SCROLL COMPRESSOR

Abstract

A scroll compressor including a housing, a motor in the housing, an orbiting scroll, and a fixed scroll. An injection valve assembly is provided between the fixed scroll and the housing and further includes a cover plate, a valve plate, a gasket retainer, and an injection valve. The compressor capable of increasing a surface pressure at a position at which the injection valve of the injection valve assembly needs to be supported, and preventing deformation of the gasket retainer by reducing a bead height of the gasket retainer.

Claims

1. A scroll compressor comprising: a housing; a motor provided in the housing; a rotary shaft configured to be rotated by the motor; an orbiting scroll configured to orbit in conjunction with the rotary shaft; and a fixed scroll configured to define a compression chamber together with the orbiting scroll, wherein the housing further comprises a rear housing configured to define a discharge chamber that accommodates a refrigerant discharged from the compression chamber, wherein an injection valve assembly is provided between the fixed scroll and the rear housing, defines, in the rear housing, an introduction chamber into which the refrigerant is introduced from outside of the housing, and guides the refrigerant in the introduction chamber to the compression chamber, wherein the injection valve assembly further comprises: a cover plate coupled to the rear housing and having an inlet port into which the refrigerant in the introduction chamber is introduced; a valve plate coupled to the cover plate and having an outlet port from which the refrigerant introduced through the inlet port is discharged; a gasket retainer interposed between the cover plate and the valve plate and configured to prevent a leak of the refrigerant; and an injection valve interposed between the cover plate and the gasket retainer and configured to open or close the inlet port, wherein the valve plate has a surface pressure enhancement portion protruding toward the injection valve.

2. The scroll compressor of claim 1, wherein the surface pressure enhancement portion is provided on a surface of the valve plate, which faces the gasket retainer, and the surface pressure enhancement portion at least partially supports the gasket retainer and the injection valve.

3. The scroll compressor of claim 2, wherein the injection valve further comprises: a head portion configured to open or close the inlet port; and a leg portion extending from the head portion and configured to perform an opening operation or a closing operation, wherein the surface pressure enhancement portion is provided at a position corresponding to an end of the leg portion opposite to the head portion.

4. The scroll compressor of claim 3, wherein the inlet port is provided as a plurality of inlet ports, wherein the head portion and the leg portion of the injection valve are respectively provided as a plurality of head portions and a plurality of leg portions, wherein the injection valve further comprises a connection portion configured to connect the plurality of leg portions, and wherein the surface pressure enhancement portion is provided as a plurality of surface pressure enhancement portions and is further provided at a position corresponding to at least a part of the connection portion.

5. The scroll compressor of claim 4, wherein the surface pressure enhancement portions are configured as integrally continuous surfaces.

6. The scroll compressor of claim 4, wherein the surface pressure enhancement portions are configured as a plurality of surfaces spaced apart from one another at positions corresponding to ends of the leg portions opposite to the head portions and corresponding to at least a part of the connection portion.

7. The scroll compressor of claim 4, wherein the plurality of inlet ports further comprises: a first inlet port; and a second inlet port formed independently of the first inlet port, wherein the plurality of head portions further comprises: a first head portion configured to open or close the first inlet port; and a second head portion configured to open or close the second inlet port, wherein the plurality of leg portions further comprises: a first leg portion extending from the first head portion and configured to perform the opening operation or the closing operation; and a second leg portion extending from the second head portion and configured to perform the opening operation or the closing operation, wherein the connection portion connects the first leg portion and the second leg portion, and wherein the surface pressure enhancement portions comprise: a first surface pressure enhancement portion provided at a position facing an end of the first leg portion to which the connection portion is connected; a second surface pressure enhancement portion provided at a position facing an end of the second leg portion to which the connection portion is connected; and a connection surface pressure enhancement portion provided at a position facing at least a part of the connection portion.

8. The scroll compressor of claim 7, wherein the first surface pressure enhancement portion extends in a width direction of the first leg portion, the second surface pressure enhancement portion extends in a width direction of the second leg portion, and the first surface pressure enhancement portion and the second surface pressure enhancement portion are disposed in parallel and spaced apart from each other at a predetermined distance.

9. The scroll compressor of claim 7, wherein the valve plate further comprises an inclined space recessed in a base surface from which the surface pressure enhancement portion protrudes, and the first surface pressure enhancement portion and the second surface pressure enhancement portion each have a lower surface roughness than the inclined space.

