JP3541961B2 - Valve device of positive displacement compressor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a valve device for a positive displacement compressor, and more particularly to an improvement in a valve device for reducing pressure fluctuation and vibration noise.
[0002]
[Prior art]
In a positive displacement compressor mainly used for refrigeration, a low-pressure region and a high-pressure region in the device are communicated with a compression chamber by through holes. In a reciprocating compressor, a suction valve that opens and closes both the holes is provided. In the rotary compressor, a similar discharge valve is provided in a through hole communicating the compression chamber with the high-pressure region. In addition, a single or composite reed valve that opens and closes the through hole by a differential pressure is often used for such a valve body.
[0003]
FIG. 9 illustrates a rear portion of a reciprocating compressor widely used for vehicle air conditioning. An outer end of a cylinder block 1 having a plurality of compression chambers (bore) 1a arranged side by side is provided with a valve plate 2 interposed therebetween. The housing 3 is closed, and the valve plate 2 has through-holes for communicating the suction chamber (low-pressure area) 4 and the discharge chamber (high-pressure area) 5 formed in the housing 3 with the compression chamber 1a. The hole 4a and the discharge hole 5a are provided through. A suction valve element 6 having a plurality of reed valves 6a corresponding to the respective suction holes 4a is interposed between one valve seat surface of the valve plate 2 and the cylinder block 1. A discharge valve element 7 having a plurality of reed valves 7a corresponding to the respective discharge holes 5a is mounted on the other valve seat surface of the valve plate 2 exposed inside, and the reed valves 6a and 7a are opened. The valve (flexion) limit is regulated by a notch 8 provided at the mouth end of the compression chamber 1a and a retainer 9 fastened together with the discharge valve body 7.
[0004]
As described above, the reed valves 6a and 7a are seated on the respective valve seat surfaces where the suction hole 4a and the discharge hole 5a are opened and are opened and closed by the relative pressure difference with the compression chamber 1a. In order to ensure the tightness with the reed valves 6a and 7a and the sealing property between the cylinder block 1 and the housing 3 that sandwich the reed valves 6a and 7a, the surface roughness is generally extremely smooth with a surface roughness of about 2 to 3 μm RZ. It is finished.
[0005]
[Problems to be solved by the invention]
Fine lubricating oil particles are mixed in the refrigerant gas flowing in the compressor, and the valve seat surface and the reed valves 6a and 7a are both placed in an environment where the lubricating oil particles adhere. Each of the reed valves 6a and 7a in the closed state seated on the valve seat surface having extremely high smoothness as described above seals the entire opening of the suction hole 4a and the discharge hole 5a by planar contact. Therefore, even at the time of opening the valve, the lubricating oil interposed in the closed area mainly adheres to the valve seat surface quite strongly due to the surface tension.
[0006]
Accordingly, the reed valves 6a and 7a resist opening until the pressure in the compression chamber 1a overcomes the surface tension of the lubricating oil added to the predetermined valve opening pressure, and at the same time as the valves are opened, the refrigerant gas is rapidly aspirated. Or discharge is started at once. As a result, the instantaneous pressure wave and the shock vibration waves of the reed valves 6a and 7a colliding with the valve-opening restriction surface are combined to generate not only the suction pressure loss and the over-compression but also noise, and particularly the vehicle air conditioning. In compressors used for such purposes, it has been pointed out that such noise has long been pointed out as a serious factor impeding the operating environment.
[0007]
An object of the present invention is to solve the problem of effectively reducing combined noise in addition to suction pressure loss and over-compression, and ensuring good sealing of the reed valve.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention includes a reed valve that has a through hole that communicates a low-pressure region and a high-pressure region in the machine with a compression chamber, and opens and closes at least the through hole that opens in a valve seat surface by a differential pressure. In the displacement type compressor, on both sides in the axial direction of the valve opening straddling the through hole on the valve seat surface, the contact between the reed valve and the valve seat surface is prevented in a normal state where the reed valve is straightened , and An interference step is provided for closing the through-hole by elastic bending of the reed valve, and one of the valve seat surface and the reed valve surrounds the periphery of the through-hole, and the elasticity of the reed valve is increased. A novel configuration is adopted in which a sealing body that bends following the bending is covered.
