TW201533322A - Piston ring and compressor using same - Google Patents

Abstract

The purpose of the present invention is to provide: a piston ring that can resolve both the problem of ensuring the seal performance of a piston ring for a compressor and the problem of reducing abrasion of the piston ring due to the balance of sliding section surface pressure; and a compressor using such a piston ring. In order to resolve these problems, the piston ring is provided, in an engagement opening section thereof, with a first engagement opening section that overlaps in a step shape in the height direction of the piston ring and a second engagement opening section that overlaps in a lip shape in the radial direction of the piston ring; an end section of the first engagement opening section has, on the pressure side, a first engagement opening groove via which the inner periphery and the outer periphery of the piston ring are linked; an end section of the second engagement opening section has, on the non-pressure side, a second engagement opening groove via which the inner periphery and the outer periphery of the piston ring are not linked due to the overlap of the lip shape; and the outer periphery of the piston ring is provided with a circumferential groove that is linked to the first engagement opening groove and is not linked to the second engagement opening groove. Due to this configuration, abrasion of sliding surfaces can be reduced without causing a decrease in the performance of the piston ring.

Description

Piston ring and compressor using same

The present invention relates to a piston ring and a compressor using the same, and more particularly to a compressor that does not degrade the performance of the piston ring and reduces wear.

Japanese Patent Publication No. 1-7888 (Patent Document 1) is known as a background art in the technical field. In this publication, a structure in which a lip structure is provided on the lower side of the piston ring portion of the piston ring used in the non-oil-filled fluid compressor to prevent fluid leakage in the piston ring joint portion is described.

Japanese Patent Publication No. 59-21067 (Patent Document 2) discloses that a circumferential groove is provided on the outer circumferential surface of the piston ring in order to prevent wear of the piston ring for shutting down the internal combustion engine, and the outer circumferential surface is provided from the inner circumferential surface. The circumferential groove guides the pores of the pressure, thereby making the surface pressure balanced.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Real Fair 1-7888

[Patent Document 2] Japanese Shikai Show 59-21067

Patent Document 1 does not describe a structure in which the sliding portion of the piston ring is pressure-balanced, and the object thereof is to reduce the wear of the piston ring.

Further, Patent Document 2 does not describe the shape of the joint portion of the piston ring, and the circumferential groove In what way is set relative to the mouthpiece. Fig. 32 shows an example of the configuration of a piston ring of a general internal combustion engine. As shown in Fig. 32, the piston ring for the general internal combustion engine is made of metal such as cast iron, and the joint shape is a straight joint 72 (Fig. 32a) or a slanted corner joint 73 (Fig. 32b), because the cylinder and the ring are The same kind of metal, so the difference in thermal expansion is small and the gap can be set to several tens of micrometers. Moreover, since it is used for the internal combustion engine, there is an oil component around the piston ring. As a result, there is not much leakage in the vicinity of the joint portion including the joint portion, and the shape of the joint portion does not affect the performance. Therefore, it is considered that the details of the joint portion of the piston ring are not described. However, in the case of a particularly non-oil-loaded compressor, since the piston ring is made of a resin, in order to prevent the piston ring from expanding due to the temperature during operation, it is necessary to adopt a joint width of several millimeters, that is, an internal combustion engine. Ten times the width of the piston ring joint reduces the leakage of the joint. A and b of Fig. 33 schematically show the joint portion of the piston ring for the reciprocating oil-free compressor corresponding to Fig. 32. As shown in Fig. 33, the joints 76, 77 of Fig. 33 are larger than the joints 72, 73 of Fig. 32. In addition, the case of the step shape (step type cutting) shown in Fig. 3 is also the same. Therefore, in the case of a reciprocating oil-free compressor, the problem is to reduce the leakage of the joint portion and constitute a circumferential groove of the outer circumferential surface of the piston ring.

The present invention has been made in view of the above problems, and it is an object of the invention to provide a compressor which does not cause a decrease in performance due to leakage from a piston ring joint portion and which reduces wear.

In order to solve the above problems, for example, the configuration described in the scope of the patent application is employed. The present invention includes a plurality of mechanisms for solving the above problems, and an example thereof is a compressor including a cylinder, a piston, and a pressurizing side and a non-pressing side which are attached to the piston and seal the cylinder. a piston ring between the pistons, and a piston compresses the fluid in the cylinder to generate a compressed fluid, and the piston ring is attached to the joint portion thereof, and is provided with a first joint portion that overlaps in a stepped shape along the height direction of the piston ring, and a radial direction along the piston ring. The second joint portion that overlaps in the shape of a lip, the end portion of the first joint portion is a first joint groove having an inner circumference and an outer circumference of the piston ring on the pressure side, and an end portion of the second joint portion Attached to the above non-pressurized side a second opening groove having a lip shape overlapping and not communicating with an inner circumference and an outer circumference of the piston ring, wherein a circumferential groove that communicates with the first opening groove and does not communicate with the second opening groove is provided in the piston ring Outer week.

According to the present invention, it is possible to provide a compressor which can achieve a reduction in wear of the sliding surface of the piston ring without causing a decrease in performance.

