JP5205198B2 - Piston ring and oscillating compressor - Google Patents

Description

  The present invention relates to a piston ring and a oscillating compressor.

There is a cylinder device that reciprocates while a piston swings in the cylinder (for example, see Patent Document 1).
JP 2006-152960 A

  In the cylinder device described above, since the piston swings, the angle of the piston ring with respect to the cylinder changes, which may increase the loss.

  Therefore, an object of the present invention is to provide a piston ring and a oscillating compressor that can suppress occurrence of loss.

  In order to achieve the above object, the piston ring of the present invention is subjected to a seal improvement process corresponding to the maximum swing angle of the upward stroke of the piston at the upper outer corner on one side of the swing direction. A seal improving process corresponding to the maximum swing angle of the piston upward stroke is applied to the outer corner of the lower part on the other side.

  In the piston ring of the present invention, the center position in the axial direction of the maximum portion of the outer dimension on one side and the other side in the swing direction is different between the one side and the other side.

  In the oscillating compressor of the present invention, the piston ring is subjected to a seal improvement process corresponding to the maximum oscillating angle of the compression stroke of the piston at the upper outer corner on one side in the oscillating direction. A seal improving process corresponding to the maximum swing angle of the compression stroke of the piston is applied to the outer corner of the lower part on the other side in the direction.

  According to the present invention, loss generation can be suppressed.

  Embodiments according to the present invention will be described below with reference to the drawings.

“First Embodiment”
A piston ring and a oscillating compressor according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing the overall configuration of an oscillating compressor including a piston ring according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 showing the oscillating compressor including the piston ring according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the main part of the piston according to the first embodiment of the present invention. 4A and 4B show the piston ring according to the first embodiment of the present invention, in which FIG. 4A is a plan view, FIG. 4B is a sectional view taken along line X1-X1 in FIG. 4A, and FIG. 4C is Y1 in FIG. -Y1 sectional drawing. 5 is an X1-X1 enlarged sectional view of FIG. 4 showing the piston ring of the first embodiment according to the present invention. FIG. 6 is a perspective view showing the piston ring of the first embodiment according to the present invention. FIG. 7 is a cross-sectional view showing the relationship between the piston ring and the cylinder of the first embodiment according to the present invention, where (a) is the maximum swing state in the compression stroke, (b) is the compression completed state, and (c) is Each of the maximum swing states in the suction stroke is shown.

  The oscillating compressor 10 sucks, compresses and discharges a gas (fluid). As shown in FIGS. 1 and 2, the oscillating compressor 10 has a crankcase (case) 11, and the crankcase 11 has a crank chamber 12 inside. An electric motor 15 is attached to the crankcase 11 as shown in FIG. The electric motor 15 has a bottomed cylindrical shape having a body portion 16 and a bottom portion 17, a motor housing 18 whose opening side is connected to the crankcase 11, and a stator 19 attached to the inside of the body portion 16 of the motor housing 18. The bearing 21 held by the bearing holding part 20 of the bottom 17 of the motor housing 18, the bearing 23 held by the bearing holding part 22 of the crankcase 11, and the output shaft rotatably supported by these bearings 21, 23 And a rotor 25 including 24.

  One end side of the output shaft 24 of the electric motor 15 protrudes into the crank chamber 12, and a crank member 29 that constitutes a crank shaft (eccentric rotation shaft) 28 with the output shaft 24 of the electric motor 15 is eccentric in this portion. It is fixed in the state. A key groove 31 is formed in the output shaft 24, and a fitting hole 32 is formed in the crank member 29 so as to be eccentric with respect to the outer peripheral portion and engage the output shaft 24. 33 is formed, and the crank member 29 is integrated with the output shaft 24 by fitting the key 34 into the key grooves 31 and 33. As a result, the crankcase 11 supports the crankshaft 28 via the bearing 23.

  Further, a balance weight 37 is fixed to the output shaft 24 of the electric motor 15 by a nut 38 that abuts against the crank member 29 at an intermediate position thereof and is screwed to the output shaft 24. The cooling fan 39 is fixed. The balance weight 37 is also formed with a fitting hole 40 for fitting the output shaft 24 and a key groove 41. By fitting the key 34 into the key groove 41, the balance weight 37 is The output shaft 24 is integrated.

  On the crankcase 11, a cylindrical cylinder 45 is attached on the base end side. The cylinder 45 has a constant diameter regardless of the position of the inner peripheral surface 46 in the axial direction, and the base end side opens into the crank chamber 12. A cylinder head 50 including a valve seat plate 48 and a cylinder head main body 49 is mounted on the distal end side of the cylinder 45.

  As shown in FIG. 2, the cylinder head main body 49 includes a suction port 51 that communicates with the outside, a suction chamber 52 that communicates with the suction port 51, a discharge port 53 that communicates with the outside, and a discharge that communicates with the discharge port 53. A chamber 54 is defined.

  The valve seat plate 48 is interposed between the cylinder 45 and the cylinder head main body 49, and the valve seat plate 48 has a suction hole 57 for communicating the suction chamber 52 with the compression chamber 55 on the cylinder 45 side. A discharge hole 58 for communicating the discharge chamber 54 with the compression chamber 55 is formed. Further, a suction valve 59 and a discharge valve 60 as reed valves are attached to the valve seat plate 48, and the suction valve 59 and the discharge valve 60 are fixed to the valve seat plate 48 through screws or the like on the base end side. The suction hole 57 and the discharge hole 58 are opened and closed, respectively.

  A swinging piston 63 is slidably inserted into the cylinder 45. The piston 63 is located at one end of the piston 63 and is connected to an annular connecting portion 65 that is rotatably connected to a crank member 29 that is positioned in the crank chamber 12 and rotates eccentrically via a bearing 64. A piston rod portion 66 integrally formed with the portion 65 and extending into the cylinder 45; and a piston rod portion 66 on the other end side of the piston 63 that is integrally formed with the piston rod portion 66 so as to be orthogonal thereto and disposed in the cylinder 45. A piston main body 68 having a disc-shaped ring receiver 67, and a ring receiver 67 which is provided separately from the piston main body 68 and is fixed to the ring receiver 67 with screws 69 and disposed in the cylinder 45. A disk-shaped retainer 70 having the same diameter. In the piston main body 68, the center axis of the ring receiver 67 and the center axis of the piston rod portion 66 coincide with each other, and the center axis of the piston rod portion 66 is orthogonal to the center axis of the connecting portion 65. Further, the piston rod portion 66 has a thickness in the direction along the central axis of the connecting portion 65 that is narrower than a width in a direction perpendicular thereto. The retainer 70 is attached to the piston main body 68 so that the center axis of the retainer 70 coincides with the center axis of the ring receiver 67 and the center axis of the piston rod portion 66 to constitute the piston 63.

