JPS6026236Y2 - compressor piston - Google Patents

Description

[Detailed description of the invention] The present invention provides a compressor piston equipped with a piston ring having a stepped abutment, which efficiently reduces gas leaking from the outer peripheral opening of the lower abutment of the piston ring having the stepped abutment. It takes measures to effectively prevent the piston ring, and it relates to a piston ring that restricts the mounting position of the piston ring with respect to the piston ring groove.

Specifically, the piston ring is placed so that the outer peripheral opening side of the lower abutment of the piston ring is always located on the side thrust side where the piston slides closely through the oil film during the compression stroke with respect to the cylinder. The present invention relates to a piston disposed in a groove via a fixing means of a ring rotation prevention mechanism.

Conventionally, most of the locations where gas leaks from the piston rings are at the joints of the piston rings, so the following measures have been taken.

■By reducing the piston ring gap,
Prevents gas leakage from the piston ring gap into the crank chamber.

■Use a step cut ring to improve overall compression efficiency.

(2) In compressor pistons in which two or more piston rings are disposed in piston ring grooves, methods have been adopted in which the piston rings are installed at different positions at their joints.

However, none of these methods can reliably prevent the gas leakage.

Furthermore, the piston ring joints cannot be brought into perfect contact due to thermal expansion.

Furthermore, the position of the abutment of the piston ring is not constant due to the swinging of the piston and the rotational movement of the piston ring within the ring groove.

Therefore, if the position of the abutment moves within the ring groove to the position shown in Figure 4, that is, if the piston is not in close contact with the cylinder, there will be a large gap between the piston and cylinder below the abutment of the piston ring. Because of the gap, leakage from the outer peripheral opening of the lower abutment of the piston ring escapes directly into the crankcase chamber through the large gap between the cylinder and the piston, resulting in a large amount of leakage.

That is, since there is a structurally unavoidable gap between the piston and the cylinder, leakage occurs from the piston ring abutment through the gap.

However, the inventor of this invention took into consideration that when the piston is in the compression stroke, the side thrust side of the piston inside the cylinder is always pressed against the inner surface of the cylinder and slides in close contact with it. The compression efficiency of the compressor is always maintained by preventing gas from leaking from the outer opening of the lower joint of the piston ring to the gap between the outer circumference of the lower piston and the inner circumference of the cylinder. This makes it possible to maintain stability.

That is, in a compressor piston in which the piston is reciprocated by a crank mechanism, the outer peripheral opening of the lower abutment of the top piston ring, which has a stepped abutment that is installed at the uppermost position in the screw I cylinder, is compressed. The present invention is characterized by obtaining a piston for a compressor, which is arranged in a piston ring groove via a rotation prevention mechanism so as to be always located on the side thrust side where the piston and the piston are in close contact with each other during stroke. .

The present invention will be explained below with reference to the drawings.

In FIG. 1, 1 is a piston, 2 is a cylinder, and 3 is a piston ring attached to the piston 1, and a top ring attached to the uppermost position of the piston rings.

The top ring 3 is generally fixed to the piston 1 by a knock pin 4 in the manner shown in FIGS. 2A, 2B, and 2C, respectively, so that it cannot rotate within the ring groove of the piston.

In the case of the present invention, a knock pin is installed in the piston ring groove so that the outer peripheral opening of the lower joint of the ring is always located on the thrust side where the piston and cylinder come into close contact during the compression stroke. It is fixed by a fixing means such as No. 4 in the rotation prevention plate groove.

5 is an arrow indicating the direction of rotation of the crankshaft.

With the above configuration, as shown in FIG. 1, the piston 1 rising inside the cylinder 2 during the compression stroke is tilted in the rotation direction by the action of rotational moment via the connecting rod due to the rotation of the crankshaft, and the inner wall of the cylinder 2 As a result, as shown in FIG. 3, the outer wall of the piston 1 is in close contact with the cylinder 2 via an oil film.

Therefore, gas entering from the gap between the cylinder 2 and the piston 1 above the top ring enters the piston groove 1a through the abutment 3b above the top ring 3, and the gas enters the gap between the cylinder 2 and the piston 1 above the top ring 3. It tries to leak into the crank chamber through the gap between the cylinder 2 and the piston 1 through the opening 3a, but since the outer wall of the piston 1 is in close contact with the inner wall of the cylinder 2 via the oil film as described above, the top ring 3 The outer circumferential opening of the lower abutment 3a is closed by the inner wall of the cylinder 2 and hermetically closed, and the cylinder 2 and piston 1 below the top ring are maintained in close contact via an oil film. This eliminates the gap.

Thereby, it is possible to reliably stop the flow of gas that is about to leak into the crankcase chamber from between the piston 1 and cylinder 2 on the lower side of the top ring 3 through the outer peripheral opening of the lower abutment 3a of the top ring.

Therefore, since the piston ring rotation prevention mechanism was not provided, the top ring rotated within the ring groove of the piston, and the outer circumferential opening of the lower abutment of the top ring was located outside the side thrust side of the piston in the cylinder. When the cylinder 2 and the piston 1 are located, as shown in FIG. 4, the gap between the cylinder 2 and the piston 1 becomes large.

Therefore, the outer circumferential opening of the lower abutment 3a of the top ring 3 is not sealed up by the inner wall of the cylinder 2, and there is no space between the piston 1 and the cylinder 2 below the top ring 3. Since the gap is large, gas entering from above the top ring 3 passes through the outer peripheral opening of the lower abutment 3a, passes through the gap between the cylinder and the piston, and leaks into the crankcase chamber.

Therefore, a decrease in the compression efficiency of the compressor is observed.

If the position of the outer circumferential opening of the lower abutment of the top ring is not consistently set at the position indicated by the present invention, it will be difficult for the compressor to always produce a constant amount of compressed gas.

Therefore, in the present invention, in a piston having a fixing means for a piston ring rotation prevention mechanism, the outer circumferential opening of the lower abutment of the top ring can be attached to the side of the piston in the cylinder without requiring new parts or extensive processing. Simply install the top ring in the piston ring groove so that it is located on the thrust side using the fixing means of the rotation prevention mechanism.
Fluctuations in the compression efficiency of the compressor can be prevented, and a compressor with consistently high compression efficiency can be produced.

[Brief explanation of drawings]

FIG. 1 shows the state of the piston during the compression stroke, and is an explanatory diagram showing a situation in which the piston is biased toward the side thrust side or tilted inside the cylinder. FIGS. 2A, 2B, and 2C are enlarged views of section B in FIG. 1, and are explanatory diagrams showing a method of fixing the top ring. FIG. 3 shows A-A in each of FIGS. 2A, 2B, and 2C when the outer peripheral opening of the lower abutment of the top ring is located on the side thrust side of the piston with respect to the cylinder.
A sectional view. Figure 4 shows A in each of Figures 2A, 2B, and 2C when the lower abutment of the top ring is located at a portion other than the side thrust side of the piston relative to the cylinder.
A sectional view is shown. 1...Piston, 2...Cylinder,
3...Top ring, 3a...Lower joint of top ring.

Claims (1)

[Scope of utility model registration request] In a compressor piston in which the piston is reciprocated by a crank mechanism, the top ring, which is attached to the uppermost position of the piston ring and has a stepped abutment, has a side thrust where the piston and cylinder come into close contact during the compression stroke. A piston for a compressor, which is disposed within a piston ring groove via a fixing means of a rotation prevention mechanism so as to be always located on the side.