BACKGROUND OF THE DISCLOSURE
1. Field of the Disclosure
[0001] The present disclosure relates to a scroll compressor, and particularly, to a scroll
compressor having a structure that a rotation shaft is overlapped with a wrap of an
orbiting scroll.
2. Background of the Disclosure
[0002] Generally, a scroll compressor indicates a compressor configured to suck and compress
a refrigerant under a structure that an orbiting scroll performs an orbital motion
with respect to a fixed scroll, in a state where a fixed wrap of the fixed scroll
has been engaged with an orbiting wrap of the orbiting scroll. In this case, a compression
chamber composed of a suction chamber, an intermediate pressure chamber and a discharge
chamber is consecutively moved between the fixed wrap and the orbiting wrap.
[0003] Such scroll compressor is more advantageous than other types of compressors in the
aspect of vibration and noise, since it performs a suction process, a compression
process and a discharge process consecutively.
[0004] Behavior characteristics of the scroll compressor may be determined by a type of
the fixed wrap and the orbiting wrap. The fixed wrap and the orbiting wrap may have
any shape. However, it is general that the fixed wrap and the orbiting wrap have a
form of an involute curve which can be easily processed. The involute curve has a
path formed by the end of a string when the string wound on a basic circle having
an arbitrary radius is unwound. In case of using such involute curve, a capacity change
rate is constant because the thickness of the wrap is constant. For a high compression
ratio, the number of turns of the wrap should be increased. However, in this case,
the size of the scroll compressor may be also increased.
[0005] In the orbiting scroll, an orbiting wrap is formed at one side surface of a plate
formed in a disc shape. A boss portion is formed on a rear surface of the plate where
the orbiting wrap has not been formed, thereby being connected to a rotation shaft
which drives the orbiting scroll to perform an orbital motion. Such structure is advantageous
in that a diameter of the plate can be reduced, because the orbiting wrap is formed
on an almost entire area of the plate. However, in such structure, a point of application
to which a repulsive force of a refrigerant is applied during a compression operation,
and a point of application to which a reaction force to attenuate the repulsive force
is applied are spaced from each other in a vertical direction. This may cause an unstable
behavior of the orbiting scroll during the operation, resulting in severe vibration
or noise.
[0006] In order to solve such problems, a scroll compressor shown in FIG. 1 has been proposed.
The scroll compressor has a structure that a coupling point between a rotation shaft
1 and an orbiting scroll 2 is formed on the same surface as an orbiting wrap 2a. In
such scroll compressor, since a point of application to which a repulsive force of
a refrigerant is applied, and a point of application to which a reaction force to
attenuate the repulsive force is applied are same, a phenomenon that the orbiting
scroll 2 is tilted can be solved.
[0007] An Oldham ring 4, configured to prevent rotation of the orbiting scroll 2, is installed
between the orbiting scroll 2 and a fixed scroll 3. The orbiting scroll 2 and the
Oldham ring 4 perform a relative motion with respect to each other in a state where
key recesses 2b and keys 4a are coupled to each other. The Oldham ring 4 induces the
orbiting scroll 2 to perform an orbital motion. The key recesses 2b of the orbiting
scroll 2 and the keys 4a of the Oldham ring 4 are coupled to each other with a tolerance
gap (δ1) of about 10∼30
µm, so that the orbiting scroll 2 can perform a sliding motion with respect to the
Oldham ring 4.
[0008] However, the conventional scroll compressor may have the following problems. As shown
in FIG. 2, due to the tolerance gap (δ1) between the key recesses 2b of the orbiting
scroll 2 and the keys 41 of the Oldham ring 4, a rotation moment occurs when the orbiting
scroll 2 performs an orbital motion. Due to such rotation moment, offset is generated
at a specific part between the orbiting wrap 2a of the orbiting scroll 2 and the fixed
wrap 3a of the fixed scroll, i.e., at both sides of an arc compression surface based
on contact points formed by a tangent line and the arc compression surface, the tangent
line drawn at a center of a rotation shaft coupling portion of the orbiting scroll
2 toward the arc compression surface. Due to offset of the orbiting scroll 2 in such
offset section (β), interference (A) occurs between the orbiting wrap 2a and the fixed
wrap 3a as shown in FIG. 3. Due to such interference (A), a leakage gap (B) between
the orbiting wrap 2a and the fixed wrap 3a occurs at other parts. This may cause compression
loss.