  Here, a disc portion in which a ring receiver 67 and a retainer 70 provided on the other end side of the piston 63 reciprocate while swinging in the cylinder 45 to define a compression chamber 55 between the cylinder head 17. 71, and the disc portion 71 holds a piston ring 72 that seals the gap between the piston 63 and the cylinder 45. The outer peripheral side of the piston ring 72 slides on the inner peripheral surface 46 of the cylinder 45.

  The piston 63 is reciprocated while the connecting portion 65 is eccentrically moved by the crank member 29, so that the disk portion 71 in the cylinder 45 reciprocates while sliding the piston ring 72 held in the cylinder 45, At this time, since the connecting portion 65, the piston rod portion 66, and the disk portion 71 are integrated, it swings in a direction perpendicular to the central axis of the crankshaft 28 and perpendicular to the central axis of the cylinder 45. A direction perpendicular to the central axis of the crankshaft 28 and perpendicular to the central axis of the cylinder 45 is defined as a swinging direction. On the other hand, the piston 63 does not swing in the axial direction of the crankshaft 28. The axial direction of the crankshaft 28 is defined as a non-oscillating direction.

  Here, specifically, the swing of the piston 63 will be described. When the piston 63 is viewed along the crankshaft direction orthogonal to the swing direction, the piston rod portion 66 is swung in the swing direction (at the bottom dead center). The disc portion 71 is horizontal and is located in the center in the left-right direction. When the crank member 29 rotates from this state to perform the compression stroke and raises the piston 63, the top dead center and the bottom dead center The lower part of the piston rod 66 moves up to the middle between them while moving to one side (for example, the right side) of the swinging direction, and swings most at the center (for example, 3 o'clock position) between the top dead center and the bottom dead center. Located on one side of the direction (eg right side). At this time, the disc portion 71 is inclined most horizontally with one side of the swinging direction (for example, the left side) opposite to the one side being positioned below the other side of the swinging direction (for example, the right side). The swing angle, which is an angle with respect to the horizontal (an angle with respect to the direction perpendicular to the cylinder axis), is maximized.

  Subsequently, the lower part of the piston rod portion 66 returns to the center of the swinging direction toward the top dead center. At the top dead center, the piston rod portion 66 is positioned at the center of the swinging direction and the disk portion 71 is moved. It becomes horizontal and the compression process ends.

  When the crank member 29 rotates to perform the suction stroke from the state where the disk portion 71 is at the top dead center, the piston 63 is lowered, and the lower portion of the piston rod portion 66 is moved to the middle between the top dead center and the bottom dead center. It moves down to one side (for example, the left side) opposite to the swinging direction and descends, and at the center between the top dead center and the bottom dead center (for example, 9 o'clock position) Located in. At this time, the disk portion 71 is positioned such that the other side (for example, the right side) of the swing direction opposite to the one side opposite to the swing direction is positioned below the one side (for example, the left side) of the swing direction, Inclining in the direction opposite to the above with respect to the most horizontal, the swing angle is maximized.

  Subsequently, the lower part of the piston rod portion 66 returns to the center of the swinging direction toward the bottom dead center. At the bottom dead center, the piston rod portion 66 is positioned at the center of the swinging direction and the disk portion 71 is moved. The suction stroke ends with leveling.

  As shown in FIG. 3, the ring receiver 67 has an annular stepped portion 75 formed concentrically with the central axis of the piston rod portion 66 on the outer diameter side and the opposite side of the piston rod portion 66. A fitting recess 76 that is recessed in a circular shape in plan view at the center is formed concentrically with the central axis of the piston rod portion 66.

  The ring receiver 67 has an upper surface portion 67 </ b> A disposed in a plane orthogonal to the central axis of the piston rod portion 66, and has an annular shape centering on the central axis of the piston rod portion 66. The stepped portion 75 is composed of an outwardly facing cylindrical surface portion 75A that descends vertically from the outer peripheral edge portion of the upper surface portion 67A, and a flat surface portion 75B that extends radially outward from the lower end edge of the cylindrical surface portion 75A. The cylindrical surface portion 75A has a cylindrical shape with the central axis of the piston rod portion 66 as the center. The plane portion 75B is disposed in a plane perpendicular to the central axis of the piston rod portion 66, and has an annular shape centering on the central axis of the piston rod portion 66. The ring receiver 67 is formed with a cylindrical surface portion 67B that extends downward from the outer peripheral edge portion of the flat surface portion 75B and constitutes the maximum outer diameter portion thereof.

  The fitting recess 76 is composed of an inwardly-facing cylindrical surface portion 76A that descends vertically from the inner peripheral edge portion of the upper surface portion 67A, and a bottom surface portion 76B that extends radially inward from the lower end edge of the cylindrical surface portion 76A. The cylindrical surface portion 76 </ b> A has a cylindrical shape centered on the central axis of the piston rod portion 66. The bottom surface portion 76 </ b> B is disposed in a plane orthogonal to the central axis of the piston rod portion 66 and has a circular shape centering on the central axis of the piston rod portion 66. A screw hole 77 is formed in the axial direction at the center of the bottom surface portion 76B of the fitting recess 76.

  The retainer 70 includes a main plate portion 80 having a disc shape, and a fitting convex portion 81 projecting from the center of the main plate portion 80 to one side along the axial direction thereof. On the opposite side to the joint convex portion 81, a groove portion 82 that passes through the center of the main plate portion 80 and extends in the radial direction is formed.

  The fitting convex portion 81 has a circular shape extending outward in the radial direction perpendicular to the central axis of the fitting convex portion 81 from the outwardly facing cylindrical surface portion 81A extending downward from the main plate portion 80 and the lower end edge of the cylindrical surface portion 81A. The lower surface portion 81B.

  The main plate portion 80 is arranged in a plane orthogonal to the central axis of the fitting convex portion 81, and has an annular lower surface portion 80A concentric with the fitting convex portion 81 around the fitting convex portion 81, and a lower surface portion 80A. A cylindrical surface portion 80B that rises perpendicularly from the outer peripheral edge portion of the retainer 70 to the opposite side to the fitting convex portion 81, and is disposed in a plane perpendicular to the central axis of the cylindrical surface portion 80B. A groove bottom surface 82A extending at a constant width on the diameter of the surface portion 80B, a pair of groove wall surfaces 82B rising from both edge portions of the groove bottom surface 82A, and a plane perpendicular to the central axis of the cylindrical surface portion 80B. It has a pair of upper surface portions 80C formed at a portion surrounded by the upper end edge portion of the cylindrical surface portion 80B and the upper end edge portion of the groove wall surface 82B. Here, the groove portion 82 is formed in the swinging direction by the groove bottom surface 82A and the pair of groove wall surfaces 82B, thereby preventing the suction valve 59 and the discharge valve 60 from coming into contact with each other. A tapered counterbore 83 is formed in the axial direction at the center of the groove bottom surface 82 </ b> A of the retainer 70.

