U.S. patent application number 14/866522 was filed with the patent office on 2016-04-21 for variable-flow rate oil pump.
The applicant listed for this patent is YAMADA MANUFACTURING CO., LTD.. Invention is credited to Yuya KATO, Junichi Miyajima, Takatoshi WATANABE.
Application Number | 20160108781 14/866522 |
Document ID | / |
Family ID | 55748648 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160108781 |
Kind Code |
A1 |
Miyajima; Junichi ; et
al. |
April 21, 2016 |
VARIABLE-FLOW RATE OIL PUMP
Abstract
A variable-flow rate oil pump includes: a main oil pump; a
subsidiary oil pump; a control valve provided with a spool valve
body; a main discharge oil passage; a subsidiary discharge oil
passage merging with the main discharge oil passage; a main relief
oil passage branching from the main discharge oil passage; a
subsidiary relief oil passage branching from the subsidiary
discharge oil passage; and a check valve permitting a flow only in
one direction from the upstream side to the downstream side of the
subsidiary discharge oil passage. The control valve is positioned
at respective intermediate points of the main relief oil passage
and the subsidiary relief oil passage, and the control valve is
positioned on the upstream side of the check valve in the
subsidiary discharge oil passage, and an engine speed at which the
subsidiary discharge oil passage.
Inventors: |
Miyajima; Junichi;
(Kiryu-shi, JP) ; WATANABE; Takatoshi; (Kiryu-shi,
JP) ; KATO; Yuya; (Kiryu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
YAMADA MANUFACTURING CO., LTD. |
Kiryu-shi |
|
JP |
|
|
Family ID: |
55748648 |
Appl. No.: |
14/866522 |
Filed: |
September 25, 2015 |
Current U.S.
Class: |
137/565.11 |
Current CPC
Class: |
F01M 1/16 20130101; F01M
2001/123 20130101; F01M 1/02 20130101 |
International
Class: |
F01M 1/02 20060101
F01M001/02; F01M 1/16 20060101 F01M001/16 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 16, 2014 |
JP |
2014-211822 |
Claims
1. A variable-flow rate oil pump, comprising: a main oil pump; a
subsidiary oil pump; a control valve provided with a spool valve
body; a main discharge oil passage extending from the main oil
pump; a subsidiary discharge oil passage extending from the
subsidiary oil pump and merging with the main discharge oil
passage; a main relief oil passage branching from the main
discharge oil passage; a subsidiary relief oil passage branching
from the subsidiary discharge oil passage; and a check valve
permitting a flow only in one direction from an upstream side to a
downstream side of the subsidiary discharge oil passage, wherein
the control valve is positioned at respectively intermediate points
of the main relief oil passage and the subsidiary relief oil
passage; the control valve is positioned on the upstream side of
the check valve in the subsidiary discharge oil passage; and an
engine speed at which the subsidiary discharge oil passage is shut
off by the check valve is set to be lower than an engine speed at
which the subsidiary discharge oil passage is shut off by the spool
valve body.
2. The variable-flow rate oil pump according to claim 1, wherein an
engine speed at which oil is relieved from the subsidiary relief
oil passage by movement of the spool valve body is set to be lower
than the engine speed at which the subsidiary discharge oil passage
is shut off by the check valve.
3. A variable-flow rate oil pump, comprising: a main oil pump; a
subsidiary oil pump; a control valve provided with a spool valve
body; a main discharge oil passage extending from the main oil
pump; a subsidiary discharge oil passage extending from the
subsidiary oil pump and merging with the main discharge oil
passage; a main relief oil passage branching from the main
discharge oil passage; a subsidiary relief oil passage branching
from the subsidiary discharge oil passage; and a check valve
permitting a flow only in one direction from an upstream side to a
downstream side of the subsidiary discharge oil passage, wherein
the control valve is positioned at respective intermediate points
of the main relief oil passage and the subsidiary relief oil
passage; the control valve is positioned on the upstream side of
the check valve in the subsidiary discharge oil passage; the
subsidiary discharge oil passage is shut off by the check valve
before the subsidiary discharge oil passage is shut off due to
movement of the spool valve body to the rear side; and relief of
oil in the subsidiary relief oil passage is performed before the
subsidiary discharge oil passage is shut off by the check
valve.
4. The variable-flow rate oil pump according to claim 1, wherein a
main relief inflow port, a main relief expulsion port, a subsidiary
inflow port, a subsidiary outflow port, a subsidiary relief inflow
port, and a subsidiary relief expulsion port are provided from the
front side in a valve chamber of the control valve; the subsidiary
inflow port is provided at the same position as the subsidiary
outflow port in the axial direction; the subsidiary relief inflow
port is provided at the same position as the subsidiary relief
expulsion port in the axial direction; a small-diameter valve
chamber is provided at the front end of the valve chamber; in the
spool valve body, a pressure receiving valve section, a first
large-diameter valve section, a second large-diameter valve section
and a third large-diameter valve section are formed successively
from the front side to the rear side in the axial direction; the
first large-diameter valve section shuts off and enables
communication between the main relief inflow port and the main
relief expulsion port; the third large-diameter valve section is
configured so as to shut off and enable communication between the
subsidiary relief inflow port and the subsidiary relief expulsion
port; the pressure receiving valve section is inserted into the
small-diameter valve chamber, and an operation outflow/inflow port
is formed at the front end of the small-diameter valve chamber; the
operation outflow/inflow port communicates with an operating oil
passage that branches from the main relief oil passage; an
operating valve and an expulsion oil passage are provided at an
intermediate point of the operating oil passage; and the operating
valve is configured so as to switch between either one of
communication between the operating oil passage and the main relief
oil passage and communication between the operating oil passage and
the expulsion oil passage.