SUMMARY OF THE DISCLOSURE
[0009] Therefore, an aspect of the detailed description is to provide scroll compressor
capable of preventing occurrence of a leakage gap between an orbiting wrap of an orbiting
scroll and a fixed wrap of a fixed scroll, by preventing interference between the
orbiting wrap and the fixed wrap.
[0010] To achieve these and other advantages and in accordance with the purpose of this
specification, as embodied and broadly described herein, there is provided a scroll
compressor, comprising: a hermetic container; a fixed scroll having a fixed wrap;
an orbiting scroll having an orbiting wrap which forms a compression chamber by being
engaged with the fixed wrap, having a rotation shaft coupling portion at a center
portion thereof, having an arc compression surface which forms the compression chamber
around the rotation shaft coupling portion, and performing an orbital motion with
respect to the fixed scroll; and a rotation shaft having an eccentric portion which
is coupled to the orbiting scroll, the eccentric portion overlapped with the orbiting
wrap in a radial direction, wherein an interference prevention portion is formed at
the fixed wrap or the orbiting wrap such that an interval between the fixed wrap and
the orbiting wrap is larger than an orbiting radius of the orbiting wrap.
[0011] The interference prevention portion may be formed at the arc compression surface.
[0012] The interference prevention portion may be formed such that a starting point and
an ending point thereof are included in the arc compression surface.
[0013] The scroll compressor may further include an Oldham ring coupled to the orbiting
scroll and configured to prevent rotation of the orbiting scroll. tolerance gap may
be formed between the orbiting scroll and the Oldham ring, and a maximum depth of
the interference prevention portion may be equal to or smaller than the tolerance
gap.
[0014] A plurality of key recesses may be formed at the orbiting scroll in a radial direction,
such that keys of the Oldham ring are coupled thereto. An equation of δ2 = (δ1 ×(L2/L1))±5
µm may be obtained, where L1 is a shortest distance between the key recess and a center
of the rotation shaft coupling portion, L2 is a shortest distance between a center
line between the orbiting wraps and the center of the rotation shaft coupling portion,
δ1 is a tolerance gap between the Oldham ring and the key recess, δ2 is a depth (offset
amount) of the interference prevention portion, and α is an rotation angle of the
rotation shaft.
[0015] The rotation shaft may be coupled to the rotation shaft coupling portion of the orbiting
scroll by passing through the fixed scroll.
[0016] According to another aspect of the present invention, there is provided a scroll
compressor, including: a fixed scroll having a fixed wrap; an orbiting scroll having
an orbiting wrap which forms a first compression chamber and a second compression
chamber on an outer side surface and an inner side surface thereof by being engaged
with the fixed wrap, having a rotation shaft coupling portion at a center portion
thereof, having an arc compression surface which forms the first compression chamber
around the rotation shaft coupling portion, and performing an orbital motion with
respect to the fixed scroll; and a rotation shaft having an eccentric portion which
is coupled to the rotation shaft coupling portion of the orbiting scroll, the eccentric
portion overlapped with the orbiting wrap in a radial direction, wherein the arc compression
surface is spaced from a side wall surface of the fixed wrap by an orbiting radius,
and wherein a distance between the fixed wrap and the orbiting wrap is equal to the
orbiting radius at a first curved surface of the arc compression surface from a first
point where the arc compression surface starts to an arbitrary second point, the distance
is longer than the orbiting radius at a second curved surface of the arc compression
surface from the second point to a third point where arc compression is performed,
and the distance is equal to the orbiting radius at a third curved surface of the
arc compression surface from the third point to a fourth point where the arc compression
is ended.
[0017] A curvature of the second curved surface may be larger than that of the first curved
surface or the third curved surface.
[0018] The scroll compressor may further include an Oldham ring coupled to the orbiting
scroll and configured to prevent rotation of the orbiting scroll. tolerance gap may
be formed between the orbiting scroll and the Oldham ring, and a maximum depth of
the second curved surface may be equal to or smaller than the tolerance gap.
