Patent Description:
In a scroll compressor, an orbiting scroll and a non-orbiting scroll are engaged to be coupled with each other, and as the orbiting scroll performs an orbiting motion with respect to the non-orbiting scroll, a pair of compression chambers is formed between the orbiting scroll and the non-orbiting scroll. Each compression chamber includes a suction pressure chamber formed at an outer edge, an intermediate pressure chamber sequentially formed while gradually decreasing in volume from the suction pressure chamber toward a central portion, and a discharge pressure chamber. The suction pressure chamber typically communicates with a refrigerant suction pipe through a side surface of the non-orbiting scroll, the intermediate pressure chamber is sealed, and the discharge pressure chamber is formed to communicate with a refrigerant discharge pipe through a center of an end plate of the non-orbiting scroll.

In the scroll compressor, as the pair of compression chambers is formed, the non-orbiting scroll and the orbiting scroll should be tightly sealed in an axial direction to suppress leakage between the pair of compression chambers. Thus, the scroll compressor has a back pressure structure in which the orbiting scroll is pressed toward the non-orbiting scroll, or conversely, the non-orbiting scroll is pressed toward the orbiting scroll. The former may be defined as an orbiting back pressure method, and the latter may be defined as a non-orbiting back pressure method.

In the orbiting back pressure method, a back pressure chamber is formed between an orbiting scroll and a main frame that supports the orbiting scroll, and in the non-orbiting back pressure method, a back pressure chamber is formed on a rear surface of a non-orbiting scroll. More particularly, in the non-orbiting back pressure method, a separately manufactured back pressure chamber assembly may be fastened to the rear surface of the non-orbiting scroll.

In general, the orbiting back pressure method is applied to a structure in which the non-orbiting scroll is fixed to the main frame, and the non-orbiting back pressure method is applied to a structure in which the non-orbiting scroll is axially movable with respect to the main frame. <CIT> (hereinafter "Patent Document <NUM>") discloses a scroll compressor to which the non-orbital back pressure method is applied.

In Patent Document <NUM>, an annular back pressure chamber is formed on a back surface of a non-orbiting scroll, and a ring member forming an upper surface of the back pressure chamber is slidably inserted into the back pressure chamber. Accordingly, in Patent Document <NUM>, the ring member moves up and down by a pressure of the back pressure chamber to adjust the pressure in the back pressure chamber. However, Patent Document <NUM> does not disclose a discharge valve configured as a kind of backflow prevention valve (hereinafter, defined as a discharge valve). Accordingly, in Patent Document <NUM>, refrigerant discharged from a compression chamber to a discharge chamber may flow back into the compression chamber when the compressor is stopped, resulting in inhibiting restart.

Patent Publication No. <CIT> (hereinafter, "Patent Document <NUM>") discloses an example in which a discharge valve for opening and closing a discharge port is installed in the non-orbiting scroll back pressure method. When a compressor is stopped, a discharge valve blocks refrigerant from flowing back from a discharge chamber to a compression chamber, so that the compressor can be quickly restarted. However, in Patent Document <NUM>, as a back pressure chamber is integrally formed in a non-orbiting scroll like in Patent Document <NUM>, there is no space to install a bypass valve. As a result, a bypass valve is not installed to thereby cause an over compression, and thus, efficiency and reliability of the compressor may be reduced.

Patent Publication No. <CIT> (hereinafter, "Patent Document <NUM>") discloses an example in which a discharge valve and a bypass valve for opening and closing a discharge port are respectively installed in the non-orbiting scroll method. The discharge valve may block refrigerant from backflowing from a discharge chamber to a compression chamber when the compressor is stopped, and the bypass valve may discharge refrigerant in advance when the refrigerant is compressed due to an over compression to thereby prevent a decrease in efficiency and reliability of the compressor. In Patent Document <NUM>, a back pressure chamber assembly including a back pressure chamber is separately manufactured to be assembled on an upper surface of a non-orbiting scroll.

This is because the back pressure chamber is installed at a position radially overlapping the bypass valve (or bypass hole) in order to secure an area of the back pressure chamber, and thus, the back pressure chamber assembly configured as a separate module is assembled to the non-orbiting scroll from an upper side of the bypass valve. However, as the back pressure chamber assembly is separately manufactured to be assembled, the number of components and assembly processes therefor may increase, resulting in an increase in manufacturing costs. <CIT> discloses a scroll compressor. The invention is defined in the independent claim. Dependent claims describe preferred embodiments.

Description will now be given of a scroll compressor according to embodiments disclosed herein, with reference to the accompanying drawings. In general, scroll compressors, like other compressors, may be classified into low-pressure compressors or high-pressure compressors according to which pressure portion is formed in an inner space of a casing, particularly a space accommodating a motor unit. In the former case, the space may form a low-pressure portion and a refrigerant suction pipe may communicate with the space. In the latter case, the space may form a high-pressure portion and the refrigerant suction pipe may be formed through the casing so as to be directly connected to a compression unit. This embodiment relates to a low-pressure scroll compressor.

<FIG> is a longitudinal cross-sectional view of a low-pressure type capacity-variable scroll compressor in accordance with an embodiment. Referring to <FIG>, in the low-pressure capacity-variable scroll compressor (hereinafter, abbreviated as "scroll compressor") according to the embodiment, a drive motor <NUM> may be installed in a lower portion of the casing <NUM>, and a main frame <NUM>, an orbiting scroll <NUM>, and a non-orbiting scroll <NUM> may be sequentially installed above the drive motor <NUM>. In general, the drive motor <NUM> may constitute a motor unit, and the main frame <NUM>, the orbiting scroll <NUM>, and the non-orbiting scroll <NUM> may constitute a compression unit. The motor unit may be coupled to one or a first end of a rotational shaft <NUM>, and the compression unit may be coupled to another or a second end of the rotational shaft <NUM>. Accordingly, the compression unit may be connected to the motor unit by the rotational shaft <NUM> to be operated by a rotational force of the motor unit.

The casing <NUM> may include a cylindrical shell <NUM>, an upper cap <NUM>, and a lower cap <NUM>. The cylindrical shell <NUM> may have a cylindrical shape with upper and lower ends open, and the drive motor <NUM> and the main frame <NUM> may be fitted on an inner circumferential surface of the cylindrical shell <NUM> in an inserting manner. A terminal bracket (not shown) may be coupled to an upper portion of the cylindrical shell <NUM>, and a terminal (not shown) that transmits external power to the drive motor <NUM> may be coupled through the terminal bracket. In addition, a refrigerant suction pipe <NUM> discussed hereinafter may be coupled to the upper portion of the cylindrical shell <NUM>, for example, above the drive motor <NUM>.

The upper cap <NUM> may be coupled to cover the open upper end of the cylindrical shell <NUM>, and the lower cap <NUM> may be coupled to cover the open lower end of the cylindrical shell <NUM>. A rim of a high and low pressure separation plate <NUM> discussed hereinafter may be inserted between the cylindrical shell <NUM> and the upper cap <NUM> to be, for example, welded to the cylindrical shell <NUM> and the upper cap <NUM>, and a rim of a support bracket <NUM> discussed hereinafter may be inserted between the cylindrical shell <NUM> and the lower cap <NUM> to be, for example, welded to the cylindrical shell <NUM> and the lower cap <NUM>. Accordingly, the inner space of the casing <NUM> may be sealed.

The rim of the high and low pressure separation plate <NUM>, as discussed above, may be, for example, welded to the casing <NUM> and a central portion of the high and low pressure separation plate <NUM> may be bent into a truncated conic shape to protrude toward the upper cap <NUM> so as to be disposed above a back pressure chamber assembly <NUM> discussed hereinafter. A refrigerant suction pipe <NUM> may communicate with a space below the high and low pressure separation plate <NUM>, and a refrigerant discharge pipe <NUM> may communicate with a space above the high and low pressure separation plate <NUM>. Accordingly, a low-pressure portion 110a constituting a suction space may be formed below the high and low pressure separation plate <NUM>, and a high-pressure portion 110b constituting a discharge space may be formed above the high and low pressure separation plate <NUM>.

In addition, a through hole 115a may be formed through a center of the high and low pressure separation plate <NUM>, and a sealing plate <NUM> to which a floating plate <NUM> discussed hereinafter is detachably coupled may be inserted into the through hole 115a. Accordingly, the low-pressure portion 110a and the high-pressure portion 110b may be blocked from or communicate with each other by the floating plate <NUM> and the sealing plate <NUM>.

The sealing plate <NUM> may be formed in an annular shape. For example, a high and low pressure communication hole 1151a may be formed through a center of the sealing plate <NUM> so that the low-pressure portion 110a and the high-pressure portion 110b communicate with each other. The floating plate <NUM> may be attachable and detachable along a circumference of the high and low pressure communication hole 1151a. Accordingly, the floating plate <NUM> may be attached to or detached from the circumference of the high and low pressure communication hole 1151a of the sealing plate <NUM> while moving up and down by back pressure in an axial direction. During this process, the low-pressure portion 110a and the high-pressure portion 110b may be sealed from each other or communicate with each other.

In addition, the lower cap <NUM> may define an oil storage space 110c together with the lower portion of the cylindrical shell <NUM> constituting the low-pressure portion 110a. In other words, the oil storage space 110c may be defined in the lower portion of the low-pressure portion 110a. The oil storage space 110c may define a portion of the low-pressure portion 110a.

Hereinafter, the drive motor will be described.

Referring to <FIG>, the drive motor <NUM> according to this embodiment may be disposed under the low-pressure portion 110a and include a stator <NUM> and a rotor <NUM>. The stator <NUM> may be, for example, shrink-fitted to an inner wall surface of the cylindrical shell <NUM>, and the rotor <NUM> may be rotatably provided inside of the stator <NUM>.

The stator <NUM> may include a stator core <NUM> and a stator coil <NUM>. The stator core <NUM> may be formed in a cylindrical shape and may be, for example, shrink-fitted onto the inner circumferential surface of the cylindrical shell <NUM>. The stator coil <NUM> may be wound around the stator core <NUM> and may be electrically connected to an external power source through a terminal (not shown) coupled through the casing <NUM>.

