U.S. patent application number 14/177052 was filed with the patent office on 2015-08-13 for linear compressor.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is General Electric Company. Invention is credited to Thomas R. Barito, Gregory William Hahn.
Application Number | 20150226210 14/177052 |
Document ID | / |
Family ID | 53774551 |
Filed Date | 2015-08-13 |
United States Patent
Application |
20150226210 |
Kind Code |
A1 |
Barito; Thomas R. ; et
al. |
August 13, 2015 |
LINEAR COMPRESSOR
Abstract
A linear compressor is provided. The linear compressor includes
a piston. The piston includes a piston cylinder having a head
plate. The head plate defines a passage that extends through the
head plate. A reed valve is mounted to the head plate and
positioned over the passage of the head plate. A valve seat is
positioned at and extends about the passage of the head plate.
Inventors: |
Barito; Thomas R.;
(Louisville, KY) ; Hahn; Gregory William; (Mount
Washington, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
53774551 |
Appl. No.: |
14/177052 |
Filed: |
February 10, 2014 |
Current U.S.
Class: |
417/415 |
Current CPC
Class: |
F04B 39/0005 20130101;
F04B 35/045 20130101; F04B 39/1073 20130101; F04B 39/122
20130101 |
International
Class: |
F04B 53/10 20060101
F04B053/10; F04B 35/04 20060101 F04B035/04 |
Claims
1. A linear compressor, comprising: a driving coil; an inner back
iron assembly positioned in the driving coil, the inner back iron
assembly having an outer surface; a magnet mounted to the inner
back iron assembly at the outer surface of the inner back iron
assembly such that the magnet faces the driving coil; a cylinder
assembly defining a chamber; a piston slidably received within the
chamber of the cylinder assembly, the piston comprising a
cylindrical segment extending between a first end portion and a
second end portion; a head plate mounted to the cylindrical segment
at the second end portion of the cylindrical segment, the head
plate defining a passage that extends from the second end portion
of the cylindrical segment towards the first end portion of the
cylindrical segment through the head plate; a reed valve mounted to
the head plate and positioned over the passage of the head plate;
and a valve seat positioned at and extending about the passage of
the head plate, the valve seat also extending away from the head
plate such that the reed valve is positioned on the valve seat
above the passage of the head plate when the reed valve is in a
closed position; and a coupling extending between the inner back
iron assembly and the piston.
2. The linear compressor of claim 1, wherein a magnetic field of
the driving coil engages the magnet in order to move the inner back
iron assembly in the driving coil and the piston within the chamber
of the cylinder assembly during operation of the driving coil.
3. The linear compressor of claim 1, wherein the coupling extends
through the cylindrical segment of the piston and is mounted to the
head plate of the piston.
4. The linear compressor of claim 3, wherein the coupling is
threaded to the head plate of the piston.
5. The linear compressor of claim 1, wherein the passage defines a
substantially reniform cross-section in a plane that is parallel to
an outer surface of the head plate.
6. The linear compressor of claim 1, wherein the piston comprises a
fastener extending through the reed valve into the head plate in
order to mount the reed valve to the head plate.
7. The linear compressor of claim 1, further comprising a valve
support positioned at and extending along an outer edge of the head
plate, the valve support also extending away from the head plate,
the valve seat and the valve support defining a channel
therebetween.
8. The linear compressor of claim 7, wherein the reed valve defines
an opening that extends through the reed valve, the channel being
contiguous with the opening of the reed valve when the reed valve
is in the closed position.
9. The linear compressor of claim 7, wherein the valve seat extends
away from the head plate by a height, the valve support also
extending away from the head plate by a height, the height of the
valve seat being about equal to the height of the valve
support.
10. The linear compressor of claim 1, wherein the head plate
defines at least one additional passage that extends from the
second end portion of the cylindrical segment towards the first end
portion of the cylindrical segment through the head plate, the reed
valve positioned over the additional passage of the head plate, the
valve seat extending about the additional passage of the head
plate.
11. A linear compressor defining a radial direction, a
circumferential direction and an axial direction, the linear
compressor comprising: a cylinder assembly defining a chamber; a
piston received within the chamber of the cylinder assembly such
that the piston is slidable along a first axis within the chamber
of the cylinder assembly, the piston comprising a piston cylinder
having a head plate, the head plate positioned at an end of the
piston cylinder, the head plate defining a passage that extends
along the axial direction through the head plate; a reed valve
mounted to the head plate and positioned over the passage of the
head plate; and a valve seat positioned at and extending about the
passage of the head plate along the circumferential and radial
directions, the valve seat also extending away from the head plate
along the axial direction; and a driving coil operable to move the
piston assembly along a second axis, the first and second axes
being substantially parallel to the axial direction.
12. The linear compressor of claim 11, further comprising a
coupling, the coupling mounted to the head plate and extending from
the head plate through the piston cylinder along the axial
direction.
13. The linear compressor of claim 12, wherein the coupling is
threaded to the head plate of the piston cylinder.
14. The linear compressor of claim 11, wherein the passage defines
a substantially reniform cross-section in a plane that is
perpendicular to the axial direction.
15. The linear compressor of claim 11, wherein the piston comprises
a fastener extending through the reed valve into the head plate in
order to mount the reed valve to the head plate.
16. The linear compressor of claim 11, further comprising a valve
support positioned at and extending along an outer edge of the head
plate, the valve support also extending away from the head plate
along the axial direction, the valve seat and the valve support
defining a channel therebetween.