  On the outer end portion of the lower surface portion 80A of the main plate portion 80, a protruding portion (rotation mechanism) 84 that protrudes vertically downward from the main plate portion 80 is formed at a position 90 degrees different from both outer end portions of the groove portion 82. Yes.

  The retainer 70 described above is mounted on the ring receiver 67 of the piston main body 68 by fitting the fitting convex portion 81 into the fitting concave portion 76, and in this state, the screw 69 is inserted into the counterbore 83 and screwed. By being screwed into the hole 77, the retainer 70 is fixed to the ring receiver 67 to constitute the disk portion 71. At this time, the retainer 70 is attached so that the extending direction of the groove portion 82 coincides with the width direction of the piston rod portion 66 of the piston main body 68, that is, the swinging direction, and as a result, the protrusion 84 is the disc portion 71. Is disposed at the end in the non-oscillating direction.

  The disk portion 71 formed in this manner has a radially inner portion on the outer peripheral side between the flat surface portion 75B and the cylindrical surface portion 75A of the stepped portion 75 of the ring receiver 67 and the lower surface portion 80A of the main plate portion 80 of the retainer 70. An annular ring groove 85 that is recessed in the direction is formed concentrically. The above-described protrusion 84 is formed in the ring groove 85. The above-described piston ring 72 that seals between the piston 63 and the cylinder 45 is mounted in the ring groove 85.

  The piston ring 72 is integrally formed in a substantially annular shape by a resin material having a spring property excellent in wear resistance and self-lubricating property. The piston ring 72 has a substantially arc-shaped main ring portion 88, and an arc-shaped joint portion 89 formed at one end of the main ring portion 88 with a half thickness of the main ring portion 88 and biased to one side in the axial direction. And the other end of the main ring portion 88 has an arcuate abutment portion 90 formed with a half thickness of the main ring portion 88 and biased to the opposite side in the axial direction. Here, the joint portions 89 and 90 on both sides have the same length in the circumferential direction and are arranged so as to overlap each other in the axial direction. In the natural state, the piston ring 72 has a circumferential gap formed between the joint portion 89 on one end side of the main ring portion 88 and the other end portion of the main ring portion 88. A similar gap is also formed between the joint portion 90 on the other end side of the 88 and one end portion of the main ring portion 88. On the inner peripheral side of the intermediate position that is approximately 180 degrees opposite to the joint portions 89 and 90 of the main ring portion 88, a notch 91 that is recessed in the central axis direction is formed on one side in the axial direction.

  Such a piston ring 72 is disposed in the stepped portion 75 of the ring receiver 67 with the notch 91 on the non-oscillating side and the upper side before the retainer 70 is attached. In this state, the retainer 70 has the notched portion 84 notched. The piston ring 72 is held in the ring groove 85 by being fixed to the ring receiver 67 of the piston main body 68 as described above while being fitted to the portion 91. At this time, the protrusion 84 of the retainer 70 is fitted into the notch 91 of the piston ring 72 so that the rotation of the piston ring 72 relative to the disk portion 71 is restricted. Therefore, the protrusion 84 prevents the piston ring 72 from rotating. In addition, the abutting portions 89 and 90 are arranged in the non-oscillating direction while being mounted in the ring groove 85.

  With the ring groove 85 mounted in this manner, when the piston 63 swings, the piston ring 72 can be expanded or contracted along the inner diameter of the cylinder 45 by shifting the joint portions 89 and 90 in the circumferential direction. In this case, the sealing portions are maintained by the sliding contact of the joint portions 89 and 90 at all times.

  Here, when the piston ring 72 is in a natural state (diameter-expanded state) in which the joint portions 89 and 90 are separated from the main ring portion 88, the outer shape shown in FIG. 4 is the inner diameter of the cylinder 45 and the piston ring 72 with respect to the cylinder 45. The oval shape is determined by the maximum swing angle. Further, when the piston ring 72 is in a reduced diameter state in which the joint portions 89 and 90 abut against the main ring portion 88, the outer shape is a circular shape that comes into close contact with the inner peripheral surface 46 of the cylinder 45 with the center axis aligned. . In other words, when the cylinder inner diameter is d1, the cylinder has an ellipse whose major axis d2 is d2 = d1 / cos θ at a position where the maximum swing angle θ is obtained. In accordance with this, the piston ring 72 has a short diameter d1 equal to the cylinder inner diameter, and is set so that the long diameter d2 in the natural state satisfies d2 = d1 / cos θ with respect to the maximum swing angle θ. Yes.

  The annular piston ring 72 is subjected to a seal improvement process corresponding to the maximum swing angle of the compression stroke, which is the upward stroke of the piston 63, at the outer corner of the upper part (top dead center side end) on one side of the swing direction. In addition, a seal improving process corresponding to the maximum swing angle of the compression stroke of the piston 63 is applied to the outer corner of the lower part (bottom dead end side end) on the other side in the swing direction. Note that, on one side of the swing direction, only the upper outer corner is subjected to a seal improvement process, and the lower outer corner is not subjected to a seal improvement process. Further, on the other side in the swinging direction, only the lower outer corner portion is subjected to seal improvement processing, and the upper outer corner portion is not subjected to seal improvement processing.

  In other words, before the piston ring 72 is subjected to the seal improvement process, the main ring portion 88 has a rectangular cross section cut along a plane including the central axis over the entire circumference. A taper surface 72A shown in FIG. 4 to FIG. 6 having the same angle θ as the maximum swing angle θ of the piston 63 is formed by applying a seal improving process to the outer corner portion on the upper side, and the main ring portion 88 is swung. A taper surface 72B having the same angle θ as the maximum swinging angle θ of the piston 63 is formed by applying a seal improving process to the outer corner portion on the lower side on the other side in the moving direction. Since the main piston ring 72 is not formed with a tapered surface at the lower outer corner on one side of the swinging direction of the main ring part 88 and at the upper outer corner on the other side of the swinging direction, the main ring part 88 is not entirely formed. A cross section cut along a plane including the axis is substantially rectangular over the circumference. In addition, other corners of the main annular portion 88 where the tapered surface 72A (72B) is not formed may be chamfered smaller than the tapered surface 72B.

  Here, in the above-described seal improvement processing, the same processing is performed on both sides symmetrically with respect to the center of gravity of the piston ring 72. As a result, the tapered surfaces 72A and 72B on both sides have a point-symmetric shape.

