Hermetic compressor   

The present invention relates to a hermetic compressor used for a fridge-freezer and the like.

Japanese Patent Laid-Open Application No. 2002-195160 discloses an example for a conventional hermetic compressor (hereinafter referred to as “compressor”). That is, a compressor equipped with a discharge valve device for reducing noise during operation and a loss when opening/closing the discharge reed, to improve energy efficiency.

Hereinafter, a description is made for this conventional compressor, referring to FIGS. 7 through 10. FIG. 7 is a sectional view of the conventional compressor; FIG. 8, a plan view of the conventional compressor; FIG. 9, a side sectional view of the discharge valve device of the conventional compressor; and FIG. 10, an exploded view of the discharge valve device of the conventional compressor.

Hermetic container(hereinafter referred to as “container”) 1 is equipped with discharge pipe 2 and suction pipe 3, both connected to a cooling system (not illustrated); and houses electromotive element 7 that stores oil 4 in its base part and also is composed of stator 5 and rotor 6, and compression mechanism 8 rotarily driven by electromotive element 7. The inside of container 1 is filled with refrigerant 9.

Next, a description is made for the principal makeup of compression mechanism 8.

Cylinder 10 is equipped with substantially cylindrical compression chamber 11 and bearing section 12. Valve plate 13 is equipped with discharge valve device 14 on the side opposite to the side contacting cylinder 10, out of the two sides of valve plate 13, to block compression chamber 11. Head 15 covers valve plate 13. Suction muffler 16 opens its one end to the inside of container 1, and the other end of muffler 16 communicates with the inside of compression chamber 11. Crankshaft 17 has main shaft 18 and eccentric section 19, and is pivotally supported by bearing section 12 of the cylinder, with rotor 6 press-fitted and fixed. Piston 20 is inserted into compression chamber 11 reciprocably slidably and connected to eccentric section 19 with connecting rod 21.

Next, a description is made for discharge valve device 14 provided in compression mechanism 8.

Valve plate 13 has recess 22 on the side opposite to cylinder 10. Recess 22 is equipped with discharge hole 23 communicating with cylinder 10, valve sheet 24 formed so as to surround discharge hole 23, and pedestal 25 formed on the substantially same plane as valve sheet 24. Discharge reed 26, spring reed 27, and stopper 28 are fixed to pedestal 25 with rivet 29 in sequence.

Discharge reed 26, made of a lingulate a leaf-spring member, is equipped with discharge reed holding part 30 fixed to pedestal 25, and opening/closing part 31 for opening/closing valve sheet 24.

Spring reed 27, made of a lingulate a leaf-spring member, is equipped with spring reed holding part 32 fixed to pedestal 25, and movable part 33, and has bending part 34 in the proximity of the basal portion of opening/closing part 31 of discharge reed 26.

Stopper 28 is equipped with stopper holding part 35 fixed to pedestal 25 and regulation part 36 for regulating the action of discharge reed 26. The side of regulation part 36 of stopper 28 is shaped substantially parallel to the plane including valve sheet 24 and pedestal 25. Movable part 33 of spring reed 27 is adjusted by the bending angle of bending part 34 so that given clearance is formed between movable part 33, and both opening/closing part 31 of discharge reed 26 and regulation part 36 of stopper 28.

Hereinafter, a description is made for the action of the compressor composed as mentioned above.

Supplying electromotive element 7 with electricity causes rotor 6 to rotate and crankshaft 17 to be rotarily driven. In this case, as a result that an eccentric rotational movement of eccentric section 19 transmits to piston 20 through connecting rod 21, piston 20 reciprocably moves in compression chamber 11.

As piston 20 reciprocably moves, refrigerant 9 in container 1 is inhaled from suction muffler 16 to compression chamber 11, and also low-pressure refrigerant 9 flows from a cooling system (not illustrated) through suction pipe 3 into container 1. Refrigerant 9 inhaled into compression chamber 11 is compressed and discharged through discharge valve device 14 of valve plate 13 into head 15. Further, a high-pressure gas discharged into head 15 is discharged through discharge pipe 2 to the cooling system (not illustrated).

However, in the above-mentioned conventional makeup, the following phenomenon is occasionally observed. That is, a state of low freezing capacity remains for a relatively long time as compared to its original freezing capacity, immediately after the compressor starts up. This mechanism can be described as hereinafter by means of behavior analysis of discharge reed 26 and spring reed 27.

When starting a compressor in which this phenomenon of low freezing capacity tends to occur, oil 4 returns along with refrigerant 9 from the refrigeration cycle (not illustrated). A large amount of oil 4 results in intervening in discharge reed 26 and spring reed 27, because oil 4, as well as refrigerant 9, is compressed and discharged.

