JPH0558879U - Reciprocating compressor - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent a gap from being created between the tension ring and the piston ring, and improve the discharge efficiency of the reciprocating compressor. [Structure] The tension ring 21 is formed with a missing portion 21C, and the inner peripheral side of the piston ring 22 has a mating portion 22C.
A locking projection 22D is provided so as to project inward by a thickness of the tension ring 21 from a portion facing to. The engagement protrusion 22D of the piston ring 22 is inserted into the lacking portion 21C of the tension ring 21 to fit the tension ring 21 in the piston ring 22 and prevent mis-assembly, and at the same time, Abutment part 22
It is possible to prevent a gap from being formed in the vicinity of C with the tension ring 21.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a reciprocating compressor preferably used for compressing gas such as air, and more particularly to a reciprocating compressor capable of maintaining airtightness between a piston and a cylinder for a long period of time.

[0002]

[Prior Art]

 4 to 6 show a reciprocating compressor according to the prior art.

In the figure, 1 is a crank case, 2 is a cylinder mounted on the crank case 1, and a valve seat member 3 having a suction hole 3 A and a discharge hole 3 B is mounted on the cylinder 2. ing. A suction valve 4 is provided in the suction hole 3A of the valve seat member 3, and a discharge valve 5 is provided in the discharge hole 3B. Reference numeral 6 denotes a cylinder head mounted on the cylinder 2 via the valve seat member 3, and the inside of the cylinder head 6 is divided into a suction chamber 6B and a discharge chamber 6C by a partition wall 6A, and the suction chamber 6B has a suction port 6B. 6B1 and a discharge port 6C1 are formed in the discharge chamber 6C.

Reference numeral 7 denotes a piston slidably mounted in the cylinder 2, and the piston 7 is a flat piston head 7A and extends from the periphery of the piston head 7A toward the lower end side. It has a cylindrical shape with a lid and a cylindrical skirt portion 7B. The skirt portion 7B has a piston ring groove 8 as a ring groove on the outer peripheral side near the piston head 7A side. A rider ring groove 9 is formed near the lower end of the, and a tension ring 12 and a piston ring 13, which will be described later, are stacked in the piston ring groove 8.

Reference numeral 10 denotes a connecting rod that connects a crankshaft (not shown) and the piston 7, and the connecting rod 10 has a large end portion (not shown) connected to the crankshaft in the crankcase 1. The small end portion 10A is connected to the piston 7 by a piston pin 11 in the skirt portion 7B of the piston 7.

Reference numeral 12 denotes a tension ring, and the tension ring 12 is formed by bending an elastic metal plate into an annular shape as shown in FIG. 5, and one end 12A side and the other end 12B side extend over about half a circumference. The tension rings 12 are formed so as to be overlapped with each other, and when the overlapped portion is widened and deformed so as to reduce the diameter, the tension ring 12 is provided with a spring property that tends to widen in the diameter expansion direction.

Reference numeral 13 denotes a piston ring. The piston ring 13 is formed in an annular shape with one notch, and a lower step portion 13A formed by notching an upper part on one end side of the notch part and the other end. The upper step portion 13B is formed by cutting out the lower part on the side, and the lower step portion 13A and the upper step portion 13B form a mating portion 13C. The piston ring 13 is inserted into the piston ring groove 8 of the piston 7 by inserting the tension ring 12 on the inner peripheral side as shown by the arrow A, and at this time, the piston ring 13 is attached to the cylinder 2 Inside, the lower step portion 13A and the upper step portion 13B of the abutment portion 13C abut against each other to form a ring capable of contracting and expanding the diameter. Further, the tension ring 12 covers the back surface of the mating portion 13C of the piston ring 13 and constantly presses the piston ring 13 in the radial expansion direction so that the inner peripheral surface of the cylinder 2 is brought into sliding contact with the outer peripheral surface of the piston ring 13. Thus, the airtightness between the cylinder 2 and the piston 7 is maintained.

Reference numeral 14 denotes a rider ring, which is fitted in a rider ring groove 9 of the piston 7, and the rider ring 14 extends along the inner peripheral surface of the cylinder 2 to form the skirt portion 7 B of the piston 7. It is designed to slide smoothly.

When the piston 7 is mounted inside the cylinder 2, a compression chamber 15 is defined between the valve seat member 3 and the upper end of the piston head 7A, and the compression chamber 15 is defined in the cylinder 2 of the reciprocating compressor. While the piston 7 reciprocates, the gas is sucked into the compression chamber 15 through the suction valve 4 in the suction stroke, and the compressed gas is discharged from the compression chamber 15 through the discharge valve 5 in the discharge stroke. ing.

[0010]

[Problems to be solved by the device]

 By the way, in the above-described reciprocating compressor according to the prior art, the tension ring 12 mounted in the piston ring groove 8 of the piston 7 presses the piston ring 13 in the radial expansion direction, and the piston ring 13 becomes the inner circumference of the cylinder 2. The sliding contact with the surface seals the inside of the crankcase 1 and the compression chamber 15 side, and at this time, the abutment portion 13C of the piston ring 13 is abutted with the lower step portion 13A and the upper step portion 13B. Thus, the airtightness between the crankcase 1 side and the compression chamber 15 is maintained.