[0019] A plurality of key recesses may be formed at the orbiting scroll in a radial direction,
such that keys of the Oldham ring are coupled thereto. An equation of δ2 = (δ1 ×(L2/L1))±5
µm may be obtained, where L1 is a shortest distance between the key recess and a center
of the rotation shaft coupling portion, L2 is a shortest distance between a center
line of the orbiting wraps and the center of the rotation shaft coupling portion,
δ1 is a tolerance gap between the Oldham ring and the key recess, δ2 is a depth (offset
amount) of the second curved surface, and α is an rotation angle of the rotation shaft.
[0020] The rotation shaft may be coupled to the rotation shaft coupling portion of the orbiting
scroll by passing through the fixed scroll.
[0021] According to another aspect of the present invention, there may be provided a scroll
compressor, including: a fixed scroll having a fixed wrap; an orbiting scroll having
an orbiting wrap which forms a first compression chamber and a second compression
chamber on its outer side surface and inner side surface by being engaged with the
fixed wrap, and performing an orbital motion with respect to the fixed scroll; a rotation
shaft having an eccentric portion overlapped with the orbiting wrap in a radial direction;
and a driving unit configured to drive the rotation shaft, wherein a rotation shaft
coupling portion, to which the eccentric portion is coupled, is formed in a central
portion of the orbiting scroll, wherein a protruded portion is formed on an inner
circumferential surface of an inner end portion of the fixed wrap, wherein a recess
portion, which forms a compression chamber by contacting the protruded portion, is
formed on an outer circumferential surface of the rotation shaft coupling portion,
and wherein an interference prevention portion is formed at the fixed wrap or the
orbiting wrap such that an interval between the fixed wrap and the orbiting wrap is
larger than an orbiting radius of the orbiting wrap.
[0022] The interference prevention portion may be formed at the arc compression surface.
[0023] The interference prevention portion may be formed such that a starting point and
an ending point thereof are included in the arc compression surface.
[0024] The scroll compressor may further include an Oldham ring coupled to the orbiting
scroll and configured to prevent rotation of the orbiting scroll. tolerance gap may
be formed between the orbiting scroll and the Oldham ring, and a maximum depth of
the interference prevention portion may be equal to or smaller than the tolerance
gap.
[0025] A plurality of key recesses may be formed at the orbiting scroll in a radial direction,
such that keys of the Oldham ring are coupled thereto. An equation of δ2 = (δ1 ×(L2/L1))±5
µm may be obtained, where L1 is a shortest distance between the key recess and a center
of the rotation shaft coupling portion, L2 is a shortest distance between a center
line of the orbiting wraps and the center of the rotation shaft coupling portion,
δ1 is a tolerance gap between the Oldham ring and the key recess, δ2 is a depth (offset
amount) of the second curved surface, and α is an rotation angle of the rotation shaft.
[0026] A thickness of the rotation shaft coupling portion may be increased within a predetermined
section, toward an opposite direction to a moving direction of the compression chamber
at the recess portion. A thickness of the fixed wrap may be decreased within a predetermined
section, toward an opposite direction to a moving direction of the compression chamber
at the protruded portion.
[0027] In the scroll compressor according to the present invention, the interference prevention
portion may be formed on a side wall surface of at least one of a fixed wrap and an
orbiting wrap. Under such configuration, the end of the fixed wrap does not interfere
with the orbiting wrap at an arc compression surface of the orbiting wrap, but is
inserted into the interference prevention portion. Accordingly, occurrence of a gap
between the fixed wrap and the orbiting wrap can be prevented, and thus compression
efficiency can be enhanced.
[0028] Further scope of applicability of the present application will become more apparent
from the detailed description given hereinafter. However, it should be understood
that the detailed description and specific examples, while indicating preferred embodiments
of the disclosure, are given by way of illustration only, since various changes and
modifications within the spirit and scope of the disclosure will become apparent to
those skilled in the art from the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The accompanying drawings, which are included to provide a further understanding
of the disclosure and are incorporated in and constitute a part of this specification,
illustrate exemplary embodiments and together with the description serve to explain
the principles of the disclosure.
