JPS60113866A - Piston device - Google Patents

Abstract

PURPOSE:To increase the seal length between a piston body and a cylinder by connecting a tubular body to a bottomed tubular piston body connected to a connecting rod through a pivot connected structure. CONSTITUTION:A bottomed tubular piston body 11 is provided to reciprocate in a hollow portion of a tubular cylinder 12. Also, the piston body 11 is formed in the hollow bottom surface with a spherical recess 13 to constitute a pivot connected structure with a spherical body 14 of a connecting rod 15. A tubular body 16 is connectively provided axially in the opening side end of the piston body 11 and has the overall outer diameter dimension slightly smaller than that of the piston body 11. And since the piston body 11 and the tubular body 16 increase the length of contact with the cylinder 12 in the gas compression stroke, the seal property in this portion can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a piston device that is incorporated into a compressor used in a refrigerator or the like.

[Technical background of the invention and its problems]

BACKGROUND ART In a compressor used in a refrigerator or the like, refrigerant gas sucked into a cylinder is compressed and discharged using a piston device, and then supplied to a cooling system.

Conventionally, this type of piston device, as shown in FIG. There is a device in which a connecting rod 5 having a spherical body 4 at one end is inserted into a spherical recess 3, and the spherical body 4 is inserted into the spherical recess 3 and connected in a so-called pivot connection structure in which the spherical body 4 is loosely fitted in a caulking process.

However, in such a piston device, there is a gap a of about 6 to 8 μm between the cylinder 1 and the piston body 2, so there is no possibility that the gas compressed within the cylinder l will flow out through the gap a. . For this reason, normally, the lubricating oil sealed in the compressor is atomized from the back of the piston body 2 in conjunction with the drive of the connecting rod 5 to seal the gap a and prevent the compressed gas in the cylinder 1 from leaking to the outside. We are trying to prevent this. In this case, the sealability of the oil is determined by the viscosity of the oil in the gap a1 and the length of contact between the cylinder 1 and the piston body 2, that is, the seal length.

However, if the gap a is made smaller, metal contact between the cylinder 1 and the piston body 2 becomes more likely to occur, leading to a decrease in the reliability of the compressor, and a decrease in the penetration force of oil with high viscosity (intrusion into the compressor). . Therefore, the most effective way to improve sealing performance is to increase the seal length.

However, in the piston device shown in FIG. 1, if the length of the piston body 2 is increased in order to increase the seal length, the above-mentioned pivot connection structure becomes unstable. That is, in the caulking process of such a pivot connection structure, a caulking tool with a large length l of the piston body 2 and a large mating tip size is used, but as the length dimension of the piston body 2 increases, the mechanical strength of the caulking tool itself Not only does the strength decrease and it becomes easily damaged, but the caulking part cannot be reliably caulked and a stable pivot connection cannot be obtained.

[Purpose of the invention]

This invention was made to eliminate the above-mentioned drawbacks, and it is possible to stabilize the pivot connection structure between the piston body and the connecting rod, and at the same time improve the sealing performance between the piston body and the cylinder, and improve the volumetric efficiency of the compressor. It is an object of the present invention to provide a piston device that can greatly contribute to improving the base area coefficient.

[Summary of the invention]

In the piston device according to the present invention, a cylindrical body is connected to a bottomed cylindrical piston body to which a connecting rod is connected by a pivot connection structure, and the seal length between the piston body and the cylinder is increased.

〔Effect of the invention〕

According to this invention, since the seal length between the piston body and the cylinder can be increased, the sealing performance of this part can be improved, and the compressed gas in the cylinder can be prevented from leaking to the outside, improving the volumetric efficiency of the compressor. It can also greatly contribute to improving the base coefficient. In addition, since the cylindrical body is attached with the connecting rod connected to the piston body by the pivot connection structure, the caulking process in the pivot connection structure can be performed reliably, and the structure can be stabilized.
can.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, reference numeral 11 denotes a piston body having a cylindrical shape with a bottom, and this piston body 11 is provided in a hollow portion of a cylindrical cylinder 12 so as to be able to reciprocate υ).

Further, a spherical recess 13 is formed on the bottom surface of the hollow portion of the piston body 11. Then, the spherical body 14 of the connecting rod 15 having the spherical body 14 is inserted into one end of the recess 13f, and the connecting rod 15 is loosely connected in a caulking process, thereby forming a so-called pivot connection structure.

