JPH03206377A - Noise reducing construction for piston type compressor - Google Patents

Abstract

PURPOSE:To smoothly discharge refrigerant gas and avoid over compression to reduce noise by forming discharge introducing grooves connecting to discharge ports on the surfaces of the compression chamber side of valve plates in which suction ports and discharge ports are provided. CONSTITUTION:By reciprocating a duplex piston 5 in a pair of front and rear cylinder bores 1a, 2a of a pair of front and rear cylinder blocks 1, 2 due to rotation of a swash plate 3 fixedly secured on a rotating shaft 4, refrigerant gas sucked from suction ports 9a, 13a is compressed and hereafter discharged from discharged ports 9b, 13b. In such swash plate type compressor, in the face territory on the piston side of respective valve plates 9, 13, fan shaped discharge introducing grooves 9c, 13c penetrating valve forming plates 10, 14 and a converging to discharge ports 9b, 13b are formed. Further, these discharged introducing grooves 9c, 13c are provided with inclination which gradually increase their depth facing to the discharge ports 9b, 13b.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is capable of sucking refrigerant gas from a suction chamber into a compression chamber through a suction port on a valve plate by the backward movement of a piston, and also by the forward movement of a piston. This invention relates to a noise reduction structure in a piston type compressor that discharges refrigerant gas from a compression chamber to a discharge chamber through a discharge port on a valve plate upon operation.

[Prior Art] In this type of piston compressor, the gap between the head end surface of the piston at the top dead center position and the end wall forming the compression chamber, that is, the top clearance, is made as small as possible to increase volumetric efficiency. This improvement in volumetric efficiency is intended to improve the performance of the compressor. On the other hand, if the volumetric efficiency is maximized while taking assembly errors into consideration, an overcompression phenomenon occurs in which the pressure inside the compression chamber becomes higher than the discharge pressure, resulting in increased noise.

In order to avoid such an increase in noise due to over-compression, Japanese Patent Application Laid-Open No. 60-209674 proposes a countermeasure in which a recess is bored in an area on the end face of the piston head away from the area facing the discharge port. is planned. In the pressure distribution on the end face of the piston's head when the piston is at the top dead center position, the pressure rises significantly in the area away from the area facing the discharge port, and by drilling the above-mentioned recess in such an abnormal pressure rise area, Abnormal pressure rise can be suppressed.

[Problems to be Solved by the Invention] A structure in which a concave portion is bored in an area of abnormal pressure increase provides an escape route for the medium gas in an area where it is difficult to escape from the compression chamber to the discharge chamber via the discharge port. The recess on the end face also has the function of preventing the refrigerant gas from flowing out within the compression chamber.

Therefore, the smoothness of the discharge action from the compression chamber through the discharge port is hindered, even if only slightly, and this leads to an increase in noise, albeit slightly.

An object of the present invention is to provide a noise reduction structure for a piston compressor that can further improve noise suppression than the conventional noise countermeasures.

[Means for Solving the Problems] For this purpose, in the present invention, a discharge guide groove connected to a discharge port on the valve plate is provided on the compression chamber side surface of a valve plate that partitions and forms a compression chamber.

[Function] Due to the movement of the piston during the compression stroke, refrigerant gas in the compression chamber flows out from the compression chamber via the discharge port, but in the region near the valve plate in the compression chamber, the refrigerant gas flow follows the valve plate surface. Head to the discharge port. Therefore, in the area near the valve plate in the compression chamber, the flow of refrigerant gas becomes worse in the area farther from the discharge port, but a discharge guide groove is recessed on the valve plate that goes from the area where the flow of refrigerant gas is poor to the discharge port. By doing so, the refrigerant gas flow from the area away from the discharge port toward the discharge port is also smoothed. Therefore, smooth discharge action and avoidance of over-compression are both achieved when the piston is at the top dead center position.

[Example] Hereinafter, an example in which the present invention is embodied in a swash plate compressor will be described based on FIGS. 1 to 4.

As shown in FIG. 1, a rotating shaft 4 to which a swash plate 3 is fixed is supported by a pair of front and rear cylinder blocks 1 and 2 that are tightly joined together. A plurality of cylinder bores la, 2a are formed. A double-headed piston 5 is installed in the cylinder bores la and 2a that form a pair at the front and rear.
is housed in a reciprocating manner, and a shoe 6 is interposed between the double-headed piston 5 and the swash plate 3. Therefore, as the swash plate 3 rotates, the double-headed piston 5 moves back and forth within the cylinder bores la, 2a.

A housing 8 is joined to the end face of the cylinder block 1 via a valve plate 9 and a pair of valve forming plates 10, 11, and a housing 12 is joined to the end face of the cylinder block 2 via a valve plate 13 and a pair of valve forming plates l4. , 15. Both housings 8
, 12 include suction chambers 8a, 12a and discharge chambers 8b. 12
b is shaped. The suction chambers 8a, 12a are connected to the cylinder bores la, 2a via suction ports 9a, 13a on the valve plates 9, 13, and the discharge chambers 8b, 12
b is the discharge port 9b.b on the valve plate 9.13. 13
It is connected to cylinder bores la and 2a via b.

