U.S. patent application number 10/755353 was filed with the patent office on 2004-10-14 for rotating fluid machine.
Invention is credited to Honma, Kensuke, Makino, Hiroyuki, Ohta, Naoki.
Application Number | 20040200350 10/755353 |
Document ID | / |
Family ID | 33135721 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040200350 |
Kind Code |
A1 |
Makino, Hiroyuki ; et
al. |
October 14, 2004 |
Rotating fluid machine
Abstract
An expander includes a rotor rotatably supported by a casing, a
group of axial pistons and cylinders installed so that its axis is
surrounded by the rotor, and a swash plate having a rotating
surface inclined with respect to the axis of the rotor and is
rotatably supported by the casing. The relative rotation of the
swash plate and the rotor around the axis is restricted and the
relative shifting of the swash plate and rotor in the direction of
the axis is allowed, by fitting a slider, fixed to the swash plate
by a synchro-pin, into a long hole of an output shaft. Therefore,
it is possible to prevent wrenching between the swash plate and the
rotor due to thermal expansion while reducing the bending moment
acting on the pistons of the group of axial pistons and cylinders
of the expander.
Inventors: |
Makino, Hiroyuki; (Wako-shi,
JP) ; Ohta, Naoki; (Wako-shi, JP) ; Honma,
Kensuke; (Wako-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
33135721 |
Appl. No.: |
10/755353 |
Filed: |
January 13, 2004 |
Current U.S.
Class: |
91/499 ; 417/269;
92/12.2 |
Current CPC
Class: |
F01B 3/0032 20130101;
F04C 2/102 20130101; F04C 15/0088 20130101 |
Class at
Publication: |
091/499 ;
092/012.2; 417/269 |
International
Class: |
F01B 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2003 |
JP |
2003-6691 |
Dec 15, 2003 |
JP |
2003-416234 |
Dec 15, 2003 |
JP |
2003-416235 |
Claims
1. A rotating fluid machine comprising a rotor supported rotatably
by a casing, a group of axial pistons and cylinders disposed on the
rotor so as to surround its axis, a swash plate having a rotating
surface inclined relative to the axis of the rotor and is supported
rotatably by the casing, connecting rods for linking the pistons of
the group of axial pistons and cylinders to the swash plate, and
linking means for linking the swash plate to the rotor, wherein
said linking means restricts the rotation of the swash plate and
the rotor relative to each other around the axis and permits the
movements of the swash plate and the rotor relative to each other
in the axial direction.
2. The rotating fluid machine according to claim 1, wherein said
linking means is arranged within the rotating surface of the swash
plate which passes the intersection point between the axis of the
rotor and the axis of the swash plate and is orthogonal to the axis
of the swash plate.
3. The rotating fluid machine according to claim 1, wherein a
plurality of said linking means are arranged.
4. The rotating fluid machine according to claim 3, wherein said
plurality of linking means are radially arranged within the
rotating surface of the swash plate which is orthogonal to the axis
of the swash plate.
5. The rotating fluid machine according to claim 1, wherein pivotal
portions of the connecting rods on the swash plate side are offset
by a prescribed distance toward the piston side of the swash plate
in the axial direction with respect to the rotating surface of the
swash plate which passes the intersection point between the axis of
the rotor and the axis of the swash plate and is orthogonal to the
axis of the swash plate.
6. A rotating fluid machine comprising a rotor supported rotatably
by a casing, a group of axial pistons and cylinders disposed on the
rotor so as to surround its axis, a swash plate having an axis
inclined relative to the axis of the rotor and is supported
rotatably by the casing, connecting rods for linking the pistons of
the group of axial pistons and cylinders to the swash plate via
pivotal portions of the pistons, and linking means for linking the
swash plate to the rotor, wherein the pivotal portions of the
connecting rods on the swash plate side are offset by a prescribed
distance toward the piston side of the swash plate in the axial
direction with respect to the rotating surface of the swash plate
which passes the intersection point between the axis of the rotor
and the axis of the swash plate and is orthogonal to the axis of
the swash plate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a rotating fluid machine
which performs conversion between pressure energy and mechanical
energy of a working medium via a group of axial pistons and
cylinders, and a swash plate.
[0003] 2. Description of the Related Art
[0004] Such rotating fluid machines are publicly known through
Japanese Patent Laid-Open No. 2002-256805 and Japanese Patent
Laid-Open No. 50-100406. The one described in Japanese Patent
Laid-Open No. 2002-256805 is provided with a first group of axial
pistons and cylinders arranged inside in the radial direction and a
second group of axial pistons and cylinders arranged outside in the
radial direction; the spherical heads of the pistons of the first
group of axial pistons and cylinders are in contact with dimples
formed in the swash plate, and the pistons of the second group of
axial pistons and cylinders are linked to the swash plate by
connecting rods. The phase of a rotor supporting the first and
second groups of axial pistons and cylinders and that of the swash
plate are kept the same by the contact between the spherical heads
of the pistons of the first group of axial pistons and cylinders
and the dimples in the swash plate.
[0005] In Japanese Patent Laid-Open No. 50-100406, the pistons of
the first group of axial pistons and cylinders arranged in a casing
and a swash plate rotatably supported by the output shaft are
linked by connecting rods, and the phase of the casing and that of
the swash plate are kept the same by the meshing of gears provided
on both.
[0006] Also, in Japanese Patent Laid-Open No. 2002-256805, the
phases of the rotor and the swash plate are maintained to be the
same by placing the spherical heads of the pistons of the first
group of axial pistons and cylinders in contact with the dimples in
the swash plate, so that the bending moment applied by the swash
plate to the pistons may invite the occurrence of wrenching between
the pistons and cylinder sleeves, leading to abnormal wear.
Especially in an expander using high temperature high pressure
steam as the working medium, since water resulting from the
condensation of steam inevitably becomes mixed with oil, the
lubricating conditions between the pistons and the cylinder sleeves
may deteriorate to aggravate abnormal wear.
[0007] In Japanese Patent Laid-Open No. 50-100406, as the pistons
and the swash plate are linked by the connecting rods, no bending
moment is applied by the swash plate to the pistons. However, as
the phases of the casing and the swash plate are maintained to be
the same by engaging the gears provided on these two elements, if
there is a difference in the amount of thermal expansion in the
axial direction between the output shaft supporting the swash plate
and the casing, the engagement between the gears may deteriorate to
invite the occurrence of wrenching.