The rotor <NUM> may include a rotor core <NUM> and permanent magnets <NUM>. The rotor core <NUM> may be formed in a cylindrical shape, and may be rotatably inserted into the stator core <NUM> with a preset or predetermined gap therebetween. The permanent magnets <NUM> may be embedded in the rotor core <NUM> at preset or predetermined intervals along a circumferential direction.

The rotational shaft <NUM> may be coupled to a center of the rotor <NUM>. An upper end portion of the rotational shaft <NUM> may be rotatably inserted into the main frame <NUM> discussed hereinafter so as to be supported in a radial direction, and a lower end portion of the rotational shaft <NUM> may be rotatably inserted into the support bracket <NUM> so as to be supported in the radial and axial directions. The main frame <NUM> may be provided with a main bearing <NUM> that supports the upper end portion of the rotational shaft <NUM>, and the support bracket <NUM> may be provided with a sub bearing <NUM> that supports the lower end portion of the rotational shaft <NUM>. The main bearing <NUM> and the sub bearing <NUM> each may be configured as a bush bearing.

An eccentric portion <NUM> that is eccentrically coupled to the orbiting scroll <NUM> discussed hereinafter may be formed on the upper end portion of the rotational shaft <NUM>, and an oil feeder <NUM> that absorbs oil stored in the lower portion of the casing <NUM> may be disposed in the lower end portion of the rotational shaft <NUM>. An oil supply hole <NUM> may be formed through the rotational shaft <NUM> in the axial direction.

The main frame <NUM> according to this embodiment may be disposed above the drive motor <NUM> and may be, for example, shrink-fitted or welded to an inner wall surface of the cylindrical shell <NUM>. The main frame <NUM> may be formed of, for example, cast iron.

Referring to <FIG>, the main frame <NUM> may include a main flange portion <NUM>, a main bearing portion <NUM>, an orbiting space portion <NUM>, a scroll support portion <NUM>, an Oldham ring accommodation portion <NUM>, and a frame fixing portion <NUM>. The main flange portion <NUM> may be formed in an annular shape and accommodated in the low-pressure portion 110a of the casing <NUM>. An outer diameter of the main flange portion <NUM> may be formed smaller than an inner diameter of the cylindrical shell <NUM> so that an outer circumferential surface of the main flange portion <NUM> is spaced apart from an inner circumferential surface of the cylindrical shell <NUM>. However, the frame fixing portion <NUM> discussed hereinafter may protrude from the outer circumferential surface of the main flange portion <NUM> in the radial direction, and an outer circumferential surface of the frame fixing portion <NUM> may be brought into close contact with and fixed to the inner circumferential surface of the casing <NUM>. Accordingly, the main frame <NUM> may be fixedly coupled to the casing <NUM>.

The main bearing portion <NUM> may protrude downward from a lower surface of a central portion of the main flange portion <NUM> toward the drive motor <NUM>. The main bearing portion <NUM> may be provided with a cylindrical bearing hole 132a formed therethrough in the axial direction, and the main bearing <NUM> configured as the bush bearing may be fixedly coupled to an inner circumferential surface of the bearing hole <NUM> in an inserted manner. The rotational shaft <NUM> may be inserted into the main bearing <NUM> to be supported in the radial direction.

The orbiting space portion <NUM> may be recessed from the central portion of the main flange portion <NUM> toward the main bearing portion <NUM> with a predetermined depth and outer diameter. The orbiting space portion <NUM> may be larger than an outer diameter of a rotational shaft coupling portion <NUM> provided on the orbiting scroll <NUM> discussed hereinafter. Accordingly, the rotational shaft coupling portion <NUM> may be pivotally accommodated in the orbiting space portion <NUM>.

The scroll support portion <NUM> may be formed in an annular shape on an upper surface of the main flange portion <NUM> along a periphery of the orbiting space portion <NUM>. Accordingly, the scroll support portion <NUM> may support the lower surface of an orbiting end plate <NUM> discussed hereinafter in the axial direction.

The Oldham ring accommodation portion <NUM> may be formed in an annular shape on an upper surface of the main flange portion <NUM> along an outer circumferential surface of the scroll support portion <NUM>. Accordingly, an Oldham ring <NUM> may be inserted into the Oldham ring accommodation portion <NUM> to be pivotable.

The frame fixing portion <NUM> may be formed to extend radially from an outer periphery of the Oldham ring accommodation portion <NUM>. The frame fixing portion <NUM> may extend in an annular shape or may extend to form a plurality of protrusions spaced apart from one another at preset or predetermined intervals. This embodiment illustrates an example in which the frame fixing portion <NUM> has a plurality of protrusions along the circumferential direction.

For example, a plurality of the frame fixing portion <NUM> may be provided disposed at preset or predetermined intervals along the circumferential direction. The plurality of frame fixing portions <NUM> may be provided with bolt coupling holes 136a, respectively, that are formed therethrough in the axial direction.

The frame fixing portions <NUM> may be formed to correspond to respective guide protrusions <NUM> of non-orbiting scroll <NUM> discussed hereinafter in the axial direction, and the bolt coupling holes 136a may be formed to correspond to respective guide insertion holes 155a provided in the guide protrusions <NUM> in the axial direction.

An inner diameter of the bolt coupling hole 136a may be smaller than an inner diameter of guide insertion hole 155a. Accordingly, a stepped surface that extends from an inner circumferential surface of the guide insertion hole 155a may be formed on a periphery of an upper surface of the bolt coupling hole 136a, and a guide bush <NUM> that is inserted through the guide insertion hole 155a may be placed on the stepped surface so as to be supported on the frame fixing portion <NUM> in the axial direction.

The guide bush <NUM> may be formed in a hollow cylindrical shape through which the bolt insertion hole 137a may be formed in the axial direction. Accordingly, each guide bolt <NUM> may be inserted through the bolt insertion hole 137a of the guide bush <NUM> to be coupled to the bolt coupling hole 136a of the frame fixing portion <NUM>. The non-orbiting scroll <NUM> may thus be slidably supported on the main frame <NUM> in the axial direction and fixed to the main frame <NUM> in the radial direction.

Hereinafter, the orbiting scroll will be described.

The orbiting scroll <NUM> according to this embodiment may be disposed on an upper surface of the main frame <NUM>. Accordingly, it may be advantageous in terms of motor efficiency that the orbiting scroll <NUM> is formed of a hard material such as aluminum. In addition, as it is formed of a different material, from the main frame <NUM>, which is cast iron, it may be advantageous in terms of wear resistance.

The orbiting scroll <NUM> may include an orbiting end plate <NUM>, an orbiting wrap <NUM>, and rotational shaft coupling portion <NUM>. The orbiting end plate <NUM> may be formed approximately in a disk shape. An outer diameter of the orbiting end plate <NUM> may be mounted on the scroll support portion <NUM> of the main frame <NUM> to be supported in the axial direction.

The orbiting wrap <NUM> may be formed in a spiral shape that protrudes from an upper surface of the orbiting end plate <NUM> facing the non-orbiting scroll <NUM> by a predetermined height. The orbiting wrap <NUM> may correspond to non-orbiting wrap <NUM> to perform an orbiting motion by being engaged with non-orbiting wrap <NUM> of the non-orbiting scroll <NUM> discussed hereinafter. The orbiting wrap <NUM> may define a compression chamber V together with the non-orbiting wrap <NUM>.

The compression chamber V may include first compression chamber V1 and second compression chamber V2 discussed hereinafter. The first compression chamber V1 may be formed at an outer surface of the non-orbiting wrap <NUM>, and the second compression chamber V2 may be formed at an inner surface of the non-orbiting wrap <NUM>. Each of the first compression chamber V1 and the second compression chamber V2 may include a suction pressure chamber (no reference numeral), an intermediate pressure chamber (no reference numeral), and a discharge pressure chamber (no reference numeral) that are consecutively formed.

The rotational shaft coupling portion <NUM> may protrude from a lower surface of the orbiting end plate <NUM> toward the main frame <NUM>. The rotational shaft coupling portion <NUM> may be formed in a cylindrical shape, and an eccentric portion bearing <NUM> may be coupled to an inner circumferential surface of the rotational shaft coupling portion <NUM> in an inserted manner. The eccentric portion bearing <NUM> may be configured as a bush bearing.

A length of the rotational shaft coupling portion <NUM> may be shorter than a depth of the orbiting space portion <NUM>, and an outer diameter of the rotational shaft coupling portion <NUM> may be smaller than an inner diameter of the orbiting space portion <NUM> by at least twice an orbiting radius. Accordingly, the rotational shaft coupling portion <NUM> may perform the orbiting motion while being accommodated in the orbiting space portion <NUM>.

The Oldham ring <NUM> may be provided between the main frame <NUM> and the orbiting scroll <NUM> to restrict rotational motion of the orbiting scroll <NUM>. As described above, the Oldham ring <NUM> may be slidably coupled to the main frame <NUM> and the orbiting scroll <NUM>, respectively, or slidably coupled to the orbiting scroll <NUM> and the non-orbiting scroll <NUM>, respectively.

Hereinafter, the non-orbiting scroll will be described.

The non-orbiting scroll <NUM> according to an embodiment may be disposed on the orbiting scroll <NUM> to define the compression chamber together with the orbiting scroll <NUM>. Accordingly, it may be advantageous in terms of wear resistance that the non-orbiting scroll <NUM> is formed of cast iron, which is different from the material forming the orbiting scroll <NUM>.

The non-orbiting scroll <NUM> may be fixedly coupled to the main frame <NUM>, or may be coupled to the main frame <NUM> to be movable up and down. This embodiment illustrates an example in which the non-orbiting scroll <NUM> is coupled to the main frame <NUM> to be movable relative to the main frame <NUM> in the axial direction.

The non-orbiting scroll <NUM> may include non-orbiting end plate <NUM>, non-orbiting side wall <NUM>, and non-orbiting wrap <NUM>. The non-orbiting end plate <NUM> may be formed in a disk shape and disposed in a horizontal direction in the low-pressure portion 110a of the casing <NUM>. A discharge port <NUM>, a bypass hole <NUM>, and a back pressure hole <NUM> may be formed through a central portion of the non-orbiting end plate <NUM> in the axial direction.

The discharge port <NUM> may be located at a position at which a discharge pressure chamber (no reference numeral) of the first compression chamber V1 and a discharge pressure chamber (no reference numeral) of the second compression chamber V2 communicate with each other. Although not shown in the drawings, a discharge guide groove may be formed on an end of the discharge port <NUM>.