1‧‧‧storage tank

2‧‧‧Motor

3‧‧‧Compressor body

4‧‧‧Belt

5‧‧‧Compressor pulley

6‧‧‧ crankshaft

7‧‧‧Connecting rod

8‧‧‧Piston

9‧‧‧Piston ring

10‧‧‧ Guide ring

11‧‧‧Inhalation silencer

12‧‧‧Spray outlet

13‧‧‧Cylinder

14‧‧‧Fitting Department

15‧‧‧Fitting Department

21‧‧‧ lip

21a‧‧‧ Lip front end

21b‧‧‧ lip roots

22‧‧‧ lip containment

25‧‧‧Fitting Department

30‧‧‧Piston ring

31‧‧‧ lip

31a‧‧‧ lip front end

31b‧‧‧ lip root

32‧‧‧The lip receiving area

33‧‧‧circular groove

33-1‧‧‧Circular groove

33-2‧‧‧Circular groove

34‧‧‧Upper side slot

35‧‧‧Bottom joint groove

36‧‧‧Connecting slot

37‧‧‧Connecting slot

38‧‧‧circular groove

39‧‧‧Connected holes

40‧‧‧ board

50‧‧‧Piston

51‧‧‧Second face of the piston

52‧‧‧Piston skirt

53‧‧‧Piston ring on the press side (top)

Piston ring below 54‧‧‧

55‧‧‧The joint of the upper piston ring

56‧‧‧The joint of the piston ring below

57‧‧‧Settings for the ring of the piston

58‧‧‧ leak path

60‧‧‧ cylinder

70‧‧‧Piston rings for internal combustion engines

71‧‧‧Piston rings for internal combustion engines

72‧‧‧ Straight joints

73‧‧‧ corner cut

74‧‧‧Piston ring for oil-free reciprocating compressor

75‧‧‧Piston ring for oil-free reciprocating compressor

76‧‧‧ Straight line

77‧‧‧ corner cut

80‧‧‧Support fixture

81‧‧‧ Supporting ring support surface for clamps

82‧‧‧Drawing fixture

83‧‧‧ milling cutter

E‧‧‧ circumferential groove depth

E ₁ ‧‧‧ circumferential groove depth

E ₂ ‧‧‧ circumferential groove depth

h ₁ ‧‧‧ piston ring height

h ₂ ‧‧‧ piston ring height

h ₃ ‧‧‧ circumferential groove height

h ₄ ‧‧‧ piston ring height

h ₅ ‧‧‧ piston ring height

h ₆ ‧‧‧Cutting cutter thickness

L ₁ ‧‧‧Distance between the lower joint groove and the end of the circumferential groove

L ₂ ‧‧‧Distance between the lower joint groove and the end of the circumferential groove

T ₁ ‧‧‧ lip thickness

T ₂ ‧‧‧ lip thickness

Pc‧‧‧ cylinder pressure

P ₁ ‧‧‧Sliding surface pressure

P ₂ ‧‧‧Sliding surface pressure

II‧‧‧Area

δ‧‧‧Restricted wear

1(A) and 1(B) are views showing a schematic configuration of a reciprocating compressor.

Fig. 2 is a view showing a sectional shape of a piston ring to which a piston is attached.

Fig. 3 is a view showing a general joint shape (corner cut) of a piston ring.

Fig. 4 is a view showing a section A-A of Fig. 3.

5(A) and (B) are a plan view and a side view of a piston ring provided with a previous lip shape.

Fig. 6 is a perspective view of the piston ring of Fig. 5 as seen from the inner diameter side.

Fig. 7 is a view showing the state of the previous lip seal.

Fig. 8 is a view showing the state of wear of the sliding surface on the outer circumference of the previous piston ring.

Fig. 9 is a view showing a section B-B of Fig. 7.

Fig. 10 is a view showing a section C-C of Fig. 7.

Figure 11 is a view showing a section D-D of Figure 7.

Figure 12 is a diagram illustrating the surface pressure balance of the prior piston ring.

Fig. 13 is a view showing the configuration of the piston ring of the first embodiment.

Fig. 14 is a view showing the surface pressure balance formed by the circumferential groove of the first embodiment.

Fig. 15 is a view showing the configuration of the piston ring of the second embodiment.

Fig. 16 is a view showing the configuration of the piston ring of the second embodiment.

Fig. 17 is a view showing the configuration of the piston ring of the third embodiment.

Fig. 18 is a view showing the configuration of the piston ring of the fourth embodiment.

Fig. 19 is a view showing the configuration of the piston ring of the fifth embodiment.

Fig. 20 is a view showing the configuration of the piston ring of the embodiment 6.

Fig. 21 is a view showing the configuration of the piston ring of the seventh embodiment.

Fig. 22 is a view showing the configuration of the piston ring of the eighth embodiment.

Fig. 23 is a view showing the configuration of the piston ring of the ninth embodiment.

Fig. 24 is a view showing the configuration of the piston ring of the tenth embodiment.

Fig. 25 is a view showing the configuration of the piston ring of the tenth embodiment.

Fig. 26 is a view showing the configuration of the piston ring of the tenth embodiment.

Fig. 27 is a view showing the configuration of the piston ring of the eleventh embodiment.

Fig. 28 is a view showing the state of the piston in which the piston ring is assembled in the cylinder of the twelfth embodiment.

Fig. 29 is a view showing the relative positional relationship of the two piston rings assembled to the piston of the twelfth embodiment.

Figure 30 is a partial cross-sectional view of the piston ring of Figure 28.

Figure 31 is a view showing the configuration of the piston ring of Embodiment 12.

32a and b are views showing a configuration example of a piston ring closed by an internal combustion engine.

33a and b are views showing a configuration example of a piston ring for a non-oil-operated reciprocating compressor.

Fig. 34 is a view showing a configuration example of the circumferential groove depth of the piston ring of the high-precision machining example 13.

First, the configuration of the reciprocating compressor previously proposed in the present invention and the prior piston ring configuration will be described using the drawings.

