve
61 includes a sealing wall 61a and a communication bore 61b.
[0096] The sealing wall 61a is a wall portion which extends along
the inner surface of the recessed portion 231a of the rotary shaft
231. The sealing wall 61a has a function of sealing the passage 204
in the middle so as not to discharge the bubbles to the outside of
the pump housing 201. The sealing wall 61a is disposed between the
first passage portion 241 and the second passage portion 242 and
closes the passage 204 (ensures that the bubbles may not be
discharged) in a state (refer to (A) and (B) in FIG. 8) in which
the opening/closing valve 61 abuts against the restriction portion
63.
[0097] The communication bore 61b is disposed at a position which
deviates in an axial direction (the A2 direction) of the rotary
shaft 231 with respect to the sealing wall 61a. A plurality (four)
of the communication bores 61b are provided. The plurality of
communication bores 61b are disposed at an equal angular interval
in the circumferential direction (the rotation direction) of the
shaft portion 203. The plurality of communication bores 61b extend
both linearly and radially in the radial direction of the shaft
portion 203. The communication bores 61b have a function of
communicating with the passage 204 in order to discharge the
bubbles to the outside of the pump housing 201. An annular groove
which has an annular shape extending along the inner surface of the
recessed portion 231a to surround the opening/closing valve 61 is
provided in the outside end portion of the communication bores
61b.
[0098] The communication bore 61b is disposed between the first
passage portion 241 and the second passage portion 242 and opens
the passage 204 (ensures that the bubbles may be discharged) in a
state (a state in which the rotation frequency of the engine
increases and the internal pressure of the discharging port 52 and
the pressure chamber 62 is increased) (refer to (A) and (B) in FIG.
9) in which the opening/closing valve 61 moves in the A2 direction
against the biasing force of the compressed coil spring 64 and the
opening/closing valve 61 separates from the restriction portion 63
by a predetermined distance.
Configuration of Passage
[0099] As illustrated in FIG. 11, the passage 204 is provided to
straddle the body 211 of the pump housing 201, the inner rotor 21,
and the shaft portion 203 as described above. The passage 204
includes the first passage portion 241 and the second passage
portion 242.
[0100] The first passage portion 241 is provided to straddle the
body 211, the inner rotor 221, and the shaft portion 203.
[0101] The first passage portion 241 includes a body-side passage
portion 241a which is provided in the body 211, a rotor-side
passage portion 241b which is provided in the inner rotor 221, and
a shaft portion-side first passage portion 241c and a shaft
portion-side second passage portion 241d which are provided in the
shaft portion 203.
[0102] The rotor-side passage portion 241b, the shaft portion-side
first passage portion 241c, and the shaft portion-side second
passage portion 241d rotate in synchronization with the inner rotor
221 and the rotary shaft 231. Meanwhile, the body-side passage
portion 241a does not rotate in synchronization with the inner
rotor 221 and the rotary shaft 231. The shaft portion-side second
passage portion 241d, the rotor-side passage portion 241b, the
shaft portion-side first passage portion 241c, and the body-side
passage portion 241a are disposed in order from the downstream side
(the atmosphere side) (the second passage portion 242 side) at
which the bubbles are discharged.
[0103] As illustrated in FIG. 12, the body-side passage portion
241a is provided in the sliding surface 11c of the body 211. The
body-side passage portion 241a has a letter L shape as viewed from
the A directions and is formed in a groove shape which is depressed
in the A2 direction from the sliding surface 11c. Therefore, the
body-side passage portion 241a extends in a direction which
intersects (a direction which are orthogonal to) the axial
directions (the A directions) of the shaft portion 203.
[0104] As illustrated in FIG. 7, one end on the outside (the
outside of the shaft portion 203 in the radial direction) of the
body-side passage portion 241a is disposed at a position (a
position in the vicinity of the tooth bottoms 21b) at which the
body-side passage portion 241a communicates with the space between
adjacent external teeth 21a in the pump chamber S1 when the inner
rotor 221 rotates. The other end on the inside (the inside in the
radial direction of the shaft portion 203) of the body-side passage
portion 241a is connected to the rotor-side passage portion 241b
and the shaft portion-side first passage portion 241c. In other
words, the body-side passage portion 241a communicates the pump
chamber S1 with the rotor-side passage portion 241b and the shaft
portion-side first passage portion 241c (the shaft portion-side
second passage portion 241d).
[0105] As illustrated in FIG. 11, the rotor-side passage portion
241b is provided in the A2 direction end portion on the inner
peripheral side of the inner rotor 221. The rotor-side passage
portion 241b is formed in an annular groove shape which extends to
surround the shaft portion 203.
[0106] The shaft portion-side first passage portion 241c is
disposed substantially adjacent to the rotor-side passage portion
241b on the A2 direction side. The shaft portion-side first passage
portion 241c is formed by a level difference which reduces the size
of the outer diameter of the rotary shaft 231 on the A1 direction
side. The shaft portion-side first passage portion 241c is formed
in an annular shape which extends to surround the shaft portion
203. The shaft portion-side first passage portion 241c is disposed
substantially at a position corresponding to the body-side passage
portion 241a in the A directions. The shaft portion-side first
passage portion 241c and the rotor-side passage portion 241b form
an annular space which surrounds the opening/closing valve 61.
[0107] The shaft portion-side second passage portion 241d is formed
by a through hole which is provided in the rotary shaft 231 and
extends in the radial direction of the shaft portion 203. A
plurality (four) of the shaft portion-side second passage portions
241d are provided. The plurality of shaft portion-side second
passage portions 241d are disposed at an equal angular interval in
the circumferential direction (the rotation direction) of the shaft
portion 203. The plurality of shaft portion-side second passage
portions 241d are disposed substantially at positions corresponding
to the rotor-side passage portion 241b in the A directions.
