U.S. patent application number 14/401596 was filed with the patent office on 2015-04-30 for multistage oil pump.
This patent application is currently assigned to MIKUNI CORPORATION. The applicant listed for this patent is MIKUNI CORPORATION. Invention is credited to Hiroyuki Oda.
Application Number | 20150118087 14/401596 |
Document ID | / |
Family ID | 49583812 |
Filed Date | 2015-04-30 |
United States Patent
Application |
20150118087 |
Kind Code |
A1 |
Oda; Hiroyuki |
April 30, 2015 |
MULTISTAGE OIL PUMP
Abstract
A conventional multistage oil pump, wherein the components are
formed of a ferrous material, and thus, there have been presented a
problem that the weight is large. The multistage oil pump and
rotors are connected in a series, wherein a rotor case, a first
rotor case and a second rotor case are connected in the axial
direction, and the inside thereof is partitioned by a spacer. The
first rotor case and the second rotor case are jointed to the
spacer with dowel pins. The rotors are formed of a ferrous
material, while the spacer being formed of an aluminum-based
material.
Inventors: |
Oda; Hiroyuki; (Iwate,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MIKUNI CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
MIKUNI CORPORATION
Tokyo
JP
|
Family ID: |
49583812 |
Appl. No.: |
14/401596 |
Filed: |
May 16, 2013 |
PCT Filed: |
May 16, 2013 |
PCT NO: |
PCT/JP2013/063649 |
371 Date: |
November 17, 2014 |
Current U.S.
Class: |
418/5 |
Current CPC
Class: |
F04C 15/0065 20130101;
F04C 2/103 20130101; F04C 2/102 20130101; F04C 11/001 20130101;
F01C 21/108 20130101; F04C 2240/30 20130101; F05C 2201/021
20130101; F04C 15/06 20130101; F04C 11/003 20130101 |
Class at
Publication: |
418/5 |
International
Class: |
F04C 11/00 20060101
F04C011/00; F04C 15/00 20060101 F04C015/00; F04C 2/10 20060101
F04C002/10 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2012 |
JP |
2012-113479 |
Claims
1. A multistage oil pump, a plurality of rotors being connected in
series in the direction of the rotation axis, said plurality of
rotors being accommodated in a rotor case, the inside thereof being
partitioned by a spacer, the rotor case being divided in the axial
direction, and said spacer being made of a material having a
specific gravity smaller than that for the rotor.
2. The multistage oil pump according to claim 1, wherein said
rotors are made of a ferrous material, while said spacer being made
of an aluminum-based material.
3. The multistage oil pump according to claim 1, wherein, with said
rotor case, said spacer is interposed between rotor case units, the
spacer and said respective rotor case units being jointed to each
other by dowel pins.
4. The multistage oil pump according to claim 2, wherein, with said
rotor case, said spacer is interposed between rotor case units, the
spacer and said respective rotor case units being jointed to each
other by dowel pins.
Description
TECHNICAL FIELD
[0001] The present invention relates to a multistage oil pump which
is used particularly for automobiles, and the like.
BACKGROUND ART
[0002] Conventionally, there have been proposed multistage oil
pumps in which a plurality of rotors are connected in series (for
example, refer to Patent Document 1).
[0003] As shown in FIG. 1 in Patent Document 1, trochoid pumps
(rotors) 4, 5 are directly accommodated in a housing main body 1
which is bottomed and cylindrical. [0004] Patent Document 1:
Japanese Patent Application Laid-open No. 2006-161614
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] However, with the above-mentioned structure, all the
components are formed of a ferrous material, therefore the
multistage oil pump disclosed in Patent Document 1 has presented a
problem that the weight is large.
[0006] It is an object of the present invention to provide a
multistage oil pump which can solve the above-mentioned
problem.
Means for Solving the Problem
[0007] In order to solve such a problem, the multistage oil pump of
the present invention is a multistage oil pump, a plurality of
rotors being connected in series in the direction of the rotation
axis, the plurality of rotors being accommodated in a rotor case,
the inside thereof being partitioned by a spacer, the rotor case
being divided in the axial direction, and the spacer being made of
a material having a specific gravity smaller than that for the
rotor.