Fig. 1 is a view showing a schematic configuration of a reciprocating compressor. In Fig. 1, (A) shows an overall configuration diagram, and (B) shows an enlarged view of the compressor body. In FIG. 1, the motor 2 and the compressor main body 3 are disposed in the sump 1, and the compressor pulley 5 is rotated by a belt 4 attached to a motor pulley (not shown), and the rotation of the crankshaft 6 is converted by the connecting rod 7 into Reciprocating The air that is compressed by the piston 8 and sucked into the atmosphere from the air suction muffler 11 flows from the compressor main body discharge port 12 into the storage tank 1 through a pipe (not shown). Here, the piston ring 9 attached to the piston 8 has a function of sealing between the pressurized side and the non-pressing side in the cylinder. Further, since the compressor body is compressed without lubrication in the case of the oil-free reciprocating compressor, the piston ring 9 and the guide ring 10 are made of a resin such as tetrafluoroethylene resin.

Fig. 2 is a view showing a sectional shape of a state in which the piston 8 is attached to the piston 8. In the case of a non-oil-filled compressor, since the piston ring 9 is made of tetrafluoroethylene resin or the like, the ring is inelastic unlike the oil-supply metal ring. Therefore, a backlash is provided on the inner diameter side of the piston ring 9, and the cylinder internal pressure Pc is guided to the back surface of the piston ring 9 from the originally existing piston ring upper surface gap, thereby pressing the piston ring 9 into the cylinder 13 The surface prevents the leakage of the piston ring 9 from the sliding surface of the cylinder block 13.

On the other hand, the piston ring 9 is formed in a shape in which the joint portion is cut, and can be assembled to the piston by having a joint portion. Further, the structure of the joint portion is designed so as not to cause leakage at the mouth portion during compression. The most common joint shape is the joint portion 14, 15 of the step shape (step cut) shown in Fig. 3. In this case, although there is no leakage path directly leaking from the top, the AA cross-section of FIG. 3 leaks from the lower side of the joint as shown in FIG. 4, and a leak occurs, and the leakage indicated by the arrow in the figure is generated. There is a problem with performance degradation.

On the other hand, a piston ring having a lip shape on the lower side of the piston ring as shown in FIGS. 5 and 6 to reduce leakage is provided (for example, refer to Patent Document 1). That is, in Fig. 5, Fig. 5(A) shows the surface of the lower side (the non-pressurized side in the cylinder) when the piston ring is assembled, and also shows the shape of the joint portion of the side surface of the piston ring. Further, Fig. 5(B) also shows the surface as the upper side (the pressurized side in the cylinder). Hereinafter, the upper side and the lower side are the pressurizing side or the non-pressing side in the cylinder when the piston ring is assembled to the piston. The joint portion on the upper side of the piston ring has a stepped shape as shown in Fig. 5(B), and the lower side has a lip shape as shown in Fig. 5(A). Fig. 6 is a perspective view of the lip joint portion which is the lower joint portion and the stepped joint portion which is the upper joint portion as seen from the inner side of the lower side. As shown in Figures 5 and 6, the lip joint is the radius of the piston ring. The lip 21 on the inner side and the lip receiving portion 22 on the outer side are formed.

Fig. 7 shows a case where the lip 21 is pressed from the inner diameter side to come into contact with the lip receiving portion 22 and sealed. Fig. 8 shows a case where the sliding surface of the outer circumference of the piston ring is worn by the sliding surface of the cylinder and the joint portion 25 is expanded to the limit. At this time, the outer circumference wear amount of the piston ring is the ultimate wear amount δ (that is, the amount of wear when the joint is separated).

9 to 11 show the B-B to D-D cross-section of Fig. 7, and the piston ring joint shown in Fig. 4 is shown, and any joint portion from the piston ring does not have a leak path from the back surface of the piston ring. That is, FIG. 9 shows a cross section taken along line B-B of FIG. 7 and is sealed with a lip 21. Further, Fig. 10 shows a cross section taken along the line C-C of Fig. 7, and is sealed with the lip receiving portion 22 by the lip 21. Further, Fig. 11 shows a cross section taken along the line D-D of Fig. 7, and is also sealed with the lip receiving portion 22 by the lip 21.

Further, the lip shape of the piston ring is as shown in Fig. 7, and the lip front end 21a is formed to be thinner than the lip root portion 21b. As a result, when the outer circumference of the piston ring 9 is worn and the joint is enlarged, the lip front end 21a is easily deformed, and the lip front end 21a is brought into contact with the lip receiving portion 22 to obtain the sealing property.

Next, the surface pressure balance of the piston ring will be described using FIG. Figure 12 shows the pressure balance of the piston ring with the previous case without a circumferential groove. The cylinder internal pressure Pc acts on the back surface of the piston ring 9. On the other hand, since the upper end of the sliding surface of the piston ring is the cylinder internal pressure Pc and the lower end is atmospheric pressure, the pressure distribution of the sliding surface is a triangular pressure distribution as shown. As a result, the average pressure P ₁ of the sliding surface of the piston ring is the value of the pressure of the region I divided by the sliding surface. In this case, P ₁ = Pc/2. Therefore, if the surface pressure on the sliding surface is large, the wear of the sliding surface is also large, and therefore, the problem is how to reduce the surface pressure on the sliding surface.

Thus, the object is to prevent leakage from the joint portion of the piston ring by using a piston ring having a lip shape as shown in FIGS. 5 and 6, and further reduce the surface pressure of the sliding surface of the piston ring. In order to reduce the wear of the sliding surface of the piston ring.