[0008] Further, in the case where the pistons of a group of axial
pistons and cylinders are connected to the swash plate by
connecting rods, if the diameter of the swash plate is increased to
extend the stroke of the pistons, the inclination of the connecting
rods relative to the axis of the rotor will increase; especially in
the early stage of the expansion stroke in which the reactive load
applied by the swash plate to the pistons via the connecting rods
is greater, the load in the radial direction pressing the outer
circumferential faces of the pistons against the inner
circumferential faces of the cylinder sleeves increases, so that
abnormal wear or seizure due to wrenching may arise. In order to
avoid this problem, if the diameter of the swash plate is reduced
to decrease the inclination of the connecting rods relative to the
rotor, the stroke of the pistons will become shorter, entailing a
possible drop in the output of the rotating fluid machine.
SUMMARY OF THE INVENTION
[0009] The present invention has been achieved in view of the
circumstances stated above, and it is a first object of the present
invention to prevent wrenching between the swash plate and the
rotor due to thermal expansion while reducing the bending moment
acting on the pistons of a group of axial pistons and
cylinders.
[0010] A second object of the invention is to prevent abnormal wear
and seizure by reducing the load acting in the radial direction on
the pistons while increasing the diameter of swash plate to extend
the piston stroke.
[0011] In order to achieve the first object stated above, according
to a first characteristic of the invention, there is proposed a
rotating fluid machine comprising a rotor supported rotatably by a
casing, a group of axial pistons and cylinders disposed on the
rotor so as to surround its axis, a swash plate having a rotating
surface inclined relative to the axis of the rotor and is supported
rotatably by the casing, connecting rods for linking the pistons of
the group of axial pistons and cylinders to the swash plate, and
linking means for linking the swash plate to the rotor, wherein
said linking means restricts the rotation of the swash plate and
the rotor relative to each other around the axis and permits the
movements of the swash plate and the rotor relative to each other
in the axial direction.
[0012] According to the configuration described above, since the
pistons of the group of axial pistons and cylinders and the swash
plate of the rotating fluid machine are linked by the connecting
rods, and the linking means linking the swash plate to the rotor
restricts the rotation of the swash plate and the rotor relative to
each other around the axis, it is possible to minimize the bending
moment which the pistons receive due to a reactive force from the
swash plate, to thereby avoid wrenching of the sliding faces of the
pistons and the cylinders to prevent abnormal wear, and at the same
time to reduce the frictional forces of the sliding faces to
enhance the efficiency of the rotating fluid machine. Moreover,
because of use of the connecting rods, the rotating fluid machine
can be made more compact to reduce the size of the pistons in the
axial direction, and the required strength of the pistons can be
reduced to reduce the weight of the rotating fluid machine. Aat the
same time, the efficiency of the rotating fluid machine can be
enhanced by reducing the escape of heat through the pistons.
Furthermore, as the linking means permits the swash plate and the
rotor to move relative to each other in the axial direction,
relative movements of the swash plate and rotor in the axial
direction due to thermal expansion can be absorbed to facilitate
smooth operation of the rotating fluid machine.
[0013] According to a second characteristic of the invention there
is proposed a rotating fluid machine wherein, in addition to the
first characteristic stated above, said linking means is arranged
within the rotating surface of the swash plate which passes the
intersection point between the axis of the rotor and the axis of
the swash plate and is orthogonal to the axis of the swash
plate.
[0014] According to the configuration described above, as the
linking means is arranged within the rotating surface of the swash
plate which passes the intersection point between the axis of the
rotor and the axis of the swash plate and which is orthogonal to
the axis of the swash plate, the torque of the swash plate can be
smoothly transmitted to the rotor by preventing any uneven load
from acting between the swash plate and the rotor.
[0015] According to a third characteristic of the invention, there
is proposed a rotating fluid machine wherein, in addition to the
first or second characteristic stated above, wherein a plurality of
the linking means are arranged.
[0016] According to the configuration described above, as a
plurality of the linking means are arranged, the load can be
distributed among those linking means to improve the durability of
the linking means.
[0017] According to a fourth characteristic of the invention, there
is proposed a rotating fluid machine wherein, in addition to the
third characteristic stated above, the plurality of linking means
are radially arranged within the rotating surface of the swash
plate which is orthogonal to the axis of the swash plate.
[0018] According to the configuration described above, as the
plurality of linking means are radially arranged within the
rotating surface of the swash plate which is orthogonal to the axis
of the swash plate, the phasic difference between the swash plate
and the rotor can be effectively reduced further enhance the effect
of suppressing vibration.
[0019] According to a fifth characteristic of the invention, there
is proposed a rotating fluid machine wherein, in addition to the
first characteristic stated above, pivotal portions of the
connecting rods on the swash plate side are offset by a prescribed
distance toward the piston side of the swash plate in the axial
direction with respect to the rotating surface of the swash plate
which passes the intersection point between the axis of the rotor
and the axis of the swash plate and is orthogonal to the axis of
the swash plate.
[0020] According to the configuration described above, as the
pivotal portions of the connecting rods on the swash plate side are
offset by a prescribed distance toward the piston side of the swash
plate in the axial direction with respect to the rotating surface
of the swash plate which passes the intersection point between the
axis of the rotor and the axis of the swash plate and is orthogonal
to the axis of the swash plate, it is made possible to minimize the
inclination of the pistons at the top dead center with respect to
the connecting rods and the axis of the rotor while increasing the
stroke of the pistons by extending the diameter of the swash plate,
to reduce the component of the reactive force in the radial
direction acting from the swash plate on the pistons via the
connecting rods, and thereby to prevent the occurrence of abnormal
wear or seizure.
[0021] In order to achieve the second object stated above,
according to a sixth characteristic of the invention, there is
proposed a rotating fluid machine comprising a rotor supported
rotatably by a casing, a group of axial pistons and cylinders
disposed on the rotor so as to surround its axis, a swash plate
having an axis inclined relative to the axis of the rotor and is
supported rotatably by the casing, connecting rods for linking the
pistons of the group of axial pistons and cylinders to the swash
plate via pivotal portions of the pistons, and linking means for
linking the swash plate to the rotor, wherein the pivotal portions
of the connecting rods on the swash plate side are offset by a
prescribed distance toward the piston side of the swash plate in
the axial direction with respect to the rotating surface of the
swash plate which passes the intersection point between the axis of
the rotor and the axis of the swash plate and is orthogonal to the
axis of the swash plate.
[0022] In the configuration described above, as the pivotal
portions of the connecting rods for linking the pistons of the
group of axial pistons and cylinders of the rotating fluid machine
to the swash plate on the swash plate side are offset by a
prescribed distance toward the piston side of the swash plate in
the axial direction with respect to the rotating surface of the
swash plate which passes the intersection point between the axis of
the rotor and the axis of the swash plate and is orthogonal to the
axis of the swash plate, it is made possible to minimize the
inclination of the pistons at the top dead center with respect to
the connecting rods and the axis of the rotor while extending the
stroke of the pistons by increasing the diameter of the swash
plate, to reduce the component of the reactive force in the radial
direction acting from the swash plate on the pistons via the
connecting rods, and thereby to prevent the occurrence of abnormal
wear or seizure.