The bypass hole <NUM> may include first bypass hole 1512a that communicates with the first compression chamber V1, and second bypass hole 1512b that communicates with the second compression chamber V2. The first bypass hole 1512a and the second bypass hole 1512b may be formed along the circumferential direction at a side of the discharge port <NUM> which is formed at a center of the non-orbiting scroll <NUM>. More specifically, the first bypass hole 1512a and the second bypass hole 1512b each may be formed between the discharge hole <NUM> and an inner wall portion <NUM> discussed hereinafter in the radial direction. More specifically, the first bypass hole 1512a and the second bypass hole 1512b each may be formed on an axial line the same as that of a discharge through hole <NUM> discussed hereinafter, or may be formed at a position at least partially overlapping the discharge through hole <NUM> in the radial direction or at a lower side of inner cover portion <NUM> discussed hereinafter.

The first bypass hole 1512a and the second bypass hole 1512b each may be one hole, or at least two, for example, three or more holes. <FIG> illustrates an example in which the first bypass hole 1512a and the second bypass hole 1512b are each respectively configured as one hole.

For example, when the first bypass hole 1512a and the second bypass hole 1512b are each respectively a plurality of holes, the first bypass hole 1512a and the second bypass hole 1512b may be respectively arranged in a line, or may be arranged in a curve along a profile of the non-orbiting wrap <NUM>.

In addition, inner diameters of the plurality of holes forming each of the first bypass hole 1512a and the second bypass hole 1512b may all be the same or may be different from one another. For example, an inner diameter of a hole in a middle among the plurality of holes may be larger than inner diameters of holes at opposite sides with respect to the hole in the middle. The plurality of holes respectively forming the first bypass hole 1512a and the second bypass hole 1512b may communicate with one another to form a rectangular shape, or the first bypass hole 1512a and the second bypass hole 1512b each may be formed as a single rectangular hole.

A first bypass valve <NUM> may be installed at an end of the first bypass hole 1512a, and a second bypass valve <NUM> may be installed at an end of the second bypass hole 1512b. More specifically, as the first bypass hole 1512a and the second bypass hole 1512b are formed on the same axial line same as that of the discharge through hole <NUM> or formed at the position at the lower side of the inner cover portion <NUM>, the first bypass valve <NUM> and the second bypass valve <NUM> may also be located on the same axial line as that of the discharge through hole <NUM> or installed at the lower side of the inner cover portion <NUM>.

The first bypass valve <NUM> and the second bypass valve <NUM> each may be a reed valve, one or a first end of which is fixed and another or a second end of which is free. More specifically, one or a first end of the first bypass valve <NUM> and one or a first end of the second bypass valve <NUM> each may be fixed to an upper surface of the non-orbiting end plate <NUM> by, for example, bolting, and another or a second end of the first bypass valve <NUM> and another or a second of the second bypass valve <NUM> each may be provided in a free state to open and close the end of the first bypass hole 1512a and the end of the second bypass hole 1512b, respectively.

The back pressure hole <NUM> may be formed through the non-orbiting end plate <NUM> in the axial direction. The back pressure hole <NUM> may be formed at a position that communicates with a plate side back pressure hole 1611c, which will be described later, and may communicate with the compression chamber V at an intermediate pressure, which is between a suction pressure and a discharge pressure.

The non-orbiting side wall <NUM> may extend annularly in the axial direction from a rim of a lower surface of the non-orbiting end plate <NUM>. An outer diameter of the non-orbiting side wall <NUM> may be smaller than an inner diameter of the cylindrical shell <NUM>. Accordingly, the non-orbiting scroll <NUM> of this embodiment may be spaced apart from an inner circumferential surface of the cylindrical shell <NUM> so as to axially move according to a difference between pressure at the compression chamber V and pressure at a back pressure chamber S, which will be described hereinafter.

A height of the non-orbiting side wall <NUM> may be substantially the same as a height of the non-orbiting wrap <NUM>, and an outer circumferential surface of the non-orbiting side wall <NUM> may be provided with guide protrusion <NUM> that extends therefrom in the radial direction. The guide protrusion <NUM> may have the guide insertion hole 155a described above.

A plurality of the guide protrusion <NUM> may be provided or a single guide protrusion. When the guide protrusion <NUM> is provided, the guide protrusions <NUM> may be disposed at predetermined intervals along the circumferential direction and each of the guide protrusions <NUM> may have one guide insertion hole 155a. When the guide protrusion <NUM> is provided as a single piece, a plurality of guide insertion holes 155a may be formed at predetermined intervals along the circumferential direction. <FIG> and <FIG> illustrate a case in which a plurality of the guide protrusion <NUM> is provided.

One side of the outer circumferential surface of the non-orbiting side wall <NUM> may be provided with a suction port <NUM>. One or a first end of the suction port <NUM> may communicate with the low-pressure portion 110a of the casing <NUM>, and another or a second end of the suction port <NUM> may communicate with the suction pressure chambers of the compression chambers V1 and V2. Accordingly, refrigerant may be suctioned into the low-pressure portion 110a of the casing <NUM> through the refrigerant suction pipe <NUM>, and the refrigerant may be introduced into each of the suction pressure chambers through the suction port <NUM>.

The non-orbiting wrap <NUM> may extend in the axial direction from the lower surface of the non-orbiting end plate <NUM>. The non-orbiting wrap <NUM> may be formed in a spiral shape at an inner portion of the non-orbiting side wall <NUM>, and formed to correspond to the orbiting wrap <NUM> so as to be engaged with the orbiting wrap <NUM>. Description of the non-orbiting wrap <NUM> will replaced with the description of the orbiting wrap <NUM>. A back pressure chamber portion (no reference numeral) that presses the non-orbiting scroll <NUM> toward the orbiting scroll <NUM> may be integrally formed therewith on an upper surface of the non-orbiting scroll <NUM> according to this embodiment, namely, on the non-orbiting end plate <NUM>.

<FIG> is a perspective view illustrating a state in which a back pressure chamber portion is separated from a non-orbiting scroll in <FIG>. <FIG> is a perspective cross-sectional view illustrating a state in which the back pressure chamber portion is coupled to the non-orbiting scroll in <FIG>. <FIG> is a longitudinal cross-sectional view of <FIG>. <FIG> and <FIG> are cross-sectional views, taken along line "V-V" and line "VI-VI", respectively, in <FIG>. <FIG> are enlarged cross-sectional views of portion "A" and portion "B" in <FIG>.

Referring to <FIG>, an outer wall portion <NUM> and the inner wall portion <NUM> forming a portion of the back pressure chamber portion may be formed on the upper surface of the non-orbiting end plate <NUM>. The outer wall portion <NUM> and the inner wall portion <NUM> each formed in an annular shape may be radially spaced apart from each other with a predetermined gap therebetween. Accordingly, the back pressure chamber S may be formed between an inner circumferential surface of the outer wall portion <NUM> and an outer circumferential surface of the inner wall portion <NUM>.

More specifically, the outer wall portion <NUM> may define an outer wall surface of the back pressure chamber S, and the inner wall portion <NUM> may define an inner wall surface of the back pressure chamber S. Accordingly, the upper surface of the non-orbiting end plate <NUM> disposed between the outer wall portion <NUM> and the inner wall portion <NUM> may define a bottom surface of the back pressure chamber S, and the back pressure hole <NUM> described above may be formed between the outer wall portion <NUM> and the inner wall portion <NUM> defining the bottom surface of the back pressure chamber S.

In addition, referring to <FIG>, the discharge port <NUM> described above may be formed at an approximately central position of the non-orbiting end plate <NUM>, which is a center of the inner wall portion <NUM>, and the first bypass hole 1512a and the second bypass hole 1512b described above may be formed between the discharge hole <NUM> and an inner circumferential surface of the inner wall portion <NUM>. Accordingly, while integrally forming the outer wall portion <NUM> and the inner wall portion <NUM> with the non-orbiting scroll <NUM>, the back pressure hole <NUM> as well as the first bypass hole 1512a and the second bypass hole 1512b may be formed in the non-orbiting scroll <NUM>. This is because a valve accommodating portion <NUM>, which will be described hereinafter, is formed to extend in the axial direction in the floating plate <NUM>.

The outer wall portion <NUM> may extend upwardly from a rim of the upper surface of the non-orbiting end plate <NUM> toward the high and low pressure separation plate <NUM>, and the inner wall portion <NUM> may extend upwardly from a central portion of the upper surface of the non-orbiting end plate <NUM> toward the high and low pressure separation plate <NUM>. As the outer wall portion <NUM> and the inner wall portion <NUM> are integrally formed to extend from the non-orbiting end plate <NUM>, the outer wall portion <NUM> and the inner wall portion <NUM> may be made of cast iron like the non-orbiting end plate <NUM>.

Referring to <FIG>, the inner wall portion <NUM> and the outer wall portion <NUM> may have substantially the same height (or axial length) and thickness. However, a height H1 of the outer wall portion <NUM> and a height H2 of the inner wall portion <NUM> may vary depending on shapes of the high and low pressure separation plate <NUM> and the floating plate <NUM> discussed hereinafter. For example, when the high and low pressure separation plate <NUM> is formed in a truncated conical shape and an outer circumferential surface of the floating plate <NUM> is internally inserted into the back pressure chamber S, the outer wall portion <NUM> and the inner wall portion <NUM> may have approximately the same height. However, when the high and low pressure separation plate <NUM> is formed in the truncated conical shape and the outer circumferential surface of the floating plate <NUM> is externally fitted to the back pressure chamber S, as illustrated in <FIG>, discussed hereinafter, the height H1 of the outer wall portion <NUM> may be shorter than the height H2 of the inner wall portion <NUM>.

A thickness t1 of the outer wall portion <NUM> may be approximately equal to a thickness t2 of the inner wall portion <NUM>. However, the thickness t1 of the outer wall portion <NUM> and the thickness t2 of the inner wall portion <NUM> may be adjusted depending on whether a sealing member is provided.

For example, when the first sealing member <NUM> and the second sealing member <NUM> discussed hereinafter are respectively installed on the floating plate <NUM>, the thickness t1 of the outer wall portion <NUM> and the thickness t2 of the inner wall portion <NUM> may be the same. On the other hand, when the first sealing member <NUM> or the second sealing member <NUM> is installed on the outer wall portion <NUM> or the inner wall portion <NUM>, thicknesses t1 and t2 of wall portions on which the sealing members <NUM> and <NUM> are installed may be thicker than thicknesses t1 and t2 of wall portions on which the sealing members <NUM> and <NUM> are not installed.