17. The linear compressor of claim 16, wherein the reed valve
defines an opening that extends through the reed valve, the channel
being contiguous with the opening of the reed valve when the reed
valve is in a closed position.
18. The linear compressor of claim 16, wherein the valve seat
extends away from the head plate by a height along the axial
direction, the valve support also extending away from the head
plate by a height along the axial direction, the height of the
valve seat being about equal to the height of the valve
support.
19. The linear compressor of claim 11, wherein the passage extends
between a first end portion and a second end portion along the
circumferential direction, the passage extending along the
circumferential direction at least sixty degrees between the first
and second end portions of the passage.
20. The linear compressor of claim 19, wherein the passage extends
along the circumferential direction at least ninety degrees between
the first and second end portions of the passage.
Description
FIELD OF THE INVENTION
[0001] The present subject matter relates generally to linear
compressors, e.g., for refrigerator appliances.
BACKGROUND OF THE INVENTION
[0002] Certain refrigerator appliances include sealed systems for
cooling chilled chambers of the refrigerator appliance. The sealed
systems generally include a compressor that generates compressed
refrigerant during operation of the sealed system. The compressed
refrigerant flows to an evaporator where heat exchange between the
chilled chambers and the refrigerant cools the chilled chambers and
food items located therein.
[0003] Recently, certain refrigerator appliances have included
linear compressors for compressing refrigerant. Linear compressors
generally include a piston and a driving coil. The driving coil
receives a current that generates a force for sliding the piston
forward and backward within a chamber. During motion of the piston
within the chamber, the piston compresses refrigerant. However,
friction between the piston and a wall of the chamber can
negatively affect operation of the linear compressors if the piston
is not suitably aligned within the chamber. In particular, friction
losses due to rubbing of the piston against the wall of the chamber
can negatively affect an efficiency of an associated refrigerator
appliance.
[0004] The driving coil generally engages a magnet on a mover
assembly of the linear compressor in order to reciprocate the
piston within the chamber. The magnet is spaced apart from the
driving coil by an air gap. In certain linear compressors, an
additional air gap is provided at an opposite side of the magnet,
e.g., between the magnet and an inner back iron of the linear
compressor. However, multiple air gaps can negatively affect
operation of the linear compressor by interrupting transmission of
a magnetic field from the driving coil. In addition, maintaining a
uniform air gap between the magnet and the driving coil and/or
inner back iron can be difficult.
[0005] Accordingly, a linear compressor with features for limiting
friction between a piston and a wall of a cylinder during operation
of the linear compressor would be useful. In addition, a linear
compressor with features for maintaining uniformity of an air gap
between a magnet and a driving coil of the linear compressor would
be useful. In particular, a linear compressor having only a single
air gap would be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0006] The present subject matter provides a linear compressor. The
linear compressor includes a piston. The piston includes a piston
cylinder having a head plate. The head plate defines a passage that
extends through the head plate. A reed valve is mounted to the head
plate and positioned over the passage of the head plate. A valve
seat is positioned at and extends about the passage of the head
plate. Additional aspects and advantages of the invention will be
set forth in part in the following description, or may be apparent
from the description, or may be learned through practice of the
invention.
[0007] In a first exemplary embodiment, a linear compressor is
provided. The linear compressor includes a driving coil. An inner
back iron assembly is positioned in the driving coil. The inner
back iron assembly has an outer surface. A magnet is mounted to the
inner back iron assembly at the outer surface of the inner back
iron assembly such that the magnet faces the driving coil. A
cylinder assembly defines a chamber. A piston is slidably received
within the chamber of the cylinder assembly. The piston includes a
cylindrical segment that extends between a first end portion and a
second end portion. A head plate is mounted to the cylindrical
segment at the second end portion of the cylindrical segment. The
head plate defines a passage that extends from the second end
portion of the cylindrical segment towards the first end portion of
the cylindrical segment through the head plate. A reed valve is
mounted to the head plate and positioned over the passage of the
head plate. A valve seat is positioned at and extends about the
passage of the head plate. The valve seat also extends away from
the head plate such that the reed valve is positioned on the valve
seat above the passage of the head plate when the reed valve is in
a closed position. A coupling extends between the inner back iron
assembly and the piston.
[0008] In a second exemplary embodiment, a linear compressor is
provided. The linear compressor defines a radial direction, a
circumferential direction and an axial direction. The linear
compressor includes a cylinder assembly that defines a chamber. A
piston is received within the chamber of the cylinder assembly such
that the piston is slidable along a first axis within the chamber
of the cylinder assembly. The piston includes a piston cylinder
having a head plate. The head plate is positioned at an end of the
piston cylinder. The head plate defines a passage that extends
along the axial direction through the head plate. A reed valve is
mounted to the head plate and positioned over the passage of the
head plate. A valve seat is positioned at and extends about the
passage of the head plate along the circumferential and radial
directions. The valve seat also extends away from the head plate
along the axial direction. A driving coil is operable to move the
piston assembly along a second axis. The first and second axes
being substantially parallel to the axial direction.
[0009] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A full and enabling disclosure of the present invention,
including the best mode thereof, directed to one of ordinary skill
in the art, is set forth in the specification, which makes
reference to the appended figures.
[0011] FIG. 1 is a front elevation view of a refrigerator appliance
according to an exemplary embodiment of the present subject
matter.
[0012] FIG. 2 is schematic view of certain components of the
exemplary refrigerator appliance of FIG. 1.