[0023] Incidentally, a long hole 32e, a slider 47 and a synchro-pin
46 in the embodiment corresponding to the linking means according
to the invention, and spherical parts 45a and 45b in the embodiment
corresponding to the pivotal portions according to the
invention.
[0024] The aforementioned and other objects, features and
advantages of the present invention will become apparent from the
following detailed description of the preferred embodiments thereof
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a vertical sectional view of an expander according
to a first embodiment of the invention.
[0026] FIG. 2 is an enlarged view taken on line 2-2 in FIG. 1.
[0027] FIG. 3 is an enlarged view of Part 3 in FIG. 1.
[0028] FIG. 4 is an exploded perspective view of a rotor and a
swash plate.
[0029] FIG. 5 is a sectional view taken on line 5-5 in FIG. 3.
[0030] FIG. 6 is a sectional view taken on line 6-6 in FIG. 3.
[0031] FIG. 7 is a sectional view taken on line 7-7 in FIG. 3.
[0032] FIG. 8 is a view taken from arrow 8 in FIG. 3.
[0033] FIG. 9 is a view corresponding to FIG. 8 and explaining the
operation.
[0034] FIG. 10 is a vertical sectional view of an expander
according to a second embodiment of the invention.
[0035] FIG. 11 is an enlarged view of Part 11 in FIG. 10.
[0036] FIG. 12 is a sectional view taken on line 12-12 in FIG.
11.
[0037] FIG. 13 is a view for explaining the inclination of
connecting rods accompanying the rotation of a rotor.
[0038] FIG. 14A through FIG. 14C are views for explaining the
effect of the offset of the spherical parts of the connecting rods
on the swash plate side.
[0039] FIG. 15 is a graph showing the phasic difference between the
rotor and the swash plate where the rotor and the swash plate are
coupled with a single synchro-pin.
[0040] FIG. 17 is a graph showing the phasic difference between the
rotor and the swash plate with respect to five synchro-pins
differing in phase by 72.degree. each.
[0041] FIG. 18 is a view showing the locus of the synchro-pin
shifting within a long groove along with phasic variations of the
rotor.
[0042] FIG. 19A through FIG. 19E are views showing the positional
relationship between the synchro-pin and the long groove varying
along with phasic variations of the rotor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] A first preferred embodiment of the present invention will
be described below with reference to FIG. 1 through FIG. 9.
[0044] As shown in FIG. 1 through FIG. 7, an expander E according
to the first embodiment of the present invention, which is for use
in, for instance, a Rankine cycle system, converts thermal energy
and pressure energy of high temperature high pressure steam as a
working medium into mechanical energy, and outputs the converted
energy. The casing 11 of the expander E is configured of a casing
body 12, a front cover 15 fitted to the front opening of the casing
body 12 with a plurality of bolts 14 . . . with a sealing member 13
therebetween, a rear cover 18 fitted to the rear opening of the
casing body 12 with a plurality of bolts 17 . . . with a sealing
member 16 therebetween, and an oil pan 21 fitted to the bottom
opening of the casing body 12 with a plurality of bolts 20 . . .
with a sealing member 19 therebetween.
[0045] A rotor 22 arranged to be rotatable around an axis L
extending in the middle of the casing 11 in the back and forth
directions is supported in front by combined angular bearings 23f
and 23r disposed on the front cover 15 and on the back by a radial
bearing 24 disposed on the casing body 12. Integrally formed on the
rear face of the front cover 15 is a swash plate holder 28. A swash
plate 31 is rotatably supported by this swash plate holder 28 via a
radial bearing 29 and a thrust bearing 30. The axis of the swash
plate 31 is inclined relative to the axis L of the rotor 22, and
the angle of its inclination is fixed.
[0046] The rotor 22 is provided with an output shaft 32 supported
on the front cover 15 with the combined angular bearings 23f and
23r, a rotor body 33 formed integrally with the rear part of the
output shaft 32, and a rotor head 36 connected to the rear face of
the rotor body 33 with a plurality of bolts 35 . . . with a metal
gasket 34 therebetween and supported on the casing body 12 by the
radial bearing 24.
[0047] Five sleeve supporting holes 33a . . . are bored in the
rotor body 33 around the axis L at 72.degree. intervals, and five
cylinder sleeves 37 . . . are fitted into those sleeve supporting
holes 33a . . . from behind. Formed at the rear end of each of the
cylinder sleeves 37 is a flange 37a, which is positioned in the
axial direction in contact with the metal gasket 34 in a state in
which it is fitted onto a stepped portion 33b formed in the sleeve
supporting hole 33a of the rotor body 33 (see FIG. 3). A piston 38
is slidably fitted in each of the cylinder sleeves 37. Two
compression rings 39 and 39 and one oil ring 40 are supported on
the outer circumference of the piston 38. A steam expansion chamber
42 is partitioned among the metal gasket 34, an annular lid member
41 jointed to a rotor head 36 and a top face of the piston 38.
[0048] A connecting rod holder 43 is fitted within each of the
pistons 38 on and engaged with a clip 44. A spherical part 45a at
the rear end of each connecting rod 45 is oscillatably linked to
the connecting rod holder 43, and a spherical part 45b at the front
end oscillatably linked to the swash plate 31.
[0049] The five cylinder sleeves 37 . . . and the five pistons 38 .
. . constitute a group 55 of axial pistons and cylinders.
[0050] A long hole 32e extending in the direction of the axis L
penetrates, in the radial direction, the rear part of the output
shaft 32 near the rotor body 33. A round opening 31a penetrates the
center of the swash plate 31 in the direction of the axis L, and
pin holes 31b and 31c crossing the opening 31a are bored in the
radial direction. One pin hole 31b penetrates the outer
circumferential face of the swash plate 31 from the opening 31a,
and the other pin hole 31c is made a blind hole directed from the
opening 31a toward the outer circumferential face of the swash
plate 31 to avoid interference with the spherical parts 45b at the
front ends of the connecting rods 45. A flange 46a is formed at one
end of a synchro-pin 46 to be inserted from the one pin hole 31b to
the other pin hole 31c, and a concave 31d into which this flange
46a is to be fitted is formed in the outer circumferential face of
the swash plate 31 so as to surround the one pin hole 31b.
[0051] A cylindrical slider 47 having two parallel faces 47a and
47a is fitted in the radial direction onto the inner circumference
of the opening 31a of the swash plate 31, and the penetration into
its inside by the synchro-pin 46 causes the slider 47 to be fixed
to the swash plate 31. The synchro-pin 46 is fixed to the swash
plate 31 by the press fitting of a spring pin 48. As the two end
faces 47b and 47b of the slider 47 are formed of parts of a
spherical face having its center in the middle part of the slider
47 in its lengthwise direction, the occurrence of wrenching can be
prevented and smooth assembly facilitated when fitting it into the
opening 31a of the swash plate 31.