The outer wall portion <NUM> and the inner wall portion <NUM> according to this embodiment may be formed substantially the same or the inner wall portion <NUM> may be formed thinner than the outer wall portion <NUM>. Accordingly, there may be secured a space inside the inner wall portion <NUM> large enough to fit the discharge port <NUM> and the bypass hole <NUM> described above.

Referring again to <FIG>, the back pressure chamber according to this embodiment may include the floating plate <NUM> slidably coupled to the non-orbiting scroll <NUM> in the axial direction. The floating plate <NUM> may be provided above the outer wall portion <NUM> and the inner wall portion <NUM> of the non-orbiting scroll <NUM> to cover an upper side of the back pressure chamber S, and slidably coupled to each of circumferential surfaces of the outer wall portion <NUM> and the inner wall portion <NUM>. Accordingly, the back pressure chamber S may be sealed to be separated from the low-pressure portion 110a or the high-pressure portion 110b of the casing <NUM>.

It is advantageous for the floating plate <NUM> to be formed of a material as light as possible so that the floating plate <NUM> may move up or down according to a change in back pressure during operation or stoppage of the compressor. For example, the floating plate <NUM> may be formed of engineering plastics. However, as the floating plate <NUM> collides with the sealing plate <NUM> of the high and low pressure separation plate <NUM> while moving up in the axial direction during operation of the compressor, it may be advantageous for the floating plate <NUM> to be formed of a metal material as light as possible in terms of reliability. For example, the floating plate <NUM> may be formed of a surface-treated aluminum material.

The floating plate <NUM> may include upper cover portion <NUM>, outer cover portion <NUM>, inner cover portion <NUM>, valve accommodating portion <NUM>, and discharge through hole <NUM>. The upper cover portion <NUM>, the outer cover portion <NUM>, the inner cover portion <NUM>, and the valve accommodating portion <NUM> may form a single body, and the discharge through hole <NUM> may be an opening between the inner cover portion <NUM> and the valve accommodating portion <NUM>.

The upper cover portion <NUM> may have an annular shape, and may be larger than a gap between the outer wall portion <NUM> and the inner wall portion <NUM> of the non-orbiting scroll <NUM>. Accordingly, the upper cover portion <NUM> may cover a space between the outer wall portion <NUM> and the inner wall portion <NUM> forming the upper surface of the back pressure chamber S.

An outer surface of the upper cover portion <NUM> may substantially correspond to a shape of a lower surface of the high and low pressure separation plate <NUM>. For example, as the high and low pressure separation plate <NUM> is formed in a substantially truncated conical shape, the upper cover portion <NUM> may be formed to be downwardly inclined from a center to a rim of the upper cover portion <NUM>. Accordingly, even when the floating plate <NUM> moves up, a maximum secured gap between the upper cover portion <NUM> and the high and low pressure separation plate <NUM> may ensure smooth communication between the low-pressure portion 110a and the high-pressure portion 110b when the compressor is stopped.

An upper surface of an inner circumferential side of the upper cover portion <NUM> may be provided with sealing protrusion 1651a. When the floating plate <NUM> moves up, the sealing protrusion 1651a may be brought into close contact with the sealing plate <NUM> of the high and low pressure separation plate <NUM> to separate between the low-pressure portion 110a and the high-pressure portion 110b. The sealing protrusion 1651a may have an annular shape, and may be surface-hardened to prevent abrasion.

The sealing protrusion 1651a may be formed on an upper side of the inner cover portion <NUM>, namely, on an axial line the same as that of the inner cover portion <NUM>. Accordingly, the discharge through hole <NUM> may be formed at an inner side of the sealing protrusion 1651a.

A height of the sealing protrusion 1651a may be formed to such an extent that a sufficient communication area is secured to allow refrigerant passing through the discharge through hole <NUM> to smoothly move to the high-pressure portion 110b in a state in which the floating plate <NUM> is elevated during operation of the compressor. The outer cover portion <NUM> may have an annular shape and extend from an outer circumference of the upper cover portion <NUM> toward the non-orbiting scroll <NUM> in the axial direction.

Referring to <FIG>, a height H3 of the outer cover portion <NUM> may be formed to such an extent that a state in which the outer cover portion <NUM> radially overlaps with the outer wall portion <NUM> at a position at which the floating plate <NUM> is maximally elevated is maintained. For example, an outer maximum overlapping distance L1 between the outer cover portion <NUM> and the outer wall portion <NUM> may be greater than a maximum sealing distance L2 between the floating plate <NUM> and the high and low pressure separation plate <NUM>. Accordingly, even when the floating plate <NUM> is maximally elevated, separation between the outer cover portion <NUM> and the outer wall portion <NUM> may be suppressed to thereby maintain a sealed state of the back pressure chamber S.

The outer cover portion <NUM> may be slidably fitted to the inner circumferential surface of the outer wall portion <NUM> or may be slidably fitted to the outer circumferential surface of the outer wall portion <NUM>. When the outer cover portion <NUM> is internally fitted to the outer wall portion <NUM>, an outer diameter of the floating plate <NUM> may be reduced to thereby reduce a weight of the floating plate <NUM>. Accordingly, during operation of the compressor, the floating plate <NUM> may be quickly elevated to separate the low-pressure portion 110a and the high-pressure portion 110b.

On the other hand, when the outer cover portion <NUM> is externally fitted to the outer wall portion <NUM>, a back pressure area of the back pressure chamber S may be increased to thereby tightly seal the low-pressure portion 110a from the high-pressure portion 110b. In this embodiment, an example in which the outer cover portion <NUM> is internally fitted to the outer wall portion <NUM> will be described, and an example in which the outer cover portion <NUM> is externally fitted to the outer wall portion <NUM> will be described hereinafter as another embodiment.

When the outer cover portion <NUM> is internally fitted to the outer wall portion <NUM>, outer cover member (hereinafter, "first sealing member") <NUM> may be inserted in an outer circumferential surface of the outer cover portion <NUM>. For example, an outer sealing groove (hereinafter, a "first sealing groove") 1652a may be formed in an annular shape on the outer circumferential surface of the outer cover portion <NUM>, and the first sealing member <NUM> may be inserted in the first sealing groove 1652a. The first sealing member <NUM> may be configured as a sealing member having elasticity, such as an O-ring.

The first sealing member <NUM> may be provided on the inner circumferential surface of the outer wall portion <NUM> facing the outer circumferential surface of the outer cover portion <NUM>. However, as the outer wall portion <NUM> extending from the non-orbiting end plate <NUM> is formed of cast iron, the outer wall portion <NUM> has a relatively lower roughness than the outer cover portion <NUM> of the floating plate <NUM> formed of aluminum. For this reason, when the first sealing groove 1652a is formed on the outer wall portion <NUM> of the non-orbiting scroll <NUM>, an assembly state of the first sealing member <NUM> may be poor due to the low roughness. This may cause leakage from the back pressure chamber in which refrigerant leaks from the back pressure chamber S to the low-pressure portion 110a due to the poor sealing of an outer circumferential side of the back pressure chamber S. Accordingly, the first sealing member <NUM> may be coupled to the first sealing groove 1652a, by forming the first sealing groove 1652a on the outer circumferential surface of the outer cover portion <NUM> of the floating plate <NUM>, which has a relatively higher roughness than the outer wall portion <NUM> of the non-orbiting scroll <NUM>.

Referring to <FIG>, the inner cover portion <NUM> may be formed to be substantially similar to the outer cover portion <NUM>. For example, the inner cover portion <NUM> may be formed in an annular shape and extend from an inner circumference of the upper cover portion <NUM> toward the non-orbiting scroll <NUM> in the axial direction. A height H4 of the inner cover portion <NUM> may be formed to such an extent that a state in which the inner cover portion <NUM> overlaps the inner wall portion <NUM> in the axial direction at a position at which the floating plate <NUM> is elevated to a maximum height is maintained. For example, an inner maximum overlapping distance L3 between the inner cover portion <NUM> and the inner wall portion <NUM> may be greater than the maximum sealing distance L2 between the floating plate <NUM> and the high and low pressure separation plate <NUM>. Accordingly, even when the floating plate <NUM> is maximally elevated, the inner cover portion <NUM> may be suppressed from being separated from the inner wall portion <NUM> to thereby maintain a sealed state of the back pressure chamber S.

The inner cover portion <NUM> may be slidably fitted to the inner circumferential surface of the inner wall portion <NUM> (or internally fitted to the inner wall portion <NUM>) or may be slidably fitted to the outer circumferential surface of the inner wall portion <NUM> (or externally fitted to the inner wall portion <NUM>). When the inner cover portion <NUM> is internally fitted to the inner wall portion <NUM>, an internal volume of the back pressure chamber S (or a back pressure area) may be increased. This may secure sufficient back pressure at the back pressure chamber S to thereby expand an operation range of the compressor.

On the other hand, when the outer cover portion <NUM> is externally fitted to the outer wall portion <NUM>, an area of the discharge through hole <NUM> discussed hereinafter may be expanded to reduce flow resistance to the refrigerant discharged to the high-pressure portion 110b. Accordingly, the refrigerant discharged from the compression chamber V through the discharge port <NUM> may be rapidly discharged to the high-pressure portion 110b.

Alternatively, when a width of the discharge through hole <NUM> is kept constant, a gap between an outer circumference of the discharge through hole <NUM> and the inner cover portion <NUM> may be increased. As this gap forms a surface that is pressurized by the discharged refrigerant, the back pressure area may be eventually increased to thereby quickly elevate the floating plate <NUM> during operation. In this embodiment, an example in which the inner cover portion <NUM> is internally fitted to the inner wall portion <NUM> will be described, and an example in which the inner cover portion <NUM> is externally fitted to the inner wall portion <NUM> will be described hereinafter as another embodiment.

When the inner cover portion <NUM> is internally fitted to the inner wall portion <NUM>, the height H4 of the inner cover portion <NUM> may be lower than the height H2 of the inner wall portion <NUM>. Accordingly, even when the first bypass valve <NUM> and the second bypass valve <NUM> are installed at an inner side of the inner wall portion <NUM>, the inner cover portion <NUM> may be prevented from interfering with the first bypass valve <NUM> and the second bypass valve <NUM> when the floating plate <NUM> is lowered.

