Discharge Valve Apparatus for Compressor

1. Field of the Invention

The present invention relates to a discharge valve apparatus for a compressor. The present discharge valve apparatus is suitable for a compressor for air-conditioning a vehicle, and it is especially suitable for a reciprocative type compressor therefor.

2. Description of the Related Art

As described in Japanese Unexamined Patent Publication (Kokai) No. 131985/1987, a reed valve type valve apparatus has been used as a valve apparatus for a reciprocative type compressor conventionally. For example, there has been known a reed valve type valve apparatus as illustrated in FIG. 17. In a discharge valve of the valve apparatus, there are provided a bore 100 in which a refrigerant is compressed, a discharge chamber 103, a valve plate 105 with a port 106 formed, a plate-spring-like reed valve 107, and a retainer 109. The lead valve 107 is assembled on the valve plate 105 together with the retainer 109.

In the conventional reed valve type valve apparatus, it is usually put into a closed state. When the differential pressures between the bore 100 and the discharge chamber 103 increase to a valve opening pressure or more, the reed valve 107 is designed so that it is separated from the valve plate 105 so as to open the port 106 and thereby the valve apparatus is opened. When the valve apparatus is opened, the refrigerant which has been compressed in the bore 100 is transferred through the port 106, and it is discharged into the discharge chamber 103. Here, the opening degree of the reed valve 107 is regulated by the retainer 109.

In the above-described conventional reed valve type valve apparatus, the reed valve 107 is adhered to the retainer 109 so closely that it hardly comes off the retainer 109 because of a lubricant oil contained in the refrigerant. As a result, when the discharge operation is turned into the suction operation, a discharge gas is flowed back in the reverse direction by the retardation of the reed valve 107 in the returning, thereby deteriorating the volumetric efficiency of the compressor.

It is an object of the present invention to provide a discharge valve apparatus for a compressor which inhibits the deterioration of the volumetric efficiency of the compressor satisfactorily. Here, the deterioration of the volumetric efficiency results from the retardation of the discharge reed valve in the returning.

A discharge valve apparatus for a compressor according to the present invention comprises:

a valve plate with a port opened;

a reed valve fixed on the valve plate, adapted for swingably opening and closing the port elastically, and including a substantially disk-shaped head portion and a neck portion constricted continuously from the head portion; and

a retainer fixed on the valve plate, and including an inclining surface adapted for regulating the opening degree of the reed valve, the inclining surface having an inclination varying around an area where the retainer is brought into contact with the head portion of the reed valve when the lead valve fully opens the port.

In the present discharge valve apparatus, the inclining surface is not necessarily a flat surface. The inclining surface may be constructed with a curved surface portion, or it may be constructed with a combination of a flat surface portion and a curved surface portion.

In addition, a discharge valve apparatus for a compressor according to the present invention comprises:

a valve plate with a port opened;

a reed valve fixed on the valve plate, adapted for swingably opening and closing the port elastically;

a retainer fixed on the valve plate; and

a contact projection disposed either on a surface of the retainer facing the reed valve or on a surface of the lead valve facing the retainer.

In this second form of the present discharge valve apparatus, the lead valve may be constructed so that it includes a substantially disk-shaped head portion and a neck portion constricted continuously from the head portion.

A more complete appreciation of the present invention and many of its advantages will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings and detailed specification, all of which forms a part of the disclosure:

FIG. 1 is a vertical cross sectional view of a swash plate type compressor in which a discharge valve apparatus of a First Preferred Embodiment according to the present invention is incorporated;

FIG. 2 is a plan view for illustrating a configuration of a discharge reed valve of the discharge valve apparatus of the First Preferred Embodiment;

FIG. 3 is a fragmentary cross sectional view of the discharge valve apparatus of the First Preferred Embodiment;

FIG. 4 is a fragmentary cross sectional view for illustrating an operation of the discharge valve of the First Preferred Embodiment in which the discharge reed valve is brought into contact with a retainer;