10. The scroll compressor of claim 4, wherein the valve plate further comprises a positioning groove into which a positioning pin is inserted, and the surface pressure enhancement portion has an avoidance portion recessed to prevent interference with the positioning groove.

11. The scroll compressor of claim 2, wherein a stepped portion is formed around a surface of the valve plate that faces the gasket retainer.

12. The scroll compressor of claim 11, wherein the stepped portion is defined by a stepped shape forming surface disposed radially outside the surface pressure enhancement portion and further protruding than a surface of the surface pressure enhancement portion.

13. The scroll compressor of claim 12, wherein the gasket retainer further comprises: a retainer portion inclinedly processed in a direction in which the injection valve is opened; and a bead portion protruding from one surface and configured to surround the retainer portion, wherein the bead portion faces the stepped shape forming surface.

14. A scroll compressor comprising: a housing; a motor provided in the housing; a rotary shaft configured to be rotated by the motor; an orbiting scroll configured to orbit in conjunction with the rotary shaft; and a fixed scroll configured to define a compression chamber together with the orbiting scroll, wherein the housing comprises a rear housing configured to define a discharge chamber that accommodates a refrigerant discharged from the compression chamber, wherein an injection valve assembly is provided between the fixed scroll and the rear housing, defines, in the rear housing, an introduction chamber into which the refrigerant is introduced from the outside of the housing, and guides the refrigerant in the introduction chamber to the compression chamber, wherein the injection valve assembly comprises: a cover plate coupled to the rear housing and having an inlet port into which the refrigerant in the introduction chamber is introduced; a valve plate coupled to the cover plate and having an outlet port from which the refrigerant introduced through the inlet port is discharged; a gasket retainer interposed between the cover plate and the valve plate and configured to prevent a leak of the refrigerant; and an injection valve interposed between the cover plate and the gasket retainer and configured to open or close the inlet port, wherein a stepped portion is formed around a surface of the valve plate that faces the gasket retainer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a cross-sectional view illustrating a scroll compressor in the related art.

[0034] FIG. 2 is an exploded perspective view separately illustrating an injection valve assembly in FIG. 1.

[0035] FIG. 3 is an exploded perspective view illustrating an injection valve assembly of a scroll compressor according to an embodiment of the present invention.

[0036] FIG. 4 is a rear perspective view separately illustrating a valve plate in FIG. 3.

[0037] FIG. 5 is a rear perspective view separately illustrating a gasket retainer in FIG. 3.

[0038] FIG. 6 is a top plan view of FIG. 5.

[0039] FIG. 7 is a top plan view illustrating a state in which the injection valve assembly in FIG. 3 is fastened to a rear housing.

[0040] FIG. 8 is a cross-sectional view taken along line A-A in FIG. 7.

[0041] FIG. 9 is a cross-sectional view taken along line B-B in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

[0042] Hereinafter, exemplary embodiments of a scroll compressor according to the present invention will be described with reference to the accompanying drawings.

[0043] In addition, the terms used below are defined considering the functions in the present invention and may vary depending on the intention of a user or an operator or a usual practice. The following embodiments are not intended to limit the protection scope of the present invention.

[0044] A part irrelevant to the description will be omitted to clearly describe the present invention, and the same or similar constituent elements will be designated by the same reference numerals throughout the specification. Throughout the specification, unless explicitly described to the contrary, the word comprise/include and variations such as comprises/includes or comprising/including will be understood to imply the inclusion of stated elements, not the exclusion of any other elements.

[0045] A scroll compressor according to an embodiment of the present invention includes a housing 100, a motor 200 provided in the housing 100, a rotary shaft 300 configured to be rotated by the motor 200, an orbiting scroll 400 configured to orbit in conjunction with the rotary shaft 300, a fixed scroll 500 configured to define a compression chamber C together with the orbiting scroll 400, and a discharge valve 600 disposed on one surface of the fixed scroll 500 and configured to open or close a discharge port 512 of the fixed scroll from which a refrigerant compressed in the compression chamber C is discharged. In this case, the components identical to the components of the scroll compressor of Patent Document 2 illustrated in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed descriptions of the identical components will be omitted.

[0046] Further, the scroll compressor according to the present embodiment may further include an injection valve assembly 2700 that defines and opens or closes an injection flow path configured to guide a middle-pressure refrigerant to the compression chamber C from the outside of the housing 100 (e.g., from a downstream side of a condenser in a vapor compression refrigeration cycle including a scroll compressor, the condenser, an expansion valve, and an evaporator).

