Patent Application
20050058561
The present invention relates to a compressor and, in particular, to structure of discharge valves in a reciprocating compressor and a rotary compressor.
In a reciprocating compressor and a rotary compressor including a compression chamber which is formed in a cylinder block and in which a refrigerant is compressed, a cylinder housing which is fixed to one end of the cylinder block and in which a discharge chamber into which the refrigerant in the compression chamber flows is formed, a discharge port forming member in which a discharge port interconnecting the compression chamber and the discharge chamber is formed, such as valve plate, a discharge valve interposed between the cylinder housing and the valve plate for opening and closing the discharge port, in a discharge-valve method in which a reed valve type of discharge valve generally made of steel plate is used, a means for regulating a lift amount of the discharge valve by a retainer has been known in consideration of pulsation and durability due to vibration of the discharge valve. For example, please refer to Patent Document 1 and Patent Document 2.
It is noted that Patent Document 1 is Japanese Unexamined Patent Publication No 2000-130379 (please refer to pages 2, 3 of the specification and FIGS. 1 to 4 of the drawing). It is also noted that Patent Document 2 is Japanese Unexamined Patent Publication No. 2002-31058 (please refer to pages 2 to 4 of the specification and
In the above-mentioned discharge-valve method, however, while the lift amount of the discharge valve is regulated by the retainer, resistance to discharge of a refrigerant gas to the contrary when the discharge valve is opened is increased. In addition, after the refrigerant gas is introduced from a suction chamber to the compression chamber and is compressed in the compression chamber to push the discharge valve away, and is discharged to the discharge chamber through the discharge port, and the discharge stroke ends, when the pressure differential between the compression chamber and the discharge chamber become substantially zero and the discharge valve closes the discharge port, high-pressure refrigerant gas is not sufficiently discharged and remains in a top-clearance region M that extends from a top dead center of a piston to the inside of the discharge port.
Since the remaining gas is high pressure, even if the volume of the top-clearance region M is relatively small, the remaining gas produces a large effect on the volume of suction refrigerant gas of low pressure, and therefore, compression efficiency of the compressor has not been enhanced. In addition, the increase of the resistance to discharge of the refrigerant gas when the discharge valve is opened also causes an increase of the over-compression in the compression chamber. As a result, the vibration in the compression chamber increases, and thereby causing vibration problem, noise problem and pulsation problem. In addition, due to the increase of compressive force, the load which is applied to parts inside the compressor is increased.
Although it is effective that the diameter of the discharge port is expanded to reduce the above-mentioned over-compression, since the discharge valve receives high-pressure discharge gas from the discharge chamber in a state that the discharge valve is closed in the suction stroke of the compressor, a part of the discharge valve which faces to the discharge port at least needs to sufficiently ensure its strength.
Therefore, since the expansion of the diameter of the discharge port increases compressive stress resulting from discharge pressure applied to the discharge valve, the thickness of the steel plate needs to be increased in order to ensure the strength of the discharge valve. However, as the thickness of the steel plate increase, the resistance to discharge upon opening the discharge port is further increased, thereby increasing the over-compression to the contrary. As a result, the reduction of the over-compression is not achieved. Besides, the expansion of the diameter of the discharge port increases the amount of high-pressure gas remaining in the top-clearance region M, thereby causing the reduction of the volumetric efficiency.
The present invention is directed to a discharge valve for use in a compressor, and the discharge valve includes a valve member and an arm member, which are integrally joined together, thereby casting various portions thereof in high-strength and lightweight materials that meets function and object of the various portions, and smoothly discharging a compressed refrigerant gas to a discharge chamber so as to reduce over-compression, and in addition, the discharge valve is capable of enhancing a compression efficiency of the compressor by reducing an amount of gas remaining in a top clearance region as much as possible.
