U.S. patent application number 09/861730 was filed with the patent office on 2001-12-06 for seal structure in a scroll type compressor.
Invention is credited to Gennami, Hiroyuki, Kobayashi, Kazuo, Kuroki, Kazuhiro, Watanabe, Yasushi.
Application Number | 20010048886 09/861730 |
Document ID | / |
Family ID | 18657876 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010048886 |
Kind Code |
A1 |
Kuroki, Kazuhiro ; et
al. |
December 6, 2001 |
Seal structure in a scroll type compressor
Abstract
The pressure leakage from the back pressure chamber installed at
the back side of the movable scroll to the low pressure area can be
prevented. An eccentric shaft (17) formed integrally to a drive
shaft (14) is inserted into a bushing (19). A balance weight (18)
is fixed to the bushing (19). A cylindrical portion (34) is
provided so as to protrude at the back side of the movable scroll
base (22), and the bushing (19) supports the cylindrical portion
(34) via a needle bearing (21). A seal member (35) is interposed
between the end surface of the cylindrical portion (34) and the
balance weight (18). The inside of a cylinder of the cylindrical
portion (34) is made to be a back pressure chamber (36).
Inventors: |
Kuroki, Kazuhiro;
(Kariya-shi, JP) ; Gennami, Hiroyuki; (Kariya-shi,
JP) ; Kobayashi, Kazuo; (Kariya-shi, JP) ;
Watanabe, Yasushi; (Kariya-shi, JP) |
Correspondence
Address: |
Woodcock Washburn Kurtz
Mackiewicz & Norris LLP
46th Floor
One Liberty Place
Philadelphia
PA
19103
US
|
Family ID: |
18657876 |
Appl. No.: |
09/861730 |
Filed: |
May 21, 2001 |
Current U.S.
Class: |
418/55.4 ;
418/55.5 |
Current CPC
Class: |
F04C 27/005 20130101;
F04C 2240/807 20130101; F04C 18/0215 20130101 |
Class at
Publication: |
418/55.4 ;
418/55.5 |
International
Class: |
F04C 018/04; F04C
027/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2000 |
JP |
2000-152452 |
Claims
1. A seal structure in a scroll type compressor, wherein: a fixed
scroll, on the base of which a fixed scroll wall is formed, is
opposed to a movable scroll, on the base of which a movable scroll
wall is formed; a hermetic space, the volume of which decreases
according to the orbital movement of the movable scroll, is formed
between the movable scroll wall and the fixed scroll wall; and the
movable scroll is designed so as to orbit when a rotational force
of a drive shaft is transmitted to a orbital movement mechanism,
which has an eccentric shaft in order to orbit the movable scroll;
and wherein: the eccentric axis of an eccentric rotation body that
eccentrically and integrally rotates with the eccentric shaft is
allowed to move corresponding to the eccentric axis of the movable
scroll; a seal member is interposed between the movable scroll and
the eccentric rotation body so that the seal member circumscribes
the eccentric axis of the eccentric shaft; and a back pressure
chamber, which is opposed to the movable scroll, is formed by the
movable scroll, the eccentric rotation body and the seal
member.
2. A seal structure in a scroll type compressor, as set forth in
claim 1, wherein the eccentric rotation body is a balance weight
attached to the orbital movement mechanism.
3. A seal structure in a scroll type compressor, as set forth in
claim 2, wherein: the orbital movement mechanism comprises an
eccentric shaft that rotates integrally with the drive shaft and a
transmitting means of eccentric rotation interposed between the
eccentric shaft and the movable scroll; the transmitting means of
eccentric rotation comprises a cylindrical portion that is provided
so as to protrude from the movable scroll base and a bushing that
rotates both integrally with the eccentric shaft and relatively to
the cylindrical portion in a cylinder of the cylindrical portion;
the balance weight is fixed to the bushing; and the seal member is
interposed between the end surface of the cylindrical portion and
the balance weight.