When the inner cover portion <NUM> is internally fitted to the inner wall portion <NUM>, an inner cover member (hereinafter, a "second sealing member") <NUM> may be inserted in an outer circumferential surface of the inner cover portion <NUM>. For example, an inner sealing groove (hereinafter, a "second sealing groove") 1653a may be formed in an annular shape on the outer circumferential surface of the inner cover portion <NUM>, and the second sealing member <NUM> may be inserted in the second sealing groove 1653a. Like the first sealing member <NUM>, the second sealing member <NUM> may be configured as a sealing member having elasticity, such as an O-ring.

The second sealing member <NUM> may be provided on the inner circumferential surface of the inner wall portion <NUM> facing the outer circumferential surface of the inner cover portion <NUM>. However, like the first sealing groove 1652a described above, it may be advantageous in terms of processing roughness to form the second sealing groove 1653a also on the inner cover portion <NUM> of the floating plate <NUM>.

As the second sealing member <NUM> is located adjacent to the discharge port, a separate upper cover member may be provided in the second sealing groove 1653a. In other words, as a pressure difference between a periphery of the discharge port <NUM> and an inner portion of the back pressure chamber S is large in the inner cover portion <NUM> where the second sealing member <NUM> is located, high-temperature and high-pressure refrigerant discharged through the discharge port <NUM> may be introduced into the back pressure chamber S. Accordingly, high-temperature refrigerant may contact the second sealing member <NUM> hardening the second sealing member <NUM> or reducing a sealing force. For this reason, the upper cover member <NUM> may be installed to cover an open surface of the second sealing groove 1653a that accommodates the second sealing member <NUM> therein.

The upper cover member <NUM> may be generally formed of a Teflon material, and have an annular shape like the second sealing member <NUM>. Accordingly, like the second sealing member <NUM>, inserting the upper cover member <NUM> into an inner circumferential surface of the inner cover portion <NUM> rather than inserting the upper cover member <NUM> into the outer circumferential surface of the inner cover portion <NUM> may be advantageous in terms of the assembly process.

Referring back to <FIG>, the valve accommodating portion <NUM> may serve to slidably accommodate the discharge valve <NUM> that opens and closes the discharge port <NUM>, and the valve accommodating portion <NUM> may be radially spaced apart from an inner side of the inner wall portion <NUM>, more specifically, an inner circumferential side of the inner cover portion <NUM> with a predetermined gap therebetween. The valve accommodating portion <NUM> may correspond in shape to discharge valve <NUM>. For example, as the discharge valve <NUM> according to this embodiment is configured as a piston valve formed in a cylindrical shape, the valve accommodating portion <NUM> may also be formed in a cylindrical shape.

More specifically, the valve accommodating portion <NUM> may include a valve guide surface 1654a and a valve constraint surface 1654b. The valve guide surface 1654a may be formed in a cylindrical shape extending in the axial direction and having an inner diameter greater than an outer diameter of the discharge valve <NUM>. Accordingly, an outer circumferential surface of the discharge valve <NUM> may be slidably fitted to an inner circumferential surface of the valve guide surface 1654a. However, the shape of the valve guide surface 1654a may vary depending on the shape of the discharge valve <NUM>.

Referring to <FIG> and <FIG>, a lower end of the valve guide surface 1654a may be spaced apart from the upper surface of the non-orbiting end plate <NUM> facing the lower end of the valve guide surface 1654a with a predetermined gap therebetween, and at least a portion of each of the first bypass valve <NUM> and the second bypass valve <NUM> described above may be installed between the lower end of the valve guide surface 1654a and the upper surface of the non-orbiting end plate <NUM> facing the lower end of the valve guide surface 1654a.

A height H5 of the valve guide surface (or a height of the valve accommodating portion) may be formed to such an extent that the discharge valve <NUM> does not deviate from the valve guide surface 1654a even in a state at which the floating plate <NUM> is moved up to a highest level and the discharge valve <NUM> is moved down to a lowest level. For example, the height (or an axial length) H5 of the valve guide surface 1654a may be greater than or equal to a movement length of the discharge valve <NUM>, namely, the height H4 of the inner cover portion <NUM>.

The valve constraint surface 1654b may radially extend from the inner circumferential surface of the inner cover portion <NUM> by a connection portion <NUM> to cover an upper end of the valve guide surface 1654a. A backflow prevention hole 1654c that provides communication between an inner portion of the valve guide surface 1654a and the high-pressure portion 110b may be provided at a center of the valve constraint surface 1654b. Accordingly, when the discharge valve <NUM> moves up, fluid resistance at an upper side of the discharge valve <NUM> may be reduced so that the valve rises quickly, whereas when the discharge valve <NUM> moves down, gas from the high-pressure portion 110b presses an upper surface of the valve <NUM> to quickly lower the valve.

The discharge through hole <NUM> may serve to guide the refrigerant discharged from the compression chamber V through the discharge port <NUM> to the high-pressure portion 110b. Accordingly, the discharge through hole <NUM> may be formed through the floating plate <NUM> at the inner side of the sealing protrusion 1651a. More specifically, the discharge through hole <NUM> may extend through the floating plate <NUM> between the inner circumferential surface of the inner cover portion <NUM> and an outer circumferential surface of the valve accommodating portion <NUM>.

A plurality of the discharge through hole <NUM> may be provided in an arc shape to be disposed along the circumferential direction. Accordingly, the connection portion <NUM> may be formed between the plurality of discharge through holes <NUM> in the radial direction, and the upper cover portion <NUM> may be integrally connected with the valve accommodating portion <NUM> by the connection portion <NUM>.

A circumferential length (or a total cross-sectional area) of the discharge through hole <NUM> may be longer than a circumferential length (or a total cross-sectional area) of the connection portion <NUM>. This may secure a sufficient area of the discharge through hole <NUM>.

The scroll compressor according to this embodiment may operate as follows. <FIG> is a cross-sectional view illustrating an operating state of the scroll compressor of <FIG>, and <FIG> is a cross-sectional view illustrating a stopped state of the scroll compressor of <FIG>.

Referring to <FIG>, when power is applied to the stator coil <NUM> of the stator <NUM> during operation of the compressor, the rotor <NUM> may rotate together with the rotational shaft <NUM>. Then, the orbiting scroll <NUM> coupled to the rotational shaft <NUM> may perform orbiting motion with respect to the non-orbiting scroll <NUM>, thereby forming a pair of compression chambers V between the orbiting wrap <NUM> and the non-orbiting wrap <NUM>. The compression chamber V may gradually decrease in volume while moving from outside to inside according to the orbiting motion of the orbiting scroll <NUM>.

At this time, the refrigerant may be suctioned into the low pressure portion 110a of the casing <NUM> through the refrigerant suction pipe <NUM>. A portion of this refrigerant may be suctioned directly into the suction pressure chambers of the first compression chamber V1 and the second compression chamber V2, respectively, while the rest of the refrigerant may first flow toward the drive motor <NUM> and then be suctioned into the suction pressure chambers.

Then, the refrigerant may be compressed while moving along a movement path of the compression chamber V. A portion of the compressed refrigerant may move toward the back pressure chamber S through the back pressure hole <NUM> before reaching the discharge port <NUM>. Accordingly, the back pressure chamber S formed by the non-orbiting end plate <NUM> and the floating plate <NUM> may form an intermediate pressure.

The floating plate <NUM> may be pushed up by a pressure of the back pressure chamber S toward the high and low pressure separation plate <NUM>, and the sealing protrusion 1651a provided on an upper end of the floating plate <NUM> may be brought into close contact with the sealing plate <NUM> provided at the high and low pressure separation plate <NUM>. Accordingly, the high-pressure portion 110b of the casing <NUM> may be separated from the low-pressure portion 110a, and this may prevent the refrigerant discharged from the compression chambers V1 and V2 to the high-pressure portion 110b from flowing back into the low-pressure portion 110a.

The outer cover portion <NUM> of the floating plate <NUM> may be provided with the first sealing member <NUM> and the outer circumferential surface of the inner cover portion <NUM> may be provided with the second sealing member <NUM> to tightly seal the outer wall portion <NUM> and the inner wall portion <NUM> of the non-orbiting scroll <NUM>, to thereby maintain a state in which an inner space of the back pressure chamber S is separated from the low-pressure portion 110a of the casing <NUM>.

On the other hand, the non-orbiting scroll <NUM> may be pushed down toward the orbiting scroll <NUM> by the pressure of the back pressure chamber S, so as to be brought into close contact with the orbiting scroll <NUM>. Accordingly, the refrigerant compressed in the compression chamber V may be prevented from leaking from a high-pressure side compression chamber to a low-pressure side compression chamber.

The refrigerant may be compressed up to a predetermined pressure while moving from the intermediate pressure chamber including the compression chambers V1 and V2 toward the discharge pressure chamber, but the pressure of the refrigerant may rise above the predetermined pressure due to other conditions occurring during operation of the compressor. Then, a portion of the refrigerant moving from the intermediate pressure chamber to the discharge pressure chamber may be bypassed to the high-pressure portion 110b in the intermediate pressure chamber including the compression chambers V1 and V2 through the first bypass hole 1512a and the second bypass hole 1512b before reaching the discharge pressure chamber. This may suppress the refrigerant from being over compressed above the predetermined pressure in the compression chambers V1 and V2, thereby enhancing compressor efficiency and ensuring stability.

The refrigerant moved to the discharge pressure chamber of each of the compression chambers V1 and V2 may be discharged to the high-pressure portion 110b through the discharge port <NUM> and the discharge through hole <NUM> while pushing the discharge valve <NUM>, and the refrigerant may then flow into the high-pressure portion 110b so as to be discharged through a condenser of a refrigeration cycle through the refrigerant discharge pipe <NUM>.