[0052] Two parallel cuts 46b and 46b are formed on the flange 46a
of the synchro-pin 46 and, in a state in which the synchro-pin 46
is fixed by the spring pin 48, one of the cuts 46b of the flange
46a to be fitted onto the concave 31d is flush with the rear end
face 31e of the swash plate 31 (see FIG. 8). To pull the
synchro-pin 46 out of the pin holes 31b and 31c, the spring pin 48
is removed, and then the flange 46a is turned about 90.degree. in
the concave 31d. As a result, part of the flange 46a will protrude
from the rear end face 31e of the swash plate 31, and then the
synchro-pin 46 can be easily pulled out while holding that
protruding portion with fingers (see FIG. 9).
[0053] A planar bearing holder 92 is laid over the front face of
the front cover 15 with a sealing member 91 therebetween and fixed
with bolts 93 . . . , and the pump body 95 of an oil pump 49 is
laid over the front face of that bearing holder 92 with a sealing
member 94 therebetween and fixed with bolts 96 . . . The combined
angular bearings 23f and 23r, positioned between the stepped
portion of the front cover 15 and the bearing holder 92, are fixed
in the direction of the axis L.
[0054] A shim 97 of a prescribed thickness is placed between a
flange 32d (see FIG. 3) formed in the output shaft 32 and the inner
races of the combined angular bearings 23f and 23r, and the inner
races of the combined angular bearings 23f and 23r are fastened
with nuts 98 screwed onto the outer circumference of the output
shaft 32. As a result, the output shaft 32 is positioned in the
direction of the axis L relative to the combined angular bearings
23f and 23r, namely with respect to the casing 11.
[0055] The combined angular bearings 23f and 23r are fitted in
mutually reverse orientations, and support the output shaft 32 not
only in the radial direction but also immovably in the direction of
the axis L. Thus, one combined angular bearing 23f is so arranged
as to restrict the forward movement of the output shaft 32, while
the other combined angular bearing 23r is arranged to restrict the
backward movement of the output shaft 32.
[0056] As the combined angular bearings 23f and 23r are used for
bearing the fore part of the rotor 22, one of the loads generated
in the expansion chambers 42 . . . to act on the two ends of the
axis L in a prescribed operating state of the expander E is
transmitted via the rotor 22 to the inner races of the combined
angular bearings 23f and 23r, and the other load is transmitted via
the swash plate 31 and the swash plate holder 28 of the front cover
15 to the outer races of the combined angular bearings 23f and 23r.
These two loads compress the swash plate holder 28 of the front
cover 15 held between the thrust bearing 30 supporting the swash
plate 31 and the combined angular bearings 23f and 23r supporting
the rotor 22, resulting in enhanced rigidity of the mechanism.
Moreover, the integral configuration of the swash plate holder 28
with the front cover 15 as in this embodiment of the invention
makes the structure even more rigid and simpler.
[0057] Further, by incorporating the radial bearing 29 and the
thrust bearing 30 supporting the swash plate 31 and the combined
angular bearings 23f and 23r supporting the rotor 22 into the front
cover 15, it is possible to perform the assembling for the units of
"the rotor 22 and the piston 38 . . . ", "assembly of the front
cover 15" and "the pump body 95", to thereby improve the efficiency
of tasks such as rearrangement of the piston 38 . . . and the
replacement of the oil pump 49.
[0058] The radial bearing 24 supporting the rotor head 36 which
constitutes the rear end of the rotor 22 is an ordinary ball
bearing supporting only the load in the radial direction, a gap
.alpha. is formed between the rotor head 36 and the inner race of
the radial bearing 24 (see FIG. 1) so that the rotor head 36 can
slide in the direction of the axis L relative to the radial bearing
24.
[0059] An oil passage 32a extending on the axis L is formed within
the output shaft 32 integrated with the rotor 22, and the inner
circumference of the rear end of this oil passage 32a is blocked by
an oil passage blocking member 61. The front end of the oil passage
32a branches in radial directions to communicate with an annular
groove 32b of the outer circumference of the output shaft 32, and
the middle part of the oil passage 32a, in its portion
communicating with the long hole 32e, is blocked by two sealing
members 62 and 63. Further, the front and rear parts of the oil
passage 32a communicate with each other via the oil passage 32f,
and at the same time the oil passage 32a on the rear side
communicates with an the annular groove 33c . . . formed in the
sleeve supporting hole 33a via oil holes 32c . . . extending in the
radial direction. The annular grooves 33c . . . and the outer
circumferential faces of the pistons 38 communicate with each other
via oil holes 37b . . . penetrating the cylinder sleeves 37 . .
.
[0060] A trochoidal oil pump 49 arranged between a concave 95a
formed in the front face of the pump body 95 and a pump cover 58
fixed with a plurality of bolts 57 . . . to the front face of the
pump body 95 with a sealing member 56 therebetween, is provided
with an outer rotor 50 rotatably fitted into the concave 95a, and
an inner rotor 51 fixed to the outer circumference of the output
shaft 32 to engage with the outer rotor 50. The inner space of the
oil pan 21 communicates with the intake port 53 of the oil pump 49
via an oil pipe 52 and the oil passage 95b of the pump body 95, and
the discharge port 54 of the oil pump 49 communicates with the
annular groove 32b of the output shaft 32 via the oil passage 95c
of the pump body 95.
[0061] A rotary valve 64 for supplying and discharging steam to and
from five expansion chambers 42 . . . of the rotor 22 is arranged
behind the rotor 22 on the axis L. The rotary valve 64 is provided
with a valve body 65, a stationary valve plate 66 and a moving
valve plate 67. The moving valve plate 67, in a state in which it
is positioned in the rotating direction on the rear face of the
rotor 22 with a knock pin 68, is fixed with a bolt 69 screwed onto
the oil passage blocking member 61. The stationary valve plate 66
in contact with the moving valve plate 67 via a flat sliding faces
70 is formed integrally with the valve body 65, and the valve body
65 is engaged by a knock pin 71 with the rear cover 18 to be
movable in the direction of the axis L and immovable in the
rotational direction. The stationary valve plate 66 and the moving
valve plate 67 are tightly adhered to each other on the sliding
faces 70 by pressing forward the valve body 65 relative to the rear
cover 18 with a plurality of preload springs 72 . . . so as to
surround the axis L. Then a steam feed pipe 73 is connected to the
rear face of the valve body 65.
[0062] Next will be described the operation of the expander E in
the first embodiment of the invention configured as described
above.