4. A seal structure in a scroll type compressor, as set forth in
claim 3, wherein an annular housing groove is formed on the end
surface of the cylindrical portion and the seal member is housed in
the housing groove.
5. A seal structure in a scroll type compressor, as set forth in
claim 3, wherein an annular protruding portion is formed on the end
surface of the cylindrical portion and the seal member is arranged
radially inner side the annular protruding portion.
6. A seal structure in a scroll type compressor, as set forth in
claim 1, wherein the back pressure chamber is made to be a
discharge pressure area.
7. A seal structure in a scroll type compressor, as set forth in
claim 6, wherein a discharge port is installed on the movable
scroll base and the discharge port is communicated with the back
pressure chamber.
8. A seal structure in a scroll type compressor, as set forth in
claim 1, wherein the bushing can slidably move with respect to the
eccentric shaft.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a seal structure in a
scroll type compressor.
[0003] 2. Description of the Related Art
[0004] In order to improve the quality of a seal in a hermetic
space formed between a fixed scroll and a movable scroll, a
structure in which a back pressure is applied against a rear face
of a movable scroll base, as disclosed in Japanese Unexamined
Patent Publication (Kokai) No. 3-92502 and Japanese Unexamined
Patent Publication (Kokai) No. 11-6487, is employed. At the rear
face side of the movable scroll base, a back pressure chamber is
formed, into which pressure as high as the discharge pressure is
introduced. The rear side of the movable scroll base is used
exclusively for a suction pressure area of low pressure, and a seal
ring is interposed between the back pressure chamber and the
suction pressure area in order to prevent pressure leakage from the
back pressure chamber to the suction pressure area. A seal ring in
the compressor which has been disclosed in Japanese Unexamined
Patent Publication (Kokai) No. 3-92502, is installed so as to be
contiguous with the end face of a boss cylinder and the bridge
structure of the movable scroll. A seal ring in the compressor
which has been disclosed in Japanese Unexamined Patent Publication
(Kokai) No. 11-6487, is installed so as to be contiguous with the
rear face of the movable scroll base and the inner surface of the
housing.
[0005] In order to prevent pressure leakage between the movable
scroll wall and the fixed scroll wall, it is advisable to press the
movable scroll wall against the fixed scroll wall. For this reason,
a structure is known in which the movable scroll is designed so as
to be able to slightly move with the eccentric shaft in the
direction of radius, and the movable scroll wall is pressed against
the fixed scroll wall by utilizing the pressure in the hermetic
space. In such structure, the movable scroll is allowed to tilt,
that is, the eccentric axis of the movable scroll is allowed to
tilt with respect to the axis of the eccentric shaft in the
direction of the above-mentioned movement. When the eccentric axis
of the movable scroll tilts with respect to the axis of the drive
shaft of the compressor, the contact between the seal ring and the
counterpart thereof becomes poor. Such a poor contact allows
pressure leakage from the back pressure chamber to the low pressure
area, and it is impossible to maintain a desired back pressure in
the back pressure chamber. If it is impossible to keep the desired
back pressure in the back pressure chamber, it is difficult to
maintain a high quality seal in the hermetic space formed between
the fixed scroll and the movable scroll.
SUMMARY OF THE INVENTION
[0006] The objective of the present invention is to prevent the
pressure leakage from the back pressure chamber installed at the
rear side of the movable scroll to the low pressure area.
[0007] In the present invention, therefore, a scroll type
compressor is employed, wherein: a fixed scroll, on the base of
which a fixed scroll wall is formed, is opposed to a movable
scroll, on the base of which a movable scroll wall is formed; a
hermetic space is formed between the movable scroll wall of the
movable scroll and the fixed scroll wall, and the volume of the
hermetic space decreases according to the orbital movement of the
movable scroll; and the rotational force of the drive shaft is
transmitted to the orbital movement mechanism, which comprises an
eccentric shaft to provide the orbital movement to the movable
scroll so that the movable scroll is allowed to orbit. In the first
aspect of the present invention, the eccentric axis of the
eccentric rotation body that eccentrically rotates together with
the eccentric shaft is designed to be able to move corresponding to
the eccentric axis of the movable scroll, a seal member is
interposed between the movable scroll and the eccentric rotation
body so that the seal member circumscribes the eccentric axis of
the eccentric shaft, and the back pressure chamber is formed by the
movable scroll, the eccentric rotation body and the seal
member.
