JP2521940Y2 - Compressor piston structure - Google Patents

Description

[Detailed description of the invention]

[0001]

[Purpose of the invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a piston structure of a compressor used in an automobile cooling cycle or the like.

[0003]

2. Description of the Related Art As shown in FIG. 5, for example, a piston of a compressor used in an air conditioner for an automobile includes a piston body 3 reciprocally provided in a bore 2 of a cylinder 1, and a piston body 3 as shown in FIG. Ring grooves 4a, 4b formed on the outer peripheral surface of the piston 3, compression rings 5a, 5b respectively fitted in the ring grooves 4a, 4b, and one end provided on the inner surface of the crown 6 of the piston body 3 with a spherical bearing. 7 is connected by caulking, and the other end has a rod 8 and the like connected to a drive source for reciprocating the same (for example, see Japanese Utility Model Laid-Open No. 1-71,178). In this piston P, in order to prevent the flow of gas more than necessary between the inner peripheral surface S of the cylinder and the outer peripheral surface of the piston main body 3, the tip of the piston P is moved radially outward during the forward movement of the piston. A first compression ring 5a that opens is fitted and inserted, and a second compression ring 5b whose tip opens radially outward when the piston moves backward is fitted into the other ring groove 4b. In order to lubricate such a piston P, for example, an oil reservoir is provided in the lower part of the inside of the casing of the compressor, and the lubricating oil in the oil reservoir is scraped up by an appropriate means and sprinkled with oil, or the rod 8 is inserted. There is a method of forcibly lubricating a lubricating oil passage or the like by a pump. In addition, lubricating oil is mixed into the refrigerant supplied to the piston P, and an air flow (hereinafter, blow-by) flowing between the compression ring 5 and the inner peripheral surface S of the cylinder 1 in the direction outside the cylinder (in the direction of arrow A in the figure) during compression. ) To supply lubricating oil, and this method has an advantage that it is not necessary to install an oil reservoir and a lubricating oil pump.

[0004]

In the method of supplying lubricating oil by blow-by, in order to supply a sufficient amount of lubricating oil for lubrication of the compressor, the distance between the compression ring 5 and the cylinder inner peripheral surface S is increased. There is a need to. However, if the distance between the compression ring 5 and the inner circumferential surface S of the cylinder is increased, the lubricating oil is sucked into the cylinder from the crank chamber by the airflow flowing in the cylinder direction (the direction of arrow B in the drawing) when the piston P is sucked. Therefore, the lubricating oil in the crank chamber decreases, and the lubricating oil supplied to the bearing portion 7 and the like becomes insufficient, which may cause poor lubrication. In addition, due to the airflow in the cylinder direction, the internal pressure of the cylinder is not sufficiently reduced at the time of suction, and the suction amount of the refrigerant is reduced, so that a problem such as a decrease in the efficiency of the compressor occurs.

The present invention has been made to solve the above-mentioned problems of the prior art, in which a sufficient lubricating oil is supplied by a blow-by when a cylinder is compressed, and a lubrication by an in-cylinder air flow which occurs when the cylinder is sucked. An object of the present invention is to provide a piston structure of a compressor that can effectively prevent re-suction of oil.

[0006]

[Structure of device]

[0007]

In order to achieve the above object, according to the present invention, there is provided a piston body provided reciprocally in a cylinder, and a plurality of ring grooves formed on an outer peripheral surface of the piston body. And a compression ring having a compression ring fitted in each of the ring grooves, wherein a pair of the ring grooves is formed, and one of the ring grooves has a first compression ring whose tip opens radially outward when the piston moves forward. A second compression ring, whose tip opens radially outward when the piston is moved backward, is inserted into the other ring groove, and the distance between the first compression ring and the inner peripheral surface of the cylinder is reduced. It is characterized in that it is larger than the spacing between the surfaces.

