JP3558705B2 - Hermetic compressor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a hermetic compressor for HFC-134a used in electric refrigerators and the like.
[0002]
[Prior art]
In recent years, the use of chlorine-based chlorofluorocarbon (abbreviated as CFC) has been discontinued due to the problem of depletion of the ozone layer, and a switch to hydrogenated fluorocarbon (HFC) has begun. In electric refrigerators, there has been a shift from CFC-12 to HFC-134a. Along with this, the refrigerating machine oil has been shifted from mineral oil to ester-based hydrogen-containing CFC refrigerant oil.
[0003]
However, when HFC-134a is used, there is a problem in terms of reliability such as an increase in the compression ratio of the refrigerant compressor and an increase in the impact of the discharge lead.
[0004]
Similarly, noise tends to increase and there is a problem of noise reduction.
Hereinafter, an example of the above-described conventional compressor will be described with reference to the drawings.
[0005]
FIG. 7 is an exploded perspective view of a valve plate of a compressor disclosed in Japanese Patent Application No. 4-506082.
[0006]
In the figure, a suction hole 28 penetrating into the cylinder 8 is formed in the valve plate 20. Further, two discharge holes 29 penetrating into the cylinder are formed in the valve plate 20 facing the discharge plenum.
[0007]
The suction lead 22 is formed of a flat plate, and its periphery is removed so as to leave the suction valve section 30. Holes 31 through which screws pass are formed at four corners.
[0008]
A long recess 32 is formed on the side of the valve plate 20 facing the piston, that is, on the side opposite to the opening end of the cylinder. The discharge hole 29 is located in the recess 32. Reference numeral 33 denotes an annular discharge valve seat formed on the side of the recess 32 of the discharge hole 29, which is finished concentrically. The height of the discharge valve seat 33 is shorter than the depth of the recess 32.
[0009]
Reference numeral 34 denotes a discharge lead, which has a lug 36 on the side opposite to the seal surface 35 covering the periphery of the discharge valve seat 33. In the recess 32, between the discharge hole 29 and the end 37 of the recess 32, a pair of banks 38 extending inward by the end 37 is formed. The lugs 36 of the discharge leads 34 are arranged at the formed intervals.
[0010]
At this time, since the ejection leads 34 are formed symmetrically on the top and bottom and symmetrically on the left and right, the arrangement of the ejection leads 34 in the recess 32 can be stored on both sides. Further, a step portion 39 having a height substantially equal to the height of the discharge valve 33 is formed in the recess 32 where the ear piece 36 contacts. The discharge lead 34 contacts the step 39 of the recess 32 and the discharge valve seat 33.
[0011]
Numeral 40 denotes a spring lead, which is formed of a spring material and has bent end portions 41 and shorter than the distance between the longitudinal end portions of the long recess 32. The spring lead 40 is disposed in the recess 32 in which the discharge lead 34 is accommodated, and the end 41 of the end 41 of the spring lead 40 is in contact with the end of the discharge lead 34.
[0012]
Reference numeral 42 denotes a stopper having a surface 44 for pressing the bent portion 43 of the spring lead 40, a part of which is inserted into the recess 32, and a fixing piece 45 for fixing to the valve plate 20. Two holes 46 are formed in the fixing piece 45, and the holes 47 of the valve plate 20 are aligned with the holes 46, and are fixed by rivets 48.
[0013]
Reference numerals 51 are holes formed at four corners of the valve plate 20 and through which screws pass.
By forming the discharge hole 29 in the recess 32 of the valve plate 20 and making the height smaller than the thickness of the valve plate 20, the refrigerant gas staying in this space can be reduced, so that the compression efficiency can be increased. Further, since there are a plurality of discharge holes 29, it is possible to prevent an increase in overcompression loss.
[0014]
As shown in FIG. 8, an annular discharge valve seat 33 provided so as to surround the discharge hole 29 is disposed around the discharge hole 29 of the valve plate 20, and this surface is a sealing surface. The corner 52 of the inner diameter of the discharge valve seat is raised as shown in the figure.
[0015]
On the other hand, the enlarged cross section of the discharge valve seat 33 has a shape in which a part of the projection 53 and a gentle slope 54 are provided as shown in FIG. There was one. These are due to wear and chipping of the processing tool.
