JP2006152960A - Swing type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillating compressor capable of compressing at a high pressure, reducing the manufacturing cost, and allowing a compressed fluid in a compression chamber to escape when stopped.
A piston 14 is integrally formed by a connecting portion 16, a piston rod 17, and a piston portion 18. The disc-shaped piston portion 18 swings in a cylinder 7 as the piston 14 reciprocates. A ring groove 20 is formed on the outer peripheral side of the piston portion 18, and an annular piston ring 21 is attached to the ring groove 20. Further, arc-shaped R chamfered portions 22 are formed on both ends of the piston ring 21 in the axial direction. Accordingly, high pressure compressed air can be sealed while preventing deformation of the piston ring 21 during driving, and compressed air remaining in the compression chamber 19 through the gap between the piston ring 21 and the ring groove 20 when stopped. Can be released to the crankcase 1 side.
[Selection] Figure 1

Description

  The present invention relates to an oscillating compressor that is preferably used to compress air, for example.

  In general, a oscillating compressor includes an electric motor, a crankcase rotatably provided with a crankshaft driven by the electric motor, and a piston sliding hole provided in the crankcase and surrounded by a peripheral wall. A cylinder having a piston inserted into a piston sliding hole of the cylinder and reciprocating in the cylinder by a crankshaft; a compression chamber formed in the cylinder for compressing gas while the piston reciprocates; and the compression chamber And an intake passage through which air is introduced from the outside (see, for example, Patent Document 1).

JP-A-8-28469

  Here, the oscillating compressor according to the prior art uses a locking piston in which one end side is a connecting portion that is rotatably connected to the crankshaft and the other end side is a disk portion that defines a compression chamber. A lip seal is provided on the outer peripheral side of the disc portion of the piston, and seals between the disc portion of the piston that reciprocates while swinging using the lip seal and the cylinder.

  However, in the above-described oscillating compressor according to the prior art, when high-pressure air of several MPa or more is compressed as in the high-pressure side of a two-stage compressor, for example, the lip seal is deformed and broken, and the compressed air May leak. For this reason, it is difficult to apply the oscillating compressor to the high pressure side of the two-stage compressor, and the piston and the crankshaft are connected using a connecting rod (piston rod) separate from the piston. Since a reciprocating compressor is used, there are problems of an increase in the number of parts and an increase in manufacturing cost.

  In addition, since the lip seal is pressed against the cylinder regardless of whether the compressor is operating or stopped, the sealing performance of the lip seal is maintained even after the compressor is stopped. As a result, since the high pressure compressed air remains in the compression chamber when the operation is stopped, the remaining compressed air acts as a load when the compressor is restarted, making it difficult to restart the compressor. There is also.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to enable a high-pressure compression, reduce the manufacturing cost, and allow the compressed fluid in the compression chamber to escape when stopped. It is to provide a compressor.

  In order to solve the above-described problems, the present invention has a crankcase that rotatably supports a crankshaft, a cylinder that is provided in the crankcase and on which a cylinder head is mounted, and one end side is rotatably connected to the crankshaft. This is applied to an oscillating compressor comprising a piston which is a disk part defining the compression chamber between the cylinder head and the other end side reciprocating while oscillating in the cylinder.

  The feature of the configuration adopted by the invention of claim 1 is that a ring groove located on the outer peripheral side is provided in the disk portion of the piston, and the ring groove has a non-lip shape that seals between the piston and the cylinder. The piston ring is attached.

  According to a second aspect of the present invention, the piston ring is formed such that the outer diameter dimension at both ends in the reciprocating direction of the piston is smaller than the outer diameter dimension at the intermediate side.

  According to a third aspect of the present invention, an arcuate R chamfered portion is provided on the outer peripheral side of the piston ring so as to be located at both end sides in the reciprocating direction of the piston.