However, when the tension ring 12 and the piston ring 13 are mounted in the piston ring groove 8 of the piston 7 so as to overlap with each other, the piston 2 may be erroneously assembled in the cylinder 2 due to incorrect assembly during assembly or use of the reciprocating compressor. When 7 repeatedly slides and the tension ring 12 and the piston ring 13 relatively rotate in the circumferential direction, the other end 12B of the tension ring 12 and the mating portion 13C of the piston ring 13 come close to each other as shown in FIG. There is a case. In such a case, a gap S is formed between the tension ring 12 and the piston ring 13 between the lower step portion 13A and the upper step portion 13B as shown in FIG. There is a problem that the high-pressure gas in the compression chamber 15 may leak to the crankcase 1 side in the direction of arrow B via S, and the discharge efficiency of the compressed gas may decrease.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention allows the tension ring to be prepositioned with respect to the piston ring during the assembly operation, and the piston slides in the cylinder. Even so, it is an object of the present invention to provide a reciprocating compressor capable of surely preventing the discharge efficiency from being lowered due to the relative position being displaced and the airtightness being lowered.

[0013]

[Means for Solving the Problems]

 The feature of the configuration adopted by the present invention to solve the above-mentioned problems is that the piston ring is provided with a stopper portion that restricts relative rotation of the tension ring, and the gap between the mating portion of the piston ring and the tension ring is provided. Is to keep the airtight.

Further, the stopper portion may be provided at a position separated from the mating portion of the piston ring.

[0015]

[Action]

 With the above configuration, the tension ring can be pre-positioned with respect to the piston ring during assembly work, and the piston ring is prevented from rotating in the circumferential direction on the outer peripheral side of the tension ring when the reciprocating compressor is used. Since this can be prevented, it is possible to maintain the airtight state between the mating portion of the piston ring and the tension ring for a long period of time.

[0016]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. In the embodiment, the same components as those of the above-mentioned conventional technique are designated by the same reference numerals and the description thereof will be omitted.

First, FIG. 1 shows a first embodiment of the present invention.

In the figure, reference numeral 21 denotes a tension ring used in this embodiment, and the tension ring 21 is formed by bending an elastic metal plate in the same manner as the tension ring 21 described in the prior art. When the distance between the one end 21A side and the other end 21B side is narrowed and the diameter is reduced and deformed, it has a spring property of expanding in the diameter expanding direction. Further, the tension ring 21 has a gap 21C between the one end 21A and the other end 21B which are separated from each other in advance.

Reference numeral 22 denotes a piston ring, which has a joint portion 22C including a lower step portion 22A and an upper step portion 22B, which is similar to the piston ring 13 described in the prior art. Although formed in a ring shape, the piston ring 22 is provided with a locking projection 22D as a stopper portion. Here, the locking projection 22D is formed in an arc shape by protruding by the thickness of the tension ring 21 from a position on the inner peripheral side of the piston ring 22 that faces the facing portion 22C in the radial direction.

Then, as shown by the arrow C, the tension ring 21 is inserted into the inner peripheral side of the piston ring 22, and the locking projection 22D of the piston ring 22 is inserted into the missing portion 21C of the tension ring 21. The tension ring 21 and the piston ring 22 are mounted in the piston ring groove 8 of the piston 7. At this time, the tension ring 21 covers the back surface of the mating portion 22C of the piston ring 22, presses the piston ring 22 in the radial expansion direction, and makes sliding contact with the inner peripheral surface of the cylinder 2, so that the cylinder 2 and piston 7 Seal between the spaces.

The present embodiment has the configuration described above, and there is no particular difference in the basic operation from the prior art.

However, in this embodiment, the tension ring 21 is formed with the defective portion 21C, and the piston ring 22 is inwardly inward from the portion facing the mating portion 22C on the inner peripheral side by the thickness of the tension ring 21. When the tension ring 21 and the piston ring 22 are mounted in the piston ring groove 8 of the piston 7, a locking projection 22D of a circular arc shape protruding to the inside is provided. Since the projection 22D is inserted and the tension ring 21 and the piston ring 22 are formed into an integral ring, the tension ring 21 can be easily positioned with respect to the piston ring 22 during assembly work, for example. The fitting portion 22C and the defective portion 21C of the tension ring 21 are arranged so as to face each other in the radial direction. Since it is determined, it is possible to prevent a gap from being formed between the compression ring 15 and the crankcase 1 side in the vicinity of the mating portion 22C of the piston ring 22, so that gas leakage occurs. Can be prevented.

Even when the reciprocating compressor is used, one end 21A or the other end 21B of the tension ring 21 is engaged with the locking protrusion 22D of the piston ring 22, so that the tension ring 21 and the piston ring 22 are connected to each other. Can be prevented from rotating relative to each other in the circumferential direction, so that the mating portion 22C of the piston ring 22 and the lacking portion 21C of the tension ring 21 can be prevented from being aligned with each other, and the airtightness between the piston 7 and the cylinder 2 can be maintained for a long time. Can be maintained for a long time, and the discharge efficiency of compressed gas can be improved.