[0008] The eccentric rotation body is able to similarly tilt
according to the inclination of the movable scroll. Therefore, the
seal member interposed between the movable scroll and the eccentric
rotation body is always in good contact with the movable scroll and
the eccentric rotation body.
[0009] The present invention may be more fully understood from the
description of the preferred embodiments of the invention set forth
below, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In the drawings:
[0011] FIG. 1 is a profile cross-sectional view of the entire
compressor in the first embodiment.
[0012] FIG. 2 is a section view with the major components
magnified.
[0013] FIG. 3 is a section view taken along line A-A in FIG. 1.
[0014] FIG. 4 is a section view taken along line B-B in FIG. 1.
[0015] FIG. 5 is a section view taken along line C-C in FIG. 1.
[0016] FIG. 6 is a profile cross-sectional view with the major
components magnified in the second embodiment.
[0017] FIG. 7 is a profile cross-sectional view with the major
components magnified in the third embodiment.
[0018] FIG. 8 is a profile cross-sectional view with the major
components magnified in the fourth embodiment.
[0019] FIG. 9 is a profile cross-sectional view with the major
components magnified in the fifth embodiment.
[0020] FIG. 10 is a profile cross-sectional view with the major
components magnified in the sixth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The first embodiment, in which the present invention is
embodied, is explained according to FIG. 1 to FIG. 5.
[0022] As shown in FIG. 1, a center housing 12 is coupled to a
fixed scroll 11 and a motor housing 13 is coupled to the center
housing 12. A drive shaft 14 is rotatably supported by the center
housing 12 and the motor housing 13 via radial bearings 15 and 16,
and an eccentric shaft 17 is formed integrally with the drive shaft
14.
[0023] As shown in FIG. 4, an insertion hole 191 is formed in a
bushing 19 and the eccentric shaft 17 is inserted into the
insertion hole 191. A space H is provided between the eccentric
shaft 17 and the insertion hole 191, and the bushing 19 is able to
slidably move in the direction of the arrow R with respect to the
eccentric shaft 17. The bushing 19 and the eccentric shaft 17
rotate both integrally and eccentrically. A balance weight 18 is
fixed to the bushing 19. The balance weight 18, which is an
eccentric rotation body and eccentrically rotates together with the
eccentric shaft 17, comprises a ring portion 181 fixed to the
circumferential surface of the bushing 19 and a weight portion 182
formed integrally with the ring portion 181.
[0024] As shown in FIG. 1, a movable scroll 20 is supported by the
bushing 19 via a needle bearing 21 so that the movable scroll 20 is
opposed to the fixed scroll 11 and performs a rotation relative
thereto. The needle bearing 21 is housed in a cylinder of a
cylindrical portion 34, which is provided so as to protrude at the
rear side of a movable scroll base 22 of the movable scroll 20. A
fixed scroll base 23 and a fixed scroll wall 24 of the fixed scroll
11, and the movable scroll base 22 and a movable scroll wall 25 of
the movable scroll 20 form hermetic spaces S0 and S1, as shown in
FIG. 5. The movable scroll 20 orbits according to the rotation of
the eccentric shaft 17, and the balance weight 18 cancels out the
centrifugal force caused by the orbital movement of the movable
scroll 20 and the bushing 19. The eccentric shaft 17, which rotates
integrally with the drive shaft 14, the bushing 19, the cylindrical
portion 34 and the needle bearing 21 interposed between the
eccentric shaft 17 and the cylindrical portion 34 of the movable
scroll 20 constitute a orbital movement mechanism. The cylindrical
portion 34, the needle bearing 21 and the bushing 19 constitute a
transmitting means for eccentric rotation that transmits the
eccentric rotation of the eccentric shaft 17 to the movable scroll
20.
