KR910000563B1 - Device for forcing piston ring radially outwardly - Google Patents

Abstract

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Description

Radial outward extrusion device of piston ring

1 is a partial cross-sectional view of the first embodiment of the present invention.

2 is a view used to explain the manner of operation of the first embodiment when the axis of the plunger is misaligned with respect to the axis of the conical hole in the piston ring.

3 is a partial cross-sectional view of a second embodiment of the present invention.

Figure 4 is used to explain the operation of the second embodiment when the axis of the plunger is misaligned with respect to the axis of the conical hole in the piston ring.

5 is a cross-sectional view of a piston and cylinder using a conventional apparatus for extruding the piston ring radially outwards against the inner wall of the cylinder.

FIG. 6 is an enlarged perspective view showing the relationship between the plunger and the piston ring in the conventional apparatus shown in FIG.

7 is a view used to explain the manner of operation of the conventional device shown in FIG.

* Explanation of symbols for main parts of the drawings

1,15 plunger 2,18 head

3,16: piston ring 4,13: hole

5,20: centerline 6: cap

11 cylinder 12 piston

14: coil spring 17: rod

19: groove

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radially outward extrusion device of a piston ring, and more particularly to a radially outward extrusion device of a piston ring suitable for use in a reciprocating compressor or for a piston valve or air cylinder drive valve reciprocating in a cylinder under gas pressure. It is about.

Generally, oil-free reciprocating compressors have piston rings for compressing gases. This piston ring is pushed against the inner wall of the cylinder to minimize the leakage of compressed gas. Several methods have been proposed for pushing the piston ring radially outward against the inner wall of the cylinder, one of which uses a plunger as shown in FIG.

In Fig. 5, reference numeral 11 denotes a cylinder, 12 denotes a piston, 13 denotes a radial hole of the piston 12, 14 denotes a coil spring, and 15 loosely fits into the radial hole 13 so that the coil spring 14 is compressed. The plunger, 16 to fit, represents a piston ring that fits loosely into the circumferential piston ring groove of the piston 12.

As shown enlarged in FIG. 6, the plunger 15 consists of a hollow cylindrical rod 17 and a head 18 integrated at the radially outer end of the rod 17. A groove 19 for receiving the plunger head 18 is formed in the inner circumferential surface of the piston ring 16. In particular, the coil spring 14 is inserted into the plunger rod 17 and is compressed when the rod 17 is fitted into the radial hole 13, thereby always pushing the plunger 15 toward the cylinder 11. That is, the plunger head 18 is forcibly pushed into the groove 19 so that the piston ring 16 is always in close contact with the inner wall of the cylinder 11.

In the conventional apparatus described above with reference to FIGS. 5 and 6, the contact surface between the plunger head 18 and the bottom of the groove 19 is flat. The head 18 and the recess 19 must be machined with high precision to avoid deflection or deviation due to misalignment.

In addition, there is a problem that a right angle state must be maintained between the contact surface and the axis of the rod 17 with high precision. That is, as shown in FIG. 7, when the shaft of the plunger 15 is not in line with the centerline 20 of the groove 19, the piston ring 16 is in FIG. The parts marked A may be damaged or initially damaged at the connection B of the rod 17 and the head 18.

In addition, since the plunger head 18 is inserted into the groove 19 to reciprocate integrally with the piston ring 16, the problem that the head 18 collides with the piston 12 and leaves a recess in the piston wall is also caused. have.

The present invention has been made to overcome the above and other problems encountered in conventional devices for extruding the piston ring radially outwards against the inner wall of the cylinder. It is therefore a primary object of the present invention to provide a radially outward extrusion device of a piston ring which is capable of preventing damage at an early stage of use due to misalignment between the centerline of the groove on the piston ring and the axis of the plunger.

In order to achieve the above and other objects, the present invention provides a radial outward direction of the piston ring such that the spring and plunger are received in each hole on the piston, so that the reaction force of the spring causes the plunger to push the piston ring against the inner wall of the cylinder. The extrusion apparatus is characterized in that the plunger is made of a rod-shaped member, has a convex hemispherical head, and the piston ring has a conical hole for receiving the head.

The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of the preferred embodiments with reference to the accompanying drawings.