Hereinafter, embodiments of the present invention for solving the above problems will be described using the drawings.

[Example 1]

Fig. 13 is a view showing the configuration of the piston ring 30 of the present embodiment. In Fig. 13, in the piston ring 30, a circumferential groove 33 is provided on the outer circumference of the piston ring (the sliding surface with the cylinder). The circumferential groove 33 is exemplified in the center of the height of the piston ring. Here, the height of the piston ring means a direction parallel to the sliding surface of the piston ring with respect to the cylinder, and the radial direction of the piston ring means the thickness of the piston ring.

The right end portion of the circumferential groove 33 is configured to communicate with the upper side joint groove 34 on the upper side of the piston ring (pressing side in the cylinder), and it is easy to guide the piston ring back pressure or the cylinder pressure to the circumferential groove. Alternatively, it may be configured such that a hole is provided in the circumferential groove 33 and the back pressure is guided. The configuration in which the holes are provided in this manner is also the same in the other embodiments described below. Further, the end portion on the opposite side (the left side in the drawing) of the circumferential groove 33 is provided in the vicinity of the lower side closing groove 35 on the side of the lip receiving portion 32 of the piston ring, but is not in communication with the lower closing groove 35. As a result, it is possible to guide the compressed air in the cylinder from the upper opening groove 34 to the circumferential groove 33 without separately machining the communication hole from the back surface of the piston ring. On the other hand, since the opposite side of the circumferential groove 33 is not in communication with the lower closing groove 35, it is possible to prevent air leakage in the circumferential groove and to deteriorate performance.

Next, Fig. 14 is a view showing the balance of the surface pressure formed by the circumferential groove 33. In Fig. 14, for the circumferential groove 33, as described above, the in-cylinder pressure Pc is guided. Therefore, the pressure Pc above the circumferential groove 33 acts fixedly, the lower end of the groove is Pc, and the lower end of the piston ring is the sliding surface pressure distribution of the atmosphere. In this case, the upper side of the circumferential groove 33 is balanced with the pressure Pc of the back surface of the piston ring. Therefore, the value P ₂ of the pressure in the sliding surface division region II becomes the sliding surface pressure of the present embodiment, and the relationship with the previous sliding surface pressure P ₁ shown in FIG. 12 is P ₂ <P ₁ . Embodiments can achieve a reduction in surface pressure. Further, Fig. 14 is drawn such that the lower end of the circumferential groove is 1/2 of the height of the piston ring, in which case P ₂ = P ₁ /2, and it is judged that the surface pressure can be lowered to 1/2.

Here, the circumferential groove 33 is formed in a groove (rectangular shape) having a fixed width in the depth direction. Therefore, even if the outer circumference of the ring is worn, the width of the circumferential groove 33 is kept constant, so that the balance of the surface pressure can be stably achieved above the circumferential groove 33.

As described above, according to the present embodiment, the piston ring is provided with the circumferential groove avoiding the joint portion, and the surface pressure balance of the piston ring can be reduced and the wear of the sliding surface of the piston ring can be reduced without causing a decrease in performance due to leakage of the joint portion.

Further, the shape of the joint portion of the piston ring 30 of the present embodiment is as shown in Fig. 13, and the thickness of the lip front end 31a and the lip root portion 31b are substantially the same size, and the contact faces of the respective ones are substantially concentric. As a result, when the outer circumference of the piston ring 30 is worn and the lower side opening groove 35 is enlarged, since the lip 31 and the lip receiving portion 32 are substantially concentric, the front end of the lip 31 is deformed without sealing. As long as it slides on the back side of the moving lip receiving portion 32, it is a line contact with respect to the point contact as in the previous configuration, so that the contact length is long, so that even if the lip front end 31a is thick, the joint portion can be obtained. Sealing performance.

Further, it is characterized in that the strength of the vicinity of the front end portion of the lip can be improved by thickening the leading end 31a of the lip, as shown in Fig. 8, even if the piston ring is worn so that the opening is opened.

As described above, in the present embodiment, the piston ring is configured such that the first joint portion (stepped joint portion) that overlaps in the stepped shape in the height direction of the piston ring is provided in the joint portion of the piston ring, and along the piston ring. a second joint portion (lip joint portion) in which a radial shape is overlapped by a lip shape, and an end portion of the first joint portion has a first joint groove (upper joint groove 34) that communicates inside and outside in a radial direction of the piston ring. The end portion of the second joint portion has a second joint groove (lower joint groove 35) that is non-connected in the radial direction of the piston ring by overlapping the lip shape, and is provided on the outer circumference of the piston ring. A circumferential groove in which the first opening groove communicates and does not communicate with the second opening groove. In other words, the circumferential groove has a configuration in which one end communicates with the first joint groove and the other end is formed in the vicinity of the second joint groove. Alternatively, the circumferential groove may be formed on the outer circumference of the piston ring while avoiding the second opening groove.

Further, the present embodiment is a compressor having a cylinder, a piston, and a pressurizing side and a non-pressing side which are attached to the piston and seal the cylinder. a piston ring that generates a compressed fluid by compressing a fluid in the cylinder, wherein the piston ring is provided at a joint portion thereof with a first joint portion that overlaps in a step shape along a height of the piston ring, and a radial direction along the piston ring a second joint portion in which the lip shape is overlapped, and an end portion of the first joint portion is a first joint groove having an inner circumference and an outer circumference of the piston ring on the pressure side, and an end portion of the second joint portion is a second joint groove having a lip shape and a non-communication between the inner circumference and the outer circumference of the piston ring on the non-pressurized side, and the outer circumference of the piston ring is connected to the first joint groove and is not connected to the first 2 The circumferential groove connecting the joint groove.