[0030] In the drawings:
FIG. 1 is a longitudinal section view of a scroll compressor in accordance with the
conventional art;
FIG. 2 is a planar view illustrating a coupled state between an orbiting scroll and
an Oldham ring in the scroll compressor of FIG. 1;
FIG. 3 is a planar view illustrating a relation between a fixed scroll and an orbiting
scroll in the scroll compressor of FIG. 2;
FIG. 4 is a longitudinal section view of a scroll compressor according to the present
invention;
FIG. 5 is an exploded perspective view of a compression part in the scroll compressor
of FIG. 4;
FIG. 6 is a planar view illustrating a coupled state between an orbiting scroll and
an Oldham ring in the scroll compressor of FIG. 5;
FIG. 7 is a planar view illustrating a compression part in the scroll compressor of
FIG. 4;
FIG. 8 is a perspective view of an orbiting scroll in the scroll compressor of FIG.
4;
FIG. 9 is an enlarged view for explaining an interference prevention portion of FIG.
8;
FIG. 10 is a planar view illustrating a relation between a fixed scroll and an orbiting
scroll in the scroll compressor of FIG. 4; and
FIG. 11 is a planar view illustrating another embodiment of an interference prevention
portion in the scroll compressor of FIG. 4.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0031] Description will now be given in detail of the exemplary embodiments, with reference
to the accompanying drawings. For the sake of brief description with reference to
the drawings, the same or equivalent components will be provided with the same reference
numbers, and description thereof will not be repeated.
[0032] Hereinafter, a scroll compressor according to the present invention will be explained
in more detail with reference to the attached drawings.
[0033] Referring to FIGS. 4 to 9, in a scroll compressor according to the present invention,
a driving motor 20 may be installed in a hermetic container 10, and a fixed scroll
30 integrally formed with a main frame may be fixedly installed above the driving
motor 20. An orbiting scroll 40, which is engaged with the fixed scroll 30 and configured
to compress a refrigerant while performing an orbit motion by being coupled to a rotation
shaft 23 of the driving motor 20, may be installed above the fixed scroll 30.
[0034] The hermetic container 10 may include a cylindrical casing 11, and an upper shell
12 and a lower shell 13 coupled to an upper part and a lower part of the casing 11
by welding so as to cover the upper part and the lower part of the casing 11. A suction
pipe 14 may be installed on a side surface of the casing 10, and a discharge pipe
15 may be installed above the upper shell 12. The lower shell 13 may also serve as
an oil chamber for storing therein oil to be supplied to the compressor for a smooth
operation of the compressor.
[0035] The driving motor 20 may include a stator fixed to an inner surface of the casing
10, and a rotor 22 positioned in the stator 22 and rotating by a reciprocal operation
with the stator 22. A rotation shaft 23, which rotates together with the rotor 22,
may be coupled to a central part of the rotor 22.
[0036] An oil passage (F) may be penetratingly-formed at a central region of the rotation
shaft 23, in a lengthwise direction. An oil pump 24, configured to supply oil stored
in the lower shell 13 to the upper side, may be installed at a lower end of the rotation
shaft 23. A pin portion 23c may be formed at an upper end of the rotation shaft 23,
in an eccentric manner from the center of the rotation shaft.
[0037] The fixed scroll 30 may be fixed as its outer circumferential surface is forcibly-inserted
between the casing 11 and the upper shell 12 by shrinkage fitting. Alternatively,
the fixed scroll 30 may be coupled to the casing 11 and the upper shell 12 by welding.
[0038] A boss portion 32 may be formed at a central region of a plate portion 31 of the
fixed scroll 30. A shaft accommodating hole 33, configured to accommodate the rotation
shaft 23 in a penetrating manner, may be formed at the boss portion 32. A fixed wrap
34 may be formed on an upper surface of the plate portion 31 of the fixed scroll.
The fixed wrap 34 is engaged with an orbiting wrap to be explained later, and forms
a first compression chamber (S1) on an outer side surface of the orbiting wrap 42
and a second compression chamber (S2) on an inner side surface of the orbiting wrap
42.
[0039] The orbiting scroll 40 may be supported at an upper surface of the fixed scroll 30.
The orbiting scroll 40 may include the plate portion 41 formed in an approximately
circle shape, and the orbiting wrap 42 formed on an upper surface of the plate portion
41. The orbiting wrap 42 forms a pair of compression chambers S1 and S2 which move
consecutively, by being engaged with the fixed wrap 34. Each of the compression chambers
S1 and S2 may be composed of a suction chamber, an intermediate pressure chamber and
a discharge chamber. A rotation shaft coupling portion 43, which has an approximately
circle shape and to which the pin portion 23c of the rotation shaft 23 is rotatably
insertion-coupled, may be formed at a central region of the plate portion 41.