[0063] High temperature high pressure steam generated by heating
water in an evaporator flows from the steam feed pipe 73, and
reaches the sliding face 70 of the moving valve plate 67 via a
steam passage formed in the valve body 65 of the rotary valve 64
and the stationary valve plate 66. The steam passage opening in the
sliding face 70 momentarily communicates for a prescribed air
intake period with a matching steam passage formed in the moving
valve plate 67 turning integrally with the rotor 22, and the high
temperature high pressure steam is supplied to the expansion
chamber 42 within the cylinder sleeve 37 from the steam passage of
the moving valve plate 67.
[0064] Even after the steam supply to the expansion chamber 42 is
cut off along with the rotation of the rotor 22, expansion of high
temperature high pressure steam in the expansion chamber 42 causes
the piston 38 fitted into the cylinder sleeve 37 to be thrust
forward from the top dead center to the bottom dead center, and the
connecting rod 45 connected to the piston 38 presses the swash
plate 31. As a result, the reaction force from the swash plate
holder 28 gives a rotational torque to the swash plate 31, and that
rotational torque is transmitted to the output shaft 32 via the
long hole 32e from the slider 47 fitted onto the outer
circumference of the synchro-pin 46 fixed to the swash plate 31,
causing the output shaft 32 to turn together with the rotor 22.
Every time the rotor 22 turns a 1/5 round, high temperature high
pressure steam is supplied to the adjoining new expansion chamber
43 to drive the rotor 22 for continuous rotation.
[0065] While the piston 38 having reached the bottom dead center
along with the rotation of the rotor 22 is pushed by the swash
plate 31 to recede toward the top dead center, low temperature low
pressure steam thrust out of the expansion chamber 42 is discharged
to a condenser via the moving valve plate 67 integrated with the
rotor 22, the sliding faces 70, the stationary valve plate 66 and
the valve body 65.
[0066] The oil pump 49 provided on the output shaft 32 is actuated
along with the rotation of the rotor 22, oil sucked from the oil
pan 21 via the oil pipe 52, the oil passage 95b of the pump body 95
and the intake port 53 is discharged from the discharge port 54,
and is supplied via the oil passage 95c of the pump body 95, the
annular groove 32b of the output shaft 32, the oil passages 32a,
32f and 32a of the output shaft 32, the oil holes 32c . . . of the
output shaft 32, the annular groove 33c . . . of the rotor body 33,
and the oil holes 37b of the cylinder sleeves 37 to the sliding
faces between the pistons 38 . . . and the cylinder sleeves 37 . .
. to lubricate those sliding faces.
[0067] When the thrust in the direction of the axis L generated by
the pistons 38 . . . of the group of axial pistons and cylinders 55
is converted via the swash plate 31 into the rotational force of
the rotor 22, as the pistons 38 . . . are not brought into direct
contact with the swash plate 31 but the pistons 38 . . . are linked
to the swash plate 31 via the connecting rods 45 . . . , the
bending moment caused to work on the pistons 38 . . . by a reaction
force from the swash plate 31 can be minimized. Thus, even if water
resulting from the condensation of high temperature high pressure
steam becomes mixed with oil to deteriorate the lubricating
conditions, it is possible to avert wrenching of the sliding faces
between the pistons 38 . . . and the cylinder sleeves 37 . . . to
prevent abnormal wear from occurring and to reduce the frictional
force of the sliding faces to increase the efficiency of the
expander E. Moreover, as the bending moment of the pistons 38 . . .
is minimized, it is possible to reduce the size of the expander E
by shortening the dimension of the pistons 38 . . . in the
direction of the axis L and to lighten the weight by reducing the
required strength of the pistons 38 . . . Furthermore, as the heat
mass is reduced as a result of the decrease in the size of the
pistons 38 . . . , it is possible to enhance the efficiency of the
expander E by reducing the escape of heat through the pistons 38 .
. .
[0068] As the slider 47 supported by the synchro-pin 46 is slidably
fitted into the long hole 32e of the output shaft 32, the swash
plate 31 and the rotor 22 are allowed to move in the direction of
the axis L in a relative manner, and it is possible to absorb any
difference in the quantity of thermal expansion in the direction of
the axis L between the rotor 22 and the casing 11 to enable the
expander E to operate smoothly. Further, as the two parallel faces
47a and 47a of the slider 47 supported by the synchro-pin 46 are
brought into face contact with the long hole 32e without fitting
the synchro-pin 46 directly into the long hole 32e, the wear of its
sliding portion is minimized to thereby prevent chattering.
[0069] Incidentally, when assembling the expander E, the magnitude
of the dead volume between the bottom of the cylinder sleeves 37
(i.e. the rotor head 36 to which the lid member 41 is jointed) and
the top of the pistons 38, namely the volume of the expansion
chambers 42 when the pistons 38 are at the top dead center, has to
be adjusted. If the shim 97 intervening between the flange 32d of
the output shaft 32 and the inner races of the combined angular
bearings 23f and 23r is thinned, the output shaft 32 will shift
forward (rightward in FIG. 1) and accordingly the rotor head 36
will also shift forward, but as the pistons 38 cannot move forward
because of the restriction by the swash plate 31, the dead volume
will decrease. Conversely, if the shim 97 is thickened, the rotor
head 36 will move backward (leftward in FIG. 1) together with the
output shaft 32, and accordingly the dead volume will increase. As
a result, it is possible to adjust the dead volume as desired by
merely replacing the shim 97, and the step otherwise needed for
dead volume adjustment can be eliminated to achieve a substantial
saving of time.
[0070] Further, as it is possible adjust the dead volume only by
sandwiching a single shim 97 having a prescribed thickness between
the flange 32d of the output shaft 32 and the combined angular
bearings 23f and 23r and fastening, with a single nut 98, the front
cover 15 incorporating the radial bearing 29, the thrust bearing 30
and the combined angular bearings 23f and 23r and the rotor 22
incorporating the pistons 38 . . . , the adjusting task is
simplified as compared with the conventional adjustment process in
which the thicknesses of two shims, front and rear, are
individually manipulated. Moreover, since the rotor 22
incorporating the pistons 38 . . . can be kept assembled into the
casing body 12 when adjusting the dead volume, the adjusted dead
volume can be confirmed by directly watching the state of contact
between the pistons 38 . . . and the swash plate 31.
[0071] When the position of the output shaft 32 relative to the
combined angular bearings 23f and 23r is adjusted back and forth by
varying the thickness of the shim 97 as described above, the
position of the rotor head 36 at the rear end of the rotor 22 also
shifts back and forth, but there is no trouble in adjusting the
position of the output shaft 32 because the rotor head 36 is
slidable in the direction of the axis L relative to the inner race
of the radial bearing 24 disposed between it and the casing body
12, and the long hole 32e bored in the output shaft 32 can slide in
the direction of the axis L relative to the slider 47 provided on
the swash plate 31.