  Further, in the above-described seal improvement processing, the outer corner position in the swinging direction has the largest processing amount, and the processing amount gradually decreases as it approaches the non-swinging side. It is applied in a range of a little less than half a circle before the both end positions. As a result, the taper surfaces 72A and 72B have both the radial width and the axial height at the end positions in the oscillating direction, and the radial width and the axial height increase as they approach the non-oscillating side. Both of them are shaped to gradually become smaller and are formed in a range of a little less than a half circumference of the piston ring 72. Here, the tapered surfaces 72 </ b> A and 72 </ b> B on both sides are formed independently without intermingling with each other in the piston ring 72. Further, the tapered surfaces 72A and 72B on both sides are arranged in substantially the same cylindrical surface having the same diameter as the inner diameter of the cylinder 45.

  Here, since the piston ring 72 has no tapered surfaces 72A and 72B formed at the lower outer corner portion on one side of the swinging direction of the main ring portion 88 and the upper outer corner portion on the other side of the swinging direction, The axial thickness is larger than the maximum axial height of the tapered surfaces 72A and 72B. As a result, the outer peripheral smooth surface 72C along the axial direction of the piston ring 72 is formed on the entire outer periphery. Yes. The piston ring 72 has a flat surface along the axis orthogonal direction over the entire circumference except for the joint portions 89 and 90 also in the upper surface portion 72D and the lower surface portion 72E. The piston ring 72 also has an inner peripheral side smooth surface 72F along the axial direction of the piston ring 72 on the entire inner periphery.

  Here, the piston ring 72 has the maximum axial dimension of the outer peripheral smooth surface 72C in the non-oscillating direction in which the tapered surfaces 72A and 72B are not formed. Further, the maximum axial height of the tapered surfaces 72A and 72B is equal to the minimum axial height of the outer peripheral side smooth surface 72C. Further, the tapered surfaces 72A and 72B are formed point-symmetrically with respect to the center of gravity of the piston ring 72, so that the axial center position of the outer peripheral side smooth surface 72C, which is the maximum part of the outer dimensions, is one side of the swing direction. It will be different on the other side. Specifically, the axial center position of the outer peripheral smooth surface 72C on one side in the swinging direction is shifted downward with respect to the axial center position of the outer peripheral smooth surface 72C on the other swinging direction. . The tapered surface 72A is formed continuously from one side in the swing direction of the outer peripheral side smooth surface 72C, which is the maximum part of the outer dimension, and the tapered surface 72B is also the outer peripheral side smoother, which is the maximum part of the outer dimension. It is formed continuously from the other side in the swing direction of the surface 72C.

  Here, the above-described process of improving the seal of the piston ring 72 can be performed as follows, for example.

  On the rotation center of the rotating jig so that the material of the piston ring 72 in which the main ring portion 88 is cut along a plane including the axis line is rectangular over the entire circumference cannot be deformed in a natural state. Attach it in a state tilted by the maximum swing angle θ. Then, a cutting blade is directed toward the center of rotation, and a tool capable of approaching and separating the cutting blade from the center of rotation is cut close to the piston ring 72 and a predetermined amount while rotating the rotating jig. At this time, by setting the distance between the tip of the cutting edge and the rotation center to the same length as the radius of the inner diameter of the cylinder, the tapered surfaces on both sides in the natural state are within the same cylindrical surface having the same diameter as the cylinder inner diameter. Can be arranged.

  The oscillating compressor according to the first embodiment has the above-described configuration, and the operation thereof will be described next.

  When the electric motor 15 is rotationally driven, the crank member 29 fixed to the output shaft 24 performs an eccentric rotational motion. Then, the piston 63 rotatably connected to the crank member 29 via the bearing 64 reciprocates the disk portion 71 and the piston ring 72 in the cylinder 45. In the suction stroke, the compression chamber 55 is expanded by the movement of the disk portion 71 and the piston ring 72 in the direction opposite to the cylinder head 17, and the suction valve 59 is opened while the discharge valve 60 is closed, so that the gas is sucked into the suction port 51. The suction chamber 52 is introduced into the compression chamber 55. In the subsequent compression stroke, the compression chamber 55 is contracted by the movement of the disk portion 71 and the piston ring 72 toward the cylinder head 17, and the discharge valve 60 is opened while the suction valve 59 is closed to discharge the compressed gas from the compression chamber 55. Discharge into the chamber 54 and the discharge port 53.

  During the above operation, the disk portion 71 and the piston ring 72 reciprocate while swinging in the cylinder 45.

  That is, when viewed along a direction (cylinder axis direction) orthogonal to the swinging direction of the piston 63, the piston rod portion 66 is located at the center in the left-right direction at the bottom dead center where the compression chamber 55 is expanded most. The disk part 71 and the piston ring 72 are horizontal. Therefore, the piston ring 72 is pressed by the inner peripheral surface 46 of the cylinder 45 and reduced in diameter into a circular shape, and the outer peripheral side smooth surface 72C has a length in the axial direction and is in close contact with the inner peripheral surface 46 in its entirety. . Thereby, the space between the disk portion 71 and the cylinder 45 can be sufficiently sealed.

  When the crank member 29 is rotated to perform the compression stroke from this state and the piston 63 is raised and the disk portion 71 and the piston ring 72 are moved in the direction of reducing the compression chamber 55, the intermediate between the top dead center and the bottom dead center is obtained. The lower part of the piston rod part 66 moves up to one side in the left-right direction and rises, and the lower part of the piston rod part 66 is the one in the left-right direction at the center of the top dead center and the bottom dead center (for example, 3 o'clock) Located outside. At this time, the disk part 71 and the piston ring 72 are most oscillated and inclined with respect to the horizontal. At this time, the piston ring 72 follows the enlargement of the gap with the cylinder 45 in the swinging direction that expands by swinging, and expands in the swinging direction to become an oval state. The outer peripheral smooth surface 72C is in close contact with the non-swinging direction, and the taper surface 72A and the taper surface 72B are in close contact with each other in the swinging direction as shown in FIG. Thereby, the space between the disk portion 71 and the cylinder 45 can be sufficiently sealed. Further, between the bottom dead center and the maximum swing position, the piston ring 72 is in an annular line contact with the inner peripheral surface 46 of the cylinder 45, but the tapered surface 72A and the tapered surface 72B are the inner periphery of the cylinder 45. Since the state is almost parallel to the surface 46, substantially the same action as the surface contact is obtained, and the space between the disk portion 71 and the cylinder 45 can be sufficiently sealed.