  According to a fourth aspect of the present invention, tapered C chamfered portions are provided on the outer peripheral side of the piston ring so as to be positioned at both end sides in the reciprocating direction of the piston.

  According to a fifth aspect of the present invention, an arcuate surface portion having an arc shape is provided on the outer peripheral side of the piston ring over the entire length of the piston in the reciprocating direction.

  According to the first aspect of the present invention, since the non-lip shaped piston ring is attached to the disk portion of the piston via the ring groove, the piston and the cylinder can be sealed using the piston ring. Further, in the lip seal of the prior art, the lip portion that is in sliding contact with the cylinder tends to bend and wear out unevenly, and the compressed fluid leaks, whereas the piston ring is used in the present invention. Is not present, the strength of the piston ring can be increased, and durability and reliability can be improved. As a result, for example, the locking piston in which the connecting portion and the disk portion are integrally formed can be used on the high pressure side of the two-stage compressor, and the number of parts can be reduced to reduce the manufacturing cost and the size of the apparatus. be able to.

  Furthermore, since the piston ring is attached to the disk portion of the piston via the ring groove, the compressed fluid in the compression chamber can be released to the crankcase side through the gap between the ring groove and the piston ring when the compressor is stopped. For this reason, since the compression chamber can be always kept in a low pressure state when the compressor is started, the load at the time of restart can be reduced.

  According to the invention of claim 2, since the outer diameter dimension at both ends of the piston ring is smaller than the outer diameter dimension at the intermediate side, even if the piston swings due to reciprocation, both ends of the piston ring The corners on the side can be prevented from locally contacting the cylinder, and the piston ring can be smoothly brought into contact with the cylinder.

  According to invention of Claim 3, it is set as the structure which provides an arc-shaped R chamfering part in the outer peripheral side of a piston ring. At this time, when a corner is formed on the outer peripheral side of the piston ring, the corner of the piston ring locally contacts the cylinder when the swing angle of the piston becomes the maximum, and uneven wear or compressed fluid There is a risk of leakage. On the other hand, since the R chamfered portion is provided on the outer peripheral side of the piston ring in the present invention, even when the piston has the maximum swing angle, the R chamfered portion can prevent local contact with the cylinder, The compression performance can be improved and the reliability can be improved.

  According to the invention of claim 4, since the tapered C chamfered portion is provided on the outer peripheral side of the piston ring, for example, by forming the C chamfered portion corresponding to the maximum swing angle of the piston, the piston can be swung maximum. Even when it becomes a corner, the piston ring can be brought into surface contact with the cylinder. As a result, local contact with the cylinder can be prevented by the C chamfered portion, the compression performance can be improved, and the reliability can be improved.

  According to the fifth aspect of the present invention, since the arcuate surface portion having an arc shape is provided on the outer peripheral side of the piston ring over substantially the entire surface, for example, by forming the arcuate surface portion in accordance with the oscillation of the piston, the piston is swung. Regardless of the moving angle, the piston ring can be brought into smooth contact with the cylinder. As a result, local contact with the cylinder can be prevented by the circular arc surface portion, the compression performance can be improved, and the reliability can be improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a swing type compressor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  1 to 5 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a crankcase in which a crank chamber 2 is defined. A crankshaft 5 is fixed to the output shaft 4 of the electric motor 3 and is rotatably supported. A balance weight 6 is attached to the output shaft 4 in contact with the crankshaft 5.

  Reference numeral 7 denotes a cylindrical cylinder mounted on the crankcase 1. The cylinder 7 has a proximal end opened into the crank chamber 2 and an inner peripheral surface 7A serving as a sliding surface of a piston 14 described later. Yes. A cylinder head 8 is mounted on the tip side of the cylinder 7, and a suction chamber 9 communicating with the outside through the suction port 9A and a discharge communicating with the outside through the discharge port 10A are provided in the cylinder head 8. A chamber 10 is defined.