Further, a compressor generally inhales at a high pressure when starting up, and compresses and discharges refrigerant 9 with relatively high density, until the inside of container 1 is decompressed. Consequently, a heavy load is imposed on opening/closing part 31 of discharge reed. Meanwhile, the displacement in opening/closing part 31 of discharge reed 26 is regulated by regulation part 36 of stopper 28. As a result, opening/closing part 31 of discharge reed 26 is strongly pressed due to high-density refrigerant 9 against movable part 33 of spring reed 27 allocated between opening/closing part 31 and regulation part 36 of stopper 28.

Then, a large pressing load as mentioned above causes adsorption of opening/closing part 31 of discharge reed 26 and movable part 33 of spring reed 27, due to oil 4. In this way, discharge reed 26 and spring reed 27 are integrated and perform opening/closing operations as if they are one thick discharge reed.

Here, movable part 33 of spring reed 27 is bent at bending part 34 in a direction in which discharge reed 26 opens, and as a result, the spring force acts in the direction opposite to that in which discharge reed 26 closes. In this way, discharge reed 26 is pulled in the direction in which it opens, thus delaying timing for closing.

Consequently, the time while discharge reed 26 is open becomes long, after piston 20 passes the top dead center and proceeds to a suction stroke in compression chamber 11. In the meantime, a high-pressure refrigerant flows back in compression chamber 11, and thus the substantial volume displaced by the piston decreases, causing a phenomenon of low freezing capacity to occur.

While this phenomenon of low-freezing capacity is occurring, the compressor decreases its efficiently and increases its power consumption, and at the same time, causes a problem in which a freezing machine loaded with this compressor is deadened in its freezing capacity.

The present invention provides a hermetic compressor in which the side of the spring reed is shaped in a substantially crank-like form, and clearance is formed between the spring reed, and both the discharge reed and stopper, at the position corresponding to the discharge reed opening/closing part.

This makeup prevents adsorption of the discharge reed and spring reed due to oil intervening between them and a delay in closing the discharge reed, thus providing a highly efficient hermetic compressor.

FIG. 1 is a sectional view of a compressor according to the embodiment of the present invention.

FIG. 2 is a plan view of a compressor according to the embodiment of the present invention.

FIG. 3 is a side sectional view of a discharge valve device when closed, according to the embodiment of the present invention.

FIG. 4 is an exploded view of a discharge valve device according to the embodiment of the present invention.

FIG. 5 is a side sectional view of a discharge valve device when open, according to the embodiment of the present invention.

FIG. 6 is a diagram for the spring characteristic of a discharge valve device according to the embodiment of the present invention.

FIG. 7 is a sectional view of a conventional compressor.

FIG. 8 is a plan view of a conventional compressor.

FIG. 9 is a side sectional view of a discharge valve device of a conventional compressor.

FIG. 10 is an exploded view of a discharge valve device of a conventional compressor.

The present invention relates to a compressor including a compression mechanism; an electromotive element for rotarily driving the compression mechanism; and a container for housing the compression mechanism and the electromotive element, and for storing oil. The compression mechanism has a piston, a cylinder in which the piston reciprocably moves, and a valve plate that seals an open end of the cylinder and also is equipped with a discharge valve device on the side opposite to the cylinder. The discharge valve device is formed on the valve plate formed with a discharge hole communicating with the inside of the cylinder, a valve sheet provided outside the discharge hole, and a pedestal formed on the substantially same plane as the valve sheet. In the discharge valve device, a discharge reed, made of a leaf-spring member, is equipped with an opening/closing part for opening/closing the discharge hole, and a discharge reed holding part fixed to the pedestal; a spring reed, made of a leaf-spring member, equipped with a movable part, and a spring reed holding part fixed to the pedestal; and a stopper equipped with a regulation part, and a stopper holding part fixed to the pedestal, are fixed on the pedestal in this sequence. Further, the side of the spring reed is shaped in a substantially crank-like form, and clearance is formed between the spring reed, and both the discharge reed and stopper, at the position corresponding to the discharge reed opening/closing part. In this way, oil intervenes between the discharge reed and spring reed when starting up, for example, and thus a space is formed between the movable part of the spring reed and the opening/closing part of the discharge reed, even if an excessive load is imposed on the discharge reed. This makeup prevents a delay in closing the discharge reed, because both the movable part and the opening/closing part are not adsorbed each other, thus providing a compressor that suppresses a decrease in its freezing capacity and has high energy efficiency.