[0108] The second passage portion 242 is formed to extend in the A
directions by the inner portion space of the opening/closing valve
61, the inner portion space of the recessed portion 231a, and the
through hole of the plug 232 (refer to FIG. 7).
[0109] One end of the second passage portion 242 on the A1
direction side is connected to the outer surface (the outside) of
the pump housing 201. In other words, one end of the second passage
portion 242 on the A1 direction side is connected to the
atmosphere. The vicinity of the other end of the second passage
portion 242 on the A2 direction side is connected to the first
passage portion 241 in a state (a state in which the internal
pressure of the pressure chamber 62 is high) in which the
opening/closing valve 61 is separated from the restriction portion
63.
Operation of Open-Close Mechanism
[0110] A description will be given of the operations of the
opening/closing mechanism 6 with reference to (A) and (B) in FIG. 8
and (A) and (B) in FIG. 9.
[0111] The opening/closing mechanism 6 is configured to open and
close the passage 204 by causing the opening/closing valve 61 to
move reciprocally in the A directions. (A) and (B) in FIG. 8
illustrate a state in which the passage 204 is closed (a state in
which the opening/closing valve 61 moves to the A2 direction side).
Meanwhile, (A) and (B) in FIG. 9 illustrate a state in which the
passage 204 is open (a state in which the opening/closing valve 61
moves to the A1 direction side). Hereinafter, a description will be
given of the open state and the closed state of the passage 204, in
order.
[0112] As illustrated in (A) and (B) in FIG. 8, in a case in which
the internal pressure of the discharging port 52 and the pressure
chamber 62 is low, the opening/closing mechanism 6 is configured
such that the sealing wall 61a is disposed between the first
passage portion 241 and the second passage portion 242 in a state
in which the opening/closing valve 61 and the restriction portion
63 abut against each other due to the biasing force of the
compressed coil spring 64. Accordingly, the opening/closing
mechanism 6 is configured to close the passage 204. A case in which
the internal pressure of the discharging port 52 and the pressure
chamber 62 is low is a case in which the rotation frequency (the
rotational speed) of the rotary shaft 231 is comparatively low.
[0113] Meanwhile, as illustrated in (A) and (B) in FIG. 9, in a
case in which the internal pressure of the discharging port 52 and
the pressure chamber 62 is high, the opening/closing mechanism 6 is
configured such that, instead of the sealing wall 61a, the
communication bore 61b is disposed between the first passage
portion 241 and the second passage portion 242 in a state in which
the opening/closing valve 61 and the restriction portion 63 are
separated by a predetermined distance against the biasing force of
the compressed coil spring 64 via the opening/closing valve 61 due
to the internal pressure of the pressure chamber 62. Accordingly,
the opening/closing mechanism 6 is configured to open the passage
204. A case in which the internal pressure of the discharging port
52 and the pressure chamber 62 is high is a case in which the
rotation frequency (the rotational speed) of the rotary shaft 231
is comparatively high.
[0114] For example, as illustrated in FIG. 13, the opening/closing
mechanism 6 opens the passage 204 using the opening/closing valve
61 in a case in which a rotation frequency R per unit time of the
engine is greater than or equal to 4000 rpm and closes the passage
204 using the opening/closing valve 61 in a case in which the
rotation frequency R is less than 4000 rpm. Accordingly, the oil
pressure of the main gallery inside the engine is reduced in a
high-speed rotation region. FIG. 13 illustrates a graph of an
inscribed gear pump of the related art using a dotted line as a
comparative example. The inscribed gear pump of the related art is
configured to discharge the bubbles at all engine rotation
frequencies regardless of the engine rotation frequency.
Discharging Operation of Bubbles
[0115] Next a description will be given of the discharging
operation of the bubbles from the pump chamber Si via the passage
204 of the inscribed gear pump 200 with reference to FIGS. 14(A) to
14(E). In each of the states of FIGS. 14(A) to 14(E), the passage
204 is in an open state (a state in which the communication bore
61b of the opening/closing valve 61 is disposed between the first
passage portion 241 and the second passage portion 242).
[0116] First, as illustrated in FIG. 14(A), the oil is supplied
into the pump chamber S1 from the suction port 51 in a state in
which the opening 51a of the suction port 51 and the pump chamber
S1 communicate with each other.
[0117] When the pump chamber S1 rotates in the arrow R direction
from the state of FIG. 14(A), the pump chamber S1 assumes the state
of FIG. 14(B) while expanding in volume. In the state of FIG.
14(B), the communication between the suction port 51 and the pump
chamber S1 is shut off in a state in which the oil is supplied into
the pump chamber S1, and the pump chamber S1 reaches the maximum
volume. In this state, the pump chamber S1 does not communicate
with any of the suction port 51, the discharging port 52, and the
passage 204.
[0118] When the pump chamber S1 rotates in the arrow R direction
from the state of FIG. 14(B), the pump chamber S1 assumes the state
of FIG. 14(C) while contracting in volume from the maximum volume.
In this state, the pump chamber S1 does not communicate with any of
the suction port 51, the discharging port 52, and the passage
204.
[0119] When the pump chamber S1 rotates in the arrow R direction
from the state of FIG. 14(C), the pump chamber S1 assumes the state
of FIG. 14(D) while further contracting in volume. In the state of
FIG. 14(D), since the pump chamber S1 communicates with the
body-side passage portion 241a which is shaped like a groove in a
character L shape, the pump chamber S1 communicates with the
outside of the pump housing 201 via the passage 204. In other
words, the first passage portion 241 and the second passage portion
242 communicate with each other and the bubbles are discharged via
the passage 204.