FIG. 5 is a fragmentary cross sectional view of a discharge valve apparatus of a Second Preferred Embodiment according to the present invention;

FIG. 6 is a fragmentary cross sectional view for illustrating an operation of the discharge valve apparatus of the Second Preferred Embodiment in which a discharge reed valve is brought into contact with a retainer;

FIG. 7 is a fragmentary cross sectional view of a discharge valve apparatus of a Third Preferred Embodiment according to the present invention;

FIG. 8 is a fragmentary cross sectional view for illustrating an operation of the discharge valve apparatus of the Third Preferred Embodiment in which a discharge reed valve is brought into contact with a retainer;

FIG. 9 is a fragmentary cross sectional view of a discharge valve apparatus of a Fourth Preferred Embodiment according to the present invention;

FIG. 10 is a fragmentary cross sectional view for illustrating an operation of the discharge valve apparatus of the Fourth Preferred Embodiment in which a discharge reed valve is brought into contact with a retainer;

FIG. 11 is an enlarged schematic cross sectional view of a curved surface portion of an inclining surface of a retainer in a modified version of the discharge valve apparatuses of the First and the Second Preferred Embodiments;

FIG. 12 is a fragmentary cross sectional view of another modified version of the discharge valve apparatuses of the First and the Second Preferred Embodiments;

FIG. 13 is a fragmentary cross sectional view of a still another modified version of the discharge valve apparatuses of the First and the Second Preferred Embodiments;

FIG. 14 is a fragmentary cross sectional view of a modified version of the discharge valve apparatus of the Fourth Preferred Embodiment;

FIG. 15 is a fragmentary cross sectional view of another modified version of the discharge valve apparatus of the Fourth Preferred Embodiment;

FIG. 16 is a plan view for illustrating a construction of a discharge reed valve in a still another modified version of the discharge valve apparatus of the Fourth Preferred Embodiment; and

FIG. 17 is a fragmentary cross sectional view of the conventional reed valve type valve apparatus.

As having been described previously, in the first form of discharge valve apparatus according to the present invention, the reed valve is swung by a discharge pressure so as to open the port, and it is brought into contact with the inclining surface of the retainer during the discharge operation.

In the first form of discharge valve apparatus according to the present invention, the inclination of the inclining surface is varied around an area where the retainer is brought into contact with the head portion of the reed valve when the lead valve fully opens the port. Because the head portion of the reed valve has a large flexural rigidity, it cannot follow the inclining surface of the retainer whose inclination is varied, and accordingly there arises a clearance between the head portion of the reed valve and the inclining surface of the retainer when the reed valve is brought into contact with the retainer. Therefore, the contacting area between the reed valve and the retainer is reduced by the clearance, and accordingly the reed valve is more likely to come off the retainer.

Further, even if the head portion of the reed valve has a small flexural rigidity, or even if the inclination of the inclining surface is varied slightly, the head portion may undergo an elastic deformation so that it follows the inclining surface whose inclination is varied, and so that it may be adhered to the inclining surface of the retainer without forming the clearance. However, if such is the case, the reed valve is still likely to come off the retainer because it exhibits a large elastic recovery force which results from the head portion having the large flexural rigidity and undergoing the large elastic deformation.

Moreover, in the second form of the discharge valve apparatus according to the present invention, the reed valve is brought into contact with the retainer by way of the contact projection which is disposed either on the retainer surface or on the reed valve surface. Hence, there also arises a clearance between the reed valve and the retainer. Therefore, the contacting area between the reed valve and the retainer is reduced, and accordingly the reed valve is more likely to come off the retainer.

As having been described so far, in the discharge valve apparatus for a compressor according to the present invention, the reed valve can be effectively inhibited from adhering on the retainer through the lubricant contained in the refrigerant and from being less likely to come off the retainer. Hence, with the discharge valve apparatus according to the present invention, it is possible to successfully inhibit the volumetric efficiency deterioration which results from the retardation of the reed valve in the returning.

Having generally described the present invention, a further understanding can be obtained by reference to the specific preferred embodiments which are provided herein for purposes of illustration only and are not intended to limit the scope of the appended claims.