[0013] FIG. 3 provides a perspective view of a linear compressor
according to an exemplary embodiment of the present subject
matter.
[0014] FIG. 4 provides a side section view of the exemplary linear
compressor of FIG. 3.
[0015] FIG. 5 provides an exploded view of the exemplary linear
compressor of FIG. 4.
[0016] FIG. 6 provides a side section view of certain components of
the exemplary linear compressor of FIG. 3.
[0017] FIG. 7 provides a perspective view of a piston flex mount of
the exemplary linear compressor of FIG. 3.
[0018] FIG. 8 provides a perspective view of a coupling according
to an exemplary embodiment of the present subject matter.
[0019] FIG. 9 provides a perspective view of a machined spring of
the exemplary linear compressor of FIG. 3.
[0020] FIG. 10 provides a perspective view of a piston of the
exemplary linear compressor of FIG. 3.
[0021] FIG. 11 provides an exploded view of the piston of FIG.
10.
[0022] FIG. 12 provides a rear perspective view of the piston of
FIG. 10.
[0023] FIG. 13 provides a top, plan view of certain components of
the piston of FIG. 10.
[0024] FIG. 14 provides an exploded view of a piston according to
another exemplary embodiment of the present subject matter.
DETAILED DESCRIPTION
[0025] Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0026] FIG. 1 depicts a refrigerator appliance 10 that incorporates
a sealed refrigeration system 60 (FIG. 2). It should be appreciated
that the term "refrigerator appliance" is used in a generic sense
herein to encompass any manner of refrigeration appliance, such as
a freezer, refrigerator/freezer combination, and any style or model
of conventional refrigerator. In addition, it should be understood
that the present subject matter is not limited to use in
appliances. Thus, the present subject matter may be used for any
other suitable purpose, such as vapor compression within air
conditioning units or air compression within air compressors.
[0027] In the illustrated exemplary embodiment shown in FIG. 1, the
refrigerator appliance 10 is depicted as an upright refrigerator
having a cabinet or casing 12 that defines a number of internal
chilled storage compartments. In particular, refrigerator appliance
10 includes upper fresh-food compartments 14 having doors 16 and
lower freezer compartment 18 having upper drawer 20 and lower
drawer 22. The drawers 20 and 22 are "pull-out" drawers in that
they can be manually moved into and out of the freezer compartment
18 on suitable slide mechanisms.
[0028] FIG. 2 is a schematic view of certain components of
refrigerator appliance 10, including a sealed refrigeration system
60 of refrigerator appliance 10. A machinery compartment 62
contains components for executing a known vapor compression cycle
for cooling air. The components include a compressor 64, a
condenser 66, an expansion device 68, and an evaporator 70
connected in series and charged with a refrigerant. As will be
understood by those skilled in the art, refrigeration system 60 may
include additional components, e.g., at least one additional
evaporator, compressor, expansion device, and/or condenser. As an
example, refrigeration system 60 may include two evaporators.
[0029] Within refrigeration system 60, refrigerant flows into
compressor 64, which operates to increase the pressure of the
refrigerant. This compression of the refrigerant raises its
temperature, which is lowered by passing the refrigerant through
condenser 66. Within condenser 66, heat exchange with ambient air
takes place so as to cool the refrigerant. A fan 72 is used to pull
air across condenser 66, as illustrated by arrows A.sub.C, so as to
provide forced convection for a more rapid and efficient heat
exchange between the refrigerant within condenser 66 and the
ambient air. Thus, as will be understood by those skilled in the
art, increasing air flow across condenser 66 can, e.g., increase
the efficiency of condenser 66 by improving cooling of the
refrigerant contained therein.
[0030] An expansion device (e.g., a valve, capillary tube, or other
restriction device) 68 receives refrigerant from condenser 66. From
expansion device 68, the refrigerant enters evaporator 70. Upon
exiting expansion device 68 and entering evaporator 70, the
refrigerant drops in pressure. Due to the pressure drop and/or
phase change of the refrigerant, evaporator 70 is cool relative to
compartments 14 and 18 of refrigerator appliance 10. As such,
cooled air is produced and refrigerates compartments 14 and 18 of
refrigerator appliance 10. Thus, evaporator 70 is a type of heat
exchanger which transfers heat from air passing over evaporator 70
to refrigerant flowing through evaporator 70.
[0031] Collectively, the vapor compression cycle components in a
refrigeration circuit, associated fans, and associated compartments
are sometimes referred to as a sealed refrigeration system operable
to force cold air through compartments 14, 18 (FIG. 1). The
refrigeration system 60 depicted in FIG. 2 is provided by way of
example only. Thus, it is within the scope of the present subject
matter for other configurations of the refrigeration system to be
used as well.
[0032] FIG. 3 provides a perspective view of a linear compressor
100 according to an exemplary embodiment of the present subject
matter. FIG. 4 provides a side section view of linear compressor
100. FIG. 5 provides an exploded side section view of linear
compressor 100. As discussed in greater detail below, linear
compressor 100 is operable to increase a pressure of fluid within a
chamber 112 of linear compressor 100. Linear compressor 100 may be
used to compress any suitable fluid, such as refrigerant or air. In
particular, linear compressor 100 may be used in a refrigerator
appliance, such as refrigerator appliance 10 (FIG. 1) in which
linear compressor 100 may be used as compressor 64 (FIG. 2). As may
be seen in FIG. 3, linear compressor 100 defines an axial direction
A, a radial direction R and a circumferential direction C. Linear
compressor 100 may be enclosed within a hermetic or air-tight shell
(not shown). The hermetic shell can, e.g., hinder or prevent
refrigerant from leaking or escaping from refrigeration system
60.