5. The variable-flow rate oil pump according to claim 4, wherein a
length in the axial direction of the first large-diameter valve
section of the spool valve body is smaller than a maximum interval
in the axial direction between the main relief expulsion port and
the subsidiary outflow port.
6. The variable-flow rate oil pump according to claim 4, wherein a
length in the axial direction of the first large-diameter valve
section of the spool valve body is equal to or greater than a
maximum interval in the axial direction between the main relief
expulsion port and the subsidiary outflow port.
7. The variable-flow rate oil pump according to claim 3, wherein a
main relief inflow port, a main relief expulsion port, a subsidiary
inflow port, a subsidiary outflow port, a subsidiary relief inflow
port, and a subsidiary relief expulsion port are provided from the
front side in a valve chamber of the control valve; the subsidiary
inflow port is provided at the same position as the subsidiary
outflow port in the axial direction; the subsidiary relief inflow
port is provided at the same position as the subsidiary relief
expulsion port in the axial direction; a small-diameter valve
chamber is provided at the front end of the valve chamber; in the
spool valve body, a pressure receiving valve section, a first
large-diameter valve section, a second large-diameter valve section
and a third large-diameter valve section are formed successively
from the front side to the rear side in the axial direction; the
first large-diameter valve section shuts off and enables
communication between the main relief inflow port and the main
relief expulsion port; the third large-diameter valve section is
configured so as to shut off and enable communication between the
subsidiary relief inflow port and the subsidiary relief expulsion
port; the pressure receiving valve section is inserted into the
small-diameter valve chamber, and an operation outflow/inflow port
is formed at the front end of the small-diameter valve chamber; the
operation outflow/inflow port communicates with an operating oil
passage that branches from the main relief oil passage; an
operating valve and an expulsion oil passage are provided at an
intermediate point of the operating oil passage; and the operating
valve is configured so as to switch between either one of
communication between the operating oil passage and the main relief
oil passage and communication between the operating oil passage and
the expulsion oil passage.
8. The variable-flow rate oil pump according to claim 7, wherein a
length in the axial direction of the first large-diameter valve
section of the spool valve body is smaller than a maximum interval
in the axial direction between the main relief expulsion port and
the subsidiary outflow port.
9. The variable-flow rate oil pump according to claim 7, wherein a
length in the axial direction of the first large-diameter valve
section of the spool valve body is equal to or greater than a
maximum interval in the axial direction between the main relief
expulsion port and the subsidiary outflow port.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates in particular to a
variable-flow rate oil pump, which can send oil to an automobile
engine at an appropriate pressure in accordance with a rotational
speed thereof.
[0003] 2. Description of the Related Art
[0004] Conventionally, there have been variable-flow rate oil pumps
equipped with two pumps, namely, a main oil pump and a subsidiary
oil pump, and an oil pressure adjustment valve which adjusts the
respective discharge amounts thereof. Japanese Patent Application
Publication No. 2013-204487 discloses one oil pump of this kind.
Japanese Patent Application Publication No. 2013-204487 discloses
an oil pump unit (101) provided with an oil path switching valve
(121) which adjusts the supply oil pressure from a main oil pump
(106) and a subsidiary oil pump (107) to an oil pressure supply
destination.
SUMMARY OF THE INVENTION
[0005] The oil pump unit (101) disclosed in Japanese Patent
Application Publication No. 2013-204487 is configured so as to
smoothly adjust the flow direction of the oil discharged from the
main oil pump (106) and the subsidiary oil pump (107) by an oil
path switching valve (121), in such a manner that oil can be
supplied to the engine at an even more appropriate pressure
corresponding to the speed of the engine.
[0006] Looking at FIG. 7 of Japanese Patent Application Publication
No. 2013-204487, it is interpreted that a non-reversing valve (145)
is disposed downstream of the oil path switching valve (121). As
described in paragraphs [0037] and [0043], it is only indicated
that the non-reversing valve (145) permits a flow of oil from the
oil path switching valve (121) to a merging section (142d), but
shuts off the flow of oil from a main discharge flow passage (141)
to the oil path switching valve (121). In this way, the
relationship between the non-reversing valve (145) and the spool
valve (123) is not disclosed in particular, and therefore the
effect of the non-reversing valve (145) in improving fuel
consumption is not disclosed or suggested. Therefore, the object of
the present invention (the technical problem to be solved) is to
provide a variable-flow rate oil pump in which fuel consumption can
be improved further.