[0040] The pin portion 23c of the rotation shaft 23 may be insertion-coupled to the rotation
shaft coupling portion 43. The pin portion 23c may be coupled to the rotation shaft
coupling portion 43 of the orbiting scroll 30, through the plate portion 31 of the
fixed scroll 30.
[0041] The orbiting wrap 42, the fixed wrap 34 and the pin portion 23c may be formed to
overlap one another, in a radius direction of the scroll compressor. During a compression
operation of the scroll compressor, a repulsive force of a refrigerant is applied
to the fixed wrap 34 and the orbiting wrap 42. As a reaction force of the repulsive
force, a compressive force is applied between the rotation shaft coupling portion
43 and the pin portion 23c. In the case where the pin portion 23c of the rotation
shaft 23 overlaps the wrap in a radius direction through the plate portion 41 of the
orbiting scroll 40, a repulsive force of a refrigerant and a compressive force are
applied to the same side surface based on the plate portion 41 of the orbiting scroll.
Therefore, the repulsive force and the compressive force may be attenuated from each
other.
[0042] An Oldham ring 50, configured to prevent rotation of the orbiting scroll 40, may
be coupled to an upper side of the orbiting scroll 40. The Oldham ring 50 may include
a ring portion 51 having an approximately circle shape and fitted into a rear surface
of the plate portion 41 of the orbiting scroll 40, and a pair of first keys 52 and
a pair of second keys 53 protruding from one side surface of the ring portion 51.
[0043] The first keys 52 may be protruded with a length greater than a thickness of an outer
circumferential surface of the plate portion 41 of the orbiting scroll 40, and may
be inserted into first key recesses 31 a of the fixed scroll 30.
[0044] The second keys 53 may be fitted into second key recesses 41 a formed on an outer
circumference of the plate portion 41 of the orbiting scroll 40.
[0045] The first key recess 31 a and the first key 52 are preferably formed so that both
side surfaces of the first key 52 slidably-contact both side surfaces of the first
key recess 31 a. Likewise, the second key recess 41a and the second key 53 are preferably
formed so that both side surfaces of the second key 53 slidably-contact both side
surfaces of the second key recess 41a. In this case, if the keys 52, 53 contact the
key recesses 31 a, 41 a too closely, frictional resistance is increased between the
keys 52, 53 and the key recess 31a, 41a. As a result, the orbiting scroll 40 may not
smoothly perform an orbital motion. In order to solve such problem, as shown in FIG.
6, a tolerance gap (δ1) may be formed between the key recess 31 a and the key 52,
and between the key recess 41 a and the key 53. In this case, the tolerance gap (δ1)
is large enough for the orbiting scroll 40 can perform an orbital motion as the keys
52, 53 are smoothly slid on the key recesses 31 a, 41 a.
[0046] Each of the fixed wrap 34 and the orbiting wrap 42 may be formed in an involute curve.
However, in some cases, the fixed wrap 34 and the orbiting wrap 42 may be formed in
other curve rather than an involute curve. Referring to FIG. 4, under an assumption
that the center of the rotation shaft coupling portion 43 is 'O' and two contact points
are 'P1' and 'P2', an angle (α) defined by two straight lines is smaller than 360°,
the straight lines formed by connecting the center 'O' of the rotation shaft coupling
portion 43 to the two contact points 'P1' and 'P2', respectively. Also, a distance
(ℓ) between a normal vector of the contact point 'P1' and a normal vector of the contact
point 'P2 is larger than 0. Under such configuration, the scroll compressor can have
an increased compression ratio, because it has a smaller volume than in a case where
the first compression chamber (S1) prior to discharge has the fixed wrap 34 and the
orbiting wrap 42 of an involute curve. The orbiting wrap 42 and the fixed wrap 34
have a shape that a plurality of arcs having different diameters and origins are connected.
In this case, the outermost curve may have an approximately oval shape with a major
axis and a minor axis.