[0120] When the pump chamber S1 rotates in the arrow R direction
from the state of FIG. 14(D), the pump chamber S1 assumes the state
of FIG. 14(E) while further contracting in volume. In the state of
FIG. 14(E), the communication between the pump chamber S1 and the
passage 204 is nullified and the pump chamber S1 and the opening
52a of the discharging port 52 are communicated with each other.
The inscribed gear pump 200 assumes a state in which it is possible
to discharge, to the engine parts (not illustrated) via the
discharging port 52, the oil in which the discharging of the
bubbles from the pump chamber S1 via the passage 204 is
substantially completed and which does not substantially contain
the bubbles. Hereinabove, the series of operations for discharging
the bubbles from the pump chamber S1 is completed.
Effects of Second Embodiment
[0121] In the second embodiment, it is possible to obtain the
following effects.
[0122] In the second embodiment, as described above, the shaft
portion 203 includes the opening/closing mechanism 6 which opens
and closes the passage 204. Accordingly, since it is possible to
close the passage 204 in a period (at a timing) in which the
discharging of the bubbles to the outside of the pump housing 201
is unnecessary using the opening/closing mechanism 6, it is
possible to prevent the oil from flowing out to the outside of the
pump housing 201 together with the bubbles via the passage 204 in
the period in which the discharging of the bubbles is unnecessary.
The period in which the discharging of the bubbles is unnecessary
is, for example, a period in which the rotation frequency of the
engine is low and the bubbles are not easily formed in the oil.
[0123] In the second embodiment, as described above, the passage
204 includes the first passage portion 241 which is provided to
straddle the pump housing 201, the inner rotor 221, and the shaft
portion 203 and extends in a direction intersecting the axial
directions of the shaft portion 203, and the second passage portion
242 which is provided in the shaft portion 203 and extends in the
axial directions, the shaft portion 203 includes the rotary shaft
231 which rotationally drives the inner rotor 221, the rotary shaft
231 includes the opening/closing mechanism 6 which opens and closes
the passage 204, the opening/closing mechanism 6 includes the
opening/closing valve 61 including the sealing wall 61a and the
communication bore 61b which is disposed at a position deviated in
an axial direction of the rotary shaft 231 with respect to the
sealing wall 61a and the opening/closing valve 61 is capable of
moving in the axial direction of the rotary shaft 231, and the
opening/closing mechanism 6 is configured to close the passage 204
by moving in one of the axial directions of the rotary shaft 231 to
dispose the sealing wall 61a between the first passage portion 241
and the second passage portion 242 and to open the passage 204 by
moving in the other axial direction of the rotary shaft 231 to
dispose, instead of the sealing wall 61a, the communication bore
61b between the first passage portion 241 and the second passage
portion 242. Accordingly, since it is possible to open and close
the passage 204 merely by providing the sealing wall 61a which has
a function of blocking the passage 204 and the communication bore
61b which has a function of communicating with the passage 204 in a
single member (the opening/closing valve 61) and moving the single
member (the opening/closing valve 61), it is possible to easily
perform the opening and closing of the passage 204 and it is
possible to simplify the configuration of the opening/closing
mechanism 6.
[0124] In the second embodiment, as described above, the
opening/closing mechanism 6 is configured to move the
opening/closing valve 61 according to an internal pressure of the
discharging port 52 and is configured to close the passage 204 by
disposing the sealing wall 61a between the first passage portion
241 and the second passage portion 242 in a case in which the
internal pressure of the discharging port 52 is low and to open the
passage 204 by disposing, instead of the sealing wall 61a, the
communication bore 61b between the first passage portion 241 and
the second passage portion 242 in a case in which the internal
pressure of the discharging port 52 is high. Accordingly, in a case
in which the rotation frequency of the engine is lowered and the
internal pressure of the discharging port 52 is low to an extent in
which the bubbles are not easily formed in the oil, it is possible
to close the passage 204. However, in a case in which the rotation
frequency of the engine is raised and the internal pressure of the
discharging port 52 is high to an extent in which the bubbles are
easily formed in the oil, it is possible to open the passage 204.
In other words, it is possible to effectively remove the bubbles
contained in the oil while suppressing the flowing out of the oil
to the outside of the pump housing 201.
[0125] In the second embodiment, as described above, the
opening/closing mechanism 6 includes the pressure chamber 62 which
is provided on one side in the axial directions of the rotary shaft
231 of the opening/closing valve 61, communicates with the
discharging port 52 via the pressure passage 211a, and pressurizes
the opening/closing valve 61 to move the opening/closing valve 61,
the compressed coil spring 64 which is provided on another side in
the axial directions of the rotary shaft 231 of the opening/closing
valve 61 and biases the opening/closing valve 61 toward the
pressure chamber 62, and the restriction portion 63 which restricts
movement of the opening/closing valve 61 to the pressure chamber 62
side, and the opening/closing mechanism 6 is configured to close
the passage 204 by disposing the sealing wall 61a between the first
passage portion 241 and the second passage portion 242 in a state
in which the opening/closing valve 61 and the restriction portion
63 are caused to abut against each other by a biasing force of the
compressed coil spring 64 in a case in which the internal pressure
of the discharging port 52 and the pressure chamber 62 is low and
to open the passage 204 by disposing, instead of the sealing wall
61a, the communication bore 61b between the first passage portion
241 and the second passage portion 242 in a state in which the
opening/closing valve 61 and the restriction portion 63 are
separated against the biasing force of the compressed coil spring
64 via the opening/closing valve 61 by the internal pressure of the
pressure chamber 62 in a case in which an internal pressure of the
discharging port 52 and the pressure chamber 62 is high.