Further, in the compressor of the present invention, the bending part of discharge reed is bent at the side close to opening/closing part, to the side of the valve sheet. In this way, a force to press the opening/closing part of the discharge reed against the valve sheet is stably available, and thus sealability between the opening/closing part of the discharge reed and valve sheet is improved, further improving energy efficiency.

Meanwhile, in the compressor of the present invention, the discharge reed bending part is to be positioned at an undercut part formed between the valve sheet and pedestal. In this way, the tilt amount of the discharge reed can be stabilized, and thus a force to press the opening/closing part of the discharge reed against the valve sheet is stably available. Consequently, sealability between the opening/closing part of the discharge reed and valve sheet is improved, further improving energy efficiency.

In addition, in the compressor of the present invention, a touch part is formed on the regulation part of the stopper, that is bent to the side of the spring reed. In this way, the method of supporting the movable of the spring reed changes from “cantilever” to “center impeller” by the time when displacement of the discharge reed is regulated by the regulation part of the stopper, and thus the spring force by the movable part of the spring reed is available more effectively in the meantime. This allows setting stepwise a required spring characteristic. Consequently, an optimum spring characteristic is available in the regions of both low circulation amount and high circulation amount, further improving energy efficiency.

Hereinafter, a detailed description is made for the embodiment of the compressor according to the present invention, referring to FIGS. 1 through 6. Here, the drawings are schematic and do not correctly illustrate each positional relationship dimensionally.

Container 101 is equipped with discharge pipe 102 and suction pipe 103, both connected to a cooling system (not illustrated); stores oil 104 in its base part; houses electromotive element 107 including stator 105 rotor 106, and compression mechanism 108 rotarily driven by this electromotive element 107. The inside of container 101 is filled with refrigerant 109.

Refrigerant 109 is desirably irrelevant to CFCs corresponding to environmental issues of recent years, and a refrigerant such as R134a and R600a is used.

Next, a description is made for the principal makeup of compression mechanism 108.

Cylinder 110 is equipped with substantially cylindrical compression chamber 111 and bearing section 112. Valve plate 113 is equipped with discharge valve device 114 on the side opposite to the side contacting cylinder 110, out of the two sides of valve plate 113, to block compression chamber 111. Head 115 covers valve plate 113. Suction muffler 116 opens its one end to the inside of container 101, and the other end of the muffler communicates with the inside of compression chamber 111. Crankshaft 117 has main shaft 118 and eccentric section 119, is pivotally supported by bearing section 112 of cylinder 110, and is press-fitted into stator 105 and fixed. Piston 120 is inserted into compression chamber 111 reciprocably slidably and connected to eccentric section 119 with connecting rod 21.

Next, a description is made for discharge valve device 114 provided in compression mechanism 108. Valve plate 113 has recess 122 that is provided with discharge hole 123 communicating with cylinder 110, valve sheet 124 formed so as to surround discharge hole 123, and pedestal 125 formed on the substantially same plane as valve sheet 124.

Discharge reed 126, spring reed 127, and stopper 128 are fixed to pedestal 125 with rivet 129 in sequence. Discharge reed 126, made of a lingulate a leaf-spring member, is equipped with discharge reed holding part 130 fixed to pedestal 125, and opening/closing part 131 for opening/closing valve sheet 124.

Spring reed 127, made of a lingulate a leaf-spring member, is equipped with spring reed holding part 132 fixed to pedestal 125, and movable part 133, and is shaped in a substantially crank-like form by means of first bending part 134 and second bending part 135 provided on movable part 133.

Further, first bending part 134 is positioned in the proximity of the basal portion of movable part 133 of spring reed 127, and second bending part 135 is positioned at movable part 133 of spring reed 127.

Stopper 128 is equipped with stopper holding part 136 fixed to pedestal 125, and regulation part 137 for regulating the action of discharge reed 126. The side of regulation part 137 is shaped substantially parallel to the plane including valve sheet 124 and pedestal 125.

The bending angles of respective bending parts are set so that movable part 133 of spring reed 127 has clearance between the movable part, and both opening/closing part 131 of discharge reed 126 and regulation part 137 of stopper 128.

Discharge reed bending part 138 of discharge reed 126 is bent at the side close to opening/closing part 131 to the side of valve sheet 124.

Undercut part 139 that is deeper than pedestal 125 is formed between valve sheet 124 and pedestal 125, and discharge reed bending part 138 is positioned in undercut part 139.

Stopper 128 forms touch part 140 bent to the side of spring reed 127, at regulation part 137 of stopper 128, and the side of touch part 140 is shaped substantially parallel to the plane including valve sheet 124 and pedestal 125.

A description is made for the operations and actions of the compressor composed as mentioned above.