[0047] A protruded portion 35, which protrudes toward the rotation shaft coupling portion
43, may be formed near an inner end portion of the fixed wrap 34. A contact portion
35a may be further formed at the protruded portion 35, in a protruding manner from
the protruding portion 35. Accordingly, the inner end portion of the fixed wrap may
have a larger thickness than other parts.
[0048] The thickness of the fixed wrap 34 is gradually decreased, starting from the inner
contact point P1 of the two contact points (P1, P2) defining the first compression
chamber (S1) upon initiating the discharge operation. More specifically, a first decrease
part 35b is formed adjacent to the contact point (P1) and a second decrease part 35c
is connected to the first decrease part 31 b. A thickness reduction rate at the first
decrease part is higher than that at the second decrease part. After the second decrease
part, the fixed wrap may be increased in thickness within a predetermined interval.
[0049] A recess portion 44, which is engaged with the protruded portion 35, may be formed
at the rotation shaft coupling portion 43. One side wall of the recess portion 44
may contact the contact portion 35a of the protruded portion 35, thereby forming the
contact point 'P1' of the first compression chamber (S1).
[0050] One side wall of the recess portion 44 may include a first increase part 45a where
a thickness is relatively greatly increased, and a second increase part 45b connected
to the first increase part 45a and having a thickness increased at a relatively low
rate. These correspond to the first decrease part 35b and the second decrease part
35c of the fixed wrap 34. The first increase part 45a, the first decrease part 35b,
the second increase part 45b and the second decrease part 35c may be obtained by turning
a generating curve toward the rotation shaft coupling portion. Accordingly, the inner
contact point (P1) of the first compression chamber (S1) may be positioned at the
first increase part and the second increase part, and the length of the first compression
chamber right before a discharge operation may be shortened so as to enhance a compression
ratio.
[0051] Another side wall of the recess portion 44 may be formed to have an arc compression
surface 46 having a circular shape and formed by connecting lines to one another,
the lines formed as the orbiting wrap contacts the end of the fixed wrap 34 while
the orbiting scroll 40 performs an orbital motion. A diameter of the arc of the arc
compression surface 46 is determined by the wrap thickness of the end of the fixed
wrap, and an orbiting radius of the orbiting wrap. If the wrap thickness of the end
of the fixed wrap is increased, the diameter of the arc is increased. As a result,
the thickness of the orbiting wrap near the arc is increased, and thus durability
of the scroll compressor is enhanced. Further, a compression path is increased, and
thus a compression ratio of the second compression chamber (S2) is increased.
[0052] An operation of the scroll compressor according to the present invention is as follows.
Once the rotation shaft 43 rotates as power is supplied to the driving motor 40, the
orbiting scroll 60 eccentrically-coupled to the rotation shaft 43 performs an orbital
motion along a predetermined path. And the compression chamber (P) formed between
the orbiting scroll 60 and the fixed scroll 30 moves to the center of the orbital
motion consecutively, to thus have a decreased volume. In the compression chamber
(P), a refrigerant is sucked, compressed and discharged consecutively. Such processes
are repeatedly performed.
[0053] The orbiting scroll 40 performs an orbital motion while its rotation is prevented
by the Oldham ring 50. A tolerance gap (δ1) of approximately 10∼30
µm is required between the key recess 41 a of the orbiting scroll 40 and the key 52,
and between the key recess 31 a of the fixed scroll 30 and the key 53, so that the
orbiting scroll 40 and the Oldham ring 50 can perform a sliding motion with respect
to each other. In this case, the orbiting scroll 40 generates a rotation moment due
to the tolerance gap (δ1). As a result, when the scroll compressor is substantially
operated, wrap interference (A) may occur between the fixed wrap 34 and the orbiting
wrap 42 as shown in FIG. 3.
[0054] In this embodiment, as shown in FIGS. 6 to 9, an interference prevention portion
46a having a predetermined depth in a thickness direction of the orbiting wrap 42
may be formed at the arc compression surface 46 of the recess portion 44 of the orbiting
scroll 40.
[0055] The interference prevention portion 46a may be formed to have a depth δ2 from an
orbiting radius (r) which is obtained in a state where the fixed wrap 34 and the orbiting
wrap 42 have been aligned to be concentric with each other.