[0008] Further, the present invention features that the rotor is
made of a ferrous material, while the spacer being made of an
aluminum-based material.
[0009] Further, the present invention features that, with the rotor
case, the spacer is interposed between rotor case units, the spacer
and the respective rotor case units being jointed to each other by
dowel pins.
Advantages of the Invention
[0010] In accordance with the present invention, the spacer is made
of a material which has a specific gravity smaller than that for
the rotor, whereby weight reduction can be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of a multistage oil pump in one
embodiment of the present invention;
[0012] FIG. 2 is a front view of the multistage oil pump in FIG.
1;
[0013] FIG. 3 is an exploded perspective view of the multistage oil
pump in FIG. 1 when viewed from the cover side;
[0014] FIG. 4 is an exploded perspective view of the multistage oil
pump in FIG. 1 when viewed from the housing side;
[0015] FIG. 5 is an exploded perspective view of the multistage oil
pump in FIG. 1 when viewed from the cover side;
[0016] FIG. 6 is an exploded perspective view of the multistage oil
pump in FIG. 1 when viewed from the housing side;
[0017] FIG. 7 is a sectional view taken in the direction of the
arrows of the line A-A in FIG. 2; and
[0018] FIG. 8 is a figure showing the flow of oil in the multistage
oil pump.
BEST MODE FOR CARRYING OUT THE INVENTION
[0019] Hereinbelow, with reference to the drawings, the best mode
for carrying out the present invention will be explained.
[0020] As shown in FIGS. 1 to 6, a multistage oil pump 1 includes a
housing 2; a cover 3, which closes the housing 2; a rotor case 4,
which is accommodated in the housing 2; and first and second rotors
6, 7, which are accommodated in the rotor case 4, being connected
in series.
[0021] The housing 2 is bottomed and cylindrical, having a pump
discharge port 21 and fitting holes 22. In the cover 3, fitting
holes 31 are formed. The rotor case 4 is divided into a first rotor
case 41 and a second rotor case 42 in the axial direction, the
first rotor case 41 and the second rotor case 42 being partitioned
with a spacer 5.
[0022] In the first rotor case 41, the first rotor 6 is
accommodated, while, in the second rotor case 42, the second rotor
7 is accommodated. In the first rotor case 41, a circular first
rotor accommodating bore 411, the axis of which is made eccentric
with respect to the first rotor case 41, and fitting holes 412 are
formed. In the second rotor case 42, a circular second rotor
accommodating bore 421, the axis of which is made eccentric with
respect to the second rotor case 42, and fitting holes 422 are
formed. The first rotor case 41 and the second rotor case 42 are
disposed in the housing 2, the axis of the first rotor
accommodating bore 411 and that of the second rotor accommodating
bore 421 being offset from each other.
[0023] With the spacer 5, an insertion hole 51 for the drive shaft
11, a first rotor discharge port 52, a second rotor suction port
53, and a first rotor suction port 54 are provided in a disk which
has the same outside diameter as that of the first rotor case 41
and that of the second rotor case 42. The first rotor discharge
port 52 is formed in one face of the spacer 5, while the second
rotor suction port 53 being formed in the other face of the spacer
5, the first rotor discharge port 52 and the second rotor suction
port 53 being communicated to each other. From the one face and the
other face of the spacer 5, dowel pins 8 are protruded,
respectively. The dowel pin 8 is formed of SUJ (a high carbon
bearing steel).
[0024] The spacer 5 is formed of an aluminum-based material which
has a specific gravity smaller than that for the first and second
rotors 6, 7. As the aluminum-based material, specifically, ADC12,
ADC10 and ADC14 (for die casting), AC2A and AC4B (for sand mold
casting), A2014, A2017, and the like, can be used.
[0025] Between the first rotor case 41 and the cover 3, a side
plate 9 and a sealing material 12 are disposed in this order from
the side of the first rotor case 41. With the side plate 9, an
insertion hole 91 for the drive shaft 11, a purging port 92, and
fitting holes 94 are provided in a disk which has the same outside
diameter with that of the first rotor case 41. The sealing material
12 seals between the cover 3 and the side plate 9.