[0007] Therefore, as a result of thorough repeated research aimed
at resolving the abovementioned problem, the present inventors
resolved the abovementioned problem by configuring a first
embodiment of the present invention as a variable-flow rate oil
pump, including: a main oil pump; a subsidiary oil pump; a control
valve provided with a spool valve body; a main discharge oil
passage extending from the main oil pump; a subsidiary discharge
oil passage extending from the subsidiary oil pump and merging with
the main discharge oil passage; a main relief oil passage branching
from the main discharge oil passage; a subsidiary relief oil
passage branching from the subsidiary discharge oil passage; and a
check valve permitting a flow only in one direction from an
upstream side to a downstream side of the subsidiary discharge oil
passage, wherein the control valve is positioned at respective
intermediate points of the main relief oil passage and the
subsidiary relief oil passage; the control valve is positioned on
the upstream side of the check valve in the subsidiary discharge
oil passage; and an engine speed at which the subsidiary discharge
oil passage is shut off by the check valve is set to be lower than
an engine speed at which the subsidiary discharge oil passage is
shut off by the spool valve body.
[0008] The inventors resolved the abovementioned problem by
configuring a second embodiment of the present invention as the
variable-flow rate oil pump according to the first embodiment,
wherein an engine speed at which oil is relieved from the
subsidiary relief oil passage by movement of the spool valve body
is set to be lower than the engine speed at which the subsidiary
discharge oil passage is shut off by the check valve.
[0009] The inventors resolved the abovementioned problem by
configuring a third embodiment of the present invention as a
variable-flow rate oil pump, including: a main oil pump; a
subsidiary oil pump; a control valve provided with a spool valve
body; a main discharge oil passage extending from the main oil
pump; a subsidiary discharge oil passage extending from the
subsidiary oil pump and merging with the main discharge oil
passage; a main relief oil passage branching from the main
discharge oil passage; a subsidiary relief oil passage branching
from the subsidiary discharge oil passage; and a check valve
permitting a flow only in one direction from an upstream side to a
downstream side of the subsidiary discharge oil passage, wherein
the control valve is positioned at respective intermediate points
of the main relief oil passage and the subsidiary relief oil
passage; the control valve is positioned on the upstream side of
the check valve in the subsidiary discharge oil passage; the
subsidiary discharge oil passage is shut off by the check valve
before the subsidiary discharge oil passage is shut off due to
movement of the spool valve body to the rear side; and relief of
oil in the subsidiary relief oil passage is performed before the
subsidiary discharge oil passage is shut off by the check
valve.
[0010] The inventors resolved the abovementioned problem by
configuring a fourth embodiment of the present invention as the
variable-flow rate oil pump according to the first or third
embodiment, wherein a main relief inflow port, a main relief
expulsion port, a subsidiary inflow port, a subsidiary outflow
port, a subsidiary relief inflow port, and a subsidiary relief
expulsion port are provided from the front side in a valve chamber
of the control valve; the subsidiary inflow port is provided at the
same position as the subsidiary outflow port in the axial
direction; the subsidiary relief inflow port is provided at the
same position as the subsidiary relief expulsion port in the axial
direction; a small-diameter valve chamber is provided at the front
end of the valve chamber; in the spool valve body, a pressure
receiving valve section, a first large-diameter valve section, a
second large-diameter valve section and a third large-diameter
valve section are formed successively from the front side to the
rear side in the axial direction; the first large-diameter valve
section shuts off and enables communication between the main relief
inflow port and the main relief expulsion port; the third
large-diameter valve section is configured so as to shut off and
enable communication between the subsidiary relief inflow port and
the subsidiary relief expulsion port; the pressure receiving valve
section is inserted into the small-diameter valve chamber, and an
operation outflow/inflow port is formed at the front end of the
small-diameter valve chamber; the operation outflow/inflow port
communicates with an operating oil passage that branches from the
main relief oil passage; an operating valve and an expulsion oil
passage are provided at an intermediate point of the operating oil
passage; and the operating valve is configured so as to switch
between either one of communication between the operating oil
passage and the main relief oil passage and communication between
the operating oil passage and the expulsion oil passage.
[0011] The inventors resolved the abovementioned problem by
configuring a fifth embodiment of the present invention as the
variable-flow rate oil pump according to the fourth embodiment,
wherein a length in the axial direction of the first large-diameter
valve section of the spool valve body is smaller than a maximum
interval in the axial direction between the main relief expulsion
port and the subsidiary outflow port. The inventors resolved the
abovementioned problem by configuring a sixth embodiment of the
present invention as the variable-flow rate oil pump according to
the fourth embodiment, wherein a length in the axial direction of
the first large-diameter valve section of the spool valve body is
equal to or greater than a maximum interval in the axial direction
between the main relief expulsion port and the subsidiary outflow
port.
[0012] In the present invention, the pressure of the oil discharged
from the subsidiary pump increases as the engine speed increases
from a low speed, and the spool valve body of the control valve
moves towards the rear side from an initial state. Due to the
movement of the spool valve body towards the rear side, the spool
valve body performs a shut-off operation so as to gradually reduce
the cross-sectional surface area of the subsidiary discharge oil
passage and ultimately close same completely.
[0013] However, since the check valve which is positioned to the
downstream side of the control valve in the subsidiary discharge
oil passage shuts off the subsidiary discharge oil passage
previously, the spool valve body does not completely close off the
subsidiary discharge oil passage, hence the flow of oil in the
subsidiary discharge oil passage is stopped. Consequently, the
subsidiary oil pump stops sending oil to the engine, and the fuel
consumption can be improved accordingly.