Accordingly, it is possible to configure the opening/closing
mechanism 6 from only structural and mechanical configuration
elements (the pressure chamber 62, the opening/closing valve 61,
the compressed coil spring 64, and the restriction portion 63)
without using electrical configuration elements. Therefore, since
it is not necessary to provide a configuration for supplying
electrical power or the like to the opening/closing mechanism 6, it
is possible to simplify the configuration of the opening/closing
mechanism 6.
[0126] The other effects of the second embodiment are similar to
those of the first embodiment.
Third Embodiment
[0127] Next, a description will be given of the third embodiment
with reference to FIG. 15. In the third embodiment, instead of the
first embodiment in which the configuration is provided with the
inscribed gear rotor 2, a description will be given of an example
of a configuration which is provided with a vane rotor 302. In the
figures, configurations that are the same as those of the first
embodiment are depicted with the same reference numerals as in the
first embodiment.
[0128] As illustrated in FIG. 15, a vane pump (the oil pump) 300 in
the third embodiment of the disclosure is provided with a pump
housing 301, a cam ring 307, the vane rotor 302 containing a rotor
main body 321 and a plurality of (eight) vanes 322, the shaft
portion 3, and the passage 4. In other words, the third embodiment
is provided with the same configuration as the first embodiment in
relation to the shaft portion 3 and the passage 4.
[0129] The pump housing 301 includes a circular cylindrical space
on the inside. The annular cam ring 307 is fitted into the inside
of the space.
[0130] The vane rotor 302 has an annular shape and is disposed
inside the cam ring 307. A gap (a space) is formed between an outer
peripheral surface of the vane rotor 302 and the inner peripheral
surface of the cam ring 307.
[0131] The shaft portion 3 is inserted through the rotor main body
321. The rotor main body 321 is configured so as to be rotated by
the shaft portion 3 inside the pump housing 301.
[0132] The vanes 322 are provided to protrude outward from the
rotor main body 321. The vanes 322 extend in the radial direction
of the rotor main body 321 (the shaft portion 3). The plurality of
vanes 322 are disposed at a substantially equal angular interval in
the circumferential direction of the rotor main body 321 (the shaft
portion 3). In other words, the plurality of vanes 322 are disposed
radially as viewed from the axial directions of the shaft portion 3
(as viewed from the A directions).
[0133] The vanes 322 are attached to the rotor main body 321 to be
capable of proceeding and withdrawing in the radial direction of
the rotor main body 321 (the shaft portion 3). A back pressure
groove (not illustrated), which is a space which is connected to
the inside end surface of the vanes 322, is provided on the inside
of the rotor main body 321. The back pressure groove is configured
such that a back pressure oil is supplied to the back pressure
groove to cause (to bias) the vanes 322 to move to the outside in
the radial direction of the rotor main body 321 (the shaft portion
3). Accordingly, the outside end portion of the vanes 322 maintains
a state of being in contact (a pressing state) with the inner
peripheral surface of the cam ring 307. A pump chamber S301 is
formed between the adjacent vanes 322, the inner peripheral surface
of the cam ring 307, and the outer peripheral surface of the rotor
main body 321.
[0134] A suction port 351 and a discharging port 352 are formed in
the pump housing 301. The suction port 351 and the discharging port
352 are not directly continuous with each other and are provided at
angular positions in the circumferential direction (the rotation
direction) of the shaft portion 3 so as not to overlap each
other.
[0135] The vane pump 300 (the vane rotor 302) causes the pump
chamber S301 to rotate in the arrow R direction around the shaft
portion 3 to pump the oil from the suction port 351 to the
discharging port 352.
[0136] In the third embodiment, the passage 4 is provided to
straddle the rotor main body 321 and the shaft portion 3. The
portion (the outer passage portion 41a) of the passage 4 on the
rotor main body 321 side is provided, one between each pair of
adjacent vanes 322. The passage 4 communicates the pump chamber
S301 and the outside of the pump housing 301 with each other. The
vane pump 300 is configured to discharge the bubbles contained in
the oil inside the pump chamber S301 to the outside of the pump
housing 301 via the passage 4.
[0137] The other configurations of the third embodiment are similar
to those of the first embodiment.
Effects of Third Embodiment
[0138] In the third embodiment, it is possible to obtain the
following effects.
[0139] In the third embodiment, as described above, the vane rotor
302 which includes the rotor main body 321 and the plurality of
vanes 322 which are provided to protrude outward from the rotor
main body 321 and form the pump chamber S301 is used. Accordingly,
it is possible to render the vane pump 300 a simple shape in which
foreign matter and the like do not easily get stuck using the vane
rotor 302.
[0140] The other effects of the third embodiment are similar to
those of the first embodiment.
Fourth Embodiment
[0141] Next, a description will be given of the fourth embodiment
with reference to FIGS. 16 to 18. In the fourth embodiment, a
description will be given of an example of a configuration in
which, unlike in the first embodiment in which the fixed shaft 32
is configured from a single member, the fixed shaft 32 is
configured from a plurality of (two) members. In the figures,
configurations that are the same as those of the first embodiment
are depicted with the same reference numerals as in the first
embodiment.
[0142] As illustrated in FIG. 16, an inscribed gear pump (the oil
pump) 400 in the fourth embodiment of the disclosure is provided
with a shaft portion 403.
[0143] The shaft portion 403 includes the rotary shaft 31 and a
fixed shaft 432.
[0144] The fixed shaft 432 includes a first member 433 which is
fixed to the cover 12 of the pump housing 1 and a second member 434
which is inserted into the recessed portion 31c and is connected to
the first member 433 in a state of being capable of moving in a
direction orthogonal to the axial directions. The second member 434
is disposed (is floating mounted) in a state of being interposed
between the rotary shaft 31 and the first member 433 without being
fixed to the other configurations.