The discharge valve apparatus of the First Preferred Embodiment according to the present invention will be hereinafter described with reference to FIGS. 1 through 4. The discharge valve apparatus is incorporated in a swash plate type compressor.

As illustrated in FIG. 1, in the swash plate type compressor, a pair of cylinder blocks 1a and 1b is disposed oppositely at the front and rear, and accordingly a swash plate chamber 3 is formed at the connection between the cylinder blocks 1a and 1b. The swash plate chamber 3 is communicated with a return refrigerant suction port 2. At a front end of the cylinder block 1a and at a rear end of the cylinder block 1b, the cylinder blocks 1a and 1b are enclosed with a front housing 6 and a rear housing 7 by way of valve plates 4 and 5, respectively. In the front housing 6 and the rear housing 7, there are formed suction chambers 8 and 9 on their radially outer side, and there are further formed discharge chambers 10 and 11 on their radially inner side. The suction chambers 8 and 9 are communicated with the swash plate chamber 3 through suction passages 22 and 23. The front discharge chamber 10 is communicated with the rear discharge chamber 11 through a discharge passage (not shown), and the rear discharge chamber 11 is communicated with a discharge port (not shown).

A driving shaft 12 is inserted into a common central axial bore formed between the cylinder blocks 1a and 1b, and it is engaged with the cylinder blocks 1a and 1b by way of radial bearings. Further, the driving shaft 12 is disposed so as to penetrate through the front valve plate 4, and it is supported detachably by the front housing 6. Furthermore, the driving shaft 12 is provided with a swash plate 13. The swash plate 13 is fixed around the driving shaft 12 so as to be rotatable in the swash plate chamber 3, and it is supported detachably by the cylinder blocks 1a and 1b by way of thrust bearings. Moreover, there are formed a plural pair of bores 14 and 14 at the front and rear in the cylinder blocks 1a and 1b. The bores 14 are disposed in parallel around the driving shaft 12. Double-headed pistons 16 are inserted into and engaged with the bores 14 reciprocatively, and they are anchored at the periphery of the swash plate 13 by way of a pair of shoes 15 and 15.

In the front valve plate 4, there are formed a suction port 17 and a discharge port 18. The suction port 17 communicates the front suction chamber 8 with the bore 14, and the discharge port 18 communicates the front discharge chamber 10 with the bore 14. Further, a suction reed valve 19 is disposed on the front valve plate 4 on the front cylinder block 1a side, and it is assembled thereto so as to open and close the suction port 17 elastically and swingably. Furthermore, a discharge reed valve 20 is disposed on the front valve plate 4 on the front housing 6 side, it is assembled thereto together with a retainer 21 so as to open and close the discharge port 18 elastically and swingably. Moreover, as illustrated in FIG. 3, the opening degree of the discharge reed valve 20 is regulated by an inclining surface 21a of the retainer 21 which is assembled to the front valve plate 4 together with the discharge reed valve 20. The inclining surface 21a of the retainer 21 is disposed so as to incline by a predetermined angle with respect to the front valve plate 4. On the other hand, the opening degree of the suction reed valve 19 is regulated by a cut-off groove (not shown) which is carved adjacent to an opening of the bore 14 at the end of the front cylinder block 1a.

Likewise, in the rear valve plate 5, there are formed a suction port 17 and a discharge port 18. The suction port 17 communicates the rear suction chamber 9 with the bore 14, and the discharge port 18 communicates the rear discharge chamber 11 with the bore 14. Further, a suction reed valve 19 is disposed on the rear valve plate 5 on the rear cylinder block 1b side, and it is assembled thereto so as to open and close the suction port 17 elastically and swingably. Furthermore, a discharge reed valve 20 is disposed on the rear valve plate 5 on the rear housing 7 side, it is assembled thereto together with a retainer 21 so as to open and close the discharge port 18 elastically and swingably. Moreover, as can be understood from FIG. 3, the opening degree of the discharge reed valve 20 is regulated by an inclining surface 21a of the retainer 21 which is assembled to the rear valve plate 5 together with the discharge reed valve 20. The inclining surface 21a of the retainer 21 is disposed so as to incline by a predetermined angle with respect to the rear valve plate 5. On the other hand, the opening degree of the suction reed valve 19 is regulated by a cut-off groove (not shown) which is carved adjacent to an opening of the bore 14 at the end of the rear cylinder block 1b.