  Subsequently, the lower part of the piston rod portion 66 returns to the center in the left-right direction as it goes to the top dead center, and the piston rod portion 66 is located at the center in the left-right direction at the top dead center where the compression chamber 55 is most contracted. At the same time, the disk portion 71 and the piston ring 72 become horizontal, and the compression stroke ends. At this time, the piston ring 72 is pressed by the inner peripheral surface 46 of the cylinder 45 and reduced in diameter into a circular shape, and the outer peripheral side smooth surface 72C is in close contact with the inner peripheral surface 46 as shown in FIG. Therefore, leakage to the crank chamber 12 is restricted with respect to the high pressure of the gas in the compression chamber 55. Thereby, the space between the disk portion 71 and the cylinder 45 can be sufficiently sealed. Further, the piston ring 72 is in an annular line contact with the inner peripheral surface 46 of the cylinder 45 from the maximum swing position to the top dead center, but the tapered surface 72A and the tapered surface 72B are the inner periphery of the cylinder 45. Since the surface is nearly parallel to the surface 46, substantially the same action as the surface contact can be obtained, and sufficient sealing can be achieved.

  In the above compression stroke, the pressure in the compression chamber 55 is introduced into the ring groove 85, and a back pressure is applied to the piston ring 72 to be pressed against the inner peripheral surface 46 of the cylinder 45, thereby ensuring sealing performance. To do. In addition, when the pressing force is the maximum top dead center, the piston ring 72 comes into surface contact with the inner peripheral surface 46 of the cylinder 45, so that the surface pressure is kept low and wear is kept small.

  When the crank member 29 rotates to perform the suction stroke from the state in which the disk portion 71 is at the top dead center, the piston 63 moves the disk portion 71 and the piston ring 72 in the direction in which the compression chamber 55 is expanded. The lower part of the piston rod portion 66 moves downward in the left-right direction to the middle between the upper dead center and the bottom dead center. Is located outside the other in the left-right direction. At this time, the disk portion 71 and the piston ring 72 are inclined in the opposite direction to the above with respect to the most horizontal, and the piston ring 72 is annularly formed on the inner peripheral surface 46 of the cylinder 45 as shown in FIG. Touch the line.

  Subsequently, the lower part of the piston rod portion 66 returns to the center in the left-right direction as it goes to the bottom dead center, and the piston rod portion 66 is positioned at the center in the left-right direction at the bottom dead center where the compression chamber 55 is expanded most. At the same time, the disk portion 71 is horizontal and the suction stroke is completed.

  Here, in the suction stroke, the piston ring 72 is in an annular line contact with the inner peripheral surface 46 of the cylinder 45 between the top dead center and the bottom dead center, and the sealing performance is reduced, but the suction stroke is There is no problem because the pressure in the compression chamber 55 is low. Further, in the suction stroke, the piston ring 72 has an inner peripheral surface of the cylinder 45 whose right outer corner at the lower part on one side in the swinging direction of the main ring part 88 and at the upper right on the other side in the swinging direction. 46, the pressure receiving area is reduced and the load is increased. However, since the pressure in the compression chamber 55 is low, there is no significant wear.

  During the above period, the piston ring 72 is always in sliding contact with the inner peripheral surface 46 of the cylinder 45, so that the space between the piston 63 and the cylinder 45 is hermetically sealed, and the gas in the compression chamber 55 leaks toward the crank chamber 12. To prevent it. In particular, the piston ring 72 is brought into surface contact with the cylinder 45 by the tapered surfaces 72A and 72B while expanding in the swinging direction against the enlargement of the gap due to the swinging in the compression stroke in which the gas pressure in the compression chamber 55 increases. And improve sealing performance.

  Here, in the conventional techniques including the above-described Patent Document 1 and the like, the piston swings, and therefore, when swinging, the piston ring comes into line contact with the cylinder, and gas leaks from the compression chamber to the crank chamber. There was a problem that loss occurred and compression efficiency was lowered.

  On the other hand, in the above-described piston ring 72, a seal improvement process corresponding to the maximum swing angle of the upward stroke of the piston 63 is applied to the outer corner portion on the one side in the swing direction, and the other end in the swing direction Since the outer corner of the lower side is subjected to seal improvement processing corresponding to the maximum swing angle of the upward stroke of the piston 63, the seal improvement processing of the piston ring 72 is performed at the time of swing of the upward stroke of the piston 63. The both side portions thus made can be brought into contact with the cylinder 45, so that loss can be suppressed and compression efficiency can be improved. Therefore, the axial height of the piston ring 72 can be made lower than when chamfering is formed on both sides in the axial direction, and the height of the cylinder 45 and the material cost of the piston ring 72 can be reduced.

  Further, the piston ring 72 continues to the maximum part of the outer dimension because the axial center position of the maximum part of the outer dimension on the one side and the other side in the swing direction is different between the one side and the other side. The portion has a smaller outer dimension, and when the piston 63 swings, the portion having the smaller outer dimension can be brought into contact with the cylinder 45, and loss generation can be suppressed and compression efficiency can be improved.

  Further, the oscillating compressor 10 is provided with a ring ring 85 provided on the outer peripheral side of the disk portion 71 of the piston 63, and an annular piston ring 72 having a substantially rectangular cross section for sealing between the piston 63 and the cylinder 45. The piston ring 72 has joint portions 89 and 90 and is mounted so that the diameter of the piston 63 can be expanded and contracted along the inner diameter of the cylinder 45 when the piston 63 swings. The seal improvement processing corresponding to the maximum swing angle of the compression stroke of the piston 63 is applied to the outer corner of the lower portion on the other side in the swing direction, and the seal improvement processing corresponding to the maximum swing angle of the compression stroke of the piston 63 is applied. Therefore, both sides of the piston ring 72 that have been subjected to the seal improving process can be brought into contact with the cylinder 45 during the swinging of the upward stroke of the piston 63, and the occurrence of loss can be suppressed. Efficiency becomes possible to improve.

  In addition, since the processing amount of the seal improvement processing gradually decreases as the processing amount approaches the non-oscillation side with the outer corner portion in the oscillation direction being maximized, it is possible to closely adhere to the shape of the cylinder 45, and the compression efficiency is further improved. It becomes possible to improve.

  Since the piston ring 72 is provided with a smooth surface 72 </ b> C over the entire outer periphery, the top dead center position that does not tilt with respect to the cylinder 45 (the position where the pressure in the compression chamber 55 is maximized) The smooth surface 72C can be in close contact with the peripheral surface 46, and the sealing performance can be enhanced. Therefore, the compression efficiency can be further improved. In addition, since the seal surface pressure can be reduced, wear of the piston ring 72 can be suppressed and the life can be extended.