[0047] The housing 100 includes a center housing 110 penetrated by the rotary shaft 300, a front housing 120 configured to define a motor accommodation space that accommodates the motor 200, and a rear housing 130 configured to define a discharge chamber D that accommodates the refrigerant discharged from the compression chamber C. The injection valve assembly 2700 may be interposed between the fixed scroll 500 and the rear housing 130. The injection valve assembly 2700 defines, in the rear housing 130, an introduction chamber I into which the refrigerant is introduced from the outside of the housing. The injection valve assembly 2700 guides the refrigerant in the introduction chamber I to the compression chamber C.

[0048] Specifically, as illustrated in FIG. 3, the injection valve assembly 2700 includes a cover plate 710 coupled to the rear housing 130 and having inlet ports 712 into which the refrigerant in the introduction chamber I is introduced, a valve plate 2730 coupled to the cover plate 710 and having an outlet port 736 from which the refrigerant introduced through the inlet ports 712 is discharged, a gasket retainer 2790 interposed between the cover plate 710 and the valve plate 2730 and configured to prevent a leak of the refrigerant, and an injection valve 720 interposed between the cover plate 710 and the gasket retainer 2790 and configured to open or close the inlet ports 712. In this case, the components identical to the components of the scroll compressor of Patent Document 2 are denoted by the same reference numerals, and detailed descriptions of the identical components will be omitted. That is, the configurations of the cover plate 710 and the injection valve 720 are identical to those of the scroll compressor of Patent Document 2.

[0049] As illustrated in FIGS. 3 and 4, the valve plate 2730 of the present embodiment is identical to the valve plate 730 of Patent Document 2 in that the protruding portion 732, the inclined spaces 734, the outlet port 736, the first fastening hole 739a, and the second positioning groove 739b are applied in the same way. However, the valve plate 2730 of the present embodiment differs from the valve plate 730 of Patent Document 2 in that surface pressure enhancement portions 2738 and a stepped portion are formed on a surface of the valve plate 2730 that faces the gasket retainer 2790. That is, in Patent Document 2, the surface of the valve plate 730, which faces the gasket retainer 790, is formed as a flat surface, except for the inclined spaces 734. However, in the present embodiment, three surfaces with different heights are provided on the surface of the valve plate 2730, which faces the gasket retainer 2790, except for the inclined spaces 734. Hereinafter, the surface of the valve plate 2730, which faces the gasket retainer 2790, is referred to as an upper surface, and a surface opposite to the surface of the valve plate 2730, which faces the gasket retainer 2790, is referred to as a rear surface.

[0050] Specifically, the upper surface of the valve plate 2730 has a base surface 2737 in which the inclined spaces 734 are recessed. In addition, the upper surface of the valve plate 2730 has the surface pressure enhancement portion 2738 protruding from the base surface 2737 toward the injection valve 720. That is, a height of the base surface 2737 is lower than that of the surface pressure enhancement portion 2738. As the surface pressure enhancement portion 2738 protrudes from the base surface 2737, the surface pressure enhancement portion 2738 at least partially support the gasket retainer 2790 and the injection valve 720.

[0051] In this case, the surface pressure enhancement portion 2738 may support a start portion of the injection valve 720 where an operation of opening or closing the injection valve 720 is performed. That is, the surface pressure enhancement portion 2738 may support a portion that serves as a reference point at the time of performing the operation of opening or closing the injection valve 720. Therefore, the surface pressure may be increased at the position at which the injection valve 720 needs to be supported, thereby assuredly supporting the injection valve.

[0052] Specifically, in case that the injection valve 720 includes head portions 722 configured to open or close the inlet ports, and leg portions 724 extending from the head portions 722 and configured to perform the opening or closing operation, the surface pressure enhancement portion 2738 may be provided at a position corresponding to ends of the leg portions 724 opposite to the head portions 722.

[0053] In the present embodiment, as in Patent Document 2, the inlet port 712 is provided as a plurality of inlet ports 712. The plurality of inlet ports 712 includes a first inlet port 712a and a second inlet port 712b that independently communicate with the introduction chamber I. In addition, in the present embodiment, the head portion 722 and the leg portion 724 of the injection valve 720 are also respectively provided as a plurality of head portions 722 and a plurality of leg portions 724. The injection valve 720 further includes a connection portion 726 that connects the plurality of leg portions 724. In this case, to stably support the injection valve 720, the surface pressure enhancement portion 2738 may be further provided at a position facing at least a part of the connection portion 726.