Thus, the constructions around the front and the rear valve plates 4 and 5 are identical with each other substantially. Accordingly, only the construction around the front valve plate 4 will be hereinafter described in detail.

As illustrated in FIG. 2, the discharge reed valve 20 includes a substantially disk-shaped head portion 20a which has a large flexural rigidity, and a neck portion 20b which has a small flexural rigidity and which is constricted continuously from the head portion 20a. The discharge reed valve 20 opens and closes the discharge port 18 with the head portion 20a.

As illustrated in FIG. 3, the inclining surface 21a of the retainer 21 includes two portions, i.e., a curved surface portion 21b on the left-hand side in FIG. 3 with respect to the center line "C" of the discharge port 18, and a flat surface portion 21c on the right-hand side in FIG. 3 with respect thereto. That is to say, the curved surface portion 21b faces a portion of the discharge reed valve 20, portion which extends from a substantial center of the head portion 20a to the neck portion 20b. An inclination of the inclining surface 21a is varied around an area where the retainer 21 is brought into contact with the head portion 20a of the discharge reed valve 20 when the discharge reed valve 20 fully opens the port 18.

Also in the swash plate type compressor equipped with the thus constructed discharge valve apparatus of First Preferred Embodiment, a return refrigerant is introduced into the swash plate chamber 3 from a refrigerant circuit (not shown) by way of the suction port 2. The return refrigerant is further introduced into the suction chambers 8 and 9 through the suction passages 22 and 23. As a result, the rotation of the driving shaft 12 moves the pistons 16 reciprocatively in the bores 14 by way of the swash plate 13.

In the meantime, the suction reed valves 19 are separated from the valve plates 4 and 5 so as to open the suction ports 17 by the pressure decrements in the bores 14, and accordingly the return refrigerant in the suction chambers 8 and 9 is sucked through the suction ports 17 into the bores 14 whose volumes are increasing. At the same time, the discharge reed valves 20 are seated on peripheries of the discharge ports 18 in the valve plates 4 and 5 so as to close the communication between the bores 14 and the discharge chambers 10 and 11 by the pressure decrements in the bores 14 and by the high pressures in the discharge chambers 10 and 11. Thereafter, the pressures in the bores 14 increase so as to open the discharge reed valves 20 assembled to the valve plates 4 and 5 because of the reciprocative movement of the pistons 16, and accordingly the compressed refrigerant in the bores 14 whose volumes are decreasing is discharged through the discharge ports 18 to the discharge chambers 10 and 11. At the same time, the suction reed valves 19 are seated on peripheries of the discharge ports 17 so as to close the communication between the bores 14 and the suction chambers 8 and 9 by the pressure increments in the bores 14 and by the low pressures in the discharge chambers 8 and 9.

Thus, in the compressed refrigerant in the front discharge chamber 10 is collected in the discharge port 11 via a discharge passage (not shown), and the compressed refrigerant in the rear discharge chamber 11 is circulated again to the refrigerating circuit through a discharge port (not shown).

In the discharge valve apparatus of the First Preferred Embodiment, the retainer 21 includes the curved surface portion 21b which faces the portion of the discharge reed valve 20 extending from the substantial center of the head portion 20a to the neck portion 2Ob. The discharge reed valve 20 includes the neck portion 20b which has the small flexural rigidity and the head portion 20a which has the large flexural rigidity.