[0145] As illustrated in FIG. 17, the fixed shaft 432 includes a
turn-stopping portion 435 which connects the first member 433 and
the second member 434 to each other in a state in which the second
member 434 is capable of moving in a direction orthogonal to the
axial directions relative to the first member 433.
[0146] As illustrated in FIG. 16, the second member 434 is
substantially rod shaped and extends in the A directions. The
second member 434 is formed in a cylindrical shape such that the A2
direction side of the second member 434 is inserted into the
recessed portion 31c of the rotary shaft 31. It is preferable that
the distance between the inner surface which extends in the A
directions of the recessed portion 31c and the cylindrical inner
surface of the second member 434 be maintained at less than or
equal to 0.1 mm, for example. Accordingly, it is possible to
continue forming an oil membrane between the inner surface which
extends in the A directions of the recessed portion 31c and the
cylindrical inner surface of the second member 434 without the
sealing properties being damaged. The second member 434 is
positioned by the inner surface of the recessed portion 31c in a
direction orthogonal to the A directions.
[0147] The first member 433 is attached to the cover 12 in a fixed
manner using a fixing means such as a bolt (not illustrated). The
A2 direction end portion of the first member 433 includes an
engagement recessed portion 433a which functions as the
turn-stopping portion 435. The A1 direction end portion of the
second member 434 includes an engagement protruding portion 434a
which functions as the turn-stopping portion 435.
[0148] The engagement protruding portion 434a is formed in a
substantially rectangular shape as viewed from the A1 direction
side. In detail, the engagement protruding portion 434a is formed
such that the opposing sides of one pair of sides are linearly
parallel to each other as viewed from the A1 direction side, and
the opposing sides of the other pair of sides are formed in a
curved shape which expands toward the outside.
[0149] The engagement recessed portion 433a is depressed in the A1
direction from the A2 direction end portion of the first member
433. The engagement recessed portion 433a is formed in a shape (a
substantially rectangular shape) corresponding to the engagement
protruding portion 434a as viewed from the A2 direction side. In
detail, the engagement recessed portion 433a is formed in a shape
substantially corresponding to a shape in which a shape of the
engagement protruding portion 434a as viewed from the A1 direction
side is slightly offset to the outside.
[0150] Therefore, the engagement protruding portion 434a is
configured to be capable of being inserted into the engagement
recessed portion 433a from the A2 direction side. The engagement
recessed portion 433a is configured to allow the rotation and
movement in a direction orthogonal to the A directions of the
engagement protruding portion 434a (the second member 434) in a
range that does not inhibit the positioning of the second member
434 by the inner surface of the recessed portion 31c and to
restrict movement of the second member 434 greater than or equal to
a predetermined amount of movement.
[0151] The (outside surface of the) engagement protruding portion
434a is disposed on the inner surface of the engagement recessed
portion 433a to be separated from (the inner surface of) the
engagement recessed portion 433a by a tiny gap in a direction
orthogonal to the A directions. According to the tiny gap which are
orthogonal to the A directions, the second member 434 is configured
to be capable of moving in the direction orthogonal to the A
directions with respect to the first member 433 which is fixed to
the cover 12.
[0152] The second member 434 is disposed to be separated from each
of the bottom portion 31d of the recessed portion 31c of the rotary
shaft 31 and the first member 433 at both ends in the A directions
by a tiny gap (for example, a gap of less than or equal to 0.5 mm
on one side) of a degree which allows inclination and movement of
the second member 434.
[0153] As illustrated in FIG. 18, during the movement of the rotary
shaft 31 from the stopped state to the driving state, although the
second member 434 also rotates a little together with the rotation
of the rotary shaft 31, the rotation of the second member 434 is
swiftly restricted due to the second member 434 abutting against
the first member 433 from the inside.
[0154] The second passage portion 42 which penetrates the fixed
shaft 432 in the A directions is provided in the fixed shaft 432
(the first member 433 and the second member 434). The first passage
portion 41 (the lateral hole) which communicates with the second
passage portion 42 from the outside is provided in the second
member 434.
[0155] The other configurations of the fourth embodiment are
similar to those of the first embodiment.
Effects of Fourth Embodiment
[0156] In the Fourth embodiment, it is possible to obtain the
following effects.
[0157] In the fourth embodiment, as described above, the shaft
portion 403 includes the rotary shaft 31 which includes the
recessed portion 31c having a circular cross-section that is
orthogonal to the axial directions of the shaft portion 403 and
extends in the axial directions and which rotates together with the
inscribed gear rotor 2, and the fixed shaft 432 which includes the
first member 433 which is fixed to the pump housing 1 and the
second member 434 which is inserted into the recessed portion 31c
and is connected to the first member 433 in a state of being
capable of moving in a direction orthogonal to the axial
directions. Accordingly, since it is possible to allow the movement
of the fixed shaft 432 (the second member 434) in a direction
orthogonal to the axial directions relative to the rotary shaft 31,
it is possible to more uniformly maintain the clearance between the
fixed shaft 432 (the second member 434) and the recessed portion
31c in the circumferential direction of the fixed shaft 432 (the
second member 434) as compared to a case in which the entirety of
the fixed shaft is completely fixed to the pump housing.
Accordingly, it is possible to suppress the clearance between the
fixed shaft 432 and the recessed portion 31c in the circumferential
direction of the fixed shaft 432 becoming too great and the sealing
properties being inhibited. It is possible to suppress the
clearance between the fixed shaft 432 and the recessed portion 31c
becoming too small and the rotation of the rotary shaft 31 being
prevented by the fixed shaft 432. In a case in which the entirety
of the fixed shaft is completely fixed to the pump housing, it is
necessary to consider, during the manufacturing, the tolerance
between the rotary shaft and the fixed shaft and the tolerance
between the fixed shaft and the configurations (the flange and the
like) for attaching the fixed shaft to the pump housing. However,
in the configuration of the fourth embodiment, it is sufficient to
only consider the tolerance between the rotary shaft 31 and the
first member 433 during the manufacturing. In other words, it is
possible to easily maintain a uniform clearance between the fixed
shaft 32 (the second member 434) and the engagement recessed
portion 433a.