[0054] Specifically, the injection valve 720 includes a first head portion 722a configured to open or close the first inlet port 712a, a first leg portion 724a extending from the first head portion 722a and configured to perform the opening or closing operation, a second head portion 722b configured to open or close the second inlet port 712b, a second leg portion 724b extending from the second head portion 722b and configured to perform the opening or closing operation, and the connection portion 726 configured to connect the first leg portion 724a and the second leg portion 724b.

[0055] In this case, as illustrated in FIG. 3, the positions at which the injection valve 720 needs to be supported are an end (portion a) of the first leg portion 724a to which the connection portion 726 is connected, and an end (portion b) of the second leg portion 724b to which the connection portion 726 is connected. This is because the first head portion 722a opens or closes the first inlet port 712a while being bent about portion a as a reference point, and the second head portion 722b opens or closes the second inlet port 712b while being bent about portion b as a reference point. Therefore, the surface pressure enhancement portions 2738 may include a first surface pressure enhancement portion 2738a provided at a position corresponding to portion a, and a second surface pressure enhancement portion 2738b positioned at a position corresponding to portion b, thereby supporting portion a and portion b of the injection valve 720.

[0056] In this case, the first surface pressure enhancement portion 2738a extends in a width direction of the first leg portion 724a, and the second surface pressure enhancement portion 2738b extends in a width direction of the second leg portion 724b. In particular, the first surface pressure enhancement portion 2738a and the second surface pressure enhancement portion 2738b may be disposed in parallel and spaced apart from each other at a predetermined distance.

[0057] In addition, the surface pressure enhancement portions 2738 include a connection surface pressure enhancement portion 2738c provided at a position corresponding to at least a part of the connection portion 726. The connection surface pressure enhancement portion 2738c may be disposed in a longitudinal direction of the connection portion 726 and provided between the first and second surface pressure enhancement portion 2738a and 2738b spaced apart from each other at a predetermined distance. That is, the surface pressure enhancement portions 2738 may be provided at the positions corresponding to portion a and portion b and provided at the position that traverses the injection valve. In the present embodiment, the surface pressure enhancement portions 2738 are configured as integrally continuous surfaces so that the surface pressure enhancement portions 2738 are formed at the same height. That is, the first surface pressure enhancement portion 2738a, the second surface pressure enhancement portion 2738b, and the connection surface pressure enhancement portion 2738c are integrally connected. However, the present invention is not limited thereto. The surface pressure enhancement portions 2738 may be configured as a plurality of surfaces spaced apart from one another. That is, the first surface pressure enhancement portion 2738a, the second surface pressure enhancement portion 2738b, and the connection surface pressure enhancement portion 2738c may be spaced apart from one another.

[0058] In addition, in some instances, the surface pressure enhancement portions 2738 may include an avoidance portion 2738d formed to be recessed to prevent interference with the second positioning groove 739b.

[0059] In the embodiment, the first and second surface pressure enhancement portions 2738a and 2738b may each have lower surface roughness than the inclined spaces 734. Because the inclined space 734 need not be precisely processed, the inclined space 734 may be formed to have a material surface. However, because the first and second surface pressure enhancement portions 2738a and 2738b are required to uniformly and constantly increase the surface pressure and importantly minimize the tolerance, the first and second surface pressure enhancement portions 2738a and 2738b need to be formed by precise processing.

[0060] Moreover, the upper surface of the valve plate 2730 may not only have the surface pressure enhancement portions 2738 but also have the stepped portion formed around the upper surface of the valve plate 2730. In this case, the stepped portion may be defined by a stepped shape forming surface 2739 disposed radially outside the surface pressure enhancement portions 2738 and further protruding than the surfaces of the surface pressure enhancement portions 2738.

[0061] Therefore, the heights of the surface of the valve plate 2730 facing the gasket retainer 2790 decrease in the order of the stepped shape forming surface 2739, the surface pressure enhancement portions 2738, and the base surface 2737.

[0062] In this case, the stepped shape forming surface 2739 faces bead portions 2792 of the gasket retainer 2790 to be described below. Therefore, when the injection valve assembly 2700 is fastened to the rear housing 130 by fastening bolts 770, the stepped shape forming surface 2739 may press and deform the bead portion 2792 to form surface pressure and seal a portion between the valve plate 2730 and the cover plate 710.