[0009]
In a preferred embodiment of the present invention, the sealing body is a circular coating coated on the reed valve, and a more preferable sealing body is an acrylonitrile butadiene rubber coating. The reed valve is mounted on the upper surface of the interference step only on the base end side and the distal end side in the valve opening axial direction. Further, the interference step portion is formed by coating a resin film on either or the valve seat surface to intaglio a valve seat surface directly.
[0010]
[Action]
In the valve device of the present invention, on both sides in the axial direction of the valve opening straddling the through hole on the valve seat surface, the contact between the reed valve and the valve seat surface is prevented in a normal state where the reed valve is straightened , and Since the interference step portion that closes the through hole by the elastic bending of the reed valve is provided, the reed valve at the time of no load is mounted on the upper surface of the interference step portion at the base end side and the distal end side in the valve opening axial direction. The straightened state is maintained , the contact between the reed valve and the valve seat surface is prevented, and the closing of the through hole is prevented.
[0011]
However, once the relative pressure difference with the compression chamber acts in the direction to close the reed valve, the reed valve immediately bends and closes the through hole by abutting the entire opening periphery of the through hole, and at the same time, The sealing body also follows the bending of the reed valve and bends to tightly seal the periphery of the through hole. It should be noted that the closing of the through hole performed in association with such bending of the reed valve significantly reduces the substantial contact area of the reed valve in the sealing area around the opening, and therefore, is based on the surface tension of the lubricating oil. Valve opening resistance is significantly reduced. Thereafter, when the relative pressure difference between the compression chamber and the compression chamber is reversed and reaches the valve opening pressure of the reed valve, in addition to the effect of the surface tension reduced to an almost harmless degree, the reaction force for restoring from the above-mentioned bent posture is increased. In order to effectively assist the opening of the reed valve, the instantaneous refrigerant gas pressure wave and the collision vibration wave with the valve opening regulating surface are skillfully attenuated. In addition, the intervention of the above-mentioned sealing body surrounding the periphery of the through hole ensures good sealing even at the time when the acting differential pressure becomes small and the closing performance of the reed valve is most attenuated, and the abnormal flow of the refrigerant gas. To prevent
[0012]
【Example】
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
1 to 3 show a valve plate 2 portion of the reciprocating compressor illustrated in FIG. 9 and a discharge valve element 7 mounted on one valve seat surface 2a of the valve plate 2. The plurality of reed valves 7a constituting the valve body 7 have through holes (discharge holes) 5a opened in the valve seat surface 2a in accordance with a relative pressure difference between the compression chamber 1a and the high pressure region (discharge chamber) 5. It opens and closes periodically.
[0013]
Now, the valve seat surface 2a of this embodiment is coated with, for example, a fluorine-based resin film 10, and the resin film 10 having a thickness of about 0.1 to 0.2 mm is formed on each of the through holes 5a. It is configured in a form in which only the annular region P covering the periphery is missing. That is, on both sides in the valve opening axis XX direction straddling each through hole 5a, planar contact between the valve seat surface 2a and the reed valve 7a is prevented by the thickness of the resin film 10, and the reed valve Interference step portions P ₁ and P ₂ for closing the through-hole 5a by the elastic bending of 7a are formed. The distance from the opening edge of the through hole 5a to each of the interference step portions P ₁ and P ₂ and the distance from the tip of the reed valve 7a to the interference step portion P ₁ are based on the plate thickness and the bending characteristics of the reed valve 7a. It is appropriately selected.