[0025] As shown in FIG. 1, a orbiting ring 26 is interposed between
the movable scroll base 22 and the center housing 12. Plural (four
in the present embodiment) cylindrical self-rotation preventing
pins 27 penetrate through and are fixed to the orbiting ring 26. An
annular pressure-applied plate 28 is interposed between the center
housing 12 and the orbiting ring 26. As shown in FIG. 3,
self-rotation preventing holes 281, as many as there are
self-rotation preventing pins 27, are arranged circumferentially on
the pressure-applied plate 28. Self-rotation preventing holes 222,
as many as there are self-rotation preventing pins 27, are arranged
circumferentially on the movable scroll base 22. Both the
self-rotation preventing holes 281 and 222 are equally spaced at
the same angles. The end portion of each self-rotation preventing
pin 27 is inserted into the self-rotation preventing holes 281 and
222.
[0026] A stator 29 is fixed to the inner circumferential surface of
the motor housing 13 and a rotor 30 is supported by the drive shaft
14. Both the stator 29 and the rotor 30 constitute a motor and the
rotor 30 and the drive shaft 14 rotate integrally when electrical
energy is supplied to the stator 29.
[0027] The movable scroll 20 orbits according to the rotation of
the eccentric shaft 17 integrally formed with the drive shaft 14,
and the refrigerant gas introduced from an inlet 111 flows between
the fixed scroll base 23 and the movable scroll base 22 from the
circumferential sides of both the scrolls 11 and 20. According to
the orbital movement of the movable scroll 20, the circumferential
surface of the self-rotation preventing pin 27 comes into slidable
contact with the circumferential surfaces of the self-rotation
preventing holes 222 and 281. The relation D=d+r is specified,
where D is a diameter of the self-rotation preventing holes 222 and
281, d is a diameter of the self-rotation preventing pin 27 and r
is an orbit radius of the orbital movement of the bushing 19. This
relation sets the radius of the orbital movement of the movable
scroll 20 to r, and the orbiting ring 26 orbits with a radius half
the orbit radius r of the movable scroll 20.
[0028] The orbiting ring 26 is prone to self-rotate spontaneously.
But because three or more self-rotation preventing pins 27 are in
contact with the inner circumferential surface of the fixedly
arranged self-rotation preventing hole 281, the orbiting ring 26
does not self-rotate. The movable scroll 20 is prone to self-rotate
spontaneously about the central axis of the bushing 19, but,
because the inner circumferential surface of the self-rotation
preventing hole 222 on the side of the movable scroll base 22 is in
contact with the three or more self-rotation preventing pins 27 on
the orbiting ring 26 that does not self-rotate, the movable scroll
20 does not self-rotate about the central axis of the bushing 19.
Therefore, the movable scroll 20 and the orbiting ring 26 orbit
without self-rotation. The hermetic spaces S1 and S0 shown in FIG.
5 continue to reduce their volumes according to the orbital
movement of the movable scroll 20, and converge between the inner
end portions 241 and 251 of the scroll walls 24 and 25 of the
scrolls 11 and 20.
[0029] As shown in FIG. 1, a discharge port 221 is formed on the
movable scroll base 22. The discharge port 221 communicates with
the final hermetic space S0. The discharge port 221 is opened and
closed by a float valve 31. A gas passage 32 is formed through the
eccentric shaft 17 and the drive shaft 14.