[0063] Further, an inner portion of the gasket retainer 2790 and the injection valve 720 may be seated in a cavity formed inside the stepped shape forming surface 2739. Because the inner portion of the gasket retainer 2790 and the injection valve 720 are seated in the cavity as described above, a height of the bead portion 2792 may be reduced in comparison with Patent Document 2 in which the height h by which the bead portion 792 protrudes needs to be equal to or larger than the thickness t of the injection valve 720. Therefore, it is possible to prevent the deformation of the gasket retainer 2790 and advantageously facilitate the forming of the gasket retainer and maintain a bolt fastening force. This configuration will be described below more specifically together with the description of the gasket retainer 2790.

[0064] As in Patent Document 2, with reference to FIGS. 5 and 6, the gasket retainer 2790 of the present embodiment includes retainer portions 794 inclinedly processed in a direction in which the injection valve 720 is opened, and a plurality of third fastening holes 796 disposed and penetratively formed radially outside the retainer portion 794 so that the fastening bolts 770 are inserted into the plurality of third fastening holes 796. However, there is a difference from the related art in that the bead portion 2792 includes a first half-bead 2792a and a second half-bead 2792b and main flow holes 2790c and a pair of auxiliary flow holes 2790d and 2790e are different in shapes.

[0065] Specifically, the bead portion 2792 includes a first half-bead 2792a protruding from one surface and extending radially inward from each of the plurality of third fastening holes 796 while surrounding the retainer portion 794, and a second half-bead 2792b protruding from one surface and extending radially outward from each of the plurality of third fastening holes 796 while surrounding the first half-bead 2792a.

[0066] In this case, unlike Patent Document 2, the first half-bead 2792a and the second half-bead 2792b protrude from a gasket retainer lower surface 790b facing the valve plate 2730. However, the present invention is not limited thereto.

[0067] In this case, in a portion where the plurality of third fastening holes 796 is spaced apart from one another, i.e., in a space between the adjacent third fastening holes 796, the first half-bead 2792a and the second half-bead 2792b are in contact with each other to define a full-bead having a convex shape. As illustrated in FIGS. 5 and 6, when the full-bead having a convex shape extends and then approaches the third fastening hole 796, the full-bead is divided into the first and second half-beads 2792a and 2792b. The first and second half-beads 2792a and 2792b respectively extend inward and outward from the third fastening hole 796 and then merged, such that the full-bead extends.

[0068] For example, the first half-bead 2792a and the second half-bead 2792b each have a quadrant cross-sectional shape. In the portion where the plurality of third fastening holes 796 is spaced apart from one another, the first half-bead 2792a and the second half-bead 2792b may be in contact with each other to define a semicircular cross-sectional shape.

[0069] Because the bead portions are also formed around the plurality of third fastening holes 796 as described above, the bolt fastening force may be enhanced even at the peripheries of the third fastening holes 796 when the injection valve assembly 2700 is fastened to the rear housing 130 by the fastening bolts 770, which may minimize the deformation of the valve plate 2730.

[0070] In particular, the first half-bead 2792a and the second half-bead 2792b are separately provided to support the fastening bolt 770 at the periphery of the third fastening hole 796 where the surface pressure is high, and the first half-bead 2792a and the second half-bead 2792b are in contact with each other to define the full-bead at the portion where the third fastening holes 796 are spaced apart from each other and the surface pressure is low. Therefore, the deformation of the valve plate 2730 may be prevented by the uniform surface pressure.

[0071] In addition, the gasket retainer 2790 has a hole extending to surround an outer side of one end of the retainer portion 794 to prevent one end of the retainer portion 794, where the inclination is started, from being connected directly to the first half-bead 2792a. In the present embodiment, a first auxiliary flow hole 2790d, will be described below, serves as the hole extending to surround the outer side of one end of the retainer portion 794. Therefore, the deformation, which is caused when the bead portion 2792 is pressed, is not transferred to an inner portion of the bead portion 2792 that supports the injection valve 720.

[0072] Specifically, as in Patent Document 2, the retainer portion 794 is inclinedly processed by cutting a body of the gasket retainer 2790. To maintain an inclination angle of the retainer portion 794, the gasket retainer 2790 further includes a pair of wing portions 795 that connects two opposite sides of the retainer portion 794 and the body of the gasket retainer 2790 that faces the two opposite sides of the retainer portion 794. In this case, the pair of wing portions 795 may be connected to two opposite sides of the other end of the retainer portion 794 opposite to one end of the retainer portion 794 where the inclination is started.