The suction ports 9a, 13a are opened and closed by the suction valves 10a, 14a on the valve-shaped plates 10, 14, and the discharge ports 9b, 13b are opened and closed by the discharge valves 10a, 14a on the valve-shaped plates 11, 15.
It is opened and closed by 1 a + 1 5 a. During the return stroke on the head end surface 5a side of the double-headed piston 5, the refrigerant gas in the suction chamber 8a pushes aside the suction valve 10a and is sucked into the compression chamber P1 between the head end surface 5a and the valve plate 9. During the forward stroke of the double-headed piston 5 on the head end surface 5a side, the refrigerant gas in the compression chamber P1 is discharged from the discharge valve 11a.
is pushed away and discharged into the discharge chamber 8b.

Similar suction and discharge are performed on the compression chamber P2 side between the other head end surface 5b of the double-headed piston 5 and the valve plate 13.

A discharge guide groove 9C is recessed in a surface area of the valve plate 9 corresponding to the head end surface 5a of the double-headed piston 5.

As shown in FIG. 2, the discharge guide groove 9C is shaped like a fan that passes through the annuloplasty plate 10 and converges on the discharge port 9b.As shown in FIG. A slope is formed that gradually becomes deeper from the distal end toward the discharge port 9b.

In FIG. 1, the piston head end surface 5a is at the bottom dead center position, and the piston head end surface 5b is at the top dead center position. When the piston head end face 5a moves toward the valve plate 9, the refrigerant gas in the compression chamber P1 pushes away the discharge valve 11a and flows out into the discharge chamber 8b. Piston head end face 5
When the distance between a and the valve-shaped plate 10 approaches the top clearance, the pressure in the compression chamber P1 increases rapidly, but the compressed refrigerant gas in the compression chamber P1 flows through the discharge port 9b.
If it does not flow smoothly, overcombination will occur.

When the piston head end surface 5a approaches the top clearance, the flow direction of the refrigerant gas in the compression chamber P1 is significantly restricted, and the refrigerant gas in the compression chamber P1 is directed toward the valve plate 9.
along the direction toward the discharge port 9b. However, the discharge guide groove 9c on the surface area of the valve plate 9 facing the piston head end surface 5a guides the high pressure refrigerant gas in the compression chamber P1 to the discharge port 1-9b, and
From the area on the suction port 9a side away from the discharge port 9b
The flow of refrigerant gas towards will be smoother.

Therefore, overcondensation due to overcompression in the distal region of the fan-shaped discharge guide groove 9C is eliminated.
Noise caused by over-compression is suppressed. Furthermore, the smooth flow of refrigerant gas is superior in terms of noise suppression, even if only slightly, compared to the conventional noise reduction structure in which excess refrigerant gas is stored in a recess on the end face of the piston head.

The curve D shown by the chain line in the graph of FIG. 4 is the pressure curve in the compression chamber P1 when no countermeasure against overcompression is taken, and the curve E shown by the solid line is the pressure curve in the case where the discharge guide groove 9C of this embodiment is provided. This is the pressure curve for the case. The protruding portion of the pressure curve D indicated by the chain line represents an overcompression state, and the temporal connection of the pressure curves D in the plurality of pistons, that is, the repetition of overcompression, produces a large noise. By eliminating this overcompression part, noise can be suppressed.
Discharge guide groove 9c of this embodiment. 13c provides this avoidance of overcompression while smoothing the flow of refrigerant gas.

Note that the shape of the discharge guide groove is, for example, as shown in FIG. 5(a).
As shown in (b), a fan-shaped discharge guide groove 9d that surrounds the discharge port 9b is also possible.

Further, as shown in FIGS. 6(a) and (b), there are linear discharge guide grooves 9e, and as shown in FIG. 7, there are three-pronged discharge guide grooves 9.
It is also possible to adopt a discharge guide groove having a constant depth everywhere.

[Effects of the Invention] As detailed above, in the present invention, the discharge guide groove connected to the discharge port is provided on the valve plate, so that even when the end face of the piston head approaches the top dead center position, it does not separate from the discharge port. The refrigerant gas in the area where the overcompression occurs is also guided by the discharge guide groove and flows toward the discharge port, thereby smoothly guiding the refrigerant gas in the area where overcompression is likely to occur to the discharge port, thereby preventing overcompression that can lead to noise. It has the excellent effect of being evasive.

[Brief explanation of drawings]

1 to 4 show embodiments embodying the present invention;
The figure is a side sectional view of the entire compressor, Figure 2 is a sectional view taken along the line A-A in Figure 1, Figure 3 is an enlarged sectional view taken along the line B-B in Figure 2, and Figure 4 shows the pressure inside the compression chamber. 5(a) is a longitudinal sectional view showing another example, FIG. 5(b) is an enlarged sectional view taken along the line C-C of FIG. 5(a), and FIG. 6(a) is an another example. Longitudinal sectional view shown, No. 6
FIG. 6(b) is an enlarged sectional view taken along the line DD in FIG. 6(a), and FIG. 7 is a vertical sectional view showing another example. Piston head end surfaces 5a, 5b, valve plates 9, l
3. Discharge ports 9b, 13b, discharge guide grooves 9c, 13c
, compression chamber PI, P2.

Claims (1)

[Claims] 1 A piston that sucks refrigerant gas into the compression chamber through the suction port on the valve plate by the backward movement of the piston, and discharges refrigerant gas from the compression chamber through the discharge port on the valve plate by the forward movement of the piston. A noise reduction structure in a piston type compressor, wherein a discharge guide groove connected to the discharge port is provided on the compression chamber side surface of the valve plate.