[0056] For instance, as shown in FIG. 9, a starting point of a second curved surface (P12
- P13) which forms the interference prevention portion 46a may be positioned at a
first curved surface (P11 ∼ P12) between a first point (P11) where arc compression
starts and an arbitrary second point (P12). And an ending point of the second curved
surface (P12 - P13) which forms the interference prevention portion 46a may be positioned
at a third curved surface (P13 - P14) between an arbitrary third point (P13) closer
to a discharge opening than the second point (P12) and a fourth point (P14) where
compression is ended.
[0057] A depth of the interference prevention portion 46a may be equal to or smaller than
tolerance gap (δ1). If the depth of the interference prevention portion 46a is larger
than the tolerance gap (δ1), a gap is generated between the fixed wrap 34 and the
orbiting wrap 42. This may cause compression performance to be significantly lowered.
[0058] Referring to FIG. 6, it is assumed that an rotation angle (radian) of the rotation
shaft 23 is α, tolerance gap is δ1, a shortest distance between the second key recess
and a center of the rotation shaft coupling portion is L1, a shortest distance between
a center line of the orbiting wraps and the center of the rotation shaft coupling
portion is L2, a depth (offset amount) of the interference prevention portion is δ2.
Under such assumption, δ2 may be calculated as follows.

[0059] When the formula 1 is applied to the formula 2, δ2 = δ1×(L2/L1).
[0060] For instance, δ2 = 30x23/53 = 13.0
µm, in a case where the tolerance gap (δ1) is 30
µm, the shortest distance (L1) between the second key recess 41 a and a center of the
rotation shaft coupling portion 43 is 53 mm, and the shortest distance (L2) between
a center line of the orbiting wraps and the center of the rotation shaft coupling
portion is 23 mm. Accordingly, an equation of δ2 =(δ1×(L2/L1))±5
µm may be obtained.
[0061] As shown in FIG. 10, the end of the fixed wrap 34 does not interference with the
orbiting wrap 42 at the arc compression surface 46 of the orbiting wrap 42, but is
inserted into the interference prevention portion 46a. Accordingly, occurrence of
a gap between the fixed wrap 34 and the orbiting wrap 42 can be prevented, and thus
compression efficiency can be enhanced.
[0062] In the aforementioned embodiment, the interference prevention portion 46a is formed
at the arc compression surface 46 of the orbiting scroll 42. However, in this embodiment,
as shown in FIG. 11, the interference prevention portion 46a may be formed at a starting
end of the fixed wrap 34 of the fixed scroll 30, the fixed wrap which corresponds
to the arc compression surface 46 of the orbiting scroll 40.
[0063] In this case, an interference prevention portion 32a may be formed to have a predetermined
depth in a thickness direction of the fixed wrap 34, on an outer circumferential surface
of the fixed wrap 34 which contacts the arc compression surface 46, within a section
where arc compression is performed based on the orbiting scroll 40.
[0064] Like in the aforementioned embodiment, it is preferable that the depth of the interference
prevention portion 32a is equal to or smaller than the tolerance gap (δ1) formed between
the key recess 41 a of the orbiting scroll 40 and the key 53 of the Oldham ring 50.
The effects in this embodiment are almost the same as those in the aforementioned
embodiment, and thus detailed explanations thereof will be omitted.
[0065] The foregoing embodiments and advantages are merely exemplary and are not to be considered
as limiting the present disclosure. The present teachings can be readily applied to
other types of apparatuses. This description is intended to be illustrative, and not
to limit the scope of the claims. Many alternatives, modifications, and variations
will be apparent to those skilled in the art. The features, structures, methods, and
other characteristics of the exemplary embodiments described herein may be combined
in various ways to obtain additional and/or alternative exemplary embodiments.
[0066] As the present features may be embodied in several forms without departing from the
characteristics thereof, it should also be understood that the above-described embodiments
are not limited by any of the details of the foregoing description, unless otherwise
specified, but rather should be considered broadly within its scope as defined in
the appended claims, and therefore all changes and modifications that fall within
the metes and bounds of the claims, or equivalents of such metes and bounds are therefore
intended to be embraced by the appended claims.