Referring to <FIG>, during stoppage of the compressor, the pressure in the intermediate pressure chamber communicating with the back pressure hole <NUM> may be reduced to thereby reduce the pressure in the back pressure chamber S, and as the pressure in the back pressure chamber S is reduced, the floating plate <NUM> may be moved down in a direction toward the non-orbiting scroll <NUM>. Then, the sealing protrusion 1651a of the floating plate <NUM> may be spaced apart from the sealing plate <NUM> of the high and low pressure separation plate <NUM> to allow the low-pressure portion 110a and the high-pressure portion 110b to communicate with each other. Then, the refrigerant in the high-pressure portion 110b may leak into the low-pressure portion 110a to achieve a flat pressure between the high-pressure portion 110b and the low-pressure portion 110a.

At this time, the pressure in the compression chamber V may be reduced to thereby weaken the force pushing up the discharge valve <NUM>, whereas the high-pressure refrigerant in the high-pressure portion 110b at the upper surface of the discharge valve <NUM> may be introduced into the valve accommodating portion <NUM> through the backflow prevention hole 1654c to form high pressure. Then, the discharge valve <NUM> may be pushed down by the refrigerant from the high-pressure portion 110b to block the discharge port <NUM>. This may block a reverse flow of the refrigerant from the high-pressure portion 110a into the compression chamber V.

As described above, as the outer wall portion <NUM> and the inner wall portion <NUM> forming the back pressure chamber S are integrally formed on the upper surface of the non-orbiting scroll <NUM>, the number of components may be reduced compared to separately manufacturing and assembling a back pressure chamber assembly, and this may reduce the number of assemblers and/or assembly steps to thereby reduce manufacturing costs.

In addition, as the floating plate <NUM> provided between the outer wall portion <NUM> and the inner wall portion <NUM> to form the back pressure chamber S is further provided with the valve accommodating portion <NUM> to accommodate the discharge valve <NUM>, the bypass valves <NUM> and <NUM> may be installed inside of the inner wall portion <NUM> of the non-orbiting scroll <NUM> without having to separately assemble the back pressure chamber. In addition, as the non-orbiting scroll <NUM> is formed of cast iron and the floating plate <NUM> is formed of an aluminum material, the sealing grooves 1652a and 1653a may be formed on the floating plate <NUM> having relatively high processing roughness to accommodate the sealing members <NUM> and <NUM> therein. Accordingly, not only the sealing grooves 1652a and 1653a may be easily processed, but also the processing roughness of the sealing grooves 1652a and 1653a may be increased to enhance an assembly degree of the sealing members <NUM> and <NUM> and the upper cover member <NUM>, thereby increasing a sealing degree of the back pressure chamber S.

In addition, as the inner cover portion <NUM> of the floating plate <NUM> is internally fitted to the inner wall portion <NUM> of the non-orbiting scroll <NUM>, the annular sealing member <NUM> that seals between the inner cover portion <NUM> and the inner wall portion <NUM> may be installed on the outer circumferential surface of the inner cover portion <NUM>. This may allow the annular sealing member <NUM> to be easily installed.

Hereinafter, description will be given of another embodiment of the floating plate. In the previous embodiment, the outer cover portion of the floating plate is fitted to the inner circumferential side of the outer wall portion of the non-orbiting scroll, and the inner cover portion of the floating plate is fitted to the inner circumferential side of the inner wall portion, respectively. However, in some cases, the outer cover portion may be fitted to the inner circumferential side of the outer wall portion and the inner cover portion may be fitted to the outer circumferential side of the inner wall portion, respectively.

<FIG> is a perspective cross-sectional view and <FIG> is a cross-sectional view of a floating plate according to another embodiment. Referring to <FIG>, non-orbiting scroll <NUM> according to this embodiment may be integrally formed by extending outer wall portion <NUM> and inner wall portion <NUM> from an upper surface of non-orbiting end plate <NUM>.

The outer wall portion <NUM> and the inner wall portion <NUM> may be formed substantially the same as in the embodiment of <FIG> described above. For example, the outer wall portion <NUM> and the inner wall portion <NUM> may be spaced apart with a predetermined gap therebetween in the radial direction, and a height and a thickness of the outer wall portion <NUM> may be approximately the same as a height and a thickness of the inner wall portion <NUM>. In addition, the outer wall portion <NUM> may be formed as close to an outer circumferential surface of the non-orbiting end plate <NUM> as possible, while the inner wall portion <NUM> may be formed as close to discharge port <NUM> as possible within a range in which first bypass hole 1512a and second bypass hole 1512b may be formed.

Floating plate <NUM> according to this embodiment may be formed substantially similarly to the embodiment of <FIG> described above. More specifically, the floating plate <NUM> may include upper cover portion <NUM>, outer cover portion <NUM>, inner cover portion <NUM>, valve accommodating portion <NUM>, and discharge through hole <NUM>. The upper cover portion <NUM>, the outer cover portion <NUM>, the inner cover portion <NUM>, the valve accommodating portion <NUM>, and the discharge through hole <NUM> may be formed substantially the same as in the embodiment of <FIG>.

However, the outer cover portion <NUM> may be slidably fitted to an inner circumferential surface of the outer wall portion <NUM> (or internally fitted to the inner circumferential surface), while the inner cover portion <NUM> may be slidably fitted to an outer circumferential surface of the inner wall portion <NUM> (or externally fitted to the outer circumferential surface).

In other words, both the outer cover portion <NUM> and the inner cover portion <NUM> may be located inside of the outer wall portion <NUM> and the inner wall portion <NUM> forming back pressure chamber S. Accordingly, a gap between the outer cover portion <NUM> and the inner cover portion <NUM> may be narrower than the above-described embodiment of <FIG>.

Also, in this case, first sealing member <NUM> may be installed on an outer circumferential surface of the outer cover portion <NUM>, and second sealing member <NUM> may be installed on an inner circumferential surface of the inner cover portion <NUM>, respectively. In particular, the second sealing member <NUM> may be inserted in second sealing groove 1653a formed on the inner circumferential surface of the inner cover portion <NUM> from an inner circumferential side. Accordingly, the second sealing member <NUM> having an annular shape, like an O-ring may be inserted into the second sealing groove 1653a by shrinking instead of stretching, thereby allowing the second sealing member <NUM> to be easily installed.

As described above, when the inner cover portion <NUM> is externally fitted to an outer circumferential side of the inner wall portion <NUM>, a gap between the outer cover portion <NUM> and the inner cover portion <NUM> is reduced, so that an area supporting the floating plate <NUM>, namely, an area of the floating plate <NUM> exposed to the back pressure chamber S (hereinafter, defined as a back pressure area of the back pressure chamber) may be reduced. In particular, when the outer cover portion <NUM> is internally fitted to the outer wall portion <NUM> and the inner cover portion <NUM> is externally fitted to the outer circumferential side of the inner wall portion <NUM> as in this embodiment, the outer cover portion <NUM> and the inner cover portion <NUM> both may be placed inside of the back pressure chamber. Accordingly, the back pressure area of the floating plate <NUM> may be reduced by approximately a thickness of the inner wall portion <NUM> or a thickness of the inner cover portion <NUM> compared to the embodiment of <FIG>.

This may reduce a back pressure supporting the floating plate <NUM> so as to quickly move down the floating plate <NUM> during stoppage of a compressor, and therefore, a flat pressure between low-pressure portion 110a and high-pressure portion 110b may be quickly and smoothly achieved. In addition, as the inner cover portion <NUM> is externally fitted to the inner wall portion <NUM> as in this embodiment, a cross section of the inner cover portion <NUM> may be excluded from a periphery of the discharge port <NUM> to thereby form a discharge passage flat without curves. This allows refrigerant passing through the discharge port <NUM> to move to the discharge through hole <NUM> along the inner circumferential surface of the flat inner wall portion <NUM>, so that flow loss due to a vortex in the vicinity of the discharge port <NUM> is prevented.

In addition, in this embodiment, the floating plate <NUM> including the inner cover portion <NUM> is formed of an aluminum material, and thus, has a relatively high processing roughness compared to the inner wall portion <NUM> formed of cast iron. Accordingly, when the second sealing member <NUM> is inserted in the second sealing groove 1653a formed on the inner circumferential surface of the inner cover portion <NUM>, a sealing force of the second sealing member <NUM> inserted in the second sealing groove 1653a may be improved due to high processing roughness of the second sealing groove 1653a. In addition, as the second sealing member <NUM> and upper cover member <NUM> formed in an annular shape as in this embodiment are installed on the inner circumferential surface of the inner cover portion <NUM>, the second sealing member <NUM> and the upper cover member <NUM> may be easily installed.

Hereinafter, description will be given of still another embodiment of the floating plate.

In the previous embodiment, the outer cover portion is slidably fitted to the inner circumferential surface of the outer wall portion, but in some cases, the outer cover portion may be slidably fitted to the outer circumferential surface of the outer wall portion. <FIG> is a perspective cross-sectional view and <FIG> is a cross-sectional view of a floating plate according to still another embodiment.

Referring to <FIG>, non-orbiting scroll <NUM> according to this embodiment may be formed by integrally extending outer wall portion <NUM> and inner wall portion <NUM> from an upper surface of non-orbiting end plate <NUM>. The outer wall portion <NUM> and the inner wall portion <NUM> may be formed substantially the same as in the embodiment of <FIG> described above. For example, the outer wall portion <NUM> and the inner wall portion <NUM> may be spaced apart with a predetermined gap therebetween in the radial direction, and a height and a thickness of the outer wall portion <NUM> may be approximately the same as a height and a thickness of the inner wall portion <NUM>. In addition, the outer wall portion <NUM> may be formed as close to an outer circumferential surface of the non-orbiting end plate <NUM> as possible, while the inner wall portion <NUM> may be formed as close to discharge port <NUM> as possible within a range in which first bypass hole 1512a and a second bypass hole 1512b may be formed.

Floating plate <NUM> according to this embodiment may be formed substantially similarly to the embodiment of <FIG> described above. More specifically, the floating plate <NUM> may include upper cover portion <NUM>, outer cover portion <NUM>, inner cover portion <NUM>, valve accommodating portion <NUM>, and discharge through hole <NUM>. The upper cover portion <NUM>, the outer cover portion <NUM>, the inner cover portion <NUM>, the valve accommodating portion <NUM>, and the discharge through hole <NUM> may be formed substantially similarly to the embodiment of <FIG>.