[0158] In the fourth embodiment, as described above, the fixed
shaft includes the turn-stopping portion 435 (the engagement
recessed portion 433a and the engagement protruding portion 434a)
which connects the first member 433 and the second member 434 to
each other in a state in which the second member 434 is capable of
moving in a direction orthogonal to the axial directions relative
to the first member 433. Accordingly, it is possible to easily
realize a configuration which connects the second member 434 and
the first member 433 to each other in a state in which the movement
of the fixed shaft 432 (the second member 434) in a direction
orthogonal to the axial directions relative to the rotary shaft 31
using the turn-stopping portion 435 (the engagement recessed
portion 433a and the engagement protruding portion 434a).
[0159] The other effects of the fourth embodiment are similar to
those of the first embodiment.
MODIFICATION EXAMPLE
[0160] It should be understood that the embodiments disclosed
herein have been presented for the purpose of illustration and
description but not limited in all aspects. It is intended that the
scope of the disclosure is indicated not by the description of the
embodiments but by the scope of the claims and encompasses all
modifications (modification examples) equivalent in meaning and
scope to the claims.
[0161] For example, although an example is depicted in which the
biasing member of the disclosure is configured using a compressed
coil spring in the second embodiment, the disclosure is not limited
thereto. In the disclosure, the biasing member of the disclosure
may be configured using an elastic member other than a compressed
coil spring such as a rubber member.
[0162] Although an example is depicted in which the rotation
frequency of the engine is configured to open the opening/closing
mechanism in a high-speed rotation region greater than or equal to
4000 rpm in the second embodiment, the disclosure is not limited
thereto. In the disclosure, the rotation frequency of the engine
may be configured to open the opening/closing mechanism at a
predetermined rotation frequency which is lower than or greater
than or equal to 4000 rpm.
[0163] Although an example is depicted in which the passage is
provided to straddle at least the inner rotor in the first and
second embodiments, the disclosure is not limited thereto. In the
disclosure, the passage may not be provided to straddle the inner
rotor. For example, the passage may be provided to straddle only
the pump housing and the shaft portion.
[0164] Although an example (an example in which the opening/closing
mechanism is a structural, mechanical configuration) is depicted in
which the opening/closing mechanism is configured to open and close
using the internal pressure of the discharging port (the pressure
chamber) in the second embodiment, the discharging port is not
limited thereto. In the disclosure, for example, the
opening/closing mechanism may be configured (may adopt an
electrical configuration) to open and close based on an electrical
signal without using the internal pressure of the discharging port
(the pressure chamber).
[0165] Although an example is depicted of a configuration in which
the passage (the outer passage portion of the first passage
portion) is connected to all of the tooth bottoms of the inner
rotor in the first embodiment, the disclosure is not limited
thereto. In the disclosure, a configuration may be adopted in which
the passage (the outer passage portion of the first passage
portion) is connected to the tooth bottoms of a portion of the
plurality of tooth bottoms of the inner rotor.
[0166] Although an example is depicted in which the inner passage
portion of the first passage portion is configured using a single
through hole in the first embodiment, the disclosure is not limited
thereto. In the disclosure, the inner passage portion of the first
passage portion may be configured using a plurality of through
holes.
[0167] Although an example is depicted in which the first passage
portion is disposed in a middle position in the thickness
directions of the inner rotor in the axial directions of the shaft
portion in the first embodiment, the disclosure is not limited
thereto. In the disclosure, the first passage portion may be
disposed at a position which is deviated from the middle position
in the thickness directions of the inner rotor. The first passage
portion may be disposed at a position which is deviated in the
circumferential direction (the rotation direction) of the shaft
portion from that of the first passage portion of the first
embodiment.
[0168] Although an example is depicted in which the inner passage
portion is configured using a through hole having a smaller inner
diameter than the outer passage portion in the first and third
embodiments, the disclosure is not limited thereto. In the
disclosure, the inner passage portion may be configured using a
through hole having an inner diameter of a size greater than or
equal to that of the outer passage portion.
[0169] Although an example is depicted in which the passage on the
cover side and the atmosphere communicate with each other in the
first to third embodiments, the disclosure is not limited thereto.
In the disclosure, the passage on the body side and the atmosphere
may communicate with each other.
[0170] Although an example is depicted in which the movement of the
second member in a direction orthogonal to the axial directions
with respect to the first member (a fixed configuration) is
rendered possible by a clearance which is provided between the
first member and the second member in the fourth embodiment, the
disclosure is not limited thereto. In the disclosure, for example,
the first member and the second member may be connected to each
other using an elastic member such as rubber to render the movement
of the second member in a direction orthogonal to the axial
directions with respect to the first member (a fixed configuration)
possible.
[0171] An oil pump according to an aspect of this disclosure
includes a pump housing having a rotor accommodation space in an
inner portion of the pump housing, a rotor accommodated in the
rotor accommodation space, a shaft portion disposed inside the
rotor, and a passage which is provided to straddle at least one of
the pump housing and the rotor and the shaft portion and which
communicates a pump chamber which is formed by the rotor inside the
pump housing with an outside of the pump housing.