[0026] The dowel pins 8, which are protruded from the one face of
the spacer 5, are fitted to the fitting holes 422 in the second
rotor case 42 and the fitting holes 22 in the housing 2, thereby
jointing the second rotor case 42 and the housing 2 to the spacer 5
as shown in FIG. 7. The dowel pins 8, which are protruded from the
other face of the spacer 5, are fitted to the fitting holes 412 in
the first rotor case 41, the fitting holes 94 in the side plate 9,
and the fitting holes 31 in the cover 3, thereby jointing the first
rotor case 41, the side plate 9, and the cover 3 to the spacer
5.
[0027] With the first rotor 6, a first inner rotor 62 is provided
in the inside of a first outer rotor 61, the first rotor 6 being
formed of a ferrous material. As the ferrous material,
specifically, an iron-copper-carbon based material, SMF4030 (JPMA
standard), or the like, can be used. With the first outer rotor 61,
an oil filling bore 611 is provided in a disk which has an outside
diameter substantially equal to the inside diameter of the first
rotor accommodating bore 411, the first outer rotor 61 being
rotatably disposed in the first rotor accommodating bore 411. The
oil filling bore 611 is provided, the axis thereof being aligned to
the axis of the first outer rotor 61.
[0028] Between the first outer rotor 61 and the first inner rotor
62, there are formed four oil accommodating chambers which are
partitioned by the inner peripheral part of the oil filling bore
611, the outer peripheral part of the first inner rotor 62, the
spacer 5, and the side plate 9.
[0029] The first inner rotor 62 is fixed to the drive shaft 11,
being disposed in the first outer rotor 61 with the axis of the
drive shaft 11 being aligned to the axis of the first rotor case
41.
[0030] With the second rotor 7, the second inner rotor 72 is
disposed in the inside of the second outer rotor 71. With the
second outer rotor 71, an oil filling bore 711 is provided in a
disk which has the same shape as that of the first outer rotor 61,
the second outer rotor 71 being rotatably disposed in the second
rotor accommodating bore 421. The second inner rotor 72 has the
same shape as that of the first inner rotor 62, being disposed in
the second outer rotor 71 with the axis of the drive shaft 11 being
aligned to the axis of the second rotor case 42.
[0031] Between the second outer rotor 71 and the second inner rotor
72, there are formed four oil accommodating chambers which are
partitioned by the inner peripheral part of the oil filling bore
711, the outer peripheral part of the second inner rotor 72, the
spacer 5, and the housing 2.
[0032] Next, the method of assembling the multistage oil pump 1
will be explained.
[0033] First, the drive shaft 11 is inserted into the spacer 5 and
positioned with a pin; the inner rotor is assembled to the drive
shaft 11; and to the inner rotors 62, 72, the outer rotors 61, 71
are fitted, respectively. Then, the dowel pins 8 are mounted to the
spacer 5; to the one face and the other face of the spacer 5, the
rotor cases 41, 42 are assembled, respectively; and further, to the
first rotor case 41, the side plate 9 is assembled. After thus
making temporal assembling, the assembly is accommodated in the
housing 2, and the cover 3 is mounted to the housing 2.
[0034] Next, the operation of the multistage oil pump 1 will be
explained.
[0035] Let's assume that, as shown in FIG. 8, to the oil
accommodating chambers in the first rotor 6, oil has already been
supplied from the first rotor suction port 54. When the drive shaft
11 is rotated, the first outer rotor 61 is rotated by the first
inner rotor 62 in the direction of rotation of the drive shaft 11,
the respective oil accommodating chambers being also moved around
the drive shaft 11. The respective oil accommodating chambers
increase their volumes as they are moved away from the drive shaft
11, sucking the oil from the first rotor suction port 54 by the
amount equal to the respective volumes increased. Further, the
respective oil accommodating chambers decrease their volumes as
they approach the drive shaft 11, discharging the oil from the
purging port 92 and the first rotor discharge port 52 by the amount
equal to the respective volumes decreased.