[0033] Turning now to FIG. 4, linear compressor 100 includes a
casing 110 that extends between a first end portion 102 and a
second end portion 104, e.g., along the axial direction A. Casing
110 includes various static or non-moving structural components of
linear compressor 100. In particular, casing 110 includes a
cylinder assembly 111 that defines a chamber 112. Cylinder assembly
111 is positioned at or adjacent second end portion 104 of casing
110. Chamber 112 extends longitudinally along the axial direction
A. Casing 110 also includes a motor mount mid-section 113 and an
end cap 115 positioned opposite each other about a motor. A stator,
e.g., including an outer back iron 150 and a driving coil 152, of
the motor is mounted or secured to casing 110, e.g., such that the
stator is sandwiched between motor mount mid-section 113 and end
cap 115 of casing 110. Linear compressor 100 also includes valves
(such as a discharge valve assembly 117 at an end of chamber 112)
that permit refrigerant to enter and exit chamber 112 during
operation of linear compressor 100.
[0034] A piston assembly 114 with a piston head 116 is slidably
received within chamber 112 of cylinder assembly 111. In
particular, piston assembly 114 is slidable along a first axis A1
within chamber 112. The first axis A1 may be substantially parallel
to the axial direction A. During sliding of piston head 116 within
chamber 112, piston head 116 compresses refrigerant within chamber
112. As an example, from a top dead center position, piston head
116 can slide within chamber 112 towards a bottom dead center
position along the axial direction A, i.e., an expansion stroke of
piston head 116. When piston head 116 reaches the bottom dead
center position, piston head 116 changes directions and slides in
chamber 112 back towards the top dead center position, i.e., a
compression stroke of piston head 116. It should be understood that
linear compressor 100 may include an additional piston head and/or
additional chamber at an opposite end of linear compressor 100.
Thus, linear compressor 100 may have multiple piston heads in
alternative exemplary embodiments.
[0035] Linear compressor 100 also includes an inner back iron
assembly 130. Inner back iron assembly 130 is positioned in the
stator of the motor. In particular, outer back iron 150 and/or
driving coil 152 may extend about inner back iron assembly 130,
e.g., along the circumferential direction C. Inner back iron
assembly 130 extends between a first end portion 132 and a second
end portion 134, e.g., along the axial direction A.
[0036] Inner back iron assembly 130 also has an outer surface 137.
At least one driving magnet 140 is mounted to inner back iron
assembly 130, e.g., at outer surface 137 of inner back iron
assembly 130. Driving magnet 140 may face and/or be exposed to
driving coil 152. In particular, driving magnet 140 may be spaced
apart from driving coil 152, e.g., along the radial direction R by
an air gap AG. Thus, the air gap AG may be defined between opposing
surfaces of driving magnet 140 and driving coil 152. Driving magnet
140 may also be mounted or fixed to inner back iron assembly 130
such that an outer surface 142 of driving magnet 140 is
substantially flush with outer surface 137 of inner back iron
assembly 130. Thus, driving magnet 140 may be inset within inner
back iron assembly 130. In such a manner, the magnetic field from
driving coil 152 may have to pass through only a single air gap
(e.g., air gap AG) between outer back iron 150 and inner back iron
assembly 130 during operation of linear compressor 100, and linear
compressor 100 may be more efficient than linear compressors with
air gaps on both sides of a driving magnet.
[0037] As may be seen in FIG. 4, driving coil 152 extends about
inner back iron assembly 130, e.g., along the circumferential
direction C. Driving coil 152 is operable to move the inner back
iron assembly 130 along a second axis A2 during operation of
driving coil 152. The second axis may be substantially parallel to
the axial direction A and/or the first axis A1. As an example,
driving coil 152 may receive a current from a current source (not
shown) in order to generate a magnetic field that engages driving
magnet 140 and urges piston assembly 114 to move along the axial
direction A in order to compress refrigerant within chamber 112 as
described above and will be understood by those skilled in the art.
In particular, the magnetic field of driving coil 152 may engage
driving magnet 140 in order to move inner back iron assembly 130
along the second axis A2 and piston head 116 along the first axis
A1 during operation of driving coil 152. Thus, driving coil 152 may
slide piston assembly 114 between the top dead center position and
the bottom dead center position, e.g., by moving inner back iron
assembly 130 along the second axis A2, during operation of driving
coil 152.
[0038] Linear compressor 100 may include various components for
permitting and/or regulating operation of linear compressor 100. In
particular, linear compressor 100 includes a controller (not shown)
that is configured for regulating operation of linear compressor
100. The controller is in, e.g., operative, communication with the
motor, e.g., driving coil 152 of the motor. Thus, the controller
may selectively activate driving coil 152, e.g., by supplying
current to driving coil 152, in order to compress refrigerant with
piston assembly 114 as described above.
[0039] The controller includes memory and one or more processing
devices such as microprocessors, CPUs or the like, such as general
or special purpose microprocessors operable to execute programming
instructions or micro-control code associated with operation of
linear compressor 100. The memory can represent random access
memory such as DRAM, or read only memory such as ROM or FLASH. The
processor executes programming instructions stored in the memory.