[0014] Therefore, it is possible to resolve the problem in the
prior art, in which, when the spool valve body moves to the rear
side and the cross-sectional surface area of the subsidiary
discharge oil passage becomes smaller or narrower, then oil cannot
be discharged readily from the subsidiary oil pump, and
consequently, the oil pressure of the subsidiary oil pump rises,
energy is lost and fuel consumption becomes worse.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1A is a schematic drawing of a partial cross-section
showing the configuration of the variable-flow rate oil pump
according to the present invention, FIG. 1B is an enlarged diagram
showing a control valve and a partial cross-section of the vicinity
thereof, FIG. 1C is a principal enlarged cross-sectional diagram
showing a state where the axial-direction length of a first
large-diameter valve section of a spool valve is smaller than a
maximum interval between the main relief discharge port and the
subsidiary discharge port, and FIG. 1D is a schematic drawing of a
partial cross-section of an operating valve;
[0016] FIG. 2 is a schematic drawing showing an operation in a low
speed range of the engine according to the present invention;
[0017] FIG. 3 is a schematic drawing showing an operation in an
initial stage of a medium speed range of the engine according to
the present invention;
[0018] FIG. 4 is a schematic drawing showing an operation in a
middle stage of a medium speed range of the engine according to the
present invention;
[0019] FIG. 5 is a schematic drawing showing an operation in a
later stage of a medium speed range of the engine according to the
present invention;
[0020] FIG. 6 is a schematic drawing showing an operation in an
initial stage of a high speed range of the engine according to the
present invention;
[0021] FIG. 7 is a schematic drawing showing an operation in a
first-half middle stage of a high speed range of the engine
according to the present invention;
[0022] FIG. 8 is a schematic drawing showing an operation in a
second-half middle stage of a high speed range of the engine
according to the present invention;
[0023] FIG. 9 is a schematic drawing showing an operation in a
later stage of a high speed range of the engine according to the
present invention;
[0024] FIG. 10 an enlarged cross sectional drawing showing a main
part of a spool valve body, in which the length of a first
large-diameter valve section of the spool valve body in the axial
direction is set so to be greater than the maximum interval between
a main relief expulsion port and a subsidiary outflow port; and
[0025] FIG. 11 is a graph showing the characteristics of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] An embodiment of the present invention is described below on
the basis of the drawings. The variable-flow rate oil pump of the
present invention is provided inside an oil circuit 3 which
supplies oil to respective parts of an engine (see FIG. 1). The
configuration of the present invention principally includes a main
oil pump 1, a subsidiary oil pump 2, a control valve B, an
operating valve 8, a check valve 7, a main discharge oil passage
31, a subsidiary discharge oil passage 41, a main relief oil
passage 32 and a subsidiary relief oil passage 42. These are
combined into one unit, which is a variable-flow rate oil pump
A.
[0027] The main oil pump 1 and the subsidiary oil pump 2 can use
pumps of a variety of types, but a trochoid type internal gear pump
is particularly suitable. The main oil pump 1 and the subsidiary
oil pump 2 have different theoretical discharge amounts, and the
theoretical discharge amount of the main oil pump 1 is often set to
be greater than that of the subsidiary oil pump 2, but in order to
increase the amount of variation, the theoretical discharge amount
of the subsidiary oil pump 2 may be made greater.
[0028] The main oil pump 1 is incorporated into the oil circuit 3,
and supplies oil to an oil supply object 9, such as an engine
incorporated into the oil circuit 3 (see FIG. 1A). The main
discharge oil passage 31 extends from the discharge section of the
main oil pump 1 and is connected to the oil supply object 9. The
main discharge oil passage 31 is a portion of the oil circuit 3
(see FIG. 1A).
[0029] The subsidiary oil pump 2 is provided in parallel alignment
with the main oil pump 1 in the oil circuit 3 (see FIG. 1A). The
subsidiary oil pump 2 may be arranged adjacently to or in
integrated fashion with the main oil pump of the oil circuit 3, a
branch oil passage 36 may be provided from the oil circuit 3 for
the purpose of the subsidiary oil pump 2, and the subsidiary oil
pump 2 may be provided in the branch oil passage 36 (see FIG.
1A).
[0030] A main relief oil passage 32 branches from the main
discharge oil passage 31, and when relieving of the main oil pump 1
is required, oil is relieved (expelled) via the main relief oil
passage 32. A subsidiary discharge oil passage 41 which merges with
the main discharge oil passage 31 is provided on the discharge side
of the subsidiary oil pump 2.
[0031] A subsidiary relief oil passage 42 which branches from a
position to the downstream side of the discharge side of the
subsidiary oil pump 2 and which connects with the inlet side of the
subsidiary oil pump 2 is provided in the subsidiary discharge oil
passage 41. The subsidiary relief oil passage is used to relieve
oil when the subsidiary oil pump 2 is required to relieve oil.
[0032] The oil passages of the subsidiary discharge oil passage 41,
the main relief oil passage 32 and the subsidiary relief oil
passage 42 are concentrated into one control valve B, and the
control valve B is arranged at an appropriate position that is
midway between the respective oil passages (see FIG. 1B). In other
words, the control valve B controls the connection and
disconnection of the flow of oil that is discharged from the main
oil pump 1 and the subsidiary oil pump 2.