  Reference numeral 11 denotes a valve seat plate sandwiched between the cylinder 7 and the cylinder head 8. The valve seat plate 11 compresses a suction hole 11 </ b> A for communicating the suction chamber 9 with a compression chamber 19 described later, and a discharge chamber 10. A discharge hole 11 </ b> B communicating with the chamber 19 is formed. Further, a suction valve 12 and a discharge valve 13 as reed valves are attached to the valve seat plate 11, and the suction valve 12 and the discharge valve 13 are fixed to the valve seat plate 11 through screws or the like on the base end side. The suction end 11A and the discharge hole 11B are opened and closed respectively.

  Reference numeral 14 denotes a rocking piston (hereinafter referred to as piston 14) slidably fitted in the cylinder 7, and the piston 14 is located at one end side in the crank chamber 2 with respect to the crankshaft 5 via a bearing 15. A connecting portion 16 that is rotatably connected, a rod-shaped piston rod 17 that is integrally formed with the connecting portion 16 and extends into the cylinder 7, and a disk portion that is integrally formed on the other end side of the piston rod 17. And the piston portion 18. The piston portion 18 is formed in a substantially disc shape with an outer diameter dimension smaller than the inner diameter dimension of the cylinder 7, and defines a compression chamber 19 between the piston seat 18 and the valve seat plate 11. ing.

  Reference numeral 20 denotes a ring groove provided to be recessed on the outer peripheral side of the piston portion 18, and the ring groove 20 is constituted by an annular concave groove formed on the outer peripheral surface 18 </ b> A of the piston portion 18. A piston ring 21 described later is mounted in the ring groove 20.

  A piston ring 21 is mounted in the ring groove 20 and has a non-lip shape. The piston ring 21 is formed in a substantially annular shape by using, for example, a resin material, a metal material, or the like excellent in wear resistance and self-lubrication. . Here, the piston ring 21 is formed in a substantially quadrangular cross section having an upper end surface 21A, a lower end surface 21B, an inner peripheral surface 21C, and an outer peripheral surface 21D. Further, the upper end surface 21A and the lower end surface 21B of the piston ring 21 are located at both ends of the reciprocating direction of the piston 14 (the axial direction of the cylinder 7), and the inner peripheral surface 21C is the inner side of the ring groove 20 ( It is located on the bottom side. Furthermore, the outer peripheral surface 21 </ b> D of the piston ring 21 protrudes from the ring groove 20 and elastically contacts the inner peripheral surface 7 </ b> A of the cylinder 7. At this time, the projecting dimension of the piston ring 21 projecting from the ring groove 20 is sufficient so that the outer peripheral surface 18A of the piston portion 18 does not contact the inner peripheral surface 7A of the cylinder 7 even when the piston 14 reciprocates while swinging. It is set to a valid value.

  Further, the piston ring 21 is inserted into the cylinder 7 together with the piston 14 while being mounted in the ring groove 20. Thereby, since the outer peripheral surface 21 </ b> D side of the piston ring 21 is in sliding contact with the inner peripheral surface 7 </ b> A of the cylinder 7, the piston ring 21 seals between the cylinder 7 and the piston 14. At this time, an annular space is formed along the piston ring 21 between the inner peripheral surface 21 </ b> C of the piston ring 21 and the inner side of the ring groove 20.

  Reference numeral 22 denotes an arcuate R chamfered portion provided on the outer peripheral side of the piston ring 21, and the R chamfered portion 22 is located on both ends of the piston ring 21 in the reciprocating direction of the piston 14, and has an upper end surface 21 A It is formed at each corner on the outer peripheral side of the end face 21B and has, for example, a radius of curvature R1 of a certain size. Further, between the two R chamfered portions 22, there is provided an equal diameter surface portion 23 having the same outer diameter dimension D0 and being substantially flat in the axial direction. Therefore, an outer peripheral surface 21D is formed by the R chamfered portion 22 and the equal-diameter surface portion 23, and the outer diameter dimension D1 on both ends in the reciprocating direction of the piston 14 in the piston ring 21 is intermediate by the R chamfered portion 22. It is set to a value smaller than the outer diameter dimension D0 of the equal-diameter surface portion 23 located on the side.