Thereby, it is possible to provide a compressor which can reduce the wear of the sliding surface of the piston ring without reducing the sealing performance, thereby achieving a long life.

[Embodiment 2]

Next, the configuration of the piston ring according to the present embodiment will be described with reference to Figs. The same configurations as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 15, the height direction of the piston ring of the circumferential groove 33 is lowered toward the lower side, that is, the non-pressing side, and the circumferential groove 33 is formed between the heights of the piston rings in which the lower side opening groove 35 exists. As a result, as shown in Fig. 14, by lowering the lower end of the circumferential groove 33, the range of the surface pressure balance at which the pressure Pc above the circumferential groove 33 is fixed increases, so that the surface pressure can be further lowered. Further, the upper joint portion is provided with a communication groove 36 for connecting the upper joint groove 34 and the circumferential groove 33, thereby simplifying the processing. As a result, since the circumferential groove 33 is provided in the vicinity of the lower closing groove 35, the surface pressure of the joint portion can be further lowered.

Further, when the lip strength is a problem, as shown in Fig. 16, the right end of the circumferential groove may also terminate in the vicinity of the upper opening groove 34. Thereby, the strength of the lip portion can be ensured.

As described above, in the present embodiment, the height direction of the piston ring of the circumferential groove is set to be the height of the lower joint groove, and the communication groove that communicates with the circumferential groove and the upper joint groove is provided, whereby the surface pressure can be further reduced.

[Example 3]

Next, the configuration of the piston ring according to the present embodiment will be described using FIG. The same configurations as those of the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 17, the circumferential groove 33-2 is the same as that of Fig. 15, and is configured such that the height direction of the piston ring is lowered toward the lower side and the average surface pressure is lowered. Further, a circumferential groove 33-1 is provided in the upper joint portion. The circumferential groove 33-1 is in communication with the upper side opening groove 34, and is provided with a communication groove 37 that communicates between the circumferential grooves 33-1 and 33-2. The reason is that in the case of a piston ring having a high piston ring height, only the circumferential groove 33-2 has a higher piston ring height above the circumferential groove 33-2 and exists above the circumferential groove 33-2. Since the pressure is not fixed to Pc, the pressure above the circumferential groove 33-2 is fixed to Pc by providing the circumferential groove 33-1. Therefore, in the piston ring with a high piston ring height, the surface pressure can also be effectively reduced. Alternatively, a hole extending from the circumferential groove to the back surface of the piston ring may be provided as a configuration for guiding the pressure to the circumferential groove 33-1 or the circumferential groove 33-2. Further, in the present embodiment, although two circumferential grooves are used, a plurality of circumferential grooves may be further provided, and the surface pressure may be further uniformized.

As described above, in the present embodiment, a plurality of circumferential grooves are provided in the piston ring, and both ends of the circumferential groove on the pressure side are in communication with the upper side joint groove, and the circumferential groove on the non-pressurized side is not in communication with the lower side joint groove to connect the groove. a compressor is connected between the pressurizing side circumferential groove and the non-pressurizing side circumferential groove, or a non-pressurizing side circumferential groove is provided from the circumferential groove to the back hole, thereby being in a piston ring having a higher piston ring height. It can also effectively reduce the surface pressure.

[Example 4]

Next, the configuration of the piston ring according to the present embodiment will be described using FIG. The same configurations as those of the first to third embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 18, the depth E ₁ of the circumferential groove 33 is constituted by E ₁ > δ with respect to the limit wear amount δ of the piston ring. Further, the ultimate wear amount δ represents the sliding surface wear amount when the limit of the contact length of the sealable lip is obtained as shown in Fig. 8.

As a result, it is possible to stably reduce the surface pressure between the life of the piston ring and to reduce the wear of the piston ring. Also, by the maintenance, the depth of the circumferential groove 33 of the piston ring is confirmed. The degree of wear of the piston ring can be confirmed, and the result can be grasped.

[Example 5]

Next, the configuration of the piston ring according to the present embodiment will be described using FIG. The same configurations as those of the first to fourth embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 19, in order to indicate the position of the circumferential groove, the height above the circumferential groove 33, that is, the height from the pressurized side surface of the piston ring to the pressure side end of the circumferential groove is set to h ₄ And the height of the lower side, that is, the height from the non-pressurized side of the piston ring to the non-pressurized side end of the circumferential groove is h ₅ , the circumferential groove position is h ₄ >h ₅ , that is, the position of the circumferential groove Decreased from the center of the piston ring height. Thereby, the area II shown in FIG. 14 can be further reduced, and the surface pressure of the sliding surface can be further reduced.

[Embodiment 6]

Next, the configuration of the piston ring according to the present embodiment will be described using FIG. The same configurations as those of the first to fifth embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in FIG. 20, when the thickness h ₁ below the piston ring joint portion is smaller than the upper thickness h ₂ and the rigidity of the lip is small, the circumferential groove is formed according to the thickness of the lip. The position of 33 is offset downward. Therefore, in this case, h ₄ >h ₅ can further reduce the surface pressure.

[Embodiment 7]

Next, the configuration of the piston ring according to the present embodiment will be described using Fig. 21 . The same configurations as those of the first to sixth embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 21, the depth E _{1 of the} circumferential groove 33 is smaller than the thickness T _{1 of the} lip receiving portion. As a result, the groove bottom does not rupture from the circumferential groove 33 to cause leakage, and the surface pressure can be lowered.