  Further, the piston ring 72 has the largest axial dimension of the smooth surface 72C in the non-oscillating direction and the smallest axial dimension of the smooth surface 72C in the oscillating direction. With respect to the non-oscillating direction with a small angle, the maximum smooth surface 72C can be in close contact with the inner peripheral surface 46 of the cylinder 45. Therefore, the compression efficiency can be further improved.

  Further, since the piston ring 72 has an oval shape in a natural state, when the piston 63 swings, the piston ring 72 can follow the oval shape of the seal portion of the cylinder 45 by the piston ring 72. The cylinder 45 can be in close contact with the inner peripheral surface 46. Therefore, the compression efficiency can be further improved.

  In addition, since the abutment portions 89 and 90 are provided in part of the circumference of the piston ring 72, the diameter of the piston ring 72 can be increased and decreased while maintaining the sealing performance. Therefore, the compression efficiency can be further improved.

  Further, since the piston ring 72 has a point 72 symmetrical with respect to the center of gravity of the piston ring 72 and the continuous surfaces 72A, 72B of the maximum portion 72C of the outer dimensions, the inner peripheral surface 46 of the cylinder 45 is swung. These surfaces 72A and 72B can be satisfactorily adhered to each other. Therefore, the compression efficiency can be further improved.

  In addition, since the piston ring 72 has a taper surface shape with the continuous outer surfaces 72C and 72B having the outer dimensions 72C, the surfaces 72A and 72B are connected to the inner circumferential surface 46 of the cylinder 45 when the piston 63 swings. Good adhesion can be achieved. Therefore, the compression efficiency can be further improved.

  Further, since the piston 63 is provided with the rotation stop mechanism 84 for the piston ring 72, the piston ring 72 can always be held at an appropriate position. Therefore, the compression efficiency can be further improved.

  Since the abutting portions 89 and 90 are arranged in the non-oscillating direction, it is possible to suppress deterioration of the sealing performance due to the abutting portions 89 and 90. Therefore, the compression efficiency can be further improved.

“Second Embodiment”
Next, a second embodiment will be described mainly based on FIGS. FIG. 8 is a plan view showing a piston ring according to the second embodiment of the present invention. FIG. 9 is an enlarged cross-sectional view taken along the line X2-X2 of FIG. 8, showing the piston ring according to the second embodiment of the present invention. FIG. 10 is a view showing a cross-sectional shape for each angle shown in FIG. 8 of the generating surface of the piston ring of the second embodiment according to the present invention. FIG. 11 is a side view showing an example of a piston ring manufacturing apparatus according to the second embodiment of the present invention. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

  As in the first embodiment, the piston ring 72 ′ of the second embodiment shown in FIG. 8 has an upward stroke of the piston 63 at the outer corner of the upper part (top dead center side end) on one side in the swinging direction. A seal improvement process corresponding to the maximum swing angle of a certain compression stroke is performed, and the maximum swing angle of the compression stroke of the piston 63 is set at the outer corner of the lower part (bottom dead center side end) on the other side in the swing direction. Corresponding seal improvement processing is performed, but these seal improvement processing is different from the first embodiment. In the second embodiment as well, on one side of the swing direction, only the upper outer corner is subjected to the seal improvement process, and the lower outer corner is not subjected to the seal improvement process. Further, on the other side in the swinging direction, only the lower outer corner portion is subjected to seal improvement processing, and the upper outer corner portion is not subjected to seal improvement processing.

  The piston ring 72 ′ of the second embodiment is also the same material as that of the first embodiment before the seal improving process is performed, and the cross section of the main ring portion 88 cut along the plane including the axis is rectangular. It has become. The piston ring 72 ′ of the second embodiment is subjected to a seal improvement process different from that of the first embodiment at the upper outer corner on one side of the swinging direction of the main ring portion 88. A curved creation surface 72A ′ is formed by continuously creating chamfers corresponding to the swing angle that changes for each position, and the same is applied to the outer corner of the lower portion on the other side of the main ring portion 88 in the swing direction. By performing the seal improvement process, a curved creation surface 72B ′ is formed which is created by continuously chamfering corresponding to the swing angle that changes for each position of the compression stroke.

  That is, the generating surfaces 72A ′ and 72B ′ shown in FIG. 9 have an angle formed with the inner peripheral surface 46 of the cylinder 45 at the outer peripheral portion of the piston ring 72 ′ where the angle formed with the cylinder 45 changes at each position in the compression stroke. The shape is such that the tapered surface that contacts the inner peripheral surface 46 at a constant angle is created in the piston ring 72 ′ successively and continuously while changing in the same manner as the swing angle. At this time, the generating surfaces 72A 'and 72B' are set in consideration of the change in the diameter of the piston ring 72 'at each swing angle.

  In other words, the generating surfaces 72A ′ and 72B ′ are in a reduced diameter state in the swing direction at the bottom dead center position in the compression stroke, and gradually increase in diameter in the swing direction to an intermediate position where the swing angle is maximized. Further, the piston ring 72 ′ whose diameter gradually decreases in the swinging direction toward the top dead center position has a shape that can always contact the inner peripheral surface 46 of the cylinder 45. Further, when the piston ring 72 ′ is cut at each swing angle and the diameter in the swing direction is matched with the diameter at each swing angle, the inner peripheral surface 46 of the cylinder 45 cut at each swing angle. The cross-sectional shape is the same as the cross-sectional shape obtained.

  Since the piston ring 72 is not formed with the generating surfaces 72A ′ and 72B ′ at the lower outer corner portion on one side of the main ring portion 88 in the swinging direction and the upper outer corner portion on the other side of the swinging direction, The cross section of the portion 88 cut along the plane including the axis is substantially rectangular over the entire circumference.

  Here, in the above-described seal improvement processing, the same processing is performed on both sides symmetrically with respect to the center of gravity of the piston ring 72. As a result, the generating surfaces 72A 'and 72B' on both sides have a point-symmetric shape.

  Further, as shown in FIG. 10, the above-described seal improvement processing has the largest processing amount at the end position in the swing direction (the 90 ° position in FIGS. 8 and 10) (in other words, the axial height of the generating surface is high). As the distance from the non-oscillating side gets closer (90 ° → 75 ° → 60 ° → 45 ° → 30 ° → 15 ° → 0 ° in FIG. 8 and FIG. 10) Is gradually reduced (in other words, the axial height and radial width of the generating surface are gradually reduced), and machining is performed at the end position on the non-oscillating side (the 0 ° position in FIGS. 8 and 10). So that the amount is zero (in other words, the axial height and the radial width of the generating surface is zero), and is applied within a range of a little less than a half circumference from the position of both ends of the piston ring 72 in the non-oscillating direction. The As a result, the generating surfaces 72A ′ and 72B ′ have the maximum radial position and the axial height at the end position in the swing direction, and the radial width and the axial height become closer to the non-oscillation side. Both of them are shaped to be gradually smaller and formed in a range of a little less than a half circumference of the piston ring 72 ′. Here, the generating surfaces 72A 'and 72B' on both sides are formed independently so as not to cross each other in the piston ring 72 '.