[0172] In the oil pump according to the aspect of this disclosure,
as described above, by providing the passage to straddle the shaft
portion which is disposed on the inside of the rotor, it is
possible to dispose the passage at a closer position to the central
axis line of rotation of the rotor as compared to a case in which
the passage is provided in the pump housing. In other words, since
it is possible to ensure that a centrifugal force does not
substantially act on the bubbles which are separated from the oil
by a centrifugal force and gathered on the passage side, it is
possible to efficiently discharge the bubbles which are separated
from the oil via the passage. As a result, it is possible to
efficiently remove the bubbles contained in the oil via the
passage.
[0173] In the oil pump according to the aspect, it is preferable
that the passage includes a first passage portion which is provided
to straddle at least one of the pump housing and the rotor and the
shaft portion and extends in a direction intersecting an axial
direction of the shaft portion, and a second passage portion which
is provided in the shaft portion and extends in the axial
direction.
[0174] According to this configuration, it is possible to easily
move the bubbles to the shaft portion side using the first passage
portion and it is possible to easily discharge and remove the
bubbles which are moved to the shaft portion side by the first
passage portion to the outside of the pump housing using the second
passage portion.
[0175] In the oil pump according to the aspect, it is preferable
that the shaft portion includes an opening/closing mechanism which
opens and closes the passage.
[0176] According to this configuration, since it is possible to
close the passage in a period (at a timing) in which the
discharging of the bubbles to the outside of the pump housing is
unnecessary using the opening/closing mechanism, it is possible to
prevent the oil from flowing out to the outside of the pump housing
together with the bubbles via the passage in the period in which
the discharging of the bubbles is unnecessary. The period in which
the discharging of the bubbles is unnecessary is, for example, a
period in which the rotation frequency of the engine is low and the
bubbles are not easily formed in the oil.
[0177] In the configuration in which the passage includes the first
passage portion and the second passage portion, it is preferable
that the shaft portion includes a rotary shaft which rotationally
drives the rotor, the rotary shaft includes an opening/closing
mechanism which opens and closes the passage, the opening/closing
mechanism includes an opening/closing valve which includes a
sealing wall and a communication bore which is disposed at a
position deviated in the axial direction of the rotary shaft with
respect to the sealing wall and is capable of moving in the axial
direction of the rotary shaft, and the opening/closing mechanism is
configured to close the passage by moving to one side of the axial
direction of the rotary shaft to dispose the sealing wall between
the first passage portion and the second passage portion and to
open the passage by moving to the other side of the axial direction
of the rotary shaft to dispose, instead of the sealing wall, the
communication bore between the first passage portion and the second
passage portion.
[0178] According to this configuration, since it is possible to
open and close the passage merely by providing the sealing wall
which has a function of blocking the passage and the communication
bore which has a function of communicating with the passage in a
single member (the opening/closing valve) and moving the single
member (the opening/closing valve), it is possible to easily
perform the opening and closing of the passage and it is possible
to simplify the configuration of the opening/closing mechanism.
[0179] In the configuration in which the opening/closing mechanism
includes the sealing wall and the communication bore, it is
preferable that the opening/closing mechanism is configured to move
the opening/closing valve according to an internal pressure of a
discharging port and is configured to close the passage by
disposing the sealing wall between the first passage portion and
the second passage portion in a case in which the internal pressure
of the discharging port is low and to open the passage by
disposing, instead of the sealing wall, the communication bore
between the first passage portion and the second passage portion in
a case in which the internal pressure of the discharging port is
high.
[0180] According to this configuration, in a case in which the
rotation frequency of the engine is lowered and the internal
pressure of the discharging port is low to an extent in which the
bubbles are not easily formed in the oil, it is possible to close
the passage. However, in a case in which the rotation frequency of
the engine is raised and the internal pressure of the discharging
port is high to an extent in which the bubbles are easily formed in
the oil, it is possible to open the passage. In other words, it is
possible to effectively remove the bubbles contained in the oil
while suppressing the flowing out of the oil to the outside of the
pump housing.
[0181] In the configuration in which the opening/closing mechanism
moves an opening/closing valve according to the internal pressure
of the discharging port, it is preferable that the opening/closing
mechanism includes a pressure chamber which is provided on one side
in the axial direction of the rotary shaft of the opening/closing
valve, communicates with the discharging port via a pressure
passage, and pressurizes the opening/closing valve to move the
opening/closing valve, a biasing member which is provided on the
other side in the axial direction of the rotary shaft of the
opening/closing valve and biases the opening/closing valve toward
the pressure chamber, and a restriction portion which restricts
movement of the opening/closing valve to the pressure chamber side,
and the opening/closing mechanism is configured to close the
passage by disposing the sealing wall between the first passage
portion and the second passage portion in a state in which the
opening/closing valve and the restriction portion are caused to
abut against each other by a biasing force of the biasing member in
a case in which the internal pressure of the discharging port and
the pressure chamber is low and to open the passage by disposing,
instead of the sealing wall, the communication bore between the
first passage portion and the second passage portion in a state in
which the opening/closing valve and the restriction portion are
separated from each other against the biasing force of the biasing
member by the internal pressure of the pressure chamber via the
opening/closing valve in a case in which the internal pressure of
the discharging port and the pressure chamber is high.
[0182] According to this configuration, it is possible to configure
the opening/closing mechanism from only structural and mechanical
configuration elements (the pressure chamber, the opening/closing
valve, the biasing member, and the restriction portion) without
using electrical configuration elements. Therefore, since it is not
necessary to provide a configuration for supplying electrical power
or the like to the opening/closing mechanism, it is possible to
simplify the configuration of the opening/closing mechanism.
[0183] In the oil pump according to the aspect, it is preferable
that the rotor is an inscribed gear rotor which includes an outer
rotor including a plurality of internal teeth and an inner rotor
including a plurality of external teeth which mesh with the
internal teeth of the outer rotor, or the rotor is a vane rotor
which includes a rotor main body and a plurality of vanes which are
provided to protrude outward from the rotor main body and form the
pump chamber.