[0030] As shown in FIG. 2, an annular housing groove 341 is formed
around the end surface of the cylindrical portion 34 and an annular
seal member 35 made of synthetic resin is housed in a housing
groove 341. The seal member 35, which surrounds an eccentric axis
171 of the eccentric shaft 17, is interposed between the end face
of the cylindrical portion 34 and the ring portion 181 of the
balance weight 18. The seal member 35 defines a back pressure
chamber 36 in the cylindrical portion 34 together with the movable
scroll base 22 and the ring portion 181 of the balance weight
18.
[0031] The refrigerant gas compressed due to the reduction in
volume of the hermetic spaces S1 and S0 is discharged from the
final hermetic space S0 into the motor housing 13 through the
discharge port 221, the back pressure chamber 36 and the gas
passage 32. The refrigerant gas in the motor housing 13 is brought
to an external refrigerant circuit 33 through a passage 141 in the
drive shaft 14 and an exit 131 on the end wall of the motor housing
13. The back pressure chamber 36 in the cylindrical portion 34
becomes a high pressure discharge area and the back side of the
movable scroll base 22 outside the cylindrical portion 34 becomes a
low pressure suction area. The seal member 35 is pressed to and
made to come into contact with the ring portion 181 of the balance
weight 18 and an circumferential side surface 342 which is located
radially outer side, of the housing groove 341 by the pressure
inside the back pressure chamber 36. The seal member 35, which is
pressed to and made to come into contact with the ring portion 181
and the circumferential side surface 342 of the housing groove 341,
prevents pressure leakage between the suction pressure area of the
back side of the movable scroll base 22 and the back pressure
chamber 36.
[0032] The following effects can be obtained in the first
embodiment.
[0033] (1-1)
[0034] As shown in FIG. 5, the pressures inside the hermetic spaces
S0 and S1 bias the movable scroll 20 in the direction of the arrow
Q. As shown in FIG. 4, the bushing 19 is able to slidably move with
respect to the eccentric shaft 17 in the direction of the arrow R
and the direction of the arrow R is set so as to approximately
coincide with the direction of the arrow Q. Therefore, the movable
scroll wall 25 of the movable scroll 20, which is biased in the
direction of the arrow Q by the pressures inside the hermetic
spaces S0 and S1, is pressed to and made to come into contact with
the fixed scroll wall 24 of the fixed scroll 11. This pressing
action, in which the movable scroll wall 25 is pressed to and made
to come into contact with the fixed scroll wall 24, contributes to
preventing pressure leakage from the hermetic spaces S0 and S1
through between the fixed scroll wall 24 and the movable scroll
wall 25.
[0035] The structure which contributes to preventing pressure
leakage and in which a sliding motion is allowed between the
bushing 19 and the eccentric shaft 17, can accept the inclination
of the bushing 19 in the direction of the arrow R, that is, the
inclination, in the direction of the arrow R of an axis 192 of the
bushing 19 with respect to the eccentric axis 171 of the eccentric
shaft 17. Therefore the movable scroll 20 can incline in the
direction of the arrow R. When the movable scroll 20 inclines in
the direction of the arrow R, that is, when an eccentric axis 201
of the movable scroll 20 inclines with respect to an eccentric axis
171 of the eccentric shaft 17, the balance weight fixed to the
bushing 19 inclines in the same direction. Since the axis 192 of
the bushing 19 is also the eccentric axis of the balance weight 18,
the eccentric axis 192 of the balance weight 18 inclines the same
way that the eccentric axis 201 does, when the movable scroll 20
inclines. Therefore, the seal member 35 interposed between the
cylindrical portion 34 of the movable scroll 20 and the ring
portion 181 of the balance weight 18 comes into a good contact with
the outer side surface 342 of the housing groove 341 and the ring
portion 181. As a result, the seal member 35 can prevent pressure
leakage from the back pressure chamber 36 to the suction pressure
area at the back side of the movable scroll wall 25 without
fail.
[0036] (1-2)
[0037] The end face of the cylindrical portion 34 that constitutes
the orbital movement mechanism is a portion that comes close and is
opposed to the ring portion 181 of the balance weight 18. Such an
end face of the cylindrical portion 34 is best suited to the
forming position of the housing groove 341 that houses the seal
member 35.