  Since the piston ring 72 ′ is not formed with the generating surfaces 72A ′ and 72B ′ at the outer corner on the lower side on the one side in the swing direction of the main ring portion 88 and the outer corner on the upper side on the other side in the swing direction. The axial thickness is made larger than the maximum axial height of the generating surfaces 72A ′ and 72B ′. As a result, the outer peripheral side smooth surface 72C along the axial direction of the piston ring 72 ′ is formed on the entire outer periphery. Is formed. Further, as in the first embodiment, the piston ring 72 ′ has an upper surface portion 72D and a lower surface portion 72E that are flat surfaces along the axis orthogonal direction over the entire circumference except for the joint portions 89 and 90, and the axial direction in the entire inner periphery. An inner peripheral side smooth surface 72F is formed.

  Here, the piston ring 72 ′ also has the maximum axial dimension of the non-oscillating outer peripheral smooth surface 72 </ b> C in which the generating surfaces 72 </ b> A ′ and 72 </ b> B ′ are not formed. The maximum height in the axial direction of the generating surfaces 72A 'and 72B' is equal to the minimum height in the axial direction of the outer peripheral smooth surface 72C. Further, since the generating surfaces 72A ′ and 72B ′ are formed symmetrically with respect to each other, the axial center position of the outer peripheral side smooth surface 72C, which is the maximum part of the outer dimension, is different between one side and the other side in the swing direction. It will be. Specifically, the axial center position of the outer peripheral smooth surface 72C on one side in the swinging direction is shifted downward with respect to the axial center position of the outer peripheral smooth surface 72C on the other swinging direction. . The generating surface 72A ′ is continuously formed from one side in the swinging direction of the outer peripheral side smooth surface 72C, which is the maximum part of the outer dimensions, and the generating surface 72B ′ is also the outer periphery which is the maximum part of the outer dimensions. It is formed continuously from the other side in the swing direction of the side smooth surface 72C.

  Here, the above-described seal improvement processing of the piston ring 72 ′ is performed by applying a cylindrical cutting tool for peripheral processing to the material of the piston ring 72 ′ along the outer diameter of the material before the seal improvement processing of the piston ring 72 ′. And moving the material of the piston ring 72 'relative to the cutting tool. For example, the following manufacturing apparatus can be used.

  A manufacturing apparatus 100 shown in FIG. 11 includes a tool holding table 102 that rotatably holds a cylindrical cutting tool 101 having a cutting blade disposed therein, and a tool holding table that is provided on the side of the tool holding table 102. A swing mechanism 103 that swings the piston ring 72 ′ on the inner diameter side of the cutting tool 101 held by the head 102 in the same manner as when mounted on the swing type compressor 10 is provided.

  The swing mechanism 103 includes a moving table 105 that moves parallel to the central axis of the cylindrical cutting tool 101 held on the tool holding table 102, and a swing that is provided on the moving table 105 and that is orthogonal to the central axis of the cutting tool 101. A rotating plate 107 that rotates about a shaft 106, a swinging shaft 108 that is provided on the rotating plate 107 so as to be able to rotate in parallel with the swivel shaft 106, and a center axis of the cutting tool 101, and that includes the center axis It has a support shaft 109 that is disposed in a plane perpendicular to the support shaft 109 and is held by the swing shaft 108, and a work holding portion 110 that holds the piston ring 72 ′ at the tip of the support shaft 109. The rotation axis of the turning shaft 106 and the swing shaft 108 can be controlled.

The swing mechanism 103 moves the material of the piston ring 72 ′ in the same manner as the compression stroke at the time of mounting on the swing compressor 10, so that the piston ring 72 ′ is moved by the cylindrical cutting tool 101. The creation surfaces 72A ′ and 72B ′ are processed and formed on the material. When the work holding unit 110 is moved in the same manner as when mounted on the oscillating compressor 10, the angle formed by the line connecting the pivot shaft 106 and the pivot shaft 108 with respect to the central axis of the cutting tool 101 is θ, and the pivot axis When the distance between the swing shaft 108 and the swing shaft 108 is r, and the distance between the swing shaft 108 and the piston ring 72 ′ is L, the angle β formed by the center axis of the cutting tool 101 and the center axis of the piston ring 72 ′ is It is expressed by the following formula.
β = sin−1 (r / L × sin θ)

  The swing mechanism 103 operates the piston ring 72 'based on the above relationship. Specifically, the piston ring 72 ′ is arranged coaxially with respect to the cutting tool 101 that rotates by the tool holding base 102, and the swing shaft 108 is arranged on the opposite side of the cutting tool 101 with respect to the turning shaft 106. State. Here, the material of the piston ring 72 ′ has an outer diameter substantially the same as the inner diameter of the cylinder 45. From this state, the moving base 105 is moved to insert the material of the piston ring 72 ′ into the cutting tool 101, and the piston ring 72 ′ is then moved relative to the cutting tool 101 with the moving base 105 stopped. While moving on the same axis, the turning shaft 106 and the swinging shaft 108 are controlled to swing in the same manner as when mounted on the swinging compressor 10 to advance in the cutting tool 101. At this time, the workpiece holding unit 110 gradually expands the diameter of the piston ring 72 ′ so that the piston ring 72 ′ is in a natural state at the maximum swing angle as in the case of being mounted on the swing type compressor 10. In this way, the generating surfaces 72A 'and 72B' are formed on the piston ring 72 '.

  According to the piston ring 72 ′ of the second embodiment described above, the seal improving process is a chamfer corresponding to the swing angle that changes for each position of the compression stroke (up stroke). Since the generating surfaces 72A ′ and 72B ′ having a generating surface shape corresponding to the swing angle of the piston 63 are formed in the portion continuing from the maximum portion, the piston ring 72 is moved during the swing of the compression stroke of the piston 63. Both side portions subjected to the 'seal enhancement process can be brought into contact with the change in the cross-sectional shape of the contact portion of the cylinder 45, and loss generation can be suppressed and compression efficiency can be improved.

  In the first embodiment, as shown in FIG. 12, the piston ring 72 is divided into two divided bodies 72 a and 72 b at a cutting surface connecting the end portions on the non-oscillating side, and the divided bodies 72 a and 72 b are divided. A spring member 115 that biases them in the direction of separating them may be provided. Also in the second embodiment, similarly, the piston ring 72 ′ is divided into two divided bodies by a cut surface connecting the end portions on the non-oscillating side, and these are separated in the direction of separating them. A spring member for biasing may be provided.