[0036] Let's assume that, to the respective oil accommodating
chambers of the second outer rotor 71, oil has already been
supplied from the second rotor suction port 53. When the drive
shaft 11 is rotated, the second outer rotor 71 is rotated by the
second inner rotor 72 in the direction of rotation of the drive
shaft 11, the respective oil accommodating chambers being also
moved around the drive shaft 11. The respective oil accommodating
chambers increase their volumes as they are moved away from the
drive shaft 11, sucking the oil from the second rotor suction port
53 by the amount equal to the respective volumes increased.
Further, the respective oil accommodating chambers decrease their
volumes as they approaches the drive shaft 11, discharging the oil
from the oil discharge port 21 by the amount equal to the
respective volumes decreased.
[0037] The oil which has been discharged by the respective oil
accommodating chambers of the first rotor 6 from the first rotor
discharge port 52 is sucked from the second rotor suction port 53
into the respective oil accommodating chambers of the second rotor
7. The first rotor accommodating bore 411 is offset with respect to
the second rotor accommodating bore 421, and therefore, as the
respective oil accommodating chambers of the first rotor 6 increase
their volumes, the respective oil accommodating chambers of the
second rotor 7 decrease their volumes . Thus, the oil which has
been discharged from the first rotor discharge port 52 is sucked
from the second rotor suction port 53 in its entirety by the
respective oil accommodating chambers of the second rotor 7 that
are increasing their volumes .
[0038] According to the present embodiment, the spacer 5 is made of
a material which has a specific gravity smaller than that for the
rotor 6, 7, whereby weight reduction can be achieved.
[0039] Further, according to the present embodiment, the rotors 6,
7 are made of a ferrous material, and the spacer 5 is of an
aluminum-based material, whereby occurrence of a seizure between
any of the rotors 6, 7 and the spacer 5 can be suppressed.
[0040] In the above-described embodiment, the application where the
spacer 5 is made of an aluminum-based material has been explained,
however, the spacer 5 may be made of a magnesium-based material.
Further, the method of jointing the spacer 5 with the rotor case
41, 42 by means of the dowel pins 8 is optional, and for example,
there may be provided a configuration in which rotation stoppage
between the rotor case 41, 42 and the spacer 5 is performed by
making the outside diameter of the spacer 5 smaller than the
outside diameter of the rotor case 41, 42, providing the inner
peripheral part of the rotor case 41, 42 with a shoulder which is
fitted to the outer peripheral part of the spacer 5, and fitting
pins, such as the dowel pins 8, into the fitting parts of both from
the outside of the rotor case 41, 42.
[0041] Further, in the above-described embodiment, the application
where the oil is supplied from the side of the spacer 5 at the side
of the rotor case 4 to the oil accommodating chamber in the first
outer rotor 61 has been explained, however, there may be provided a
configuration in which the oil is supplied from the side of the
cover 3. Further, there may be a configuration in which the oil is
supplied to the oil accommodating chamber from the cover 3 through
the housing 2.
DESCRIPTION OF SYMBOLS
[0042] The symbol 1 denotes a multistage oil pump; 11 a drive
shaft; 12 a sealing material; 2 a housing; 21 a pump discharge
port; 22 a fitting hole; 3 a cover; 31 a fitting hole; 4 a rotor
case; 41 a first rotor case; 411 a first rotor accommodating bore;
412 a fitting hole; 42 a second rotor case; 421 a second rotor
accommodating bore; 422 a fitting hole; 5 a spacer; 51 an insertion
hole; 52 a first rotor discharge port; 53 a second rotor suction
port; 54 a first rotor suction port; 6 a first rotor; 61 a first
outer rotor; 611 an oil filling bore; 62 a first inner rotor; 7 a
second rotor; 71 a second outer rotor; 711 an oil filling bore; 72
a second inner rotor; 8 a dowel pin; 9 a side plate; 91 an
insertion hole; 92 a purging port; and 94 a fitting hole.
* * * * *