The present invention provides the following features. A compressor includes a compression chamber, a discharge chamber, a discharge port forming member and a discharge valve. The compression chamber is formed in a cylinder block and in the compression chamber a refrigerant is compressed. The discharge chamber is formed in a cylinder housing which is fixed to the cylinder block. The refrigerant in the compression chamber is flowed into the discharge chamber The discharge port interconnects the compression chamber and the discharge chamber. The discharge valve opens and closes the discharge port, and has a valve member and an arm member. The valve member faces to the discharge port for opening and closing the discharge port. The arm member urges the valve member toward the discharge port The arm member and the valve member are integrally joined with each other.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments, together with the accompanying drawings, in which:
A compressor according to a first preferred embodiment of the present invention will now be described with reference to
The compressor shown in
A rear cylinder housing 6 (hereinafter merely referred to a rear housing 6) is placed to one end surface of the cylinder block 4 through a discharge port forming member 5 such as a valve plate while a front cylinder housing 7 is placed to the other end surface of the cylinder block 4. On the inner circumferential side of the rear housing 6 a suction chamber 6a and a discharge chamber 6b are defined.
The valve plate 5 has formed therethrough a suction port 5a and a discharge port 5b in a place facing to the cylinder bore 4a. The ports 5a, 5b interconnect the suction and discharge chambers 6a, 6b and a compression chamber 4b which is defined between the piston 3 in the cylinder bore 4a and the valve plate 5, respectively.
Referring to
The valve member 8a includes a board portion 81a and a pillar-shaped protruding portion 81b. The board portion 81a has a larger diameter than the discharge port 5b, and is capable of closely contacting the surface of the valve plate 5 functioning as a discharge port forming member in a predetermined area when the discharge valve 8 is in a closed state. The protruding portion 81b extends from the board portion 81a toward the discharge port 5b so as to be inserted in the discharge port 5b, and has a slightly smaller diameter than the discharge port 5b. The board portion 81a and the protruding portion 81b are integrally formed so as to be solid by a forging or an injection molding.
Since a high pressure Pd1 of a discharge gas in the discharge chamber 6b is applied to a part of the valve member 8a which faces to the discharge port 5b when the discharge valve 8 is in a closed state (or during a suction stroke), the thickness of the board portion 81a of the valve member 8a is formed at least so as to be relatively large in such an extent that the valve member 8a has a strength for enduring the high pressure Pd1 of the discharge gas. Alternatively, the valve member 8a uses a high-strength material.
The material of the valve member 8a allows a metallic material. The valve member 8a is, however, more preferably cast in a resin material by an injection molder to reduce its weight in such a manner that a pressure Pd2 of the refrigerant gas compressed in the compression chamber 4b smoothly flows into the discharge chamber 6b when the discharge valve 8 is in an opened state (or during a discharge stroke).
Even if the valve member 8a is made of metallic material, the arm member 8b needs to have an appropriate rigidity of spring so as to easily open and close the discharge port 5b and have a predetermined durability and, therefore, the arm member 8b is more preferably made of metallic material which is different from the metallic material of the valve member 8a.
The discharge valve 8 of the first embodiment is operated as shown in
First, when the piston 3 starts its suction stroke, the suction valve 11 opens and suction refrigerant gas is supplied from the suction chamber 6a into the compression chamber 4b in the cylinder bore 4a. At the same time, the valve member 8a of the discharge valve 8 closes the discharge port 5b. At this point, the pressure Pd1 of the discharge gas in the discharge chamber 6b is applied to the board portion 81a of the valve member 8a, and is received by a part where the board portion 81a and the valve plate 5 contact in the area, thereby closing the discharge port 5b in a state that the board portion 81a and the valve plate 5 closely contact each other.
Although during the suction stroke of the piston 3, stress load which the pressure Pd1 of the discharge gas supplies to a part of the board portion 81a of the valve member 8a which faces to the discharge port 5b, or a middle of the board portion 81a of the valve member 8a is increased, since the valve member 8a has large thickness, or the valve member 8a uses a high-strength member, the valve member 8a does not tend to cause its plastic deformation, thereby maintaining the entire flat state. Accordingly, the board portion 81a of the valve member 8a closely contacts the surface of the valve plate 5 utilizing the pressure Pd1 of the discharge gas.