[0014]
The reed valve 7a has a sealing body 20 that surrounds the periphery of the through hole 5a within the valve seat surface 2a, that is, the area of the missing area P, and that flexes following the elastic flexure of the reed valve 7a. In this example, an annular sealing body 20a shown in FIG. 4 is provided. The sealing body 20a is a coating film of acrylonitrile-butadiene rubber (NBR) or hydrogenated nitrile-butadiene rubber (HNBR), and its film thickness is set substantially equal to that of the resin film 10.
[0015]
This embodiment is configured as described above, and the reed valve 7a at the time of no load shown in FIG. 4 is provided on the resin film 10 on which both the front end side and the base end side form the interference steps P ₁ and P _2. It is placed and held in a stretched normal state, and the closing of the through hole 5a is prevented by the minute gap formed between the valve seat surface 2a and the valve seat surface 2a.
During operation of the compressor, when the relative pressure difference between the compression chamber 1a and the high-pressure area 5 acts in a direction to close the reed valve 7a, the reed valve 7a is moved to the interference stepped portions P ₁ , P as shown in FIG. _{With the} fulcrum ₂ as a fulcrum, it bends in the centripetal direction of the through-hole 5a, and closes the through-hole 5a by abutting on the entire periphery of the opening. The periphery of the through hole 5a is tightly sealed. Although the closing of the through hole 5a performed in accordance with the bending of the reed valve 7a in this way causes some planar closeness between the valve seat surface 2a around the opening and the sealing body 20a, Since the contact area of the reed valve 7a is greatly reduced as compared with the related art, the valve opening resistance based on the surface tension of the lubricating oil is significantly reduced. Thereafter, when the relative pressure difference between the compression chamber 1a and the high-pressure area 5 reverses and reaches the valve opening pressure of the reed valve 7a, in addition to the effect of the surface tension reduced to a substantially harmless degree, Since the reaction force restored from the bent posture effectively assists the opening of the reed valve 7a, the instantaneous refrigerant gas pressure wave and the collision vibration wave with the valve opening regulating surface are skillfully attenuated.
[0016]
The closing performance of the periphery of the through hole 5a based on the bending characteristic of the reed valve 7a tends to be weakened with the valve opening axis XX as a vertex, and especially in the vicinity of the reversal period of the differential pressure acting on the reed valve 7a. Although there is a dislike that the sealing performance may remain unreliable, the sealing body 20a in this embodiment secures the sealing around the through hole 5a by the close contact with the valve seat surface 2a even in such a state. Flow is prevented.
[0017]
The sealing body 20b indicated by a chain line in FIG. 4 is formed by filling the hollow portion of the annular sealing body 20a into a circular shape, and in this example, when the reed valve 7a is bent by a differential pressure. Since the sealing body 20b directly intervenes in the opening of the through hole 5a to be closed, the impact noise generated due to the metal contact of the reed valve 7a can be effectively reduced (FIG. 6).
[0018]
FIG. 7 shows an embodiment in which the annular sealing body 20a is mounted on the valve seat surface 2a side. Further, a sealing body 20c shown by a dashed line in the figure expands the ring width of the sealing body 20a. Although the inner diameter of the lever is made to coincide with the through hole 5a, there is a difference in productivity in any of the embodiments, but there is no change in the main function and effect.
FIG. 8 shows the suction valve body 6 mounted on the other valve seat surface 2b of the valve plate 2. The plurality of reed valves 6a constituting the suction valve body 6 also have openings on the valve seat surface 2b. The opened through hole (suction hole) 4a is periodically opened and closed according to the relative pressure difference between the compression chamber 1a and the low pressure region (suction chamber) 4.