  The R chamfered portion 22 prevents the corners of the piston ring 21 from contacting locally when the piston 14 reciprocates while swinging in the cylinder 7. Is to slide smoothly.

  Reference numeral 24 denotes a cooling fan fixed to the front end side of the output shaft 4, and the cooling fan 24 blows cooling air into the crank chamber 2.

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

  First, when the electric motor 3 is rotationally driven, the piston 14 reciprocates while swinging in the cylinder 7. As a result, the air compressor repeats a suction stroke for sucking air from the suction chamber 9 into the compression chamber 19 and a compression stroke for compressing the air in the compression chamber 19 and discharging the compressed air to the discharge chamber 10. I do.

  While the compression operation is performed, the outer peripheral surface 21D of the piston ring 21 is always in sliding contact with the inner peripheral surface 7A of the cylinder 7, and either the upper end surface 21A or the lower end surface 21B is in the ring groove 20. Touch the end face. As a result, the piston ring 21 hermetically seals between the piston 14 and the cylinder 7, and prevents air in the compression chamber 19 from leaking toward the crank chamber 2.

  On the other hand, when the electric motor 3 is stopped, the reciprocation of the piston 14 is also stopped together with the electric motor 3. Here, for example, when the piston 14 stops in the compression stroke in which the air in the compression chamber 19 is compressed, high-pressure compressed air may remain in the compression chamber 19. At this time, since an annular space is formed between the piston ring 21 and the ring groove 20, the high-pressure compressed air remaining in the compression chamber 19 passes through the gap between the piston ring 21 and the ring groove 20. Leaks into the crank chamber 2. As a result, high-pressure compressed air does not remain in the compression chamber 19, so that an overload can be prevented from acting on the electric motor 3 or the like when the air compressor is restarted, and the restart is performed smoothly. be able to.

  Further, in the case where corners are formed on the outer peripheral side of the piston ring 21, when the swing angle of the piston 14 becomes maximum, the corners of the piston ring 21 locally contact the cylinder 7 and wear unevenly. There is a risk of leakage of compressed air. On the other hand, in the present embodiment, since the R chamfered portion 22 is provided on the outer peripheral side of the piston ring 21, even when the piston 14 reaches the maximum swing angle, the R 7 chamfered portion 22 locally contacts the cylinder 7. In addition, the leakage of compressed air can be prevented to improve the compression performance, and the reliability can be improved.

  Thus, according to the present embodiment, since the piston ring 21 is attached to the piston portion 18 of the piston 14 via the ring groove 20, the piston 14 and the cylinder 7 are sealed using the piston ring 21. Can do. Further, in this embodiment, since the piston ring 21 is used to seal between the piston 14 and the cylinder 7, there is no lip portion that causes bending or the like as compared with the case of using a lip seal as in the prior art. The strength of the piston ring 21 can be increased, and the durability and reliability can be improved. As a result, the locking piston 14 can be used even for a high-pressure air compressor of about several MPa, for example, and the number of parts can be reduced to reduce the manufacturing cost and the size of the apparatus.

  Further, since the piston ring 21 is attached to the piston portion 18 of the piston 14 via the ring groove 20, the compressed air in the compression chamber 19 is cranked through the gap between the ring groove 20 and the piston ring 21 when the air compressor is stopped. It can escape to the case 1 side. For this reason, since the inside of the compression chamber 19 can be always kept in a low pressure state when the air compressor is started, the load at the time of restart can be reduced.