[Embodiment 8]

Next, the configuration of the piston ring according to the present embodiment will be described using FIG. The same configurations as those of the first to seventh embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 22, the lip receiving portion thickness T ₁ is thickened with respect to the lip thickness T ₂ , that is, T ₁ > T ₂ . The groove depth E _{2 in} this case may be larger than the groove depth E ₁ shown in FIG. That is, when E ₂ >E ₁ , the allowable wear amount δ can be set to be large. That is, there is an advantage that the replacement life of the piston ring can be extended.

[Embodiment 9]

Next, the configuration of the piston ring according to the present embodiment will be described using FIG. The same configurations as those of the first to eighth embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

In the present embodiment, as shown in Fig. 23, a communication hole communicating from the circumferential groove to the back surface, that is, a communication hole 39 communicating with the groove bottom of the circumferential groove and the inner side in the radial direction of the piston ring is provided. As a result, when the abrasion powder is generated on the sliding surface, it can be discharged from the circumferential groove to the back surface, and the surface pressure can be reduced without blocking the circumferential groove.

[Embodiment 10]

In the present embodiment, a method of manufacturing a piston ring will be described.

As a step of manufacturing the piston ring in the above-described embodiment, first, in the case of the oil-free reciprocating compressor, since the rubber is compressed without lubrication, a resin such as tetrafluoroethylene resin is poured into the mold to form the catheter. And processed into a ring of circumferential shape. Next, the joint portion and the lip portion are machined by a milling cutter or the like. Thereafter, the circumferential groove is machined on the outer circumference of the ring. That is, since the circumferential groove must have one end connected to the upper side joint groove and the other end to the front side of the lower side joint groove, the circumferential groove must be machined on the basis of the joint portion, and the circumferential groove process must be performed after the joint portion is processed.

There are two main processing methods for the processing of circumferential grooves. One is as shown in Fig. 24, in which the starting points on both sides of the circumferential groove are set as arcs. For this machining, a T-slot milling cutter can be used for the milling cutter, the bite depth of the slot milling cutter is set to E along the outer circumference of the piston ring, and the groove depth E is processed. In this case, the distance L ₁ between the lower joint groove 35 and the end portion of the circumferential groove increases with the wear of the outer circumference of the piston ring during operation, but there is an advantage that the machining speed is fast.

Further, as shown in FIG. 25, the height h _{3 of the} circumferential groove 33 is set to be the same as the thickness h _{6 of the} T-groove milling cutter, that is, the milling cutter for the width of the circumferential groove and the groove. The blade has the same thickness and can be processed by one movement, so that it can be processed in a shorter time.

The other type is as shown in Fig. 26, in which the shape of the depth direction of the end of the circumferential groove 38 is processed at a right angle with respect to the circumferential surface of the piston ring. At the time of this processing, it can be processed by an end mill that opposes the outer circumference of the piston ring. This method is characterized in that even if the outer circumference of the piston ring is worn, the distance L ₂ between the lower joint groove 35 and the end portion of the circumferential groove does not change, and the surface pressure of the joint portion can be stably lowered to prevent abrasion. This processing method has the above-described characteristics although the processing speed is slower than in the case of using a T-slot milling cutter.

[Example 11]

Next, the configuration of this embodiment will be described using FIG. In Fig. 27, the shape of the piston ring is the shape of the step joint shown in Fig. 3. The pressurizing side port 15 and the non-pressurizing side port 14 are respectively communicated from the inner peripheral side to the outer peripheral side of the piston ring. In the present embodiment, the feature is that the plate 40 is used as a member that blocks the communication between the outer circumferential side and the inner circumferential side of the piston ring. In the present embodiment, a plate 40 made of a thin steel plate or the like is assembled on the inner circumferential side along the inner circumferential surface of the piston ring. Although the plate 40 is set to be about 1.5 turns in the example of Fig. 27, the length is not limited thereto. In the case of this embodiment, the leakage path indicated by the arrow of Fig. 4 is blocked by the presence of the plate 40. In this configuration, by providing the circumferential groove 33 that communicates with the pressurizing side opening 15 but not communicates with the non-pressurizing side opening 14, the back pressure of the ring can be balanced, and the surface pressure of the sliding surface can be reduced. Of course, the technique up to embodiment 10 can be applied to the idea of a circumferential groove of a piston ring.

Further, the plate 40 is not limited to a metal, and may be formed of a resin or a rubber, and may be configured such that the joint on the non-pressurized side is substantially not connected to the outer peripheral side from the inner circumferential side of the ring.

Further, although the present piston ring is difficult to distinguish between the upper and lower sides before the piston is assembled, in order to obtain this function, the side where the joint is connected to the circumferential groove 33 must be assembled as the pressurizing side joint 15 above.

[Embodiment 12]

Next, the configuration of this embodiment will be described using Figs. 28 to 31. Figure 29 shows the assembly The piston rings 53 and 54 of the piston 50 are in a relative positional relationship and the joints are offset by 180 degrees to be assembled. Figure 30 is a cross-sectional view of a portion indicated by F-F of the piston ring 53 of Figure 28 and shown above the piston.