[0073] As described above, the bead portion 2792 may not be connected directly to one end of the retainer portion 794 that supports the start portion (reference point) where the operation of opening or closing the injection valve 720 is performed, such that the deformation is not transferred. Further, the pair of wing portions 795 is connected to the other end of the retainer portion 794 by minimum connection, such that the injection valve 720 may be assuredly supported.

[0074] The main flow hole 2790c is formed at one side of the pair of wing portions 795 and has an approximately U shape while surrounding the other end of the retainer portion 794. The pair of auxiliary flow holes 2790d and 2790e is formed at the other side of the pair of wing portions 795 and extends in the longitudinal direction of the retainer portion 794. In this case, the first auxiliary flow hole 2790d of the pair of auxiliary flow holes, which is positioned at an outer side, extends to be longer than the second auxiliary flow hole 2790e positioned at an inner side and surrounds the outer side of one end of the retainer portion 794. That is, as illustrated in FIG. 6, the second auxiliary flow hole 2790e may extend straight in the longitudinal direction of the retainer portion 794. The first auxiliary flow hole 2790d may extend straight in the longitudinal direction of the retainer portion 794, be bent, and then further extend. The first auxiliary flow hole 2790d may extend until it is positioned on the same line as the second auxiliary flow hole 2790e. Alternatively, the first auxiliary flow hole 2790d may extend until the first auxiliary flow hole 2790d exceeds the second auxiliary flow hole 2790e.

[0075] Specifically, the retainer portion 794 may be provided as a plurality of retainer portions 794. The plurality of retainer portions 794 includes a first retainer portion 794a and a second retainer portion 794b spaced apart from the first retainer portion. In this case, the first auxiliary flow hole 2790d of the first retainer portion 794a may extend straight in the longitudinal direction of the first retainer portion 794a, be bent toward the main flow hole 2790c of the second retainer portion 794b, and then extend. The first auxiliary flow hole 2790d of the second retainer portion 794b may extend straight in the longitudinal direction of the second retainer portion 794b, be bent toward the main flow hole 2790c of the first retainer portion 794a, and then extend.

[0076] In some instances, like the main flow hole 2790c positioned at a lower side based on FIG. 6, the main flow hole 2790c may at least partially extend in a circumferential direction of the gasket retainer 2790.

[0077] In the present embodiment, the configuration has been described in which the gasket retainer 2790 is different in structure from the gasket retainer 790 of Patent Document 2. However, the present invention is not limited thereto. The gasket retainer 790 of Patent Document 2 may, of course, be applied.

[0078] Lastly, a state in which the injection valve assembly 2700 of the present embodiment is coupled to the rear housing 130 will be described with reference to FIGS. 7 to 9. FIG. 8 is a cross-sectional view of a portion spaced apart from the fastening bolt 770, and FIG. 9 is a cross-sectional view of a portion to which the fastening bolt 770 is fastened.

[0079] With reference to FIG. 8, at the portion spaced apart from the fastening bolt 770, the first half-bead 2792a and the second half-bead 2792b of the gasket retainer 2790 meet together to define the full-bead. In addition, the first auxiliary flow hole 2790d prevents the retainer portion 794 from being connected directly to the bead portion 2792, such that the deformation of the bead portion 2792 is not transferred to the retainer portion 794. As a result, it can be seen that the retainer portion 794 is kept in a flat state. In addition, the inner portion of the gasket retainer 2790 and the injection valve 720 are seated in the cavity formed inside the stepped shape forming surface 2739 of the valve plate 2730.

[0080] With reference to FIG. 9, at the portion to which the fastening bolt 770 is fastened, it can be seen that the first half-bead 2792a and the second half-bead 2792b of the gasket retainer 2790 are separately and respectively formed inside and outside the fastening bolt 770. Therefore, it can be seen that the valve plate 2730 may be supported, and the deformation may be minimized. As described above, the deformation of the valve plate 2730 and the gasket retainer 2790 may be minimized, the injection valve 720 may be assuredly supported, and the stable operation may be performed.

[0081] The present invention is not limited to the specific exemplary embodiments and descriptions, various modifications can be made by any person skilled in the art to which the present invention pertains without departing from the subject matter of the present invention.