[0033] The control valve B is configured by a valve chamber 5 and a
spool valve body 6, and the spool valve body 6 is accommodated in
the valve chamber 5 (see FIG. 1B). In the spool valve body 6, a
first large-diameter valve section 61, a second large-diameter
valve section 62 and a third large-diameter valve section 63 are
arranged in sequence from the front side, and these sections are
coupled via a coupling shaft 65. Furthermore, a pressure receiving
valve section 64 is formed to the front side of the first
large-diameter valve section 61. The pressure receiving valve
section 64 and the first large-diameter valve section 61 are
coupled by the coupling shaft 65 (see FIG. 1B).
[0034] Here, in the present specification, when describing the
front side and the rear side of the control valve B, the side of
the pressure receiving valve section 64 or an operation
outflow/inflow port 54a (described below), with reference to the
spool valve body 6, is regarded as the front side in the axial
direction, and the third large-diameter valve section 63 side or an
elastic member 66 (described below) side of the spool valve body 6
is regarded as the rear side in the axial direction.
[0035] With respect to the front side and the rear side of the
valve chamber 5, the same direction as the front side of the spool
valve body 6 which is accommodated in the valve chamber 5 is
regarded as the front side of the valve chamber 5, and the opposite
side thereof is regarded as the rear side; the front side and the
rear side are depicted in FIG. 1B. The front side and the rear side
of the control valve B can also be used when the control valve B is
arranged vertically, as well as when the control valve B is
arranged horizontally as depicted in the drawings. For example,
when the control valve B is arranged vertically with the front side
upwards, then the upper side is the front side and the lower side
is the rear side.
[0036] In the spool valve body 6, the diameter of the coupling
shaft 65 is smaller than the diameters of the pressure receiving
valve section 64, the first large-diameter valve section 61, the
second large-diameter valve section 62 and the third large-diameter
valve section 63. Furthermore, the diameter of the
pressure-receiving valve section 64 is smaller than the diameters
of the first large-diameter valve section 61, the second
large-diameter valve section 62 and the third large-diameter valve
section 63. The first large-diameter valve section 61, the second
large-diameter valve section 62 and the third large-diameter valve
section 63 are substantially the same (see FIG. 1B).
[0037] Gap sections exist between the pressure receiving valve
section 64, the first large-diameter valve section 61, the second
large-diameter valve section 62 and the third large-diameter valve
section 63; the gap between the pressure receiving valve section 64
and the first large-diameter valve section 61 is called a first gap
section 61s, the gap between the first large-diameter valve section
61 and the second large-diameter valve section 62 is called a
second gap section 62s, and the gap between the second
large-diameter valve section 62 and the third large-diameter valve
section 63 is called a third gap section 63s (see FIG. 1B).
[0038] The spool valve body 6 can move reciprocally forwards and
backwards in the axial direction inside the valve chamber 5, an
elastic member 66, such as a compression coil spring, is provided
between the rear end side of the spool valve body 6, in other
words, the third large-diameter valve section 63, and the rear end
side of the valve chamber 5, and the spool valve body 6 is
elastically impelled to the front side of the valve chamber 5 at
all times. A state where the spool valve body 6 is stationary at
the furthest possible position on the front side of the valve
chamber 5 is called the initial state.
[0039] A small-diameter valve chamber 54 into which the pressure
receiving valve section 64 is inserted is formed in the front-side
end section of the valve chamber 5. As described below, oil is fed
to the small-diameter valve chamber 54 via an operating oil passage
34 which branches from the main relief oil passage 32, as described
below, and the pressure receiving valve section 64 on the front
side is pressed to the rear side and the spool valve body 6 moves
to the rear side.
[0040] A subsidiary inflow port 51a, a subsidiary outflow port 51b,
a subsidiary relief inflow port 52a and a subsidiary relief
expulsion port 52b are formed in the valve chamber 5 as a
connecting portion relating to the subsidiary oil pump 2.
Furthermore, a main relief inflow port 53a and a main relief
expulsion port 53b are provided in the valve chamber 5 as a
connecting portion relating to the main oil pump 1.
[0041] The main relief inflow port 53a, main relief expulsion port
53b, subsidiary outflow port 51b and subsidiary relief expulsion
port 52b are formed in sequence from the front side of the valve
chamber 5, the subsidiary inflow port 51a is situated at the same
position as the subsidiary outflow port 51b in the axial direction,
and the subsidiary relief inflow port 52a is situated at the same
position as the subsidiary relief expulsion port 52b in the axial
direction (see FIG. 1B).
[0042] Communication between the main relief inflow port 53a and
the main relief expulsion port 53b, and between the subsidiary
inflow port 51a and the subsidiary outflow port 51b, is enabled and
shut off by the first large-diameter valve section 61 and the
second large-diameter valve section 62 of the spool valve body 6
(see FIG. 2 to FIG. 9). Furthermore, communication between the
subsidiary relief inflow port 52a and the subsidiary relief
expulsion port 52b is enabled and shut off by the third
large-diameter valve section 63 and the second large-diameter valve
section 62 (see FIG. 2 to FIG. 9).
[0043] The subsidiary discharge oil passage 41 is divided into a
first subsidiary discharge oil passage 41a which is connected to
the subsidiary inflow port 51a side with respect to the control
valve B that is provided at a midway position, and a second
subsidiary discharge oil passage 41b which is connected to the
subsidiary outflow port 51b (see FIG. 1A). The first subsidiary
discharge oil passage 41a connects the subsidiary oil pump 2 and
the control valve B, and the second subsidiary discharge oil
passage 41b connects the control valve B and the main discharge oil
passage 31 (see FIG. 1A).