First, the relationship between the piston 50, the cylinder block 60, and the piston rings 53, 54 in the present embodiment will be described. In the present embodiment, since the piston 50 is made of a resin which can directly contact and slide with the heat-resistant cylinder and has slidability, the guide ring 10 shown in Fig. 1(B) is not provided. In this configuration, in order to prevent the cylinder 60 and the piston 50 from being locked due to an increase in temperature during operation, the cylinder 60 and the piston 50 are locked at a temperature during operation. In this case, as shown in FIGS. 28 and 30, the load direction gap δ load during operation is extremely small, and the δ reverse load in the reverse load direction gap is increased. Further, the piston rings 53 and 54 are provided in two vertical directions, and the joints of the piston rings 53 and 54 do not have a pressurizing side and a non-pressing side, and become a straight joint. Further, the piston ring 53 on the pressurizing side is configured such that the joint 55 of the piston ring 53 is always in the load direction by the rotation stopper 57 formed in the annular groove of the piston as shown in FIG. Further, the lower piston ring 54 is configured such that the joint 56 is located in the opposite load direction opposite to the piston ring 53 by the rotation stopper of the lower side ring (not shown).

In the leakage passage of the joint portion in the structure, even if the joint 55 is straight as shown by the leak passage 58 of Fig. 30 and the width of the joint is large, the gap δ load between the second face portion 51 of the piston 50 and the inner surface of the cylinder is small. Thus, the area of the leak path 58 can be made extremely small, and leakage from the joint portion can be reduced. The lower ring 54 also adopts a flow path surrounded by the gap δ reverse load and the joint between the piston skirt 52 and the inner surface of the cylinder as a leakage path. Although the δ back load is larger than the δ load, that is, the δ load < δ reverse load, but the joint is in the reverse direction, the pressure of the piston ring 54 is reduced by the piston ring 53, and thus can be made lower than the piston ring 53. The leakage of the piston ring 54 is also small.

As such, in this configuration, a small leak path formed by the piston rings 53, 54 and the piston 50 can be constructed and a compressor with less leakage can be formed. Fig. 31 is a circumferential groove 33 formed to communicate with the linear joint portion 55 of the piston ring thus constructed. The piston 50 thus constructed and lived In the case of the plug rings 53, 54, even if there is a leakage flow path that directly communicates with the non-pressurized side, there is little leakage, and therefore, by forming a circumferential groove that communicates with the joint of the respective rings, leakage from the joint portion is not increased. The back pressure of the piston rings 53, 54 can be balanced and the surface pressure of the sliding surface can be reduced.

Fig. 32 shows an example in which the piston rings for the internal combustion engine are closed at 70, 71, and the shape of the joint is shown by the joints 72, 73. The ring system can of course be used in a compressor as long as it allows leakage of the joint portion. Fig. 33 is a view showing a state in which the joint portion is not expanded by thermal expansion when used in a non-oil-loading type compressor, and the joint gaps 76 and 77 which are larger than the loop shown in Fig. 32 are set. As long as the shape of the joint is applied, as long as the present embodiment is applied, it is of course possible to reduce leakage and reduce the sliding surface pressure.

Further, although an example in which the circumferential groove 33 communicating with both sides of the joint 55 of the pressurizing side piston ring 53 is provided is shown in Fig. 31, the same effect can be obtained by merely connecting one side.

Further, when the discharge pressure of the compressor is small or when the pressure on the suction side is introduced into the crankcase and the compressor is applied with a back pressure to the piston, the pressure on the pressurizing side and the non-pressurizing side of the ring The difference is small, and the leakage of the joint portion becomes small, thereby reducing the necessity of positioning the loop portion in the load direction. In this case, since the leakage of the joint portion is small even if the rotation preventing member 57 of the ring shown in Fig. 30 is not applied, the circumferential groove is provided only in the piston ring which is rotatably provided, that is, the back pressure of the balance ring And reduce the sliding surface pressure.

Further, a ring in which a plurality of piston rings having a rotation preventing member are provided with a circumferential groove may be provided, and the ring back pressure is gradually reduced by each ring. Furthermore, it is also possible to configure a plurality of rings in which a ring having a circumferential groove is provided in a ring having no rotation preventing member, and the ring back pressure is gradually reduced by each ring.

[Example 13]

This embodiment describes a method of processing a circumferential groove with high precision. The circumferential groove depth determines the important dimension of the allowable wear of the ring. In the case where the depth has a deviation, when the portion of the outer circumference of the ring is not shallow, the pressure on the side of the ring is not guided to the portion where the groove is not Within the range of the mouth communication range, the back pressure balance cannot be achieved within this range, and as a result, the sliding surface pressure rises and the wear of the portion increases.

Therefore, it is important to machine the groove depth with high precision, and a method of high-precision machining will be described using FIG. In Fig. 34, the support jig 80-ring receiving portion 81 is completed with the cylinder size ensuring the roundness. The ring 30 is inserted into the support surface 81 of the support jig 80, and is uniformly provided from the inner side pressing ring 30 using the stretching jig 82.

As a result, the outer circumference of the ring 30 is in a state in which the roundness is ensured by the inner diameter of the cylinder. On the other hand, the milling cutter 83 is positioned with high precision with respect to the ring support surface 81. Therefore, by determining the trajectory of the milling cutter 83 with respect to the center of the support surface 81, the depth E of the circumferential groove 33 can be processed with high precision from the outer circumference of the ring, and local wear can be prevented from increasing.

In addition, in Fig. 34, the milling cutter is exemplified as a T-slot milling cutter, and the same jig can be used to perform machining with an end mill or the like.

Although the above embodiments have been described, the present invention is not limited to the above embodiments, and various modifications are also possible. For example, the above-described embodiments are described in detail to explain the present invention in an easy-to-understand manner, and are not limited to all of the components that are fully described. Further, a part of the configuration of a certain embodiment may be replaced with a configuration of another embodiment, and the configuration of another embodiment may be added to the configuration of a certain embodiment. Further, it is also possible to add, remove, or replace other components in one of the configurations of the respective embodiments.