The memory can be a separate component from the processor or can be
included onboard within the processor. Alternatively, the
controller may be constructed without using a microprocessor, e.g.,
using a combination of discrete analog and/or digital logic
circuitry (such as switches, amplifiers, integrators, comparators,
flip-flops, AND gates, and the like) to perform control
functionality instead of relying upon software.
[0040] Linear compressor 100 also includes a machined spring 120.
Machined spring 120 is positioned in inner back iron assembly 130.
In particular, inner back iron assembly 130 may extend about
machined spring 120, e.g., along the circumferential direction C.
Machined spring 120 also extends between first and second end
portions 102 and 104 of casing 110, e.g., along the axial direction
A. Machined spring 120 assists with coupling inner back iron
assembly 130 to casing 110, e.g., cylinder assembly 111 of casing
110. In particular, inner back iron assembly 130 is fixed to
machined spring 120 at a middle portion 119 of machined spring 120
as discussed in greater detail below.
[0041] During operation of driving coil 152, machined spring 120
supports inner back iron assembly 130. In particular, inner back
iron assembly 130 is suspended by machined spring 120 within the
stator of the motor such that motion of inner back iron assembly
130 along the radial direction R is hindered or limited while
motion along the second axis A2 is relatively unimpeded. Thus,
machined spring 120 may be substantially stiffer along the radial
direction R than along the axial direction A. In such a manner,
machined spring 120 can assist with maintaining a uniformity of the
air gap AG between driving magnet 140 and driving coil 152, e.g.,
along the radial direction R, during operation of the motor and
movement of inner back iron assembly 130 on the second axis A2.
Machined spring 120 can also assist with hindering side pull forces
of the motor from transmitting to piston assembly 114 and being
reacted in cylinder assembly 111 as a friction loss.
[0042] FIG. 6 provides a side section view of certain components of
linear compressor 100. FIG. 9 provides a perspective view of
machined spring 120. As may be seen in FIG. 9, machined spring 120
includes a first cylindrical portion 121, a second cylindrical
portion 122, a first helical portion 123, a third cylindrical
portion 125 and a second helical portion 126. First helical portion
123 of machined spring 120 extends between and couples first and
second cylindrical portions 121 and 122 of machined spring 120,
e.g., along the axial direction A. Similarly, second helical
portion 126 of machined spring 120 extends between and couples
second and third cylindrical portions 122 and 125 of machined
spring 120, e.g., along the axial direction A.
[0043] Turning back to FIG. 4, first cylindrical portion 121 is
mounted or fixed to casing 110 at first end portion 102 of casing
110. Thus, first cylindrical portion 121 is positioned at or
adjacent first end portion 102 of casing 110. Third cylindrical
portion 125 is mounted or fixed to casing 110 at second end portion
104 of casing 110, e.g., to cylinder assembly 111 of casing 110.
Thus, third cylindrical portion 125 is positioned at or adjacent
second end portion 104 of casing 110. Second cylindrical portion
122 is positioned at middle portion 119 of machined spring 120. In
particular, second cylindrical portion 122 is positioned within and
fixed to inner back iron assembly 130. Second cylindrical portion
122 may also be positioned equidistant from first and third
cylindrical portions 121 and 125, e.g., along the axial direction
A.
[0044] First cylindrical portion 121 of machined spring 120 is
mounted to casing 110 with fasteners (not shown) that extend though
end cap 115 of casing 110 into first cylindrical portion 121. In
alternative exemplary embodiments, first cylindrical portion 121 of
machined spring 120 may be threaded, welded, glued, fastened, or
connected via any other suitable mechanism or method to casing 110.
Third cylindrical portion 125 of machined spring 120 is mounted to
cylinder assembly 111 at second end portion 104 of casing 110 via a
screw thread of third cylindrical portion 125 threaded into
cylinder assembly 111. In alternative exemplary embodiments, third
cylindrical portion 125 of machined spring 120 may be welded,
glued, fastened, or connected via any other suitable mechanism or
method, such as an interference fit, to casing 110.
[0045] As may be seen in FIG. 9, first helical portion 123 extends,
e.g., along the axial direction A, between first and second
cylindrical portions 121 and 122 and couples first and second
cylindrical portions 121 and 122 together. Similarly, second
helical portion 126 extends, e.g., along the axial direction A,
between second and third cylindrical portions 122 and 125 and
couples second and third cylindrical portions 122 and 125 together.
Thus, second cylindrical portion 122 is suspended or sprung between
first and third cylindrical portions 121 and 125 with first and
second helical portions 123 and 126.
[0046] First and second helical portions 123 and 126 and first,
second and third cylindrical portions 121, 122 and 125 of machined
spring 120 may be continuous with one another and/or integrally
mounted to one another. As an example, machined spring 120 may be
formed from a single, continuous piece of metal, such as steel, or
other elastic material. In addition, first, second and third
cylindrical portions 121, 122 and 125 and first and second helical
portions 123 and 126 of machined spring 120 may be positioned
coaxially relative to one another, e.g., on the second axis A2.
[0047] First helical portion 123 includes a first pair of helices
124. Thus, first helical portion 123 may be a double start helical
spring. Helical coils of first helices 124 are separate or spaced
apart from each other. Each helical coil of first helices 124 also
extends between first and second cylindrical portions 121 and 122
of machined spring 120. Thus, first helices 124 couple first and
second cylindrical portions 121 and 122 of machined spring 120
together. In particular, first helical portion 123 may be formed
into a double-helix structure in which each helical coil of first
helices 124 is wound in the same direction and connect first and
second cylindrical portions 121 and 122 of machined spring 120.