Supplying electromotive element 107 with electricity causes rotor 106 to rotate and crankshaft 117 to be rotarily driven. In this case, as a result that an eccentric rotational movement of eccentric section 119 transmits to piston 120 through connecting rod 121, piston 120 reciprocably moves in compression chamber 111.

As piston 120 reciprocably moves, refrigerant 109 in container 101 is inhaled from suction muffler 116 into compression chamber 111, and also low-pressure refrigerant 109 flows from a cooling system (not illustrated) through suction pipe 103 into container 101.

Refrigerant 109 inhaled into compression chamber 111 is compressed and discharged through discharge valve device 114 of valve plate 113 into head 116. Further, a high-pressure gas discharged into head 115 is discharged through discharge pipe 102 to the cooling system (not illustrated).

Here, when starting up the compressor, oil 104 returns along with refrigerant 109 from the refrigeration cycle (not illustrated). A large amount of oil 4 results in intervening between discharge reed 126 and spring reed 127, because oil 104, as well as refrigerant 109, is compressed and discharged.

Further, a compressor generally inhales at a high pressure when starting up, and compresses and discharges refrigerant 109 with relatively high density, until the inside of container 1 is decompressed. Consequently, a heavy load is imposed on opening/closing part 131 of discharge reed 126.

Meanwhile, the displacement in opening/closing part 131 of discharge reed 126 is regulated by regulation part 137 of stopper 128. Consequently, opening/closing part 131 of discharge reed 126 is strongly pressed due to high-density refrigerant 109 against movable part 133 of spring reed 127 allocated between opening/closing part 131 and regulation part 137 of stopper 128.

This causes adsorption of opening/closing part 131 of discharge reed 126 and movable part 133 of spring reed 127 due to oil 104.

However, the first and second bending parts are formed in movable part 133 of spring reed 127, and thus space 141 is formed between opening/closing part 131 of discharge reed 126 and movable part 133 of spring reed 127, as shown in FIG. 5. Accordingly, movable part 133 of spring reed 127 is immediately detached from opening/closing part 131 of discharge reed 126. In other words, the adsorption does not continue, and spring reed 127 does not integrally operate with discharge reed 126, thus preventing a delay in closing.

Consequently, a phenomenon can be prevented of low-freezing capacity caused by flowing back of a high-pressure refrigerant into compression chamber 111, thus providing a compressor with high energy efficiency.

Meanwhile, discharge reed bending part 138 of discharge reed 126 is bent at the side close to opening/closing part 131, to the side of valve sheet 124, and thus a force occurs to press opening/closing part 131 of discharge reed 126 against valve sheet 124.

This force prevents opening/closing part 131 of discharge reed 126 from floating over valve sheet 124, to keep further favorable sealability, thus providing a compressor with high energy efficiency.

In addition, undercut part 139 deeper than pedestal 125 is formed between valve sheet 124 and pedestal 125, and discharge reed bending part 138 is positioned at undercut part 139, thus preventing undercut part 139 from being pressed by a spring force of pedestal 125 and spring reed 127. Consequently, the tilt amount of opening/closing part 131 of discharge reed 126 can be stabilized, thus providing a compressor with stable freezing capacity.

Further, according to this embodiment, regulation part 137 of stopper 128 is formed with touch part 140 that is bent to the side of spring reed 127, and thus discharge reed 126 can further displaces while spring reed 127 touches touch part 140.

That is to say, the spring characteristic of discharge reed 126 has two inflection points as shown in FIG. 6, and thus three steps of spring forces are available.

In FIG. 6, the horizontal axis shows displacement; and the vertical axis, spring force. “A” and “B” show the first and second inflection points respectively. Here, the first inflection point is a point at which opening/closing part 131 of discharge reed 126 touches movable part 133 of spring reed 127, and from then on to the second inflection point, a resultant spring force is available of opening/closing part 131 of discharge reed 126 and movable part 133 of spring reed 127.

The second inflection point is a point at which movable part 133 of spring reed 127 touches touch part 140 of stopper 128, and from there on, the spring force further increases as a result that the support method of the spring reed changes from “cantilever” to “center impeller.”

As mentioned above, as a result that three steps of spring characteristics are achieved owing to having two inflection points, as discharge reed 126 opens largely, a strong spring force occurs, causing discharge reed 126 to close fast.

In this way, the present invention provides a compressor with high energy efficiency owing to a short delay in closing of discharge reed 126 even in the region of high circulation amount where discharge reed 126 largely opens.

The present invention provides compressor with high energy efficiency owing to a very short delay in closing of the discharge reed even for a relatively large circulation amount. Further, the compressor can use various types of refrigerants, and thus it is also applicable to freezing and air-conditioning devices using a CO2 refrigerant, for example.