A cylindrical body 16 is coaxially connected to the open end of the piston body 11. This cylindrical body 16 has an overall outer diameter slightly smaller than the outer diameter of the piston body 11, and has a small diameter portion 161 formed at one end via a stepped portion. It is inserted and fixed into the open end of 11.

In this case, the larger the length of the cylindrical body 16, the greater the sealing length, which is preferable.
5 does not hit the cylindrical body 16. Furthermore, any method may be used for fixing to the open end of the piston body 11 as long as it does not cause distortion to the piston body 11, such as press fitting or fixing with adhesive.

Note that such a cylindrical body 16 may be made by general lathe processing or the like.

Next, its effect will be explained.

In such a piston device, the piston body 11 is reciprocated in the cylinder 12 by the operation of the compressor, thereby repeatedly sucking, compressing, and discharging refrigerant gas.

In this case, a cylindrical body 16 is connected to the piston body 11, and the length of the piston body 11 and the cylindrical body 16 in contact with the cylinder 12 during the gas compression process is increased. Sealing performance can be improved, and compressed gas in the cylinder 12 can be prevented from leaking to the outside. This can greatly contribute to improving the volumetric efficiency, which is expressed as the ratio between the theoretical exhaust amount and the actual exhaust amount of the compressor, and to improving the build-up coefficient. Further, since such a cylindrical body 16 is attached to the open end of the piston body 11 with the connecting rod 15 connected to the histone body 11 through the pivot connection structure, the crimping process etc. in the pivot connection structure is not necessary. Not only does this not cause any hindrance, this process can be carried out simply and reliably, and the pivot connection structure can be stabilized. Furthermore, by providing the cylindrical body 1G in the piston body 11, the heat dissipation area of the piston body 11 increases, so an improvement in the cooling effect in the piston body 11 can be expected. It is possible to quickly move the piston body 11 toward the piston body 11 side to radiate heat, suppress the temperature rise of the gas, and improve the reliability of the compressor. Furthermore, in the above-described embodiment, the outer diameter of the cylindrical body 16 is slightly smaller than the outer diameter of the piston body 11, so this dimensional difference makes it easier to attach the cylindrical body 16 to the piston body 11. Errors can be compensated for, thereby making the reciprocating movement of the piston body 11 in the cylinder 12 smooth.

Next, FIG. 3 shows another embodiment of this invention. The other parts are the same as those in FIG. 2, and the explanation here will be omitted. In this way, the heat dissipation area of the piston body 11 increases considerably, the cooling effect of the piston body 11 is promoted, the temperature rise of the compressed gas can be reduced, and the reliability of the compressor can be further improved. In this case fin 1
62 may be formed directly on the inner circumferential surface of the cylindrical body 16, or a finned cylindrical body made of a material with good thermal conductivity may be attached.
You can also strain it.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications without changing the gist.

For example, in the embodiment described above, the outer diameter of the cylindrical body 16 is slightly smaller than the outer diameter of the piston body 11, but the outer diameters of the cylindrical body 16 and the piston body 11 may be equal. Furthermore, in the above description, the small diameter portion 161 is formed at one end of the cylindrical body 16, and this is inserted and fixed into the open end of the piston body 11, but the small diameter portion is formed at the open end side of the piston main body 11, This may be configured to be inserted and fixed into one open end of the cylindrical body 16. Further, the pivot connection structure between the piston body 11 and the connecting rod 15 is not limited to that of the embodiment, and other structures may be used.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a conventional piston device, FIG. 2 is a schematic diagram showing an embodiment of the present invention, and FIG. 3 is a schematic diagram showing another embodiment of the invention. It is. l... Cylinder 2... Piston body 3... Spherical recess 4... Spherical body 5... Connecting rod 11... Piston main body 12... Cylinder 13... Spherical recess 14... Spheroid 15.
...Connecting rod 16--Cylindrical body 161...Small diameter portion 162--Fin

Claims (1)

[Scope of Claims] (1) A piston body having a cylindrical shape with a bottom, a connecting rod connected to the bottom of the hollow part of the body via a pivot connection structure, and a connecting rod connected to the open end of the piston body. (2) The piston device is characterized in that the cylindrical body has an outer diameter slightly smaller than the outer diameter of the piston body. The piston device according to scope 1. (3) The patent characterized in that the cylindrical body has a small diameter part formed at one end via a stepped part, and the small diameter part is inserted and fixed into the open end of the piston body. A piston device according to claim 1 or 2. (4) Any one of claims 1 to 3, wherein the cylindrical body has fins on its inner peripheral surface. The piston device described.