[0048] Second helical portion 126 includes a second pair of helices
127. Thus, second helical portion 126 may be a double start helical
spring. Helical coils of second helices 127 are separate or spaced
apart from each other. Each helical coil of second helices 127 also
extends between second and third cylindrical portions 122 and 125
of machined spring 120. Thus, second helices 127 couple second and
third cylindrical portions 122 and 125 of machined spring 120
together. In particular, second helical portion 126 may be formed
into a double-helix structure in which each helical coil of second
helices 127 is wound in the same direction and connect second and
third cylindrical portions 122 and 125 of machined spring 120.
[0049] By providing first and second helices 124 and 127 rather
than a single helix, a force applied by machined spring 120 may be
more even and/or inner back iron assembly 130 may rotate less
during motion of inner back iron assembly 130 along the second axis
A2. In addition, first and second helices 124 and 127 may be
counter or oppositely wound. Such opposite winding may assist with
further balancing the force applied by machined spring 120 and/or
inner back iron assembly 130 may rotate less during motion of inner
back iron assembly 130 along the second axis A2. In alternative
exemplary embodiments, first and second helices 124 and 127 may
include more than two helices. For example, first and second
helices 124 and 127 may each include three helices, four helices,
five helices or more.
[0050] By providing machined spring 120 rather than a coiled wire
spring, performance of linear compressor 100 can be improved. For
example, machined spring 120 may be more reliable than comparable
coiled wire springs. In addition, the stiffness of machined spring
120 along the radial direction R may be greater than that of
comparable coiled wire springs. Further, comparable coiled wire
springs include an inherent unbalanced moment. Machined spring 120
may be formed to eliminate or substantially reduce any inherent
unbalanced moments. As another example, adjacent coils of a
comparable coiled wire spring contact each other at an end of the
coiled wire spring, and such contact may dampen motion of the
coiled wire spring thereby negatively affecting a performance of an
associated linear compressor. In contrast, by being formed of a
single continuous material and having no contact between adjacent
coils, machined spring 120 may have less dampening than comparable
coiled wire springs.
[0051] As may be seen in FIG. 6, inner back iron assembly 130
includes an outer cylinder 136 and a sleeve 139. Outer cylinder 136
defines outer surface 137 of inner back iron assembly 130 and also
has an inner surface 138 positioned opposite outer surface 137 of
outer cylinder 136. Sleeve 139 is positioned on or at inner surface
138 of outer cylinder 136. A first interference fit between outer
cylinder 136 and sleeve 139 may couple or secure outer cylinder 136
and sleeve 139 together. In alternative exemplary embodiments,
sleeve 139 may be welded, glued, fastened, or connected via any
other suitable mechanism or method to outer cylinder 136.
[0052] Sleeve 139 extends about machined spring 120, e.g., along
the circumferential direction C. In addition, middle portion 119 of
machined spring 120 (e.g., third cylindrical portion 125) is
mounted or fixed to inner back iron assembly 130 with sleeve 139.
As may be seen in FIG. 6, sleeve 139 extends between inner surface
138 of outer cylinder 136 and middle portion 119 of machined spring
120, e.g., along the radial direction R. In particular, sleeve 139
extends between inner surface 138 of outer cylinder 136 and second
cylindrical portion 122 of machined spring 120, e.g., along the
radial direction R. A second interference fit between sleeve 139
and middle portion 119 of machined spring 120 may couple or secure
sleeve 139 and middle portion 119 of machined spring 120 together.
In alternative exemplary embodiments, sleeve 139 may be welded,
glued, fastened, or connected via any other suitable mechanism or
method to middle portion 119 of machined spring 120 (e.g., second
cylindrical portion 122 of machined spring 120).
[0053] Outer cylinder 136 may be constructed of or with any
suitable material. For example, outer cylinder 136 may be
constructed of or with a plurality of (e.g., ferromagnetic)
laminations 131. Laminations 131 are distributed along the
circumferential direction C in order to form outer cylinder 136.
Laminations 131 are mounted to one another or secured together,
e.g., with rings 135 at first and second end portions 132 and 134
of inner back iron assembly 130. Outer cylinder 136, e.g.,
laminations 131, define a recess 144 that extends inwardly from
outer surface 137 of outer cylinder 136, e.g., along the radial
direction R. Driving magnet 140 is positioned in recess 144, e.g.,
such that driving magnet 140 is inset within outer cylinder
136.
[0054] A piston flex mount 160 is mounted to and extends through
inner back iron assembly 130. In particular, piston flex mount 160
is mounted to inner back iron assembly 130 via sleeve 139 and
machined spring 120. Thus, piston flex mount 160 may be coupled
(e.g., threaded) to machined spring 120 at second cylindrical
portion 122 of machined spring 120 in order to mount or fix piston
flex mount 160 to inner back iron assembly 130. A flexible or
compliant coupling 170 extends between piston flex mount 160 and
piston assembly 114, e.g., along the axial direction A. Thus,
compliant coupling 170 connects inner back iron assembly 130 and
piston assembly 114 such that motion of inner back iron assembly
130, e.g., along the axial direction A or the second axis A2, is
transferred to piston assembly 114 as discussed in greater detail
below.
[0055] FIG. 7 provides a perspective view of piston flex mount 160.