First, referring to FIG. 1 showing a first embodiment of the present invention, reference numeral 1 is a single rod-shaped plunger, 2 is a convex hemispherical head of the plunger, 3 is a piston ring, 4 is a hemispherical shape of the plunger 1 It shows the conical hole of the piston ring 3 in which the head 2 is loosely fitted. That is, the surface of the plunger 1 which comes into contact with the piston ring 3 is block and hemispherical as indicated by reference numeral 2, and the piston ring 3 is the head 2 which forms the hemispherical surface of the plunger 1. It has a conical hole 4 suitable for accommodating. In the case of a compression spring type, a coil spring (not shown) is inserted into the plunger 1.

Since the contact surface on the plunger 1 is hemispherical and the piston ring 3 is conical, even if the axis of the plunger 1 is misaligned with respect to the center line 5 as shown in FIG. 2, the plunger 1 The hemispherical head 2) maintains a uniform contact with the conical surface of the hole 4, while the plunger 1 pushes the piston ring 3 radially outward (right in FIG. 2). As a result, the eccentric load no longer acts on the piston ring 3 and the contact is maintained in a stable manner between the plunger 1 and the piston ring 3. In addition, since the hemispherical head 2 of the plunger 1 is fitted into the conical hole 4 of the piston ring 3, the plunger head 2 does not directly contact the piston.

Next, a second embodiment of the present invention will be described with reference to FIG. This second embodiment has substantially the same construction as the first embodiment described above with reference to FIG. 1 except that a cap 6 having a hemispherical end is fitted over the hemispherical head 2 of the plunger 1. similar. A hemispherical end of the cap 6 is inserted into the hole 4 of the piston ring 3 to push the piston ring 3 radially outwards against the inner wall of the cylinder. The cap 6 is made of Teflon®, reinforced plastic, rubber or asbestos.

The second embodiment is advantageous over the first embodiment in that the plunger 1 does not directly push the piston ring. Since the piston ring 3 pushes the cap, even if the piston ring 3 is made of carbon or the like, it is not damaged.

In the second embodiment, the cap 6 is fitted as a cushioning means on the hemispherical head 2 of the plunger 1, but the cushioning means is attached to the surface of the plunger 1 in direct contact with the piston ring 3. Understand that it is enough. Thus, for example, the cushion material may be coated on the plunger 1, the plunger 1 itself may be made of the cushion material, the cushioning means may be added into the plunger 1, or the cushioning means may be It may be in contact with the plunger 1 by the adhesive. As an alternative, the cushioning means may be arranged in the conical hole 4 of the piston ring 3.

As described above, according to the present invention, the plunger is made of a rod-shaped member, and its head is not enlarged but is hemispherical. The piston ring is provided with a hole suitable only for receiving the hemispherical head of the plunger therein. Therefore, the manufacture and assembly of the component parts are much easier. In particular, the contact surface of the plunger to the piston ring is convex hemispherical, and the hole of the piston ring is in contact with the conical surface. As a result, even if the axis of the plunger is deflected with respect to the center line or the axis of the conical hole of the piston ring, it is possible to maintain a uniform contact between the plunger and the piston ring. Therefore, unlike conventional devices, the plunger and the piston ring are not damaged and no recess is formed on the piston. In addition, the components need not be manufactured with high precision.

Furthermore, according to the present invention, the cushioning means is sandwiched between the contact surfaces of the plunger and the piston ring, so that, unlike the conventional apparatus, it is possible to prevent the plunger and the piston ring from being damaged, and furthermore, a recess is formed on the piston. It doesn't work.

Claims (4)

In a radially outward extrusion device of a piston ring in which a spring and a plunger are accommodated in each hole on the piston, the reaction force of the spring causes the plunger to push the piston ring against the inner wall of the cylinder, wherein the plunger is a single rod-shaped member. And a convex hemispherical head, wherein said piston ring has a conical hole for receiving said head. 2. The radially outward extrusion device of a piston ring according to claim 1, wherein a cap is fitted over the head of the plunger. 2. The radially outward extrusion device of a piston ring as recited in claim 1, wherein said plunger is at least the head of which is made of cushioning material. 2. The radial outward extrusion device of a piston ring as recited in claim 1, wherein a cushioning material is disposed in the hole of the piston ring.

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