[0044] Furthermore, the subsidiary relief oil passage 42 is divided
into a first subsidiary relief oil passage 42a which is connected
to the subsidiary relief inflow port 52a side with reference to the
control valve B that is provided at a midway position, and a second
subsidiary relief oil passage 42b which is connected to the
subsidiary relief expulsion port 52b. The first subsidiary relief
oil passage 42a branches from the first subsidiary discharge oil
passage 41a and is connected to the subsidiary relief inflow port
52a. Furthermore, the second subsidiary relief oil passage 42b is
connected from the subsidiary relief expulsion port 52b to the
inlet side of the subsidiary oil pump 2 or the branch oil passage
36 for the subsidiary oil pump 2.
[0045] The main relief oil passage 32 is divided into a first main
relief oil passage 32a which is connected to the main relief inflow
port 53a, with respect to the control valve B, and a second main
relief oil passage 32b which is connected to the main relief
expulsion port 53b side (see FIG. 1A). The second main relief oil
passage 32b is connected to merge at the inlet side of the main oil
pump 1 or at a position to the upstream side of the main oil pump 1
of the oil circuit 3.
[0046] An operation outflow/inflow port 54a is formed in the
small-diameter valve chamber 54 of the valve chamber 5. An
operating oil passage 34 is connected between the operation
outflow/inflow port 54a and the first main relief oil passage 32a.
An operating valve 8 is disposed at a midway point of the operating
oil passage 34.
[0047] The operating valve 8 is provided with a direction control
valve section 81. Furthermore, an expulsion oil passage 35 is
provided in the operating valve 8. By the operation of the
operating valve 8, it is possible to switch to either one only of
communication between the operation outflow/inflow port 54a and the
first main relief oil passage 32a, and communication between the
operation outflow/inflow port 54a and the expulsion oil passage 35
(see FIGS. 1B, 1D). The operating valve 8 employs a solenoid valve,
but may also use a hydraulic type of valve.
[0048] A check valve 7 is provided in the second subsidiary
discharge oil passage 41b of the subsidiary discharge oil passage
41. The check valve 7 is used as a non-reversing. valve (see FIG.
1B). The check valve 7 permits a flow of oil only from the upstream
side to the downstream side of the second subsidiary discharge oil
passage 41b, and shuts off the flow of oil in the opposite
direction.
[0049] In other words, oil can only be sent from the subsidiary
outflow port 51b of the control valve B in a direction that merges
with the main discharge oil passage 31, but cannot be sent in the
opposite direction. The check valve 7 is configured by a sphere
body 71 and an elastic impelling member 72, such as a compression
coil spring, which impels the sphere body 71 (see FIG. 1B).
[0050] Furthermore, due to the elastic impelling member 72, the
sphere body 71 of the check valve 7 acts so as to shut off the flow
from the upstream side to the downstream side of the second
subsidiary discharge oil passage 41b, and when the flow speed of
the oil flowing out from the subsidiary outflow port 51b of the
control valve B is small, the force of the elastic impelling member
72 is greater than the force of the oil pressure differential
caused by the flow speed, and therefore the flow of oil can be
stopped.
[0051] Moreover, in the control valve B, the length La of the first
large-diameter valve section 61 of the spool valve body 6 in the
axial direction is set to be smaller than the maximum interval Lb
in the axial direction between the main relief expulsion port 53b
and the subsidiary outflow port 51b of the valve chamber 5.
[0052] In other words,
[0053] La<Lb.
[0054] The first large-diameter valve section 61 does not
completely close off both the main relief expulsion port 53b and
the subsidiary outflow port 51b of the valve chamber 5
simultaneously, but rather leaves one thereof open. In other words,
before the first large-diameter valve section 61 finishes closing
off the subsidiary outflow port 51b, the main relief expulsion port
53b opens and relief of the main oil pump 1 can be started.
Consequently, it is possible to stop the discharge of oil into the
subsidiary discharge oil passage 41 of the subsidiary oil pump 2,
and to start relief of the main oil pump 1, in a smooth fashion,
and sudden changes in pressure can be prevented, which means that
vibrations and noise can be reduced.
[0055] Furthermore, in the control valve B, the length La of the
first large-diameter valve section 61 of the spool valve body in
the axial direction is set so to be the same as, or greater than,
the maximum interval Lb in the axial direction between the main
relief expulsion port 53b and the subsidiary outflow port 51b of
the valve chamber 5 (see FIG. 10).
[0056] In other words,
[0057] La.gtoreq.Lb.
[0058] With the abovementioned dimensional relationship, the engine
speed at which the oil discharged from the main oil pump 1 is
relieved from the main relief oil passage 32 can be moved slightly
to the higher speed range. In other words, by extending the engine
speed of the (later-stage) medium speed range, where the oil
pressure is low, towards the high speed range, it is possible to
improve fuel consumption.
[0059] Next, the operation of the present invention will be
explained principally in respect of the low speed range, the medium
speed range and the high speed range of the engine. In the
drawings, the arrows depicted along the respective oil paths
indicate the flow of the oil. The rotational states of the engine
also include idling (also called "idle rotation").