[0016]
FIG. 9 shows a conventional assembly in which the valve plate 20 and the discharge lead 34 are combined. The arrows in the figure indicate the pressure applied to the discharge lead 34. Due to the violent vertical movement of the discharge lead 34, there were a case where the discharge lead was cracked or damaged near the corner 52 of the inner diameter, and a case where crack or damage was generated from the end 56 or 57 of the intermediate recess 55.
[0017]
[Problems to be solved by the invention]
However, in the above configuration, the compression ratio is higher than that of the conventional CFC-12, and therefore, there is a problem related to reliability that the impact stress to the ejection lead increases and the ejection lead is broken.
[0018]
That is, when the refrigeration system is operated at the condensing temperature of 54.4 ° C. and the evaporating temperature of −23.3 ° C., which are the standard conditions of refrigeration, the discharge pressure is 13.7 kg / cm ² abs and the suction pressure is 1.3 kg in CFC-12. / Cm ² abs and the compression ratio is 10.54.
[0019]
With HFC-134a, the discharge pressure is 14.9 kg / cm ² abs, the suction pressure is 1.14 kg / cm ² abs, and the compression ratio is 13.07, which is 1.24 times the compression ratio of CFC-12. However, there is a problem that the ejection lead is easily damaged. In addition, noise tends to increase similarly, and there is a problem of noise recommendation.
[0020]
The present invention has been made in view of the above problems, and provides a hermetic compressor that uses HFC-134a refrigerant, does not damage a discharge lead, has high reliability, and has low noise.
[0021]
[Means for Solving the Problems]
In order to solve the above-described problems, a hermetic compressor of the present invention includes one discharge hole formed in a valve plate and an inner diameter of an annular discharge valve seat provided so as to surround the discharge hole. Is formed into a curved surface, and is provided with a discharge lead for sealing the annular discharge valve seat and a spring lead for pressing the discharge lead.
[0022]
Further, the annular discharge valve seat provided on the valve plate is precisely finished in order to remove rough surfaces, steps, and deformation.
[0023]
[Action]
According to the present invention, since the number of discharge holes is changed from two to one according to the above configuration, the number of sound sources becomes one, so that noise due to operation is reduced.
[0024]
In addition, the corner of the inner diameter of the annular discharge valve seat is machined into a curved surface, and the discharge valve seat is precision-finished to remove rough surfaces, steps, and deformation, so that the corner of the inner diameter and the concave portion in the middle are removed. The breakage and breakage of the discharge lead generated near the end of the discharge lead are prevented.
[0025]
【Example】
Hereinafter, a hermetic compressor according to an embodiment of the present invention will be described with reference to the drawings. The same parts as those in the conventional example will be described using the same reference numerals, and the same components and operations will be omitted.
[0026]
1 to 4, reference numeral 61 denotes a sealed case, 62 denotes a compression element, 63 denotes a motor, 64 denotes a crankshaft constituting the compression element 62, 65 denotes an eccentric part of the crankshaft 64, and 66 denotes an eccentric part 65 and a piston pin. Connected con-lots, 67 is a piston pin, 68 is a piston, 69 is a cylinder in which the piston 68 reciprocates, 70 is a valve plate that seals the open end of the cylinder 69, 71 is an oil supply pipe that supplies oil to each lubrication unit, and 72 is an oil supply pipe. Oil.
[0027]
Details of the valve include a valve plate 70 that seals the open end of the cylinder 69, a discharge valve device 80 attached to the opposite side of the valve plate 70 from the cylinder, and a valve plate 70 that covers the discharge valve device 80. It comprises a cylinder head 81 fixed to the cylinder 69.
[0028]
The discharge valve device 80 includes a long recess 82 formed in the valve plate 70, one discharge hole 83 opening into the long recess, and an annular discharge valve seat 84 provided to surround the discharge hole. A discharge lead 85 that opens and closes the seal and opens and closes the seal, and a spring lead 86 that presses the opening and closing portion of the discharge lead, both ends 87 of the spring lead are bent into a bent curve 88.
[0029]
The annular discharge valve seat 84 is a sealing surface, is provided so as to surround the discharge hole 83, and each of the inner diameters 91 of the discharge valve seat is processed into a curved surface.
[0030]
Further, the annular discharge valve seat is precision finished 92 in order to remove rough surface, steps and deformation.