Further, the present invention is not limited to a non-oil-operated reciprocating compressor in which a piston ring is made of a resin material such as a tetrafluoroethylene resin, but may be corresponding to a general-purpose compressor that directly inhales the atmosphere or lifts the air that has been boosted once. A pressure boosting compressor (boost compressor) or the like. Further, it is also possible to correspond to a gas compressor for compressing a gas other than air such as air and compressed air.

30‧‧‧Piston ring

31‧‧‧ lip

31a‧‧‧ lip front end

31b‧‧‧ lip root

32‧‧‧The lip receiving area

33‧‧‧circular groove

34‧‧‧Upper side slot

35‧‧‧Bottom joint groove

E‧‧‧ circumferential groove depth

Claims (21)

A compressor comprising a cylinder, a piston, a piston ring mounted between the piston and sealing between a pressurized side and a non-pressing side of the cylinder, and the piston is compressed by a fluid in the cylinder And compressing the fluid; and the piston ring has a first joint portion provided on the pressure side and a second joint portion provided on the non-pressurization side; and the first joint groove is formed between the first joint portions, a second opening groove is formed between the two joint portions, and the inner circumferential side and the outer circumferential side of the second joint portion are not communicated with each other; and the outer circumference of the piston ring is provided with a circumference that communicates with the first joint groove and does not communicate with the second joint groove. groove. The compressor according to claim 1, wherein the first joint portion has a stepped shape in which an inner peripheral side and an outer peripheral side communicate with each other, and the second joint portion has a lip shape in which an inner peripheral side and an outer peripheral side overlap each other. The compressor of claim 1, wherein the piston ring has a height of a piston ring of the circumferential groove as a height of the second opening portion; and further a communication groove that communicates with the circumferential groove and the first joint groove . The compressor of claim 1, wherein the piston ring is provided with a plurality of the circumferential grooves, and both ends of the circumferential groove on the pressurizing side of the cylinder communicate with the first joint groove, and the non-pressurized side of the cylinder The circumferential groove is not in communication with the second opening groove; and the communication groove is connected between the pressure side circumferential groove and the non-pressurization side circumferential groove, or the non-pressurization side circumferential groove is provided with a hole communicating with the back surface from the circumferential groove. The compressor of claim 1, wherein the end portion of the circumferential groove has a depth direction shape formed at a right angle with respect to the outer circumferential surface of the piston ring. The compressor of claim 1, wherein the depth E ₁ of the circumferential groove is configured to be E ₁ > δ with respect to the threshold wear amount δ of the piston ring. The compressor of claim 1, wherein the height of the pressurizing side of the piston ring to the pressurizing side end of the circumferential groove is h ₄ , and the non-pressurized side surface of the piston ring is unpressurized to the circumferential groove When the height of the side end is h ₅ , the circumferential groove is provided at a position of h ₄ > h ₅ . The compressor according to claim 1, wherein the second joint portion is formed by a lip portion on the inner side in the radial direction of the piston ring and a lip receiving portion on the outer side, and the lip receiving portion has a thickness larger than the lip portion. The thickness of the department is greater. The compressor of claim 1, wherein the width of the circumferential groove is configured to be the same as the thickness of the milling cutter for groove machining. The compressor of claim 1, wherein the piston ring is provided with a communication hole that communicates with a groove bottom of the circumferential groove and an inner side of a radial direction of the piston ring. The compressor according to claim 8, wherein the thickness of the lip portion from the front end to the root portion is substantially the same, and the contact surface between the lip portion and the lip receiving portion is substantially concentric. A compressor according to claim 1, wherein a member for blocking communication between the outer peripheral side and the inner peripheral side of the piston ring is provided. The compressor according to claim 12, wherein the first joint portion and the second joint portion have a stepped shape in which an inner circumferential side and an outer circumferential side communicate with each other. A compressor according to claim 1, wherein said circumferential groove has a rectangular shape. A piston ring is characterized in that a first joint portion is provided on a pressurizing side of a piston ring, a second joint portion is provided on a non-pressurizing side of the piston ring, and a first joint groove is formed between the first joint portions. a second joint groove is formed between the second joint portion, and the inner joint side and the outer circumference side of the second joint portion are not communicated with each other; and the first joint groove is connected to the outer circumference of the piston ring and is not connected to the second portion. A circumferential groove in which the port is connected. The piston ring of claim 15, wherein the first joint portion has a step shape in which the inner peripheral side and the outer peripheral side communicate with each other, and the second joint portion has a lip shape in which an inner peripheral side and an outer peripheral side overlap each other. The piston ring of claim 15, wherein one end of the circumferential groove is in communication with the first opening groove, and the other end is formed in front of the second opening groove. The piston ring of claim 15, wherein the circumferential groove is provided on the outer circumference of the piston ring while avoiding the second opening groove. A compressor comprising a cylinder, a piston, a piston ring mounted between the piston and sealing between a pressurized side and a non-pressing side of the cylinder, and the piston compresses fluid in the cylinder The compressed fluid is generated; and the piston is formed of a resin; and the piston ring is provided with a joint portion and a circumferential groove communicating with the joint portion. The compressor according to claim 19, wherein the joint portion has a step shape in which the inner peripheral side and the outer circumference are connected to each other. A compressor according to claim 19, wherein a plurality of said piston rings are provided.