[0072] Then, when the pressure of high temperature high pressure
steam supplied to the expansion chambers 42 presses the pistons 38
in the direction of being thrust out of the cylinder sleeves 37,
the pressing force of the pistons 38 presses forward (rightward in
FIG. 1) the outer race of the combined angular bearings 23f and 23r
via the connecting rods 45, the swash plate 31, the thrust bearing
30, the swash plate holder 28 and the front cover 15, and the
pressing force of the cylinder sleeves 37 reverse in direction to
the pressing force of the pistons 38 presses backward (leftward in
FIG. 1) the inner race of the combined angular bearings 23f and 23r
via the rotor head 36 and the output shaft 32. Thus, the load
generated by the high temperature high pressure steam supplied to
the expansion chambers 42 is cancelled within the combined angular
bearings 23f and 23r, but not transmitted to the casing body
12.
[0073] While the rotor 22 composed of the output shaft 32, the
rotor body 33 and the rotor head 36 is formed of a ferrous material
whose thermal expansion is relatively small, the casing 11 which
supports the rotor 22 via the combined angular bearings 23f and 23r
and the radial bearing 24 is formed of an aluminum-based material
whose thermal expansion is relatively large; as a consequence,
there arises a difference in the quantity of thermal expansion
especially in the direction along the axis L depending on whether
the temperature of the expander E is high or low.
[0074] The casing 11, which is greater in thermal expansion than
the rotor 22, expands more than the rotor 22 when the temperature
is high, with its dimension in the direction of the axis L
relatively increasing; conversely, when the temperature is low, it
contracts more, with its dimension in the direction of the axis L
relatively decreasing. As the casing 11 and the rotor 22 are
positioned in the direction of the axis L via the combined angular
bearings 23f and 23r, the difference in the quantity of thermal
expansion between them is absorbed by the sliding contact of the
rotor head 36 with the inner race of the radial bearing 24, and an
excessive load is prevented from acting in the direction of the
axis L on the combined angular bearings 23f and 23r, the radial
bearing 24 and the rotor 22. This not only contributes to
improvement of the durability of the combined angular bearings 23f
and 23r and of the radial bearing 24, but also to stabilized
support of the rotor 22 to facilitate its smooth rotation, and
moreover to the prevention of fluctuations in dead volume between
the bottom of the cylinder sleeves 37 (i.e. the rotor head 36 to
which the lid member 41 is jointed) and the top of the pistons 38
accompanying variations in temperature.
[0075] The reason is that, supposing that both ends of the rotor 22
are restrained by the casing 11 to be immovable in the axial
direction, as the casing 11 tends to contract in the direction of
the axis L relative to the rotor 22 when the temperature is low,
the pistons 38 whose top is in contact with the swash plate 31
supported by the swash plate holder 28, which is part of the casing
11, are pressed backward, and the rotor head 36 supported by the
casing 11 via the radial bearing 24 is pressed forward, with the
result that the pistons 38 are pressed into the cylinder sleeves 37
and the dead volume decreases accordingly. Conversely, when the
temperature is high, as the casing 11 tends to expand in the
direction of the axis L relative to the rotor 22, the pistons 38
are drawn out from the inside of the cylinder sleeves 37, resulting
in an increase in dead volume, which in turn invites an increase in
the initial volume of high temperature high pressure steam in the
normal operating state after the warming-up, i.e. a drop in thermal
efficiency due to a decrease in the volume ratio (expansion ratio)
of the expander E.
[0076] By contrast in this embodiment of the invention, as the
rotor 22 is supported in a floating state in the direction of the
axis L relative to the casing 11, the gaps between the combined
angular bearings 23f and 23r and the radial bearing 24 are
prevented from widening and thus the preloads are prevented from
decreasing, so that the dead volume is kept from fluctuations due
to temperature variations. This prevents the volume ratio
(expansion ratio) of the expander E from fluctuating, so that
stable performance to be achieved.
[0077] Especially, in the expander E which uses high temperature
high pressure steam as the working medium, the above-described
advantage is highly effective because the difference is wide
between high and low temperatures. Furthermore, whereas the
difference between high and low temperatures is particularly wide
in the vicinity of the rotary valve 64 to which high temperature
high pressure steam is supplied, the difference in thermal
expansion between the casing 11 and the rotor 22 can be absorbed
without trouble because the rotor head 36 can slide in the
direction of the axis L relative to the radial bearing 24 arranged
closer to that rotary valve 64.
[0078] Next will be described a second preferred embodiment of the
present invention with reference to FIG. 10 through FIG. 19E.
Incidentally, in the second embodiments, members having
counterparts in the first embodiment are denoted by respectively
the same signs to dispense with duplicated description.
[0079] As shown in FIG. 10 through FIG. 12, the rotor 22 is
provided with the output shaft 32 supported by the combined angular
bearings 23f and 23r to the front cover 15, a spherical member 26
fitted onto the outer circumference of the output shaft 32 and
fixed with a knock pin 25, the rotor body 33 formed integrally with
the rear part of the output shaft 32, and the rotor head 36 coupled
to the rear face the rotor body 33 by the plurality of bolts 35 . .
. with the metal gasket 34 therebetween and supported in the casing
body 12 by the radial bearing 24. The connecting rod holder 43 is
fitted within the pistons 38 and engaged by the clip 44, and the
spherical parts 45a at the rear end of the connecting rods 45 are
oscillatably linked to the connecting rod holder 43 while the
spherical parts 45b at the front end are oscillatably linked to the
swash plate 31. Then a cover member 76 is fixed to the rear face of
the swash plate 31 with a plurality of bolts 27 . . . , and the
spherical parts 45b at the frond ends of the connecting rods 45 are
prevented by this cover member 76 from coming off.
[0080] Five long grooves 26a . . . extending in the direction of
the axis L are formed at 72.degree. intervals in the spherical
member 26 fixed to the outer circumference of the output shaft 32
and, by screwing a male thread 77a into the inner circumferential
face of the opening 31a of the annularly shaped swash plate 31 or
by spigot-fitting, the heads 77b . . . of five synchro-pins 77 . .
. radially fixed at 72.degree. intervals are loosely fitted into
the respectively matching long grooves 26a . . . Therefore, the
rotational torque of the swash plate 31 is transmitted from the
long groove 26a . . . fitted onto the outer circumference of the
heads 77b . . . of the five synchro-pins 77 . . . to the output
shaft 32 via the spherical member 26, and causes the output shaft
32 to turn together with the rotor 22.