[0060] In the low speed range of the engine, as shown in FIG. 2,
the state of the spool valve body 6 of the control valve B is in an
initial state. The first large-diameter valve section closes the
main relief expulsion port 53b and the second gap section 62s opens
the subsidiary inflow port 51a and the subsidiary outflow port 51b.
Furthermore, the third large-diameter valve section 63 closes the
subsidiary relief inflow port 52a and the subsidiary relief
expulsion port 52b.
[0061] Furthermore, the operating valve 8 is set to a state of
communicating the main relief oil passage 32 and the operating oil
passage 34, and oil flows into the small-diameter valve chamber 54
from the operation outflow/inflow port 54a, but the force due to
this oil pressure is smaller than the elastic force of the elastic
member 66 and the spool valve body 6 is in the initial state.
[0062] Consequently, the main oil pump 1 discharges oil to the main
discharge oil passage 31, and supplies oil to an oil supply object
9, such as an engine. The main oil pump 1 and the subsidiary oil
pump 2 do not both relieve oil. The subsidiary oil pump 2
discharges oil to the subsidiary discharge oil passage 41, and
supplies oil directly to the oil supply object 9 from the merging
point with the main discharge oil passage 31.
[0063] In other words, the main oil pump 1 and the subsidiary oil
pump 2 both supply the full discharge amount, without alteration,
to the oil supply object 9. Here, the force generated by the flow
speed of the oil from the subsidiary oil pump 2, which acts on the
check valve 7 that is provided in the second subsidiary discharge
oil passage 41b, is greater than the elastic force of the elastic
impelling member 72 and therefore the oil flows through the second
subsidiary discharge oil passage 41b.
[0064] Next, the medium speed range of the engine is described,
separately in terms of an initial stage immediately after
transition to the medium speed range, a middle stage where the
engine speed is medium, and a later stage close to the high speed
range, as shown in FIG. 3 to FIG. 5. Immediately after transition
from the low speed range to the medium speed range, the pressure of
the oil flowing into the small-diameter valve chamber 54 increases,
the force due to this oil pressure becomes greater than the elastic
force of the elastic member 66, and the spool valve body 6 moves
slightly to the rear side. The third large-diameter valve section
63 moves and the subsidiary relief inflow port 52a and the
subsidiary relief expulsion port 52b open. In other words, the
third gap section 63s is positioned at the subsidiary relief inflow
port 52a and the subsidiary relief expulsion port 52b.
[0065] However, in the initial state of the medium speed range, the
spool valve body 6 moves by only a small amount, and therefore the
subsidiary relief inflow port 52a and the subsidiary relief
expulsion port 52b move slightly from a shut state to an open
state, and relief of a small amount is started (see FIG. 3). In
other words, the subsidiary oil pump supplies oil to the main
discharge oil passage 31 via the subsidiary discharge oil passage
41, as well as relieving a slight amount of oil.
[0066] In the middle stage of the medium speed range, the spool
valve body 6 of the control valve B moves further to the rear side.
Consequently, the first large-diameter valve section 61 closes the
subsidiary inflow port 51a and the subsidiary outflow port 51b so
as to assume a very small opening surface area. At this stage, the
oil discharged from the subsidiary oil pump 2 flows from the
subsidiary inflow port 51a to the subsidiary outflow port 51b, but
the force generated by the flow speed of the oil in this case is
smaller than the elastic force of the elastic impelling member 72
of the check valve 7. As a result of this, the check valve 7 stops
the flow of oil.
[0067] Consequently, the supply of oil from the subsidiary oil pump
2 to the oil supply object 9 is halted, and the subsidiary oil pump
2 only performs a relief operation. Furthermore, oil is supplied to
the oil supply object 9 from the main oil pump 1 only. In this
case, a relief operation by the main oil pump 1 does not start.
[0068] In the later stage of the medium speed range, as shown in
FIG. 5, the spool valve body 6 of the control valve B moves further
to the rear side. The first large-diameter valve section 61 becomes
situated to the rear side of the position of the main relief inflow
port 53a and the main relief expulsion port 53b, and the first gap
section 61s is positioned between the main relief inflow port 53a
and the main relief expulsion port 53b and communicates these with
each other.
[0069] The first main relief oil passage 32a and the second main
relief oil passage 32b are communicated, and relief by the main oil
pump 1 is started via the main relief oil passage 32. In other
words, the main oil pump 1 carries out a relief operation, at the
same time as supplying oil from the main discharge oil passage 31
to the oil supply object 9.
[0070] Next, the high speed range of the engine will be described
separately in terms of an initial stage, a first-half middle stage,
a second-half middle stage, and a later stage, as shown in FIG. 6
to FIG. 9. In the initial stage of the high speed range, as shown
in FIG. 6, the operating valve is operated, and the operating oil
passage 34 and the expulsion oil passage 35 are communicated with
each other. Consequently, the oil inside the small-diameter valve
chamber 54 of the valve chamber 5 is expelled from the expulsion
oil passage 35, and the spool valve body 6 is moved to the front
side by the elastic member 66. In other words, the spool valve body
6 is in the same initial state as the low speed range.
[0071] The first large-diameter valve section 61 opens the
subsidiary inflow port 51a and the subsidiary outflow port 51b, and
communicates the first subsidiary discharge oil passage 41a and the
second subsidiary discharge oil passage 41b with each other, via
the second gap section 62s. Consequently, the oil flows again into
the subsidiary discharge oil passage 41, and oil is supplied to the
oil supply object 9 from the main discharge oil passage 31. In
other words, the oil is supplied to the oil supply object 9 by the
main oil pump 1 and the subsidiary oil pump 2.