[0031]
The degree of precision finishing of the discharge valve seat is 5 μm or less for the convex portion and 10 μm or less for the concave portion with respect to the plane of the discharge valve seat 84, which is the sealing surface. The parallelism of the sealing surface is 0.06 / 6.5 (mm). If the accuracy is maintained such as a surface roughness of 0.4a, the above-described cracking and breakage of the discharge lead can be prevented (from the experimental results).
[0032]
The operation and effects of the present invention are described below together with test data applied to an actual machine. By changing from the conventional specification to the specification of the present invention (using a spring lead 86 with one discharge hole) with a compressor with a cylinder capacity of 7.3 cm ³ designed for electric refrigeration employment, the number of sound sources becomes one and the operating noise is reduced. Reduced. In the noise measurement, the sound power, that is, the sound power level (PWL), greatly reduced the conventional 44 dB (A) to the 38 dB (A) of the specification of the present invention.
[0033]
On the other hand, regarding the breakage of the discharge lead, when the HFC-134a is applied to the conventional type shown in FIGS. 8 to 11 and operated, the compression ratio becomes 1.24 times that of R-12 for the above-described reason. Some leads were damaged in the severe test.
[0034]
When the damaged portion was observed, a crack was generated in the seal portion 35 of the discharge lead 34, and the starting point of the crack was at or near the point of contact with the annular discharge valve seat 33. Also, when the discharge valve seat 33, which is the partner of the damaged discharge lead, was observed, deformation and dents were found in the valve seat as shown in FIGS. From this, it is considered that when the discharge lead collides with the valve seat, the deformation or dent of the valve seat generates concentrated stress, which is repeated, leading to destruction in which the impact is picked up. As a countermeasure, cracks and breakage of the discharge lead can be prevented by making the inner corner of the annular discharge valve seat a curved surface and precisely finishing the discharge valve seat as described above.
[0035]
Therefore, it is possible to provide a hermetic compressor with low operating noise and with no damage to the discharge lead and high reliability.
[0036]
【The invention's effect】
As described above, the present invention comprises a cylinder head fixed to a cylinder via a valve plate so as to cover a discharge valve device, and this discharge valve device is provided with a single discharge hole formed in a valve plate to provide a sound source. At one location, the operating noise can be greatly reduced.
[0037]
In addition, the inner diameter of the annular discharge valve seat is machined into a curved surface, and the discharge valve seat is precision-finished to remove rough surfaces, steps, and deformation, so that the discharge lead can be concentrated when it collides with the discharge valve seat. Since the stress is avoided, the breakage and breakage of the discharge lead are prevented.
[0038]
As described above, a hermetic compressor for HFC-134a with low operating noise and high reliability can be provided.
[Brief description of the drawings]
FIG. 1 is a sectional view of a hermetic compressor according to an embodiment of the present invention; FIG. 2 is a longitudinal sectional view of a compression unit section of FIG. 1; FIG. 3 is a sectional view taken along line AA of FIG. FIG. 5 is an exploded perspective view of a valve plate of the present invention. FIG. 5 is an enlarged sectional view of a discharge valve seat of the valve plate of the present invention. FIG. 6 is a sectional view of a valve plate and a discharge lead of the present invention. FIG. 8 is an enlarged sectional view of the discharge valve seat of FIG. 7; FIG. 9 is a sectional view of the valve plate and the discharge lead of FIG. 7; FIG. 10 is an enlarged sectional view of a conventional discharge valve seat; 10 is an enlarged sectional view of a discharge valve seat according to another embodiment.
68 Piston 69 Cylinder 70 Valve plate 80 Discharge valve device 83 Discharge hole 84 Annular discharge valve seat 85 Discharge lead 86 Spring lead 91 Angle of inner diameter of valve seat 92 Precision finishing

Claims (1)

A piston, a cylinder on which the piston slides, a valve plate for sealing an open end of the cylinder, a discharge valve device mounted on a side opposite to the cylinder of the valve plate, and a valve plate for covering the discharge valve device. The discharge valve device comprises one discharge hole formed in a valve plate, and an annular hole formed so as to surround the discharge hole and having an inner diameter formed into a curved surface. A discharge valve seat, a discharge lead for sealing the annular discharge valve seat, and a spring lead for elastically pressing an opening / closing portion of the discharge lead , for removing rough skin, steps and deformation of the annular discharge valve seat; A hermetic compressor characterized by precision finishing .

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