1. A scroll compressor, comprising:
a hermetic container (10);
a fixed scroll (30) fixedly-coupled to the hermetic container (10), and having a fixed
wrap (34);
an orbiting scroll (40) having an orbiting wrap (42) which forms a compression chamber
(P) by being engaged with the fixed wrap (34), having a rotation shaft coupling portion
(43) at a center portion thereof, having an arc compression surface (46) which forms
the compression chamber (P) around the rotation shaft coupling portion (43), and configured
to perform an orbital motion with respect to the fixed scroll (30); and
a rotation shaft (23) having an eccentric portion which is coupled to the orbiting
scroll (40) by passing through the fixed scroll (30), the eccentric portion overlapped
with the orbiting wrap (42) in a radial direction,
wherein an interference prevention portion (46a) is formed at the fixed wrap (34)
or the orbiting wrap (42) such that an interval between the fixed wrap (34) and the
orbiting wrap (42) is larger than an orbiting radius (r) of the orbiting wrap (42).
2. The scroll compressor of claim 1, wherein the interference prevention portion (46a)
is formed at the arc compression surface (46).
3. The scroll compressor of claim 2, wherein the interference prevention portion (46a)
is formed such that a starting point and an ending point thereof are included in the
arc compression surface (46).
4. The scroll compressor of one of claims 1 to 3, further comprising an Oldham ring (50)
coupled to the orbiting scroll (40) and configured to prevent rotation of the orbiting
scroll (40), and
wherein a tolerance gap (δ1) is formed between the orbiting scroll (40) and the Oldham
ring (50), and
wherein a maximum depth (δ2) of the interference prevention portion (46a) is equal
to or smaller than the tolerance gap (δ1).
5. The scroll compressor of claim 4, wherein a plurality of key recesses (41 a) are formed
at the orbiting scroll (40) in a radial direction, such that keys (53) of the Oldham
ring (50) are coupled thereto, and
wherein δ2 = (δ1×(L2/L1))±5 µm, where L1 is a shortest distance between the key recess (41 a) and a center of the
rotation shaft coupling portion (43), L2 is a shortest distance between a center line
of the orbiting wraps (42) and the center of the rotation shaft coupling portion (43),
δ1 is a tolerance gap between the Oldham ring (50) and the key recess (41 a), and
δ2 is a depth (offset amount) of the second curved surface.
6. The scroll compressor of one of claims 1 to 5, wherein the arc compression surface
(46) is spaced from a side wall surface of the fixed wrap (34) by an orbiting radius,
and
wherein a distance between the fixed wrap (34) and the orbiting wrap (42) is equal
to the orbiting radius at a first curved surface (P11 ∼ P12) of the arc compression
surface (46) from a first point (P11) where the arc compression surface (46) starts
to an arbitrary second point (P12),
wherein the distance between the fixed wrap (34) and the orbiting wrap (42) is longer
than the orbiting radius at a second curved surface (P12 - P13) of the arc compression
surface (46) from the second point (P12) to a third point (P13) where arc compression
is performed, wherein the interference prevention portion (46a) is formed at the second
curved surface (P12 - P13), and
wherein the distance between the fixed wrap (34) and the orbiting wrap (42) is equal
to the orbiting radius at a third curved surface (P13 - P14) of the arc compression
surface from the third point (P13) to a fourth point (P14) where the arc compression
is ended.
7. The scroll compressor of claim 6, wherein a curvature of the second curved surface
(P12 - P13) is larger than that of the first curved surface (P11 ∼ P12) or the third
curved surface (P13 ∼ P14).
8. The scroll compressor of one of claims 1 to 7, wherein a protruded portion (35) is
formed on an inner circumferential surface of an inner end portion of the fixed wrap
(34),
wherein a recess portion (44), which forms a compression chamber by contacting the
protruded portion (35), is formed on an outer circumferential surface of the rotation
shaft coupling portion (43), and
wherein a thickness of the rotation shaft coupling portion (43) is increased within
a predetermined section, toward an opposite direction to a moving direction of the
compression chamber (P) at the recess portion (44), and
wherein a thickness of the fixed wrap (34) is decreased within a predetermined section,
toward an opposite direction to a moving direction of the compression chamber (P)
at the protruded portion (35).
9. The scroll compressor of one of claims 1 to 8, wherein the rotation shaft (23) is
coupled to the rotation shaft coupling portion (43) of the orbiting scroll (40) by
passing through the fixed scroll (30).