However, an arrangement in which the floating plate <NUM> is assembled to the outer wall portion <NUM> and the inner wall portion <NUM> of the non-orbiting scroll <NUM> may be opposite to that of the embodiment of <FIG>. For example, the outer cover portion <NUM> may be slidably fitted to an outer circumferential surface of the outer wall portion <NUM> (or externally fitted to the outer circumferential surface), while the inner cover portion <NUM> may be slidably fitted to an inner circumferential surface of the inner wall portion <NUM> (or internally fitted to the inner circumferential surface).

In other words, both the outer cover portion <NUM> and the inner cover portion <NUM> may be located outside of the outer wall portion <NUM> and the inner wall portion <NUM> forming back pressure chamber S. Accordingly, a gap between the outer cover portion <NUM> and the inner cover portion <NUM> may be wider than the previous embodiments of <FIG> and <FIG>.

Also, in this case, first sealing member <NUM> may be installed on an inner circumferential surface of the outer cover portion <NUM>, and second sealing member <NUM> may be installed on an outer circumferential surface of the inner cover portion <NUM>, respectively. In particular, the first sealing member <NUM> may be inserted in first sealing groove 1652a formed on the inner circumferential surface of the outer cover portion <NUM> from an inner circumferential side. Accordingly, the first sealing member <NUM> having an annular shape, like an O-ring, may be inserted into the first sealing groove 1652a by shrinking instead of stretching, thereby allowing the first sealing member <NUM> to be easily installed.

Even when the outer cover portion <NUM> is externally fitted to the outer wall portion <NUM> as described above, the basic configuration and effects thereof may be similar to the embodiments of <FIG> and <FIG> described above. However, in this embodiment, the back pressure area of the back pressure chamber S supporting the floating plate <NUM> may be increased because the gap between the outer cover portion <NUM> and the inner cover portion <NUM> is widened. Accordingly, during operation of a compressor, the floating plate <NUM> may be quickly elevated to be strongly adhered to the high and low pressure separation plate, thereby providing a tightly seal between low-pressure portion 110a and high-pressure portion 110b.

Hereinafter, description will be given of a back pressure chamber portion according to another embodiment. In the previous embodiments, the outer wall portion and the inner wall portion forming a portion of the back pressure chamber are integrally formed with the non-orbiting scroll, but in some cases, the back pressure chamber may be formed by post-assembly of a separate back pressure chamber assembly including the outer wall portion and the inner wall portion to the non-orbiting scroll.

<FIG> is a perspective cross-sectional view and <FIG> is a cross-sectional view of a back pressure chamber according to another embodiment. Referring to <FIG>, the back pressure chamber according to this embodiment may be formed in back pressure chamber assembly <NUM> coupled to an upper surface of non-orbiting scroll <NUM>.

The back pressure chamber assembly <NUM> forming the back pressure chamber may include back pressure plate <NUM> and floating plate <NUM>. The non-orbiting scroll <NUM> according to this embodiment may include non-orbiting end plate <NUM>, and the non-orbiting end plate <NUM> may include a first end plate (no reference numeral) and a second end plate (no reference numeral) separately manufactured to be post-assembled. The first end plate may be understood as a lower end plate provided with non-orbiting wrap <NUM> to form compression chamber V, and the second end plate may be understood as an upper end plate included in back pressure plate <NUM> forming a portion of the back pressure chamber assembly <NUM> to form back pressure chamber S.

The back pressure plate <NUM> including the second end plate may have an annular shape, and an outer wall portion <NUM> and inner wall portion <NUM> may be formed on an upper surface of fixed plate portion <NUM> with a predetermined gap therebetween in the radial direction. An upper surface between outer wall portion <NUM> and inner wall portion <NUM> may be covered by the floating plate <NUM>. Accordingly, the back pressure chamber S may be formed in a space between the outer wall portion <NUM> and the inner wall portion <NUM>.

Bottom plate portion <NUM> between the outer wall portion <NUM> and the inner wall portion <NUM> may be provided with plate side back pressure hole 1611c formed therethrough, and the non-orbiting scroll <NUM> may be provided with scroll side back pressure hole <NUM> that communicates with the plate side back pressure hole 1611c. Another end of the scroll side back pressure hole <NUM> may communicate with an intermediate pressure chamber.

The outer wall portion <NUM> and the inner wall portion <NUM> may be formed in the same manner as in the previous embodiments. For example, the outer wall portion <NUM> may extend toward high and low pressure separation plate <NUM> from a rim of the non-orbiting end plate <NUM>, and the inner wall portion <NUM> may extend in the axial direction from a central portion of the non-orbiting end plate <NUM>, more specifically, from a portion between the outer wall portion <NUM> and plate-side bypass hole 1611b toward the high and low pressure separation plate <NUM>. The plate-side bypass hole 1611b may communicate with scroll-side bypass hole <NUM>. A plate-side discharge port 1611a may be formed at a central portion of the back pressure plate to communicate with discharge port <NUM> of the non-orbiting scroll <NUM>.

The floating plate <NUM> may be formed in the same manner as in the previous embodiments. For example, the floating plate <NUM> may include upper cover portion <NUM>, outer cover portion <NUM>, inner cover portion <NUM>, valve accommodating portion <NUM>, and discharge through hole <NUM>. Respective description of the upper cover portion <NUM>, the outer cover portion <NUM>, the inner cover portion <NUM>, the valve accommodating portion <NUM>, and the discharge through hole <NUM> has been omitted.

When the back pressure chamber assembly <NUM> is assembled to the non-orbiting scroll <NUM> as described above, the back pressure plate <NUM> forming a portion of the back pressure chamber assembly <NUM> may be formed of an aluminum material. Accordingly, a weight of the non-orbiting scroll <NUM> may be reduced compared to a case in which the back pressure plate <NUM> including the outer wall portion <NUM> and the inner wall portion <NUM>, and the bottom plate portion <NUM> connecting the outer wall portion <NUM> and the inner wall portion <NUM> are integrally formed with the non-orbiting scroll <NUM>.

In addition, as the non-orbiting scroll <NUM> is formed by precision machining the non-orbiting wrap <NUM> on one surface of the non-orbiting scroll <NUM>, an entire processing of the non-orbiting scroll <NUM> may be difficult when the outer wall portion <NUM> and the inner wall portion <NUM> which require precision machining are integrally formed on another surface of the non-orbiting scroll <NUM>. Accordingly, when the back pressure chamber assembly <NUM> is assembled while being separated from the non-orbiting scroll <NUM>, the non-orbiting scroll <NUM> may be easily manufactured. In addition, when the back pressure plate <NUM> included in the back pressure chamber assembly <NUM> is made of an aluminum material, this may ease the precision machining of the outer wall portion <NUM> and secure high roughness with respect to circumferential surfaces of the outer wall portion <NUM> and the inner wall portion <NUM> to thereby increase a degree of sealing with the floating plate <NUM>.

In addition, when the back pressure plate <NUM> is made of an aluminum material, the sealing groove in the previous embodiments may be easily formed on a circumferential surface of the back pressure plate <NUM>, namely, on a circumferential surface of the outer wall portion <NUM> or a circumferential surface the inner wall portion <NUM>. Accordingly, sealing members <NUM> and <NUM> and upper cover member <NUM> may be easily assembled.

Meanwhile, in the previous embodiments, a case in which the discharge valve is configured as a piston valve has been described as an example, but in some cases, the discharge valve may be configured as a reed valve in which one or a first end thereof is a fixed end and another or a second end thereof is a free end. Even in this case, positions and shapes of the outer wall portion and the inner wall portion may be the same as in the previous embodiments, and the floating plate may be formed in the same manner as in the previous embodiments except for the valve accommodating portion. The basic structure and operation effects of this embodiment are the same as or similar to those of the previous embodiments, and thus, repetitive description thereof has been omitted.

Embodiments disclosed herein provide a scroll compressor capable of simplifying a structure of a back pressure chamber in a non-orbiting back pressure method in which the back pressure chamber is formed on a rear surface of a non-orbiting scroll provided with a discharge port and a bypass hole. In addition, embodiments disclosed herein provide a scroll compressor in which a portion forming back pressure chamber is integrally formed with a non-orbiting scroll, thereby reducing the number of components and assemblers or assembly steps.

Further, embodiments disclosed herein provide a scroll compressor in which an area of a back pressure chamber may be secured while a portion forming a back pressure chamber is integrally formed with a non-orbiting scroll. Furthermore, embodiments disclosed herein provide a scroll compressor in which a degree of sealing of a back pressure chamber may be secured while a portion forming a back pressure chamber is integrally formed with a non-orbiting scroll.

In addition, embodiments disclosed herein provide a scroll compressor in which a sealing member for sealing a back pressure chamber may be easily assembled while a portion forming a back pressure chamber is integrally formed with a non-orbiting scroll. Also, embodiments disclosed herein provide a scroll compressor capable of reducing the number of components forming a back pressure chamber and the number of assemblers or assembly steps therefor when a discharge valve for opening and closing a discharge port is configured as a piston valve.

According to embodiments disclosed herein, in the non-orbiting back pressure method in which a back pressure chamber is formed on a rear surface of a non-orbiting scroll, an outer wall portion and an inner wall portion forming a portion of the back pressure chamber may extend integrally from the rear surface of the non-orbiting scroll. Accordingly, the number of components forming the back pressure chamber and the number of assemblers or assembly steps therefor may be reduced in the non-orbiting back pressure method to thereby reduce manufacturing costs.

The non-orbiting scroll may have a discharge port and a bypass hole that communicates with a compression chamber, and the discharge port and the bypass hole may be formed at an inner side than the inner wall portion. Accordingly, the inner wall portion forming a portion of the back pressure chamber may be integrally formed with the non-orbiting scroll.

A floating plate between the outer wall portion and the inner wall portion may be further provided on an upper side of the non-orbiting scroll. The floating plate may include an outer cover portion that slidingly contacts the outer wall portion and an inner cover portion that slidingly contacts the inner wall portion. Accordingly, an area of the back pressure chamber may be secured by adjusting positions of the outer cover portion and the inner cover portion.

In addition, the floating plate may be made of a material having better processability than the non-orbiting scroll. An annular sealing groove may be formed on the outer cover portion or the inner cover portion, and an annular sealing member may be inserted in the sealing groove. This may increase processing roughness of the sealing groove, thereby enhancing a degree of sealing between the outer cover portion and the outer wall portion or between the inner cover portion and the inner wall portion.

Further, the sealing member provided between the outer wall portion and the outer cover portion or between the inner wall portion and the inner cover portion may be installed on inner circumferential surfaces facing each other. As a result, assembly of the sealing member may be facilitated.

