JPH0255639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rolling piston compressor designed to reduce noise.

[Prior Art] A piston that rotates eccentrically around the inner peripheral surface of a cylinder, a vane that reciprocates in contact with the outer peripheral surface of the piston and divides the inside of the cylinder into a low pressure chamber and a high pressure chamber, and a vane that rotates compressed gas. In a rolling piston compressor that consists of a discharge port that discharges out of the cylinder and a discharge valve provided at the discharge port, overcompression can be prevented by providing a relief groove near the discharge port to prevent overcompression. Measures were taken to prevent vibration noise caused by

[Problem to be solved by the invention] Generally, rolling piston type compressors perform one compression operation per one revolution of the piston, but when the rotation speed is high and the compression ratio is high, the normal overcompression prevention The relief grooves for compressors were not able to sufficiently prevent vibration noise, causing the cylinder, piston, and other components of the compressor to vibrate, causing a sudden increase in the noise level.

[Means for Solving the Problems] The present invention aims to reduce vibration noise to a level that has almost no practical effect even in a rolling piston compressor with a high rotation speed and a high compression ratio. The position and structure of the relationship between the piston and the relief groove are devised, and the piston rotates eccentrically on the inner circumferential surface of the cylinder, and the piston moves reciprocatingly in contact with the outer circumferential surface of the cylinder, creating a low-pressure chamber and a high-pressure chamber within the cylinder. In a rolling piston compressor consisting of a vane partitioned into a cylinder, a discharge port for discharging compressed gas to the outside of the cylinder, and a discharge valve provided in the discharge port, the rotational rearward direction of the piston is located from the center of the discharge port. A relief groove with a maximum depth of about 5 to 25% of the diameter of the circle of the discharge port is provided on the side within a crank angle range of 1.5 to 4 times the diameter of a circle with an equivalent cross-sectional area to the discharge port. A rolling piston type compressor is provided, which is characterized in that it is installed in contact with an outlet.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In Figures 1 and 2, 1 is a crankshaft rotated by an electric motor or engine, 2 is a piston that rotates eccentrically on the inner peripheral surface of a cylinder 3 by the crankshaft 1, and 4 is a cylinder 3 that reciprocates in a vane groove 4a provided therein. 5a is a main bearing that supports the crankshaft 1, and 5b is a sub bearing. 6 is a compression chamber, 6a is a low pressure chamber, and 6b is a high pressure chamber. Reference numeral 7 denotes an inlet port through which gas flows into the compression chamber 6, 8 a discharge port provided on the wall of the cylinder 3 for discharging the compressed gas, and 9 formed in the cylinder wall from the discharge port 8 to the rotational rear side of the piston 2. This is a relief groove.
10 is a discharge valve provided within the discharge port 8.

In the rolling piston compressor configured as described above, gas flowing into the low pressure chamber 6a from the suction port 7 is compressed by the rotation of the piston 2 and gradually becomes high pressure gas. When the high pressure gas in the high pressure chamber 6b reaches a discharge pressure or higher, the discharge valve 10 is opened and the gas is discharged. During this compression process, when the piston 2 passes near the discharge port 8, the high-pressure gas section near the discharge port space 11 and the low-pressure chamber 6a are gradually brought into communication by the relief groove 9, so that the diaphragm of the shock wave tube is just opened. The noise caused by shock waves can be reduced in the same way as when the structure is broken.

FIG. 7 schematically shows the relationship between the groove length, groove width, and maximum depth of the relief groove with respect to the discharge port.

(1) Regarding the groove length If the length of the relief groove 9 is too long, gas leakage from the high pressure chamber 6b to the low pressure chamber 6a will increase rapidly and the essential performance will deteriorate, and the depth of the relief groove may also be too small. If it is too large or too large, the effect will decrease, so it is necessary to set it within the optimum range.

FIG. 8 is a diagram showing the relationship between the groove length (discharge port diameter ratio), noise level, and compressor efficiency. From this result, the length of the relief groove 9 is determined from the center position of the discharge port 8 to the piston 2. It has been found that noise can be reduced without changing performance within a crank angle range of 1.5 to 4 times the diameter of a circle having a cross-sectional area equivalent to the discharge port 8 on the rear side of rotation.

(2) Regarding the maximum depth of the groove Figure 9 is a diagram showing the relationship between the maximum depth of the groove (discharge port diameter ratio), noise level, and compressor efficiency. From this result, the maximum depth of the relief groove 9 is It has been found that noise can be reduced without changing performance if the diameter is within the range of about 5 to 25% of the diameter of the circle of the discharge port 8.

(3) About groove width Figure 10 is a diagram showing the relationship between groove width (discharge port diameter ratio), noise level, and compressor efficiency. From this result, it was found that if the width of the relief groove 9 is approximately equal to or larger than the diameter of the circle of the discharge port 8, noise can be reduced without changing the performance.

As to how to change the depth of the relief groove 9 with respect to the crank angle, as expected from the above explanation, it should be increased approximately in proportion to the crank angle until it reaches the discharge port 8. It's good to go.

Further, changes in the depth of the relief groove from the beginning to the end of the outlet 8 have almost no effect on noise or performance as long as the end position of the relief groove 9 is after the center position of the outlet 8.

FIG. 3 shows an embodiment of the relief groove 9. As shown in FIG. 3a, the relief groove may be provided only in the portion of each discharge port 8, or as shown in FIG. A relief groove may be provided throughout.

[Effect of the invention] Figure 4 shows a comparison diagram of the noise level between the conventional one and the embodiment of the present invention.
The noise level is in the range of −B, and in this invention, the noise level is in the range of C.
The noise level is low in the -D range.

Further, FIG. 5 shows an example of pressure waveforms in the high-pressure chamber in a conventional system and an embodiment of the present invention. FIG. 5a shows the waveform of the embodiment of the invention, and FIG. As is clear from this comparative example, in the present invention, pressure pulsation is reduced to less than half in the frequency range of 1 KPH or higher, as will be described later with reference to FIG. Furthermore, FIG. 6 shows the relationship between the compression ratio and the noise level.
It can be seen that the higher the compression ratio, the greater the noise reduction effect.

Fig. 11 shows the cylinder pressure waveform and the time waveform obtained by performing 500 Hz high-pass processing on the pressure waveform for the conventional example and the present invention, and Fig. 12 shows the frequency of the cylinder pressure waveform. These figures show the analysis, and it is clear from these figures that the present invention produces very little noise.

As described above, according to the present invention, vibration and noise caused by shock waves can be effectively reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a rolling piston compressor showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the line - - in Fig. 1, and Figs. A perspective view, FIG. 4 is a diagram showing the relationship between the compressor rotation speed and the noise level, FIGS. 5 a and b are diagrams of the high pressure chamber pressure waveform, and FIG. 6 is a diagram showing the relationship between the compression ratio and the noise level. , FIG. 7 is a diagram schematically showing the relationship between the groove length, groove width, and maximum depth of the relief groove with respect to the discharge port, and FIG. 8 is a diagram showing the relationship between the groove length and the noise level or compressor efficiency. Figure 9 is a diagram showing the relationship between the maximum groove depth and noise level or compressor efficiency, Figure 10 is a diagram showing the relationship between groove width and noise level or compressor efficiency, and Figure 11 is a cylinder pressure waveform. and a diagram showing the time waveform obtained by high-pass processing it,
FIG. 12 is a diagram showing frequency analysis of the cylinder pressure waveform. 1... Crankshaft, 2... Piston, 3... Cylinder, 4... Vane, 5a... Main bearing plate, 5b
... Sub-bearing plate, 7 ... Suction port, 8 ... Discharge port, 9
...Relief groove, 10...Discharge valve. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1 A piston that rotates eccentrically on the inner peripheral surface of the cylinder,
A vane that reciprocates in contact with the outer circumferential surface of the piston and divides the inside of the cylinder into a low pressure chamber and a high pressure chamber, a discharge port that discharges compressed gas to the outside of the cylinder, and a vane provided in the discharge port portion. In a rolling piston type compressor consisting of a discharge valve, within a crank angle range of about 1.5 to 4 times the diameter of a circle having an equivalent cross-sectional area to the discharge port from the center position of the discharge port to the rotational rear side of the piston, A rolling piston type compressor characterized in that a relief groove having a maximum depth of about 5 to 25% of the diameter of the circle is provided in contact with the discharge port.