[0072] In the first-half of the middle stage of the high speed
range, as shown in FIG. 7, oil is sent into the main relief inflow
port 53a of the control valve B from the main discharge oil passage
31, due to the increase in the discharge pressure of the main oil
pump 1. A force due to the oil pressure is then applied to the
first large-diameter valve section 61, and the spool valve body 6
moves to the rear side. Furthermore, the configuration is such
that, in the first-half of the middle stage of the high speed
range, an oil pressure is not applied to the pressure receiving
valve section 64 of the spool valve body 6, but since the pressure
of the oil flowing in the first main relief oil passage 32a is
high, then the spool valve body 6 is moved only by the force of the
oil pressure which is applied only to the pressure receiving
surface of the first large-diameter valve section 61.
[0073] Due to this movement, the third large-diameter valve section
63 opens the subsidiary relief inflow port 52a and the subsidiary
relief expulsion port 52b, and the first subsidiary discharge oil
passage 41a and the second subsidiary discharge oil passage 41b are
communicated with each other and relief by the subsidiary oil pump
2 is started. At this stage, the main oil pump 1 supplies oil to
the oil supply object 9 without relieving oil, whereas the
subsidiary oil pump 2 supplies oil to the oil supply object 9 while
relieving oil.
[0074] In the second-half of the middle stage of the high speed
range, as shown in FIG. 8, due to further increase in the discharge
pressure of the main oil pump 1, the spool valve body 6 moves to
the rear side. The subsidiary discharge oil passage 41 is shut off,
and the subsidiary oil pump 2 performs oil relief only. The main
oil pump 1 supplies oil to the oil supply object 9, but does not
relieve oil.
[0075] In the later stage of the high speed range, as shown in FIG.
9, due to the further increase in the discharge pressure of the
main oil pump 1, the spool valve body 6 moves to the rear side. The
subsidiary discharge oil passage 41 is shut off and the subsidiary
oil pump 2 performs oil relief only. The main oil pump 1 supplies
oil to the oil supply object 9, as well as relieving oil. The
relationship between the oil pressure and the engine speed in the
low speed range, medium speed range and high speed range of the
engine described above is depicted in the graph showing the
characteristics of the present invention in FIG. 11.
[0076] In a second embodiment, by adopting a configuration in which
oil is relieved from the subsidiary relief oil passage before the
subsidiary discharge oil passage is shut off by the check valve, it
is possible to further reduce the pressure of the subsidiary oil
pump, and therefore further improvement in the fuel consumption can
be achieved. In a third embodiment, it is possible to provide a
variable-flow rate oil pump which can supply oil having an even
more appropriate pressure in accordance with respective speed
ranges of the oil supply object, such as an automobile engine. In
particular, it is possible to set the pressure of the supplied oil
precisely in respect of a medium speed range and high speed range
of the engine, and hence the efficiency of lubrication can be
further improved.
[0077] The check valve can prevent the flow of oil from the main
discharge oil passage to the subsidiary discharge oil passage. In
other words, reverse flow of oil in the subsidiary discharge oil
passage is prevented and the work performed by the subsidiary oil
pump can be performed accurately. Furthermore, the check valve is
configured so as to shut off the oil passage when the oil pressure
differential before and after the check valve generated by the flow
speed of the subsidiary discharge oil passage is very small.
[0078] Consequently, the spool valve body moves to the rear side of
the valve chamber, the subsidiary relief outflow port is not
completely closed, and even if there is a slight gap in which the
oil flows, the flow speed of the oil is weak and the check valve
can stop the flow of oil in the subsidiary discharge oil passage.
Furthermore, wasteful increase in the pressure of the oil supplied
to the oil supply object from the subsidiary oil pump and via the
main discharge oil passage can be suppressed. Apart from this, the
same beneficial effects as those of claim 1 are obtained.
[0079] In a fourth embodiment, the configuration for moving the
spool valve body can be simplified. The operating valve and
expulsion oil passage are provided at an intermediate point of the
operating oil passage, and the operating valve is configured so as
to switch to either one of communication between the operating oil
passage and the main relief oil passage, and communication between
the operating oil passage and the expulsion oil passage, and
therefore the movement operation of the spool valve body can be
performed smoothly and reliably.
[0080] In a fifth embodiment, the length in the axial direction of
the first large-diameter valve section of the spool valve body is
smaller than the maximum interval in the axial direction between
the main relief expulsion port and the subsidiary outflow port, and
therefore it is possible to create a temporal overlap between the
state immediately before stopping the supply of oil by the
subsidiary discharge oil passage, and the state immediately after
the start of a relief operation in the subsidiary relief oil
passage, and shocks due to sudden changes in the oil pressure
and/or the flow speed at the instant of changing operation can be
diminished.
[0081] In a sixth embodiment, the length in the axial direction of
the first large-diameter valve section of the spool valve body is
configured to be equal to or greater than the maximum interval in
the axial direction between the main relief expulsion port and the
subsidiary outflow port, and therefore a relief operation by the
main oil pump is started after the supply of oil via the subsidiary
discharge oil passage is stopped, and hence reliable supply of oil
and relief operation can be achieved.
* * * * *