As may be seen in FIG. 7, piston flex mount 160 defines at least
one passage 162. Passage 162 of piston flex mount 160 extends,
e.g., along the axial direction A, through piston flex mount 160.
Thus, a flow of fluid, such as air or refrigerant, may pass though
piston flex mount 160 via passage 162 of piston flex mount 160
during operation of linear compressor 100.
[0056] FIG. 8 provides a perspective view of compliant coupling
170. As discussed above, compliant coupling 170 extends between
inner back iron assembly 130 and piston assembly 114, e.g., along
the axial direction A, and connects inner back iron assembly 130
and piston assembly 114. In particular, compliant coupling 170
transfers motion of inner back iron assembly 130 along the axial
direction A to piston assembly 114. However, compliant coupling 170
is compliant or flexible along the radial direction R. In
particular, compliant coupling 170 may be sufficiently compliant
along the radial direction R such little or no motion of inner back
iron assembly 130 along the radial direction R is transferred to
piston assembly 114 by compliant coupling 170. In such a manner,
side pull forces of the motor are decoupled from piston assembly
114 and/or cylinder assembly 111 and friction between piston
assembly 114 and cylinder assembly 111 may be reduced.
[0057] Compliant coupling 170 extends between a first end portion
172 and a second end portion 174, e.g., along the axial direction
A. First end portion 172 of compliant coupling 170 may be mounted
(e.g., threaded) to inner back iron assembly 130, e.g., at first
end portion 132 of inner back iron assembly 130. Second end portion
174 of compliant coupling 170 may be mounted (e.g., threaded) to
piston head 116.
[0058] FIG. 10 provides a perspective view of piston assembly 114.
FIG. 11 provides an exploded view of piston assembly 114. As may be
seen in FIG. 11, piston assembly 114 defines at least one conduit
or passage 118. Passage 118 of piston assembly 114 extends, e.g.,
along the axial direction A, through piston assembly 114. Thus, the
flow of fluid may pass though piston assembly 114 via passage 118
of piston assembly 114 into chamber 112 during operation of linear
compressor 100. In such a manner, the flow of fluid (that is
compressed by piston assembly 114 within chamber 112) may flow
through piston flex mount 160 and inner back iron assembly 130 to
piston assembly 114 during operation of linear compressor 100.
[0059] Piston assembly 114 includes a piston cylinder 180. Piston
cylinder 180 includes a cylindrical segment 182 and a head plate
184. Head plate 184 is positioned at an end of piston cylinder 180.
In particular, cylindrical segment 182 extends between a first end
portion 186 and a second end portion 188, e.g., along the axial
direction. Head plate 184 is mounted to or formed on cylindrical
segment 182 at second end portion 188 of cylindrical segment
182.
[0060] Head plate 184 defines passage 118 of piston assembly 114.
Passage 118 extends, e.g., along the axial direction A, through
head plate 184. In particular, passage 118 extends from second end
portion 188 of cylindrical segment 182 towards first end portion
186 of cylindrical segment 182 through head plate 184.
[0061] Piston assembly 114 further includes a reed valve 190. Reed
valve 190 is mounted to head plate 184, e.g., such that reed valve
190 is positioned over passage 118 of head plate 184. Reed valve
190 is selectively adjustable between an open position and a closed
position. In the open position, reed valve 190 permits fluid flow
(e.g., air or refrigerant) through passage 118 of head plate 184
into chamber 112 of cylinder assembly 111. Conversely, reed valve
190 hinders or obstructs fluid flow through passage 118 of head
plate 184 into chamber 112 of cylinder assembly 111 when reed valve
190 is in the closed position. Reed valve 190 actuates between the
open and closed position depending upon a stroke direction of
piston assembly 114 within chamber 112 of cylinder assembly 111. In
particular, reed valve 190 actuates to the closed position as
piston assembly 114 shifts from the bottom dead center position
towards the top dead center position (e.g., on the compression
stroke of piston assembly 114), and reed valve 190 actuates to the
open position as piston assembly 114 shifts from the top dead
center position towards the bottom dead center position (e.g., on
the expansion stroke of piston assembly 114).
[0062] Reed valve 190 may be mounted to piston assembly 114 using
any suitable method or mechanism. For example, a fastener 194 may
be used to secure or mount reed valve 190 to piston assembly 114.
In particular, fastener 194 may extend through reed valve 190 into
head plate 184 in order to mount reed valve 190 to head plate 184.
In alternative exemplary embodiments, reed valve 190 may be welded,
adhered, etc. to piston assembly 114.
[0063] FIG. 12 provides a rear perspective view of piston assembly
114. As may be seen in FIG. 12, piston assembly 114 includes a post
195, e.g., mounted to head plate 184 and extending into cylindrical
segment 182 along the axial direction A from head plate 184.
Compliant coupling 170 may be mounted to piston assembly 114 at
post 195. In particular, compliant coupling 170 may extend through
cylindrical segment 182 and be mounted to head plate 184, e.g., at
post 195. As an example, second end portion 174 of compliant
coupling 170 may be threaded to post 195 or any other suitable
portion of head plate 184. In such a manner, compliant coupling 170
may extend between inner back iron assembly 130 and piston assembly
114.