[0008]

With this configuration, the distance between the first compression ring, which opens radially outward during forward movement, and the inner peripheral surface of the cylinder, and the distance between the second compression ring, which opens radially outward during backward movement, and the inner peripheral surface of the cylinder, increase. Since the distance is larger than the interval, the airflow from the cylinder toward the crank chamber during compression can be increased, and the airflow from the crank chamber toward the cylinder inside during suction can be prevented. Therefore, the lubricating oil in the refrigerant can be sufficiently guided to the spherical bearing portion and the like by the blow-by, and the lubricating oil due to the reverse airflow can be effectively prevented from flowing out of the crank chamber.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a piston showing one embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of the piston, and FIGS. 3 and 4 are main parts showing another embodiment of the present invention. FIG. 6 is an enlarged sectional view, in which members common to those shown in FIG. 5 are denoted by the same reference numerals.

1 and 2, a piston P of a compressor includes a piston body 20 reciprocally provided in a cylinder 1 and a pair of ring grooves 21 and 22 formed on an outer peripheral surface of the piston body 20. , This ring groove 21,
Compression ring 2 fitted to each
3 and 24, one end of which is connected to the inner surface of the crown 6 of the piston body 20 by caulking the spherical bearing 7;
The other end has a rod 8 and the like connected to a drive source.

A first compression ring 23 is provided in a ring groove 21 inside the cylinder and a ring groove 2 outside the cylinder.
2 is provided with a second compression ring 24. These compression rings 23, 24
Is made of a synthetic resin that is relatively hard and has low frictional resistance, such as a polytetrafluoroethylene resin.

The first compression ring 23 is fitted and inserted so that the base end thereof abuts against the partition wall 25 of the ring groove 21 so that the front end opens radially outward when the piston body 20 moves forward. The compression ring 24
The base end is fitted so as to abut against the partition wall 23 of the ring groove 22 so that the distal end opens outward in the radial direction when the piston body 20 moves backward.

In this embodiment, the ring groove 21 into which the first compression ring 23 is inserted is deeper than the ring groove 22 into which the second compression ring 24 is inserted. Therefore, the distance between the first compression ring 23 and the cylinder inner peripheral surface S is larger than the distance between the second compression ring 24 and the cylinder inner peripheral surface S. In this way, as shown in FIG. 2 in particular, the first compression ring 21 has its tip open when the piston body 3 moves forward, as indicated by the dotted line in the figure. Is large, the force pressed against the inner peripheral surface S is relatively weak, and a sufficient amount of lubricating oil in the refrigerant is carried by the blow-by in the direction of the arrow X in the figure. On the other hand, the tip of the second compression ring 23 whose tip opens outward in the radial direction when the piston moves backward is tightly pressed against the inner circumferential surface S because the interval between the second compression ring 23 and the inner circumferential surface S of the cylinder is small. Is prevented from flowing into the cylinder. Therefore,
Since it is possible to effectively prevent the lubricating oil from flowing out of the crank chamber, it is possible to supply a sufficient amount of the lubricating oil during compression and to maintain the supplied lubricating oil. Further, by preventing the air flow in the cylinder direction generated at the time of suction, the pressure in the cylinder at the time of suction can be sufficiently reduced, so that the efficiency of the compressor can be improved.

As described above, in this embodiment, the first
The ring groove 22 into which the second compression ring 24 is inserted is made shallower than the ring groove 21 into which the compression ring 23 is inserted. However, in the piston structure according to the present invention, the interval between the first compression ring 23 and the inner circumferential surface S of the cylinder is different from that of the second compression ring 24.
It is sufficient that the distance is larger than the distance between the cylinder inner peripheral surface S and, for example, a structure as shown in FIG. 3 or FIG. That is, in the embodiment shown in FIG.
The knurls 33 and 34 which are convex portions extending in the circumferential direction of the piston main body 30 are provided on the bottom surfaces of the pair of ring grooves 31 and 32 provided on the outer peripheral surface of the first compression ring 23, and the first compression ring 23 is fitted therein. Knurl 3 of groove 31
3 is lower than the knurl 34 of the ring groove 32 into which the second compression ring 24 is inserted. Even in such a structure, the distance between the first compression ring 23 and the inner peripheral surface S of the cylinder is larger than the distance between the second compression ring 24 and the inner peripheral surface S of the cylinder. Since the force pressed against S becomes larger when the piston body 3 moves backward than when it moves forward, a sufficient amount of lubricating oil is carried by blow-by in the direction of arrow X in the drawing, and airflow from the crank chamber to the cylinder direction is prevented. It is possible to prevent the lubricating oil from flowing out.