Next, FIG. 2 shows a second embodiment of the present invention. The feature of this embodiment is that a recess as a stopper portion is provided on the inner peripheral side of the piston ring and at least one end side of the tension ring is provided. It is because a protrusion is provided to be engaged with the recess.

In the figure, reference numeral 31 denotes a tension ring according to this embodiment, and the tension ring 31 is substantially the same as the tension ring 21 described in the first embodiment, and is substantially C with a defective portion 31 A formed therein. The tension ring 31 has a projection 31C formed by bending the one end 31B side outward in the radial direction, although it has a letter shape.

Reference numeral 32 denotes a piston ring, which is similar to the piston ring 13 described in the prior art, and has a mating portion 32B composed of a lower step 32A and an upper step (not shown). Although it is formed in an annular shape, the piston ring 32 is used as a stopper portion for locking the protrusion 31C of the tension ring 31 at a portion facing the mating portion 32B in the radial direction. 32C is formed.

Then, the piston ring 32 is superposed on the outer peripheral side of the tension ring 31, and these are mounted in the piston ring groove 8 of the piston 7. At this time, the protrusion 31C of the tension ring 31 is locked in the recess 32C of the piston ring 32, and the tension ring 31 covers the back surface of the mating portion 32B of the piston ring 32 and the inner circumference of the piston ring 32. When the piston ring 32 is urged in the radial direction from the side, and the outer peripheral surface of the piston ring 32 is in sliding contact with the inner peripheral surface of the cylinder 2, airtightness between the cylinder 2 and the piston 7 can be maintained.

Thus, also in this embodiment configured as described above, the tension ring 31 can be positioned with respect to the piston ring 32, mis-assembly can be prevented, and the use of the reciprocating compressor is possible. Even at this time, the tension ring 31 and the piston ring 32 can be prevented from shifting in the circumferential direction.

In addition, in the second embodiment, the description has been made assuming that the tension ring 31 is provided with the defective portion 31A. However, the present invention is not limited to this, and as shown in the modification example shown in FIG. The ring 41 may be formed in an annular shape so that the other end 41B side is wound around the inner peripheral side of the one end 41A, and the protrusion 41C that locks in the recess 32C may be provided on the one end 41A side. In this case, a gap S'is formed in the overlapping portion of the tension ring 41 on the one end 41A side and the other end 41B side, and this gap S'is at the position farthest from the mating portion 32B of the piston ring 32. Since it is fixed and the upper and lower portions of the gap S'are housed in the piston ring groove 8 (not shown), the airtightness of the piston ring 32 can be maintained for a long time.

Further, in each of the above-described embodiments, the locking projection 22D (recessing recess 32C) serving as the stopper portion is located at a position facing the mating portion 22C (32B) of the piston ring 22 (32) in the radial direction. Although provided, the locking projection 22D (recessing recess 32C) may be provided at a position that is circumferentially separated from the mating portion 22C (32B).

[0031]

[Effect of the device]

 As described in detail above, according to the invention, since the piston ring is provided with the stopper portion that restricts the relative rotation of the tension ring, the tension ring is pre-positioned with respect to the piston ring during the reciprocating compressor assembly work. It is possible to prevent misassembly and prevent misalignment of the tension ring and the piston ring when using the reciprocating compressor, and to prevent the airtightness from being deteriorated, improving the discharge efficiency of compressed gas. be able to.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a tension ring and a piston ring of a reciprocating compressor according to a first embodiment of the present invention.

FIG. 2 is a front view showing a tension ring and a piston ring according to a second embodiment of the present invention.

FIG. 3 is a front view similar to FIG. 2 showing a modification of the tension ring.

FIG. 4 is a vertical sectional view showing a reciprocating compressor according to a conventional technique.

FIG. 5 is an exploded perspective view showing a tension ring and a piston ring according to a conventional technique.

FIG. 6 is an enlarged perspective view of essential parts showing a state where the tension ring and the piston ring are erroneously assembled.

[Explanation of symbols]

 2 Cylinder 7 Piston 8 Piston ring groove (ring groove) 21, 31, 41 Tension ring 22, 32 Piston ring 22C, 32B Abutment part 22D Locking protrusion (stopper part) 31C, 41C Projection part 32C Recessed part (stopper part)

Claims (2)

[Scope of utility model registration request] 1. A cylinder, and a piston slidably fitted in the cylinder and having a ring groove formed on the outer peripheral side thereof.
A piston ring, which is mounted in the ring groove of the piston to seal between the piston and the cylinder and has a mating portion so that the diameter can be reduced and expanded, and an inner peripheral side of the piston ring. In a ring groove of the piston, and a reciprocating compressor including a tension ring that presses the piston ring in a radial direction, a stopper that restricts relative rotation of the tension ring in the piston ring. A reciprocating compressor, characterized in that a portion is provided and the gap between the abutment portion and the tension ring is airtightly held. 2. The reciprocating compressor according to claim 1, wherein the stopper portion is provided at a position separated from a mating portion of the piston ring.