According to embodiments disclosed herein, a scroll compressor is provided that may include a casing having a sealed inner space, a drive motor installed in the inner space of the casing, an orbiting scroll coupled to the drive motor to perform an orbiting motion, a non-orbiting scroll provided with a compression chamber formed by being engaged with the orbiting scroll at one surface of an end plate, an outer wall portion and an inner wall portion having a predetermined gap between the outer wall portion and the inner wall portion in a radial direction and extending in an axial direction from another surface of the end plate, and a discharge port configured to discharge refrigerant compressed in the compression chamber into the inner space of the casing, and a floating plate to cover an area between the outer wall portion and the inner wall portion of the non-orbiting scroll so as to form a back pressure chamber with the non-orbiting scroll may be provided. The floating plate may include an upper cover portion having an annular shape to form an upper surface of the back pressure chamber, an outer cover portion that extends from an outer circumference of the upper cover portion toward the non-orbiting scroll in the axial direction so as to be slidably fitted to the outer wall portion, an inner cover portion that extends from an inner circumference of the upper cover portion toward the non-orbiting scroll in the axial direction so as to be slidably fitted to the inner wall portion, and a valve accommodating portion that axially extends from an inner circumferential side of the inner cover portion so as to accommodate a discharge valve configured to open and close the discharge port. This may simplify a structure of the back pressure chamber to thereby reduce manufacturing costs.

At least one discharge through hole may be provided between an outer circumferential surface of the valve accommodating portion and an inner circumferential surface of the inner cover portion to provide communication between the discharge port and the inner space of the casing. At least one connection portion may be provided between the outer circumferential surface of the valve accommodating portion and the inner circumferential surface of the inner cover portion to connect the valve accommodating portion and the inner cover portion. Accordingly, the valve accommodating portion may be integrally formed with the floating plate.

At least one discharge through hole may be provided between an outer circumferential surface of the valve accommodating portion and an inner circumferential surface of the inner cover portion to provide communication between the discharge port and the inner space of the casing. At least one connection portion may be provided between the discharge through holes to connect between the valve accommodating portion and the inner cover portion. A circumferential length of the discharge through hole may be longer than a circumferential length of the connection portion. In this way, a discharge area of the discharge through hole may be secured.

The valve accommodating portion may have a cylindrical shape, a plurality of connection portions may be spaced apart from each other along an outer circumferential surface of the valve accommodating portion, and a discharge through hole may be formed between the plurality of connection portions circumferentially adjacent to each other. Accordingly, the discharge through hole may be secured while the valve accommodating portion is integrally formed in the floating plate.

A lower end of the valve accommodating portion may be spaced apart from the another surface of the end plate of the non-orbiting scroll. Accordingly, a space for installing a bypass valve may be secured while the valve accommodating portion is formed in the floating plate.

A bypass hole to bypass refrigerant compressed in a compression chamber may be formed around the discharge port of the non-orbiting scroll. The another surface of the non-orbiting scroll may be provided with a bypass valve to open and close the bypass hole. The bypass valve may be placed between the non-orbiting scroll and the valve accommodating portion. This may allow a bypass valve to be installed between the non-orbiting scroll and the back pressure chamber while simplifying a structure of the non-orbiting scroll.

The valve guide surface may have a cylindrical shape. This may minimize an area of the vale accommodating portion to secure an installation space for the bypass valve.

The end plate of the non-orbiting scroll may be provided with a bypass hole to provide communication between the compression chamber and the inner space of the casing. The bypass hole may be formed between the discharge port and the inner wall portion in the radial direction. The another surface of the end plate of the non-orbiting scroll may be provided with a bypass valve to open and close the bypass hole. This may secure a space for the bypass hole and the bypass valve while simplifying a structure of the back pressure chamber.

The bypass valve may be located between the end plate of the non-orbiting scroll and the valve accommodating portion in the axial direction. Accordingly, the bypass valve may be installed between the discharge port and the inner wall portion.

The discharge valve may be configured as a piston valve axially sliding in the valve accommodating portion. An axial length of the valve accommodating portion may be longer than an axial movement length of the discharge valve. This may suppress removal of the discharge valve while allowing the valve accommodating portion to be spaced apart from the non-orbiting scroll.

The inner space of the casing may be provided with a high and low pressure separation plate to separate the inner space of the casing into a low-pressure portion and a high-pressure portion. A sealing protrusion that axially extends toward the high and low pressure separation plate may be provided between the upper cover portion and the inner cover portion. Accordingly, the valve accommodating portion may be integrally formed in the floating plate and refrigerant may be smoothly discharged toward the high-pressure portion.

The sealing protrusion may be formed on an axial line the same as that of the inner cover portion. Accordingly, the discharge through hole may be integrally formed in an inner portion of the sealing protrusion.

An axial length of the valve accommodating portion may be shorter than or equal to an axial length of the inner cover portion, and an end portion of the valve accommodating portion may be spaced apart from the end plate of the non-orbiting scroll. Accordingly, the valve accommodating portion may be formed in the floating plate while a bypass valve is installed between the floating plate and the non-orbiting scroll.

An outer cover member may be provided between a circumferential surface of the outer cover portion and a circumferential surface of the outer wall portion. An inner cover member may be provided between a circumferential surface of the inner cover portion and a circumferential surface of the inner wall portion. This may tightly seal between the outer wall portion and the inner wall portion forming a portion of the back pressure chamber portion.

The outer cover portion may be slidably fitted to an inner circumferential surface of the outer wall portion, and the inner cover portion may be slidably fitted to an inner circumferential surface of the inner wall portion. In this way, a back pressure area of the back pressure chamber may be secured.

An outer circumferential surface of the outer cover portion may have an annular outer sealing groove to receive an annular outer cover member. Accordingly, processing roughness of the sealing groove into which the sealing member is inserted may be increased.

An outer circumferential surface of the inner cover portion may have an annular inner sealing groove to receive an annular inner cover member. Accordingly, processing roughness of the sealing groove into which the sealing member is inserted may be increased.

The outer cover portion may be slidably fitted to an inner circumferential surface of the outer wall portion, and the inner cover portion may be slidably fitted to an outer circumferential surface of the inner wall portion. This may reduce the back pressure area of the back pressure chamber, so that when the compressor is stopped, the floating plate may quickly move down to achieve a flat pressure.

An outer circumferential surface of the outer cover portion may have an annular outer sealing groove to receive an annular outer cover member, and an inner circumferential surface of the inner cover portion may have an annular inner sealing groove to receive an annular inner cover member. This may allow the inner cover member to be easily installed while enhancing a sealing effect for the back pressure chamber.

The outer cover portion may be slidably fitted to an outer circumferential surface of the outer wall portion, and the inner cover portion may be slidably fitted to an inner circumferential surface of the inner wall portion. This may reduce the back pressure area of the back pressure chamber to allow the floating plate to be tightly brought into contact with the high and low pressure separation plate so as to tightly seal between the low-pressure portion and the high-pressure portion.

An inner circumferential surface of the outer cover portion may have an annular outer sealing groove to receive an annular outer cover member, and an outer circumferential surface of the inner cover portion may have an annular inner sealing groove to receive an annular inner cover member. This may allow the outer cover member to be easily installed while enhancing a sealing effect for the back pressure chamber.

The outer wall portion and the inner wall portion may integrally extend from the end plate of the non-orbiting scroll. Accordingly, the number of components forming the back pressure chamber and the number of assemblers and assembly steps may be reduced to simplify the back pressure chamber.

The non-orbiting scroll may include a first end plate provided with a non-orbiting wrap to form the compression chamber and a second end plate provided with the outer wall portion and the inner wall portion to form the back pressure chamber. The first end plate and the second end plate may be assembled together. In this way, a shape or components forming the back pressure chamber may be selectable as needed, thereby elevating a degree of freedom in design.

Embodiments of the disclosure are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the disclosure. Thus, embodiments of the disclosure should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.

Claim 1:
A scroll compressor, comprising:
a casing (<NUM>) having a sealed inner space;
a drive motor (<NUM>) installed in the inner space of the casing (<NUM>);
an orbiting scroll (<NUM>) coupled to the drive motor (<NUM>) to perform an orbiting motion;
a non-orbiting scroll (<NUM>) including an end plate (<NUM>) provided at a first side of the orbiting scroll (<NUM>) and having a first surface defining a compression chamber by being engaged with the orbiting scroll (<NUM>) and a second surface having an outer wall portion (<NUM>) and an inner wall portion (<NUM>) that extend in an axial direction with a predetermined gap therebetween in a radial direction, the inner wall portion (<NUM>) provided therein with a discharge port (<NUM>) configured to discharge refrigerant compressed in the compression chamber into the inner space of the casing (<NUM>); and
a floating plate (<NUM>) configured to cover an area between the outer wall portion (<NUM>) and the inner wall portion (<NUM>) of the non-orbiting scroll (<NUM>) so as to form a back pressure chamber (S) with the non-orbiting scroll (<NUM>), wherein the floating plate (<NUM>) comprises:
an upper cover portion (<NUM>) having an annular shape to form an upper surface of the back pressure chamber (S);
an outer cover portion (<NUM>) that extends from an outer circumference of the upper cover portion (<NUM>) toward the non-orbiting scroll (<NUM>) in the axial direction so as to be slidably fitted to the outer wall portion (<NUM>);
an inner cover portion (<NUM>) that extends from an inner circumference of the upper cover portion (<NUM>) toward the non-orbiting scroll (<NUM>) in the axial direction so as to be slidably fitted to an inner circumference of the inner wall portion (<NUM>); and
a valve accommodating portion (<NUM>) that axially extends from an inner circumferential side of the inner cover portion (<NUM>) so as to accommodate a discharge valve (<NUM>) configured to open and close the discharge port (<NUM>),
wherein
the upper cover portion (<NUM>), the outer cover portion (<NUM>), the inner cover portion (<NUM>), and the valve accommodating portion (<NUM>) are formed as a single body, and
characterized in that
a height (H4) of the inner cover portion (<NUM>) is formed to be lower than a height (H2) of the inner wall portion (<NUM>), so that a lower end of the inner cover portion (<NUM>) is formed higher than the lower end of the inner wall portion (<NUM>) forming the back pressure chamber (S).