[0038] (1-3)
[0039] The pressure inside the back pressure chamber 36 that
resists the pressure in the hermetic space S0, in which the
pressure is maximum in the area between the fixed scroll 11 and the
movable scroll 20, is the discharge pressure. The structure, in
which the discharge pressure is used as a back pressure directly,
is best suited to provide an appropriate back pressure.
[0040] (1-4)
[0041] The structure, in which the discharge port 221 is installed
on the movable scroll base 22, provides the shortest discharge
passage to the back pressure chamber 36 at the back side of the
movable scroll base 22. The structure that provides the shortest
passage from the discharge port 221 to the back pressure chamber 36
has advantage in avoiding a complex structure inside a compressor,
which provides a discharge passage.
[0042] Next the second embodiment shown in FIG. 6 is described. The
same symbols are used for the same elements as in the first
embodiment.
[0043] An annular protruding portion 343 is formed on the end face
of the cylindrical portion 34, and the seal member 35 is arranged
radially inner side the annular protruding portion 343. The seal
member 35 is pressed to and made to come into contact with the ring
portion 181 of the balance weight 18 and the protruding portion 343
by the pressure inside the back pressure chamber 36. The protruding
portion 343 provides a simpler structure than that of the housing
groove 341 in the first embodiment. It is advantageous to employ
the protruding portion 343 rather than the housing groove 341 in
reducing the wall thickness of the cylindrical portion 34. The
reduction in wall thickness of the cylindrical portion 34
contributes to a reduction in weight of a compressor.
[0044] Next the third embodiment shown in FIG. 7 is described. The
same symbols are used for the same elements as in the second
embodiment.
[0045] A part of an outer circumferential surface 183 of the ring
portion 181 of the balance weight 18 is designed so as to overlap
with the protruding portion 343 when viewed from the direction
perpendicular to the drive shaft 14. The outer circumferential
surface 183 prevents the seal member 35 from being pulled toward
the axis 192 of the bushing 19.
[0046] Next the fourth embodiment shown in FIG. 8 is described. The
same symbols are used for the same elements as in the first
embodiment.
[0047] The eccentric shaft 17 is inserted into the balance weight
18. A flange 193 is formed integrally to the bushing 19, which is
an eccentric rotation body, and the seal member 35 is designed so
as to be pressed to and made to come into contact with an inner
circumferential surface 344 of the cylindrical portion 34 and the
flange 193.
[0048] Next the fifth embodiment shown in FIG. 9 is described. The
same symbols are used for the same elements as in the fourth
embodiment.
[0049] A balance weight 18A is formed integrally to a bushing 19A,
which is an eccentric rotation body. The seal member 35 is designed
so as to be pressed to and made to come into contact with the inner
circumferential surface 344 of the cylindrical portion 34 and the
balance weight 18A.
[0050] Next, the sixth embodiment shown in FIG. 10 is described.
The same symbols are used for the same elements as in the first
embodiment.
[0051] The seal member 35 is housed in an annular housing groove
184 formed at the end surface of the ring portion 181 of the
balance weight 18. The seal member 35 is designed so at to be
pressed to and made to come into contact with the end surface of
the cylindrical portion 34 and the circumferential surface at the
radially outer side of the housing groove 184.
[0052] As mentioned in detail above, because the back pressure
chamber, which is opposed to the movable scroll, is formed by the
movable scroll, the eccentric rotation body, and the seal member in
the present invention, an excellent effect that the pressure
leakage from the back pressure chamber installed at the back side
of the movable scroll to the low pressure area can be prevented is
obtained.
[0053] While the invention has been described by reference to
specific embodiments chosen for the purposes of illustration, it
should be apparent that numerous modifications could be made
thereto by those skilled in the art without departing from the
basic concept and scope of the invention.
* * * * *