[0184] According to this configuration, in a case in which the
inscribed gear rotor (the inscribed gear pump) is used, it is
possible to configure the oil pump such that it is possible to
obtain a great output using a comparatively small structure. In a
case in which the vane rotor (the vane pump) is used, it is
possible to configure the oil pump using a simple shape in which
foreign matter and the like do not easily get stuck.
[0185] In the oil pump according to the aspect, it is preferable
that the shaft portion includes a rotary shaft which includes a
recessed portion having a circular cross-section that is orthogonal
to an axial direction of the shaft portion and extending in the
axial direction and which rotates together with the rotor, and a
fixed shaft which includes a first member which is fixed to the
pump housing and a second member which is inserted into the
recessed portion and is connected to the first member in a state of
being capable of moving in a direction orthogonal to the axial
direction.
[0186] According to this configuration, since it is possible to
allow the movement of the fixed shaft (the second member) in a
direction orthogonal to the axial directions relative to the rotary
shaft, it is possible to more uniformly maintain the clearance
between the fixed shaft (the second member) and the recessed
portion in the circumferential direction of the fixed shaft (the
second member) as compared to a case in which the entirety of the
fixed shaft is completely fixed to the pump housing. Accordingly,
it is possible to suppress the clearance between the fixed shaft
and the recessed portion in the circumferential direction of the
fixed shaft becoming too great and the sealing properties being
inhibited. It is possible to suppress the clearance between the
fixed shaft and the recessed portion becoming too small and the
rotation of the rotary shaft being prevented by the fixed shaft. In
a case in which the entirety of the fixed shaft is completely fixed
to the pump housing, it is necessary to consider, during the
manufacturing, the tolerance between the rotary shaft and the fixed
shaft and the tolerance between the fixed shaft and the
configurations (the flange and the like) for attaching the fixed
shaft to the pump housing. However, in the configuration of the
fourth embodiment, it is sufficient to only consider the tolerance
between the rotary shaft and the first member during the
manufacturing. In other words, it is possible to easily maintain a
uniform clearance between the fixed shaft (the second member) and
the recessed portion.
[0187] In this case, it is preferable that the fixed shaft includes
a turn-stopping portion which connects the first member and the
second member to each other in a state in which the second member
is capable of moving in the direction orthogonal to the axial
direction relative to the first member.
[0188] According to this configuration, it is possible to easily
realize a configuration which connects the second member and the
first member to each other in a state in which the movement of the
fixed shaft (the second member) in the direction orthogonal to the
axial direction relative to the rotary shaft using the
turn-stopping portion.
[0189] In the oil pump according to the aspect, it is preferable
that the passage includes a first passage portion which is provided
to straddle at least one of the pump housing and the inner rotor
and the shaft portion and extending in a direction intersecting an
axial direction of the shaft portion, and a second passage portion
which is provided in the shaft portion and extends in the axial
direction, the shaft portion includes a rotary shaft which includes
a recessed portion having a circular cross-section that is
orthogonal to the axial direction of the shaft portion and extends
in the axial direction and which rotates together with the inner
rotor, and a fixed shaft which includes a first member which is
fixed to the pump housing and a second member which is inserted
into the recessed portion and is connected to the first member in a
state of being capable of moving in a direction orthogonal to the
axial direction, and the first passage portion includes an outer
passage portion which is provided to straddle the rotary shaft and
the inner rotor and an inner passage portion which is provided in
the fixed shaft and communicates with the outer passage portion at
a predetermined rotational position of the rotary shaft.
[0190] According to this configuration, it is possible to
communicate the outer passage portion and the inner passage portion
with each other at a predetermined rotational position of the
rotary shaft. Accordingly, it is possible to effectively discharge
the bubbles to the outside of the pump housing using a higher
pressure when the outer passage portion and the inner passage
portion communicate with each other in a case in which the inner
passage portion faces the discharging port side more than the
suction port side.
[0191] In the oil pump according to the aspect, it is preferable
that a tooth bottom of the inner rotor is provided with a bubble
introduction portion which is disposed between the pump chamber and
the passage, which collects the bubbles inside the pump chamber and
introduces the collected bubbles into the passage.
[0192] According to this configuration, since it is possible to
introduce more of the bubbles into the passage than the oil by
collecting the bubbles at the bubble introduction portion, it is
possible to suppress the discharging of the oil from the passage
portion.
[0193] In the oil pump according to the aspect, it is preferable
that the passage includes a first passage portion which is provided
to straddle at least one of the pump housing and the inner rotor
and the shaft portion and extends in a direction intersecting the
axial direction of the shaft portion, and a second passage portion
which is provided in the shaft portion and extends in the axial
direction, and one end of the first passage portion is connected to
a tooth bottom of the inner rotor.
[0194] According to this configuration, since it is possible to
dispose one end of the first passage portion at a closer position
to the shaft portion at which the bubbles collect easily due to the
oil being moved to the outside of the shaft portion in the radial
direction by a centrifugal force, it is possible to more
efficiently remove the bubbles.
[0195] In the oil pump according to the aspect, it is preferable
that the passage is provided to straddle the pump housing and the
shaft portion and the passage on the pump housing side is formed in
a groove shape which communicates the pump chamber and the passage
on the shaft portion side with each other.
[0196] According to this configuration, since it is possible to
move the bubbles from the pump chamber to the shaft portion side
via the pump housing which is a configuration which does not
rotate, it is possible to stably move the bubbles to the shaft
portion side using the groove-shaped passage as compared to a case
in which the passage is provided in the inner rotor which rotates.
As a result, it is possible to stably discharge the bubbles to the
outside of the pump housing.
[0197] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the spirit of the present
invention. Accordingly, it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
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