[0019]
The resin film 10 is similarly coated on the valve seat surface 2b. In this case, in order to avoid intersecting with other refrigerant passages penetrating through the valve plate 2, the resin film 10 is cut through each of the holes. As a slot-like region P 'provided in each hole 4a (only one portion is shown in the figure and the others are omitted), interference step portions P ₁ , on both sides in the valve opening axis XX direction, also straddling the through hole 4a, P ₂ is formed. Accordingly, the suction valve body 6 also has a combined function of the closing of the through hole 4a due to the elastic bending of the reed valve 6a and the sealing body 20 which follows the bending and bends to seal the periphery of the through hole 4a. It operates very smoothly as well as the valve element 7.
[0020]
In the above-described embodiment, the annular region P covering each through hole 5a can be formed and implemented in the same manner as the elongated region P ′ provided for each through hole 4a. instead of the resin film 10, machining, stamping, electrical discharge machining the valve seat surface 2a or the like, 2b directly to intaglio, carried out to form a valve plate 2 similar interference stepped portion itself P _1, P ₂ It is also possible.
[0021]
【The invention's effect】
As described in detail above, the present invention has the configuration described in the claims, and thus has the following excellent effects.
(1) Since suction pressure loss and over-compression are reduced, it is possible to contribute to performance, especially power saving.
(2) Since the pressure pulsation of the refrigerant gas and the valve vibration are favorably attenuated by the vibration damping property at the time of opening the valve, the vibration noise disturbance is remarkably improved, and the muffler function equipment can be eliminated.
(3) The sealing body that bends following the bending of the reed valve tightly seals the periphery of the through hole, and ensures the stability required for the closing performance of the reed valve. Good flow is well prevented.
(4) In the case where the sealing member is formed so as to directly intervene in the opening of the through hole which is particularly closed, it is possible to effectively reduce the impact noise caused by the metal contact of the reed valve.
[Brief description of the drawings]
FIG. 1 is a sectional view showing the relationship between a reed valve and an interference step according to an embodiment of the present invention.
FIG. 2 is a side view showing the relationship between the reed valve and an interference step.
FIG. 3 is a side view showing a discharge valve body side of the valve plate according to the embodiment of the present invention.
FIG. 4 is an enlarged sectional view showing a state before bending of a sealing body according to the embodiment of the present invention.
FIG. 5 is an enlarged sectional view showing a state after bending of the sealing body.
FIG. 6 is an enlarged cross-sectional view showing a state after bending of the same sealing body having different shapes.
FIG. 7 is an enlarged cross-sectional view showing a state before bending of the same sealed body having different mounting surfaces.
FIG. 8 is a side view showing the intake valve body side of the valve plate according to the embodiment of the present invention.
FIG. 9 is a sectional view showing a rear part of a conventional reciprocating compressor.
[Explanation of symbols]
1a is a compression chamber, 2 is a valve plate, 2a and 2b are valve seat surfaces, 4 is a low pressure area (suction chamber), 5 is a high pressure area (discharge chamber), 4a is a through hole (suction hole), and 5a is a through hole ( Discharge holes), 6a and 7a are reed valves, P ₁ and P ₂ are interference steps, and 20 is a sealing body.

Claims (4)

A positive displacement compressor having a through-hole communicating the low-pressure area and the high-pressure area in the machine with the compression chamber, and a reed valve that opens and closes at least the through-hole opened on the valve seat surface by a differential pressure,
On both sides in the valve opening axial direction straddling the through hole on the valve seat surface, in a normal state where the reed valve is straightened, the contact between the reed valve and the valve seat surface is hindered, and the elastic bending of the reed valve causes An interference step for closing the through hole is provided, and one of the valve seat surface and the reed valve surrounds the periphery of the through hole, and flexes following the elastic bending of the reed valve. A valve device for a positive displacement compressor, wherein a valve body is provided with a buckling sealing body. The valve device according to claim 1, wherein the sealing body is a circular film coated on the reed valve. 3. The valve device according to claim 1, wherein the sealing body is made of an acrylonitrile-butadiene rubber film. 4. The valve device according to claim 1, wherein the reed valve is mounted on the upper surface of the interference step only on the base end side and the distal end side in the valve opening axial direction. 5.

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