Thus, in the discharge operation, the discharge reed valve 20 is brought into contact with the inclining surface 21b of the retainer 21, during which the neck portion 20b is deformed greatly elastically but the head portion 20a is hardly deformed elastically or it is deformed slightly so that its flat surface is maintained. In the meantime, as illustrated in FIG. 4, the flat surface portion 21c of the retainer 21 is adhered to the portion of the discharge reed valve 20 which extends from the substantially center of the head portion 20a to the free end thereof, and accordingly there arises a clearance "A" between the curved surface portion 21b of the retainer 21 and the portion of the discharge reed valve 20 which extends from the substantially center of the head portion 20a to the neck portion 21b. Therefore, the contacting area between the discharge reed valve 20 and the retainer 21 is reduced by the existence of the clearance "A." Even if the head portion 20a having the large flexural rigidity is deformed elastically, a large elastic recovery force arises and acts on the head portion 20a. As a result, the discharge reed valve 20 can be inhibited effectively from adhering on the retainer 21 through the lubricant contained in the refrigerant.

Thus, in accordance with the discharge valve apparatus of the First Preferred Embodiment, the volumetric efficiency deterioration, resulting from the retardation of the discharge reed valve 20 in the returning, can be inhibited effectively. In addition, even if a larger discharge pressure acts on the reed valve 20, the entire surface of the head portion 20a is deformed elastically considerably so as to follow the curved surface portion 21b of the retainer 21, and the discharge reed valve 20 is adhered to the retainer 21 without forming the clearance "A," a much larger elastic recovery force arises and acts on the head portion 20a so that the discharge reed valve 20 can be promptly separated from the retainer 21.

As illustrated in FIGS. 5 and 6, the discharge valve apparatus of the Second Preferred Embodiment includes a retainer 21, and the retainer 21 includes a curved surface portion 21b and a flat surface portion 21c which are disposed in a positional relationship opposite to that of the discharge valve apparatus of the First Preferred Embodiment. Namely, in the discharge valve apparatus of the Second Preferred Embodiment, the retainer 21 includes the curved surface portion 21b on the right-hand side in FIG. 5 with respect to the center line "C" of a discharge port 18, and the flat surface portion 21c on the left-side in FIG. 5 with respect thereto. Specifically speaking, the curved surface portion 21b faces a portion of a discharge reed valve 20, portion which extends from a substantial center of a head portion 20a of the discharge reed valve 20 to a free end thereof.

Thus, in the discharge operation, the discharge reed valve 20 of the discharge valve apparatus of the Second Preferred Embodiment operates as follows: The neck portion 20b having a small flexural rigidity is deformed elastically greatly by the discharge pressure, and the head portion 20a having a large flexure rigidity is hardly deformed but the free end of the head portion 20a is deformed slightly by the discharge pressure. Accordingly, as illustrated in FIG. 6, the flat surface portion 21c of the retainer 21 is adhered to the portion of the discharge reed valve 20 extending from the substantial center of the head portion 20a to the neck portion 2Ob, and there arises a clearance "A" between the curved surface portion 21b of the retainer 21 and the portion of the discharge reed valve 20 extending from the substantial center of head portion 20a to the free end. Therefore, the contacting area between the discharge reed valve 20 and the retainer 21 is reduced in a manner similar to that of the discharge valve apparatus of the First Preferred Embodiment. Even if the head portion 20a having the large flexural rigidity is deformed elastically, a large elastic recovery force arises and acts on the head portion 2Oa. As a result, the discharge reed valve 20 can be inhibited effectively from adhering on the retainer 21 through the lubricant contained in the refrigerant.

Thus, also in accordance with the discharge valve apparatus of the Second Preferred Embodiment, the volumetric efficiency deterioration, resulting from the retardation of the discharge reed valve 20 in the returning, can be inhibited effectively. In addition, even if a larger discharge pressure acts on the reed valve 20, the entire surface of the head portion 20a is deformed considerably so as to follow the curved surface portion 21b of the retainer 21, and the discharge reed valve 20 is adhered to the retainer 21 without forming the clearance "A," a much larger elastic recovery force arises and acts on the head portion 20a so that the discharge reed valve 20 can be promptly separated from the retainer 21.