In the embodiment shown in FIG. 4, a pair of ring grooves 21 provided on the outer peripheral surface of the piston body 20 are provided.
Among the 22, the first compression ring 41 inserted into the ring groove 21 located inside the cylinder is thinner than the second compression ring 42 inserted into the ring groove 22 located on the crank chamber side. Even in such a structure, as in the embodiment shown in FIGS. 1 and 2, a sufficient amount of lubricating oil can be conveyed by the blow-by in the direction indicated by the arrow X in FIG. It is possible to prevent the lubricating oil from flowing out.

[0016]

[Effects of the Invention] As described above, according to the present invention,
Since the blow-by in the direction of the crank chamber at the time of piston compression can be made larger than the airflow in the cylinder direction generated at the time of suction, the lubricating oil in the refrigerant is sufficiently guided by the blow-by to the spherical bearing portion and the like. The outflow of lubricating oil due to airflow can be effectively prevented. In addition, the amount of recompression of the refrigerant and the like decreases, and the discharge gas temperature decreases somewhat,
The durability of the compressor itself is improved. In addition, by preventing the air flow in the direction of the crank chamber generated at the time of suction, the pressure in the cylinder at the time of suction can be sufficiently reduced, and the efficiency of the compressor can be improved. Therefore, the heat exchange efficiency of the heat exchanger is improved, and the cooling power of the air conditioner for a vehicle is also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a piston showing one embodiment of the present invention;

FIG. 2 is an enlarged sectional view of a main part of the piston,

FIG. 3 is an enlarged sectional view of a main part of a piston showing another embodiment of the invention.

FIG. 4 is an enlarged sectional view of a main part of a piston showing still another embodiment of the present invention;

FIG. 5 is an explanatory sectional view showing a piston portion of a general compressor.

[Explanation of symbols]

1 ... Cylinder, 20,3
0: piston body, 21, 22, 31, 32: ring groove, 23, 41: first compression ring, 24,
44: second compression ring, 33, 34: knurl, S: inner peripheral surface of cylinder.

Claims (4)

(57) [Scope of request for utility model registration] 1. A piston body (20) provided reciprocally in the cylinder 1, a plurality of ring grooves (21, 22) formed on the outer peripheral surface of the piston body 20, and a ring groove (21). ,
22) compression ring (23,
24), a pair of the ring grooves (21, 22) is formed, and one of the ring grooves (21) is provided with a first compression ring (23) whose tip opens radially outward when the piston moves forward. The second compression ring (24) whose tip opens radially outward when the piston is moved backward is inserted into the other ring groove (22), and the first compression ring (23) and the cylinder inner peripheral surface (S) are inserted. The interval of
2nd compression ring (24) and inner circumferential surface of cylinder (S)
The piston structure of the compressor, characterized in that it is larger than the interval. 2. A ring groove (21) in which said first compression ring (23) is inserted is deeper than a ring groove (22) in which said second compression ring (24) is inserted. 2. The piston structure of the compressor according to claim 1. 3. A plurality of knurls (33, 34) forming convex portions extending in the circumferential direction of the piston body (30) are provided on the bottom surface of each of the ring grooves (31, 32). The knurl (33) of the ring groove (31) into which the ring (23) is inserted is lower than the knurl (34) of the ring groove (32) into which the second compression ring (24) is inserted. 2. The piston structure of the compressor according to claim 1. 4. The first compression ring (41)
The piston structure of a compressor according to claim 1, wherein said second compression ring (44) is thinner than said second compression ring (44).