[0081] As well illustrated in FIG. 12, while the width of each of
the long grooves 26a of the spherical member 26 is constant in the
radial direction around the axis L, the heads 77b of the
synchro-pins 77 loosely fitted into the long grooves 26a are
tapered at an angle of 2.degree. so as to become thinner toward the
outside in the radial direction. Therefore, when the output shaft
32 and the swash plate 31 have slightly turned relative to each
other, the heads 77b of the synchro-pins 77 come into linear
contact with the inner faces of the long grooves 26a, and the
resultant drop in the surface stress of the contact portions makes
it possible to suppress wear. The five synchro-pins 77 . . . are
arranged between the five connecting rods 45 . . . , and this
arrangement serves to effectively avoid interference between the
synchro-pins 77 . . . and the connecting rods 45 . . .
[0082] As shown in detail in FIG. 11 and FIG. 13, the axis L of the
rotor 22 and the axis Ls of the swash plate 31 cross each other at
an intersection point C, and the spherical parts 45b . . . of the
five connecting rods 45 . . . toward the swash plate 31 side are
offset by a prescribed distance .delta. toward the pistons 38 . . .
from the rotating surface Ps of the swash plate passing the
intersection point C (a plane orthogonal to the axis Ls of the
swash plate 31). While this offset causes the spherical parts 45b .
. . of the connecting rods 45 . . . to be displaced toward the
swash plate 31 side to deviate downward in FIG. 11, the quantity of
offset is set so that the connecting rods 45 linked to the pistons
38 at the top dead center (the pistons 38 shown in the upper part
of FIG. 11) is substantially parallel to the axis L of the rotor
22. Therefore, when the pistons 38 are at the top dead center, the
connecting rods 45 are substantially parallel to the axis L of the
rotor 22, and while they move from the top dead center to the
bottom dead center and return to the top dead center again, the
connecting rods 45 are inclined with respect to the axis L of the
rotor 22.
[0083] Further, as the five synchro-pins 77 . . . are arranged on
the rotating surface Ps of the swash plate, it is possible to
prevent any uneven load from occurring when the torque of the swash
plate 31 is transmitted to the spherical member 26, to thereby
facilitate smooth torque transmission.
[0084] The oil passage 32a extending on the axis L is formed within
the output shaft 32 integrated with the rotor 22, and the inner
circumference of the rear end of this oil passage 32a is blocked by
the oil passage blocking member 61. The front end of the oil
passage 32a branches in radial directions to communicate with the
annular groove 32b on the outer circumference of the output shaft
32, the middle part of the oil passage 32a communicates with the
oil holes 32g . . . extending in radial directions, and further the
rear end of the oil passage 32a communicates with the annular
groove 33c . . . cut in the sleeve supporting holes 33a . . . via
the oil holes 32c . . . extending in radial directions. The annular
grooves 33c . . . and the outer circumference of the pistons 38
communicate with each other via the oil holes 37b . . . penetrating
the cylinder sleeves 37 . . . , and the oil holes 32g . . .
communicate with the inner faces of the long grooves 26a . . . via
oil holes 26b . . . bored in a spherical member 26. Therefore, oil
in the oil passage 32a of the output shaft 32 is supplied to the
long grooves 26a . . . via the oil holes 32g of the output shaft 32
and the oil holes 26b . . . of the spherical member 26, and
lubricates the sliding faces of the long grooves 26a . . . and the
heads 77b of the synchro-pins 77.
[0085] Next will be described the operation of the expander E in
the second embodiment of the invention configured as described
above.
[0086] When the pistons 38 are near the top dead center, i.e. in
their suction stroke, high temperature high pressure steam is
supplied to the expansion chambers 42 to thrust the pistons 38
forward under the maximum load, and the reaction force from the
swash plate 31 strongly acts on the pistons 38 via the connecting
rods 45, as the connecting rods 45 are substantially parallel to
the axis L of the rotor 22, it is possible to minimize the load
acting in the radial direction on the sliding faces of the pistons
38 and the cylinder sleeves 37, to prevent wrenching or abnormal
wear from occurring on the sliding faces and reduce frictional
resistance, to thereby contribute to increasing the output of the
expander E.
[0087] Although the angle of inclination of the connecting rods 45
with respect to the axis L of the rotor 22 becomes greater in the
final phase of the expansion stroke or the exhaust stroke, there is
no fear of the occurrence of wrenching or abnormal wear on the
sliding faces of the pistons 38 and the cylinder sleeves 37,
because the reactive load acting from the swash plate 31 on the
pistons 38 via the connecting rods 45 becomes smaller.
[0088] As described above, even though it is attempted to boost the
output of the expander E by expanding the diameter of the swash
plate 31 to elongate the stroke of the pistons 38 . . . , the
center of the spherical parts 45b . . . is projected in the
direction of the axis L of the rotor 22 by offsetting the spherical
parts 45b . . . of the connecting rods 45 . . . toward the pistons
38 side by a prescribed distance .delta. relative to the rotating
surface Ps of the swash plate, its locus will constitute an oval
orbit whose center is offset toward the bottom dead center by
.delta..multidot.sin .alpha., so that it is possible to narrow the
angle of inclination of the connecting rods 45 of the pistons 38
near the top dead center to reduce the frictional resistance of the
sliding faces of the pistons 38 . . . and the cylinder sleeves 37 .
. . (see FIG. 14A).
[0089] By contrast, as shown in FIG. 14C, if the diameter of the
swash plate 31 is merely expanded, the angle of inclination of the
connecting rods 45 linked to the pistons 38 at the top dead center
will widen to invite an increase in the frictional resistance of
the sliding faces of the pistons 38 and the cylinder sleeves 37; or
if the diameter of the swash plate 31 is shortened as shown in FIG.
14B, though the angle of inclination of the connecting rods 45 will
narrow, the stroke of the pistons 38 will decrease, resulting in a
drop in the output of the expander E.
[0090] FIG. 15 shows the phasic difference between the rotor 22 and
the swash plate 31 in a supposed case in which the rotor 22 and the
swash plate 31 are coupled by a single synchro-pin. In this case,
as the axis L of the rotor 22 and the axis Ls of the swash plate 31
are inclined, the single synchro-pin constitutes a non-constant
velocity joint and, even if the rotor 22 turns at a constant
angular velocity, the angular velocity of the swash plate 31 will
vary. For this reason, the phase of the rotor 22 and that of the
swash plate 31 become different along with the rotation of the
rotor 22.
[0091] For instance, if the phase of the rotor 22 and that of the
swash plate 31 are identical at 0.degree. when #1 piston 38 is at
the top dead center in FIG. 15, the phasic difference between the
rotor 22 and the swash plate 31 will vary over two cycles in a sine
wave shape while the rotor 22 makes a single turn. Therefore, when
#2 piston 38 has reached the top dead center, the phasic difference
will be approximately +1.degree.; when #3 piston 38 has reached the
top dead center, the phasic difference will be approximately
-2.degree.; when #4 piston 38 has reached the top dead center, the
phasic difference will be approximately +2.degree.; and when #5
piston 38 has reached the top dead center, the phasic difference
will be approximately -2.degree..