When the piston 3 starts a compression stroke after having reached a bottom dead center, the suction valve 11 closes the suction port 5a to raise the pressure in the compression chamber 4b. When the piston 3 approaches a top dead center, the pressure Pd2 of the compression gas in the compression chamber 4b pushes the discharge valve 8 away to be opened, and the compression gas is flowed into the discharge chamber 6b.
At this point, the arm member 8b of the discharge valve 8 does not need to be thickened with the valve member 8a, and therefore, the arm member 8b tends to be easily bent by the pressure Pd2 of the compression gas. Thus, the compression gas is smoothly discharged to the discharge chamber 6b without increasing resistance to the discharge.
When the piston 3 reaches the top dead center and a large part of the compression gas in the compression chamber 4b is discharged to the discharge chamber 6b, and pressure differential between the discharge chamber 6b and the compression chamber 4b becomes slight, the valve member 8a closes the discharge port 5b by urging force of the arm member 8b. At this point, since the shape of the protruding portion 81b of the valve member 8a to be fitted into the discharge port 5b is shaped so as to closely resemble that of the discharge port 5b, and a gap between a circumferential wall of the protruding portion 81b and a wall surface of the discharge port 5b is narrowed, an amount of compression gas that remains in the gap becomes extremely small. That is, an amount of compression gas that remains in a top-clearance region M of the piston 3 becomes extremely small by reducing the volume of the top clearance region M of the piston 3. Therefore, deterioration of the volumetric efficiency due to the remaining compression gas upon starting the suction stroke is prevented.
The discharge valve of the compressor according to the present embodiment produces the following beneficial effects.
(1) A s well as the entire valve member 8a of the discharge valve 8, only a part of the valve member 8a which corresponds to the discharge port 5b is thickly cast in an independently high-strength and lightweight material irrelevantly to the thickness of the arm member 8b. Thus, even if the diameter of the discharge port 5b is expanded in order to reduce flow resistance of the pressure Pd2 of the compression gas toward the discharge chamber 6b and reduce an over-compression, sufficient strength and durability to the pressure Pd1 of the discharge gas which is applied to the valve member 8a during the suction stroke are obtained.
(2) Since the expansion of the diameter of the discharge port 5b is allowed, a flow of the compression gas of the pressure Pd2 to the discharge chamber 6b upon the compression stroke is smoothly achieved. In addition, since the shape of the protruding portion 81b of the valve member 8a is shaped so as to closely resemble that of the discharge port 5b, and a gap between the protruding portion 81b and the discharge port 5b is narrowed. Therefore, the amount of gas that remains in the top-clearance region M is reduced, and deterioration of the volumetric efficiency in compression chamber 4b upon the suction stroke is prevented.
(3) Since the arm member 8b and the valve member 8a are two individual members and are joined with each other, the material and thickness of the arm member 8b are individually selected irrelevantly to those of the valve member 8a. Therefore, the arm member 8b is capable of using a thin steel plate as a material, and the discharge valve 8 tends to be easily opened to the pressure of the compression gas upon the compression stroke. Thus, the discharge resistance of the discharge valve 8 is reduced and the over-compression is also reduced.
A compressor according to a second preferred embodiment of the present invention will now be described with reference to
A discharge valve 83 of the present embodiment is modified in material and shape of the arm member 8b of the discharge valve 8 of the above-mentioned compressor. Therefore, for convenience of explanation, the same numeric designations are used for parts in common with the first embodiment. An explanation of the configuration parts in common with the first embodiment is omitted, and the aforementioned explanation is incorporated.
As shown in
The arm member 83b has used a steel wire in place of the steel plate of the first embodiment. A basal end of the arm member 83b is fixed to the valve plate 5 by a pin, and an operational end thereof is such constructed that the distal end of the operational end is fixed to the side face or top face of the board portion 831 by an inserting means or a welding means in an embedded state, thereby urging the board portion 831 of the valve member 83a toward the side of the discharge port 5b so as to closely contact the surface of the valve plate 5. Thus, the discharge valve 83 opens and closes the discharge port 5b.