[0064] FIG. 13 provides a top, plan view of certain components of
piston assembly 114. As may be seen in FIG. 13, a valve seat 196 is
positioned on head plate 184 at passage 118. Valve seat 196 extends
about passage 118, e.g., along the circumferential direction C
and/or the radial direction R. Thus, passage 118 is surrounded or
encircled by valve seat 196 at head plate 184. Valve seat 196 also
extends away from head plate 184, e.g., along the axial direction
A. Thus, a distal end of valve seat 196 is raised above head plate
184. Reed valve 190 is positioned on and contacts valve seat 196
above passage 118, e.g., when reed valve 190 is in the closed
position. By having reed valve 190 rest on valve seat 196 in the
closed position, a force required to open reed valve 190 can be
reduced, e.g., by reducing an area that reed valve 190 contacts in
the closed position. In addition, by having reed valve 190 rest on
valve seat 196, a sealing force of reed valve 190 around passage
118 can be increased and/or leakages around reed valve 190 can be
reduced or minimized.
[0065] Piston assembly 114 also includes a valve support 197. Valve
support 197 is positioned at an outer edge 185 of head plate 184.
Valve support 197 extends, e.g., along the circumferential
direction C, along outer edge 185 of head plate 184. Valve support
197 also extends away from head plate 184, e.g., along the axial
direction A. Thus, a distal end of valve support 197 is raised
above head plate 184.
[0066] Valve seat 196 and valve support 197 defining a channel 198
therebetween. In particular, valve seat 196 and valve support 197
may be positioned on head plate 184 such that valve seat 196 and
valve support 197 are spaced apart and do not contact each other.
Thus, channel 198 may separate valve seat 196 and valve support 197
on head plate 184. Channel 198 may also assist with reducing an
area contacted by reed valve 190 when reed valve 190 is in the
closed position.
[0067] Turning back to FIG. 10, reed valve 190 defines an opening
199. Opening 199 of reed valve 190 extends through reed valve 190,
e.g., along the axial direction A. Channel 198 may be contiguous
with opening 199 of reed valve 190 when reed valve 190 is in the
closed position. In addition, at least a portion of an outer edge
193 of reed valve 190 may be positioned, e.g., directly, over
channel 198 when reed valve 190 is in the closed position.
[0068] As may be seen in FIG. 11, valve seat 196 extends away from
head plate 184 by a height HV, e.g., along the axial direction A.
The height HV of valve seat 196 may be any suitable height. For
example, the height HV of valve seat 196 may be less than about
five millimeters, less than about three millimeters or less than
about one millimeter. Valve support 197 also extends away from head
plate 184 by a height HS, e.g., along the axial direction A. The
height HS of valve support 197 may be any suitable height. For
example, the height HS of valve support 197 may be less than about
five millimeters, less than about three millimeters or less than
about one millimeter. In certain exemplary embodiments, the height
HV of valve seat 196 is about equal to the height HS of valve
support 197.
[0069] Passage 118 may have any suitable shape or cross-section.
For example, passage 118 may define a substantially reniform
cross-section, e.g., in a plane that is perpendicular to the axial
direction A or in a plane that is parallel to an outer surface of
head plate 184. The reniform cross-section of passage 118 may
assist within increasing or maximizing a flow area or hydraulic
diameter of passage 118 and reduce or minimize flow losses within
passage 118.
[0070] Passage 118 may extend between a first end portion 191 and a
second end portion 192, e.g., along the circumferential direction
C. Thus, first and second end portions 191 and 192 of passage 118
are spaced apart from each other, e.g., along the circumferential
direction C. In certain exemplary embodiments, passage 118 may
extend along the circumferential direction C at least sixty degrees
between first and second end portions 191 and 192 of passage 118.
In alternative exemplary embodiments, passage 118 may extend along
the circumferential direction C at least ninety degrees between
first and second end portions 191 and 192 of passage 118.
[0071] It should be understood that piston assembly 114 may be used
in any suitable linear compressor. Thus, while described in the
context of linear compressor 100, piston assembly 114 may be used
in any suitable linear compressor. In particular, piston assembly
114 may be used in linear compressors with moving inner back irons
or in linear compressors with stationary or fixed inner back irons.
It should be understood that piston assembly 114 may be formed or
constructed such that cylindrical segment 182, head plate 184,
valve seat 196 and valve support 197 are integral and/or continuous
with each other. Thus, as an example, cylindrical segment 182, head
plate 184, valve seat 196 and valve support 197 may be machined
from single piece of metal, such as steel.
[0072] FIG. 14 provides an exploded view of a piston assembly 200
according to another exemplary embodiment of the present subject
matter. Piston assembly 200 may be used in any suitable linear
compressor. For example, piston assembly 200 may be used in linear
compressor 100 as piston assembly 114 (FIG. 4). Piston assembly 200
includes similar features and components as piston assembly 114 and
may be constructed in a similar manner.
[0073] As may be seen in FIG. 14, a head plate 212 of piston
assembly 200 defines a plurality of passages 210. Passages 210
extend through head plate 212, e.g., along the axial direction A.
Passages 210 are disposed within a valve seat 214 of piston
assembly 200 at head plate 212. A reed valve 216 of piston assembly
200 is positioned over passages 210 and on valve seat 214 when reed
valve 216 is in the closed position.
[0074] Passages 210 may include any suitable number of passages
210. For example, passages 210 may include two, three, four, five
or more passages. Passages 210 may also have any suitable shape.
For example, passages 210 may define a circular cross-section,
e.g., in a plane that is perpendicular to the axial direction A.
Passages 210 are spaced apart from each other, e.g., along the
circumferential direction C. Passages 210 may also be positioned
equidistant from the second axis A2 along the radial direction
R.
[0075] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *