JP2019027356A - Oil-free reciprocating compressor - Google Patents

Abstract

To suppress progress of abrasion or deterioration of a rider ring or grease sealing bearing due to high-temperature blow-by in compression, in an oil-free reciprocating compressor comprising a crosshead piston configured to compress fluid.SOLUTION: An oil-free reciprocating compressor having a crosshead piston is characterized in that to a side surface of the cross head piston, a first piston ring is fitted; and at a portion lower than the first piston ring at the time when the crosshead piston is positioned at a bottom dead center of reciprocation, a communication pipe communicating between a cylinder side surface and a crank chamber is provided.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an oil-free reciprocating compressor.

  There exists patent document 2 as a prior art of a reciprocating compressor. Paragraph No. 26 of Patent Document 1 states that “the case structure of the compression unit 2 on the higher stage side has a cylinder 22 attached to a crankcase 35 with a distance piece 41 interposed therebetween as shown in FIG. A cylinder head 42 is attached to the tip (upper end) of the cylinder 22. A piston rod 31 is slidably disposed in the axial direction in the distance piece 41, and compressed gas is placed on the outer periphery of the piston rod 31. A gas seal portion 43 is formed to prevent leakage to the crankcase 35. The compressed gas leaked from the compression chamber 21 side of the cylinder 22 into the distance piece 41 is a return port 46 provided in the distance piece 41. 1 through the return passage 47 (see FIG. 1), and is returned to the suction side of the lower-stage compression section 1. In FIG. It has been described as a filter provided in the return passage 47. ".

JP2014-20284

  However, in the above-mentioned patent document, since the blow-by is returned to the suction side of the compression unit 1 on the lower stage side, another pipe connecting the high-pressure side and the low-pressure side is further added and a filter is interposed. Since the cylinders are separated from each other, the piping layout becomes complicated.

  Further, the amount of blow-by is greatly affected by the wear of the piston ring and the wear of the rider ring, so that the pressure of the intake air on the low stage side is likely to change. It is necessary to provide a filter separately.

  When blow-by occurs, the piston is in a high-pressure environment near the top dead center. The space in the crank chamber is the largest. This is because not only the intake of outside air but also the negative pressure environment can be resolved.

  An object of the present invention is to suppress the progress of wear and deterioration of rider rings and grease-filled bearings due to blow-by that has become hot during compression in an oil-free reciprocating compressor including a crosshead piston that compresses fluid. It is in.

  Therefore, in order to solve the above problems, as an example of an embodiment of the present invention, a piston that reciprocates in a cylinder, a cylinder head that closes an end of the cylinder, a connecting rod that supports the piston, It has a crankshaft that rotationally drives the connecting rod end, and a crank chamber that rotatably supports the crankshaft, and includes a communication pipe that communicates the cylinder and the crank chamber. It is comprised as a reciprocating compressor.

  According to the present invention, in an oil-free reciprocating compressor having a crosshead piston that compresses a fluid with a simple configuration, wear / deterioration of rider rings and grease-filled bearings due to blow-by that has become hot during compression. It is in suppressing progress.

It is a figure which shows schematic structure of the oil-free reciprocating compressor which concerns on Example 1 thru | or 3. It is sectional drawing which shows an internal structure when the compressor main body 1 shown in Example 1 is seen from the side surface (FIG. 1 left side). It is sectional drawing which shows an internal structure when the compressor main body 1 shown in Example 2 is seen from the side surface (FIG. 1 left side). It is sectional drawing which shows an internal structure when the compressor main body 1 shown in Example 3 is seen from the side surface (FIG. 1 left side).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an oil-free reciprocating compressor according to Examples 1 to 3, and FIG. 2 is a side view of the compressor body 1 shown in FIG. 1 (left side in FIG. 1). It is sectional drawing which shows the internal structure at the time.

  A reciprocating compressor 10 shown in FIG. 1 is fixed to the compressor main body 1, the electric motor 2 that drives the compressor main body 1, the tank 3 that stores the fluid compressed by the compressor main body 1, and the electric motor 2. A motor pulley 4, a compressor pulley 5 fixed to the compressor body 1, and a transmission belt 6 for transmitting power to the motor pulley 4 and the compressor pulley 5.

  As shown in FIG. 2, the compressor body 1 compresses a fluid. The internal structure of the compressor body 1 includes a crank chamber 21, a lower cylinder 22 having a large inner diameter that protrudes vertically from the crank chamber 21, and a lower cylinder 22. The upper cylinder 23 having a smaller inner diameter than the lower cylinder 22 projecting vertically from the upper end surface, and the upper and lower stages installed in the lower cylinder 22 and the upper cylinder 23 have different outer diameters. A crosshead piston 24 fitted into the upper cylinder 23), a cylinder head 25 that closes the upper end of the upper cylinder 23, a connecting rod 26 that supports the crosshead piston 24, and a crank that rotationally drives the end of the connecting rod 26 And a shaft 27.

  In the compressor body 1, the crankshaft 27 in the crank chamber 21 rotates, so that the crosshead piston 24 installed in the lower cylinder 22 and the upper cylinder 23 reciprocates in the vertical direction and sucks in from the cylinder head 25. The process of compressing and discharging the fluid is repeated. In FIG. 1 and FIG. 2, for the sake of simplification of explanation, the shape of the compressor is a single-cylinder single-stage compressor having only one pair of pistons and cylinders. Some compressors have a piston and cylinder.

  In the compressor body 1, the crankshaft 27 is arranged in parallel with the rotating shaft of the electric motor 2, and the compressor pulley 5 is fixed to the crankshaft 27. The compressor pulley 5 attached to the compressor main body 1 has blades, and the cooling air generated by the rotation is applied to the outer surface of the compressor main body 1 to promote the heat dissipation of the compressor main body 1 and to provide a cooling effect. Has produced.

  The detailed structure around the crosshead piston 24 of the compressor body 1 will be described below.

  An upper piston ring 28 that seals the compressed fluid in the upper cylinder 23 and prevents blow-by toward the crank chamber 21 is fitted to the upper side surface of the cross head piston 24 on the cylinder head 23 side. In FIG. 2, the number of the upper piston rings 28 is one, but a plurality of upper piston rings 28 may be formed depending on the type and pressure of the fluid to be compressed. A rider ring 30 is fitted to the lower side surface of the cross head piston 24 on the crank chamber 21 side to prevent contact with the lower cylinder 22 while receiving a lateral pressure when the cross head piston 24 reciprocates in the lower cylinder 22. Are combined.

  The side of the lower cylinder 22 or the upper cylinder 23 below the upper piston ring 28 when the crosshead piston 24 is located at the bottom dead center communicates with the crank chamber hole 32 and the communication pipe 33 of the crank chamber 21. The cylinder hole 31 is provided.

  As described above, blow-by flows directly into the crank chamber 21 along the cross-head piston 24 by flowing blow-by from the gap between the cross-head piston 24 and the upper cylinder 23 during compression into the crank chamber 21 through the communication pipe 33. Can be suppressed.

  As a result, the crank chamber 21 is filled with cooled blow-by so that the progress of wear and deterioration of the rider ring 30 and the grease-filled bearing can be suppressed.

  Further, since the communication pipe 33 is cooled by the wind generated by the rotation of the compressor pulley 5, the blow-by passing through the communication pipe 33 can be cooled.

  In order for the cooled blow-by to efficiently use the cooling air from the compressor pulley 5 in the crank chamber 21, the communication pipe 33 is connected to the lower cylinder 22 or the upper cylinder 23 as shown in FIG. It is better to be at a position where the cooling air on the 5th side efficiently hits.

  Next, Example 2 will be described. Since the rider ring 30 of the first embodiment is not provided for the purpose of sealing the fluid, there is a concern that the blow-by may pass through the gap between the lower cylinder 22 and the crosshead piston 24.

  FIG. 3 is a cross-sectional view showing the internal structure of the compressor body 1 shown in the second embodiment when viewed from the side (the left side in FIG. 1). Structures common to the respective parts of the compressor body 1 shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

  A lower piston ring 29 that prevents leakage of compressed fluid in the upper cylinder 23 to the crank chamber 21 side is fitted to the lower side surface of the crosshead piston 24 on the crank chamber 21 side.

  The lower cylinder 22 or the upper cylinder 23 below the upper piston ring 28 when the crosshead piston 24 is located at the bottom dead center and above the lower piston ring 29 when the crosshead piston 24 is located at the top dead center. A communication hole 34 communicating with the crank chamber 21 is provided on the side surface.

  In this embodiment, the blow-by from the gap between the crosshead piston 24 and the upper cylinder 23 during compression is sealed by the lower piston ring 29, so that all blow-by can flow into the crank chamber 21 through the communication pipe 33. It becomes.

  Therefore, it is possible to obtain an effect of suppressing the wear of the rider ring and the progress of deterioration of the grease-filled bearing.

  Next, a third embodiment of the present invention will be described. FIG. 4 is a cross-sectional view showing the internal structure of the compressor body 1 shown in the third embodiment when viewed from the side (the left side in FIG. 1). This figure differs from FIG. 2 only in having a cooler 35 in the middle of the communication pipe 33. Structures common to the respective parts of the compressor body 1 shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

  A cooler 35 is provided in the middle of a communication pipe 33 that connects the upper cylinder 23 or the lower cylinder 22 and the crank chamber 21.

  As described above, since the cooling effect can be obtained by the cooler 35 itself and the cooling efficiency is improved, the arrangement of the communication pipe 33 is not in the compressor pulley 5 side but in the free direction with respect to the lower cylinder 22 or the upper cylinder 23. It becomes possible to arrange in. Specifically, it can be arranged at a position where the cooling air on the opposite side of the compressor pulley 5 is not exposed.

  The reciprocating compressor according to the present invention can mainly compress air or the like, but the fluid that can be compressed is not necessarily limited to air, and can be applied to compression of various fluids. Is possible.

DESCRIPTION OF SYMBOLS 1 Compressor body 2 Motor 3 Tank 4 Motor pulley 5 Compressor pulley 6 Transmission belt 21 Crank chamber 22 Lower cylinder 23 Upper cylinder 24 Crosshead piston 25 Cylinder head 26 Connecting rod 27 Crankshaft 28 Upper piston ring 29 Lower piston ring 30 Rider Ring 31 Cylinder hole 32 Crank chamber hole 33 Communication pipe 34 Cylinder hole 35 Cooler

Claims (8)

A crosshead piston that reciprocates in the cylinder;
A cylinder head for closing an end of the cylinder;
A connecting rod for supporting the piston;
A crankshaft for rotationally driving the end of the connecting rod;
A crank chamber that rotatably supports the crankshaft,
A first piston ring is fitted to a side surface of the crosshead piston;
An oil-free reciprocating motion comprising a communication pipe that communicates the side surface of the cylinder and the crank chamber below the first piston ring when the crosshead piston is positioned at the bottom dead center of the reciprocating motion. Compressor. In claim 1,
The cylinder includes a small inner diameter portion on the cylinder head side and a large inner diameter portion on the crankshaft side,
The crosshead piston has a small diameter portion on the cylinder head side and a large diameter portion on the crankshaft side,
The oilless reciprocating compressor, wherein the first piston ring is fitted to the small diameter portion. In claim 2,
An oil-free reciprocating compressor, wherein the communication pipe is connected to the cylinder at the small inner diameter portion. In claim 1,
A second piston ring on the large diameter portion of the crosshead piston;
An oil-free reciprocating compressor, wherein the communication pipe is connected to the cylinder between the first piston ring and the second piston ring. In claim 1,
Having a rider ring in the large-diameter portion of the crosshead piston,
An oil-free reciprocating compressor, wherein the communication pipe is connected to the cylinder between the first piston ring and the rider ring. In claim 1,
It has a compressor pulley with blades that generates cooling air,
The oilless compressor, wherein the communication pipe is disposed at a position where the cooling air is applied. In claim 1,
An oil-free reciprocating compressor, wherein the communication pipe is provided with a cooler. In claim 7,
An oil-free reciprocating compressor, wherein the communication pipe is disposed at a position where the cooling air does not hit.

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