In the first and second embodiments, the swing type compressor has been described as an example. However, as long as the piston reciprocates while swinging in the cylinder, other swing type cylinder devices may be used. Applicable.
Further, in the first embodiment and the second embodiment, the content of performing the seal improvement processing and the creation surface processing on a part of the substantially rectangular cross section of the piston ring 72 has been described. It is also possible to perform chamfering processing in a narrow range.
In addition, as a method of processing the piston ring, the cutting tool is rotated and moved along the outer diameter of the piston ring, and the piston ring is swung relative to the cutting tool. It is also possible to make it swing relatively.

It is sectional drawing which shows the whole structure of the rocking | swiveling compressor containing the piston ring of 1st Embodiment which concerns on this invention. It is II-II sectional drawing of FIG. 1 which shows the rocking | fluctuation type compressor containing the piston ring of 1st Embodiment which concerns on this invention. It is a disassembled perspective view of the principal part of the piston of 1st Embodiment which concerns on this invention. The piston ring of 1st Embodiment which concerns on this invention is shown, (a) is a top view, (b) is X1-X1 sectional drawing of (a), (c) is Y1-Y1 sectional drawing of (a). It is. It is X1-X1 expanded sectional drawing of FIG. 4 which shows the piston ring of 1st Embodiment which concerns on this invention. It is a perspective view which shows the piston ring of 1st Embodiment which concerns on this invention. It is sectional drawing which shows the relationship between the piston ring and cylinder of 1st Embodiment which concerns on this invention, (a) is the maximum rocking | fluctuation state in a compression stroke, (b) is a compression completion state, (c) is the maximum in a suction stroke. Each swing state is shown. It is a top view which shows the piston ring of 2nd Embodiment which concerns on this invention. It is X2-X2 expanded sectional drawing of FIG. 8 which shows the piston ring of 2nd Embodiment which concerns on this invention. It is a figure which shows the cross-sectional shape for every angle shown in FIG. 8 of the creation surface of the piston ring of 2nd Embodiment which concerns on this invention. It is a side view which shows an example of the manufacturing apparatus of the piston ring of 2nd Embodiment which concerns on this invention. It is a top view which shows the modification of the piston ring of 1st Embodiment which concerns on this invention.

Explanation of symbols

10 Oscillating compressor (Oscillating cylinder device)
11 Crankcase (case)
28 Crankshaft (Eccentric rotary shaft)
45 Cylinder 50 Cylinder head 55 Compression chamber 63 Piston 65 Connecting part 71 Disk part 72, 72 'Piston ring 72A, 72B Tapered surface 72A', 72B 'Generating surface 72C Outer peripheral side smooth surface 72a, 72b Split body 84 Protruding part mechanism)
85 Ring groove 89,90 Joint part 115 Spring member

Claims (17)

In the piston ring having a substantially rectangular cross section provided in the piston of the oscillating cylinder device in which the piston provided in the crank member having the crank shaft reciprocates while oscillating in the cylinder,
A seal improving process corresponding to the maximum swing angle of the upward stroke of the piston is formed at the upper outer corner on one side of the swing direction that is perpendicular to the center axis of the crankshaft and perpendicular to the center axis of the cylinder. A seal improvement process corresponding to the maximum swing angle of the upward stroke of the piston is applied to the outer corner of the lower part on the other side in the swing direction. A piston ring characterized in that the outer corner is maximized and gradually decreases as it approaches the non-oscillating side . 2. The piston ring according to claim 1, wherein the seal improving process is a chamfer corresponding to a swing angle that changes for each position of the ascending stroke. In the annular piston ring provided in the piston of the swing type cylinder device that reciprocates while the piston swings in the cylinder,
A piston ring characterized in that an axial center position of a maximum portion of an outer dimension on one side and the other side in a swinging direction is different between the one side and the other side. The piston ring according to claim 3 , wherein a smooth surface is provided over the entire outer periphery. 5. The piston ring according to claim 4 , wherein the axial dimension of the smooth surface in the non-oscillating direction is the largest, and the axial dimension of the smooth surface in the oscillating direction is the smallest. The piston ring according to any one of claims 3 to 5 , wherein the piston ring has an oval shape in a natural state. The piston ring according to any one of claims 3 to 6 , wherein an abutment portion is provided on a part of the circumference. The piston ring according to any one of claims 3 to 7 , wherein a maximum surface of the outer dimension and a continuous surface have a generating surface shape that matches a swing angle of the piston. The piston ring according to any one of claims 3 to 7 , wherein the outermost dimension and the continuous surface have a tapered surface shape. Piston ring according to claim 8 or 9, characterized in that the surface to continue the maximum portion of the outer dimensions is a point symmetrical with respect to the piston ring centroid. A case for rotatably supporting the eccentric rotation shaft;
A cylinder provided in the case and mounted with a cylinder head;
One end side is a connecting portion that is rotatably connected to the eccentric rotating shaft, and the other end side is a disk portion that reciprocates while swinging in the cylinder and forms a compression chamber with the cylinder head. In a oscillating compressor consisting of:
A ring groove is provided on the outer peripheral side of the disk portion of the piston,
An annular piston ring having a substantially rectangular cross section that seals between the piston and the cylinder is mounted in the ring groove,
The piston ring has an abutment portion and is mounted so as to be able to expand and contract along the cylinder inner diameter when the piston swings, and is perpendicular to the central axis of the eccentric rotation shaft and perpendicular to the central axis of the cylinder. A seal improvement process corresponding to the maximum swing angle of the compression stroke of the piston is performed on the outer corner of the upper part on one side in a certain swinging direction, and the piston on the outer corner on the lower part on the other side in the swinging direction is applied. Seal improvement processing corresponding to the maximum swing angle of the compression stroke is performed, and the amount of processing increases gradually as the processing amount reaches the non-oscillation side with the outer corner in the swing direction being maximized. An oscillating compressor characterized by 12. The oscillating compressor according to claim 11 , wherein the seal improving process is a chamfer corresponding to an oscillating angle that changes for each position of the compression stroke. The oscillating compressor according to claim 11 or 12 , wherein a smooth surface is provided over the entire outer periphery of the piston ring. The oscillating compressor according to any one of claims 11 to 13 , wherein the seal improving process is performed point-symmetrically with respect to the center of gravity of the piston ring. The oscillating compressor according to any one of claims 11 to 14 , wherein the piston ring is provided with a rotation stop mechanism for the piston ring. The oscillating compressor according to claim 15 , wherein the joint portion is arranged in a non-oscillating direction. The oscillating compressor according to claim 11 , wherein the piston ring is divided into two divided bodies, and a spring member is provided between the two divided bodies.

Images