[0092] If in this way the phasic difference between the rotor 22
and the swash plate 31 varies from one piston 38 to another, the
volumes of the expansion chambers 42 will vary with the phasic
difference between the rotor 22 and the swash plate 31, and
accordingly the expansion ratio of high temperature high pressure
steam will differ from one expansion chamber 42 to another;
therefore, even if the optimal suction timing or exhaust timing is
set for a specific expansion chamber 42, the timing will not be
optimal for other expansion chambers 42. The difference in output
from one set of cylinder sleeve 37 and piston 38 to another would
give rise to a problem of occurrence of a low order (first or
second rotation) vibration.
[0093] In this embodiment of the invention, however, by arranging
the five synchro-pins 77 . . . at equal intervals in the
circumferential direction and causing the five synchro-pins 77 . .
. to function sequentially along with the rotation of the rotor 22,
the phasic difference between the rotor 22 and the swash plate 31
can be made uniform for every piston 38, and the problem noted
above can be thereby solved. The reason for this solution will be
further explained below.
[0094] The five sine waves shown in FIG. 16 represent variations in
the phasic differences between the rotor 22 and the swash plate 31,
in the case where the phasic difference between the rotor 22 and
the swash plate 31 is set to be 0.degree. when #1 piston 38 through
#5 piston 38 are at their respective top dead centers. Where there
is only one synchro-pin 77, the phasic difference varies within a
range of .+-.2.degree., but the successive suppression by the five
synchro-pins 77 . . . arranged at 72.degree. intervals of phasic
differences occurring between the rotor 22 and the swash plate 31
results in substantially constant phasic differences of around
+2.degree. as indicated by bold solid lines in FIG. 17; it is thus
possible to increase the output of the expander E and to suppress
vibration by setting uniform and optimal suction timing and exhaust
timing for every one of the five expansion chambers 42 . . .
[0095] FIG. 18 and FIG. 19A through FIG. 19E illustrate how a
synchro-pin 77 travels within the long grooves 26a of the spherical
member 26 of the output shaft 32; the black synchro-pins 77 in FIG.
19A through FIG. 19E represent the same synchro-pin 77 shifting
along with the rotation of the rotor 22. When the synchro-pin 77 is
at the top dead center of phase 0.degree. (see FIG. 19A), that
synchro-pin 77 is in the central position (1) of the long groove
26a in the widthwise direction (the rotational direction of the
rotor 22). When the rotor 22 has turned to the position of phase
45.degree. (see FIG. 19B), the synchro-pin 77 travels within the
long grooves 26a in the direction of the axis L forward in the
rotational direction of the rotor 22, and comes into contact with
position (2) on one side of the long groove 26a. In this state,
torque is transmitted from the swash plate 31 to the rotor 22 via
the synchro-pin 77.
[0096] When the rotor 22 has rotated to the position of phase
90.degree. (see FIG. 19C), the synchro-pin 77 shifts toward the
delayed side in the rotational direction of the rotor 22 while
traveling within the long grooves 26a in the direction of the axis
L, and returns to the central position (3) in the widthwise
direction of the long groove 26a; when the rotor 22 has further
rotated to the position of phase 135.degree. (see FIG. 19D), the
synchro-pin 77 shifts toward the delayed side in the rotational
direction of the rotor 22 while traveling within the long grooves
26a in the direction of the axis L, and comes into contact with
position (4) on another side of the long groove 26a, where the
other side of the long grooves 26a is on the delayed side in the
rotational direction of the rotor 22, and accordingly the
synchro-pin 77 does not contribute to torque transmission from the
swash plate 31 to the rotor 22. When the rotor 22 has rotated to
the position of phase 180.degree. (see FIG. 19E), the synchro-pin
77 shifts toward the advanced side in the rotational direction of
the rotor 22 while traveling within the long groove 26a in the
direction of the axis L, and returns to the central position (5) in
the widthwise direction of the long grooves 26a.
[0097] When the rotor 22 rotates in the latter half from phase
180.degree. to phase 360.degree. , the synchro-pin 77, as
represented by a chain line in FIG. 18, shifts within the long
groove 26a in the reverse direction to that in the former half from
phase 0.degree. to phase 180.degree. described above. In this
process, the synchro-pin 77 comes into contact with one side of the
long groove 26a toward the advanced side of the rotational
direction in the position of phase 225.degree. (i.e. position (6)).
In this state, the torque of the rotor 22 is transmitted from the
swash plate 31 via the synchro-pin 77. Incidentally, parenthesized
numerals (1) through (9) in FIG. 18 respectively corresponds to
parenthesized numerals (1) through (9) in FIG. 15.
[0098] Thus, the installation of the five synchro-pins 77 makes
possible continuous torque transmission from the swash plate 31 to
the rotor 22 because the five synchro-pins 77 sequentially come
into contact with one side of the long grooves 26a on the advanced
side of the rotational direction twice during a single turn of the
rotor 22. Since the timing of this torque transmission is performed
in the position of phase 45.degree. and the position of phase
225.degree. from the top dead center for every synchro-pin 77, the
five pistons 38 can contribute to even driving of the rotor 22.
[0099] Where the number of synchro-pins 77 . . . is n (n is a
natural number not smaller than 2), phase variations of the 2n-th
order will occur during a single turn of the rotor 22, and the
greater the value n, the shorter the cycle of vibration, thereby
greatly contributing to the suppression of vibration. Moreover, as
the number of the synchro-pins 77 . . . increases, the load on each
synchro-pin 77 decreases, thereby enhancing its durability.
Especially, the arrangement of the five synchro-pins 77 . . . at
equal intervals makes it possible to effectively reduce phasic
differences between the rotor 22 and the swash plate 31, and at the
same time to further enhance the effect to suppress vibration.
[0100] While the preferred embodiments of the present invention
have been described above, the invention can be modified in design
in various ways without deviating from the subject matter.
[0101] For instance, the rotating fluid machine according to the
invention is not limited to the expander E using compressive fluid
as the working medium, but can as well be a compressor using
compressive fluid as the working medium, a hydraulic pump or a
motor using non-compressive fluid as the working medium.
[0102] Further, although the second embodiment is provided with
five synchro-pins 77, the number of the synchro-pins 77 . . . can
be appropriately varied only if it is more than one, and the
greater their number, the more effectively the phasic difference
can be reduced.
[0103] Also, although the heads 77b of the synchro-pins 77 in the
second embodiment have a circular section, they may have a
rectangular or oval section. The use of a rectangular section would
bring the heads of the synchro-pins 77 into face contact with the
long grooves 26a, making it possible to further enhance their
durability.
* * * * *