It is noted that the arm member 83b formed by this steel wire may include a plurality of steel wires without limitation of the single steel wire, and that the arm member 83 is preferably made of metallic material provided with resilient force and rigidity.
When the arm member 83b is constructed by an appropriate number of steel wires, the arm member 83b is formed only by cutting the wires upon manufacturing the arm member 83b, and therefore, the material is hardly wasted. The urging force of the arm member 83b is freely modified by selecting the thickness and the number of the steel wires
A compressor according to a third preferred embodiment of the present invention will now be described with reference to
A retainer 91 of the present embodiment functions so as to regulate a lift amount of the discharge valve 8 of the above-mentioned compressor and a fitting position thereof is modified. Therefore, for convenience of explanation, the same numeric designations are used for parts in common with the first embodiment. An explanation of the configuration parts in common with the first embodiment is omitted, and the aforementioned explanation is incorporated.
As shown in
Since the retainer 91 is integrally cast with the rear housing 6, a metallic retainer is not needed, thereby achieving reduction of the number of parts and time for assembly.
A compressor according to a fourth preferred embodiment of the present invention will now be described with reference to
A valve member 84a of the present embodiment functions such that a board portion 841 of the valve member 84a is easily distanced from the valve plate 5. Therefore, for convenience of explanation, the same numeric designations are used for parts in common with the first embodiment. An explanation of the configuration parts in common with the first embodiment is omitted, and the aforementioned explanation is incorporated.
Referring to
Since the board portion 841 has formed therein the annular groove 843, in the suction stroke the area of a portion of surface contact between the board portion 841 and the valve plate 5, which are stuck to each other by oil, is relatively small. In addition, when a discharge valve 84 opens the discharge port 5b in the compression stroke, the board portion 841 is easily distanced from the discharge port forming member 5. Therefore, in the first motion of the discharge valve 84, resistance to valve opening is relatively small, thereby hardly causing resistance to discharge. Further, the annular groove 843 is formed at the time when the board portion 841 of the valve member 84a is formed, and thereby simply forming the concentric annular groove 843.
The present invention is not limited to the above-mentioned first to fourth embodiments, but is variously modified within a range of the purpose of the invention. For example, the following alternative embodiments are also practiced.
In the first preferred embodiment, although two members of the valve member 8a and the arm member 8b are integrally joined with each other by a joining means such as welding, the two members may be integrally joined with each other, for example, by sandwiching an appropriate range of the outer peripheral surface of the board portion 81a of the valve member 8a with the distal ends of the arm member 8b up and down, or by press-fitting the board portion 81a of the valve member 8a to the distal end of the arm member 8b.
In the first preferred embodiment, although two members of the valve member 8a and the arm member 8b are formed by different materials such that the valve member 8a is made of resin material and the arm member 8b is made of metallic material, if the arm member 8b is at least made of the material having rigidity of spring having urging force in a direction closing the discharge port 5b, the two members may be made of the identical material.
In the valve member 8a of the discharge valve 8 of the first preferred embodiment, although the board portion 81a and the protruding portion 81b are integrally formed so as to be solid by a forging or an injection molding, the board portion 81a and the protruding portion 81b may be are combined with each other by a means such as press-fitting or screwing after being separately cast.
In the first preferred embodiment, although the discharge valve of the wobble plate type compressor is illustrated, a discharge valve of a single headed piston type compressor may be adopted without limiting to the discharge valve of the wobble plate type compressor. For example, a discharge valve of a rotary compressor such as vane compressor or scroll type compressor may be adopted.
In the second preferred embodiment, the arm member 8b of the discharge valve 8 is formed by a steel wire. The shape of the steel wire is not limited to a round bar, but may be a thin and rectangular steel plate.
In the third preferred embodiment, although the retainer 91 is integrally formed with the inner wall surface of the discharge chamber 6b of the rear housing 6, the retainer 91 may be attached to the inner wall surface of the discharge chamber 6b of the rear housing 6 by a screw so as to permit the attachment and remove.
Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein but may be modified.
| Number | Date | Country | Kind |
|---|---|---|---|
| P2003-319996 | Sep 2003 | JP | national |