In the valve apparatuses of the First and the Second Preferred Embodiments, the curved surface portions 21b of the retainers 21 are described so that they have predetermined constant radii of curvature. However, the present invention is not limited thereto.

For example, the curved surface portion 21b of the retainer 21 may have a continuously varying radius of curvature as schematically illustrated in FIG. 11.

Further, the retainer 21 may be free from the flat surface portion 21c, but it may include the curved surface portion 21b entirely as illustrated in FIG. 12.

Furthermore, the curved surface portion 21b of the retainer 21 may have a concave cross section whose opening is opened to the discharge reed valve 20 side as illustrated in FIG. 13. In other words, the curved surface portions 21b are protruded toward the discharge reed valves 20a and the front valve plates 4 in the discharge valve apparatuses of the First and the Second Preferred Embodiments, but the curved surface 21b may be protruded toward the discharge chamber 10 in this modified version of the discharge valve apparatuses of the First and the Second Preferred Embodiments.

As illustrated in FIGS. 7 and 8, the discharge valve apparatus of the Third Preferred Embodiment comprises a retainer 21 including an inclining surface 21a. The inclining surface 21a includes two flat surface portions having different inclinations with each other. Namely, the inclining surface 21a varies the inclination at the position where it intersects the center line of a discharge port 18. Specifically speaking, the inclining surface 21 includes a flat surface 21c which faces a portion of a discharge reed valve 20 extending from the substantial center of a head portion 20a thereof to a neck portion 20b thereof, and a flat surface portion 21d which faces a portion of a discharge reed valve 20 extending from the substantial center of the head portion 20a to a free end thereof and which has an inclination larger than the flat surface portion 21c does.

It is apparent that the discharge valve apparatus of the Third Preferred Embodiment operates and provides advantageous effects in a manner similar to those of the discharge valve apparatus of the Second Preferred Embodiment. Hence, the operations and the advantageous effects will not be described herein.

As illustrated in FIGS. 9 and 10, the discharge valve apparatus of the Fourth Preferred Embodiment comprises a retainer 21 which includes an inclining surface 21a provided with a contact projection 21e. The contact projection 21e is disposed at a portion of the retainer 21 which faces a head portion 20a of a discharge reed valve 20, and it is formed so as to extend linearly in the width-wise direction (or depth-wise direction in FIG. 14) of the retainer 21. Other than the contact projection 21e, the inclining surface 21a includes a flat surface 21c.

In the discharge valve apparatus of the Fourth Preferred Embodiment, the contact projection 21e works to provide a clearance "A" between the head portion 20a of the discharge reed valve 20 and the retainer 21 as illustrated in FIG. 10, and the contacting area therebetween decreases accordingly. As a result, also in the discharge valve apparatus of the Fourth Preferred Embodiment, the discharge reed valve 20 is likely to come off the retainer 21.

As illustrated in FIG. 14, instead of the retainer 21 including the inclining surface 21a provided with the contact projection 21e, the discharge valve apparatus of the Fourth Preferred Embodiment may comprise a discharge reed valve 20 which includes a head portion 20a provided with a contact projection 20c. The contact projection 20c is disposed adjacent to a free end of the head portion 20a , and it is formed so as to extend linearly in parallel with the width-wise direction (or depth-wise direction in FIG. 14) of the retainer 21.

In addition, the contact projection 21e or 20c is not restricted in its shape, size and position. For instance, a plurality of minute projections 21e may be provided on the entire surface of the retainer 21 as illustrated in FIG. 15, or a plurality of minute projections 20c may be provided on the entire surface of the head portion 20a of the discharge reed valve 20 as illustrated in FIG. 16.

It is apparent that these modified versions of the discharge valve apparatus of the Fourth Preferred Embodiment operate and provide advantageous effects in a manner similar to those of the discharge valve apparatus of the Fourth Preferred Embodiment. Hence, the operations and the advantageous effects will not be described herein.

Having now fully described the present invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the present invention as set forth herein including the appended claims.