  Further, since the outer diameter dimension D1 on both ends of the piston ring 21 is formed smaller than the outer diameter dimension D0 on the intermediate side, even if the piston 14 swings due to the reciprocating motion, the outer diameter dimension D1 on both ends of the piston ring 21 is reduced. The corners can be prevented from contacting the cylinder 7 locally, and the piston ring 21 can be brought into smooth contact with the cylinder 7.

  In particular, in the present embodiment, since the arc-shaped R chamfered portion 22 is provided on the outer peripheral side of the piston ring 21, even when the piston 14 reaches the maximum swing angle, the R chamfered portion 22 makes a local contact with the cylinder 7. Contact can be prevented, compression performance can be improved, and reliability can be improved.

  Next, FIGS. 6 to 8 show a second embodiment of the present invention. The feature of this embodiment is that the outer periphery of the piston ring is tapered on both sides in the reciprocating direction of the piston. The C chamfered portion is provided. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  31 is a piston ring according to the present embodiment. The piston ring 31 is mounted in the ring groove 20 in substantially the same manner as the piston ring 21 according to the first embodiment, and is excellent in wear resistance and self-lubrication, for example. The resin material, the metal material, etc. are formed in the substantially annular shape. The piston ring 31 is formed in a substantially square cross section having an upper end surface 31A, a lower end surface 31B, an inner peripheral surface 31C, and an outer peripheral surface 31D. The upper end surface 31A and the lower end surface 31B are respectively in the reciprocating direction of the piston 14. The inner peripheral surface 31 </ b> C is located on the back side (bottom surface side) of the ring groove 20 while being located on both ends. Further, the outer peripheral surface 31 </ b> D of the piston ring 31 protrudes from the ring groove 20 and elastically contacts the inner peripheral surface 7 </ b> A of the cylinder 7. At this time, the projecting dimension of the piston ring 31 projecting from the ring groove 20 is sufficient so that the outer peripheral surface 18A of the piston portion 18 does not contact the inner peripheral surface 7A of the cylinder 7 even when the piston 14 reciprocates while swinging. It is set to a valid value.

  Further, the piston ring 31 is inserted into the cylinder 7 together with the piston 14 in a state of being installed in the ring groove 20, and the outer peripheral surface 31 </ b> D side is in sliding contact with the inner peripheral surface 7 </ b> A of the cylinder 7. Seals between the cylinder 7 and the piston 14. At this time, an annular space is formed along the piston ring 31 between the inner peripheral surface 31 </ b> C of the piston ring 31 and the inner side of the ring groove 20.

  32 is a tapered C chamfered portion provided on the outer peripheral side of the piston ring 31, and the C chamfered portion 32 is located on both ends of the piston ring 31 in the reciprocating direction of the piston 14, and has an upper end surface 31 </ b> A and a lower surface. It is formed at each corner on the outer peripheral side of the end face 31B. Further, between the two C chamfered portions 32, an equal-diameter surface portion 33 having the same outer diameter dimension D0 and substantially flat in the axial direction is provided. Therefore, an outer peripheral surface 31D is formed by the C chamfered portion 32 and the equal-diameter surface portion 33, and the outer diameter D1 of the piston ring 31 at both ends in the reciprocating direction of the piston 14 is intermediate by the C chamfered portion 32. It is set to a value smaller than the outer diameter dimension D0 of the equal-diameter surface portion 33 located on the side.

  The C chamfered portion 32 is formed with a constant inclination angle with respect to the equal-diameter surface portion 33, and the inclination angle is set to a value that makes surface contact with the inner peripheral surface 7A of the cylinder 7 when the piston 14 reaches the maximum swing angle, for example. Is set. Thereby, the C chamfered portion 32 prevents the corners of the piston ring 31 from contacting locally when the piston 14 reciprocates while swinging in the cylinder 7, and the C chamfered portion 32 is on the inner peripheral surface 7 </ b> A of the cylinder 7. Is to slide smoothly.

  Thus, in the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment. In particular, in the present embodiment, since the tapered C chamfered portion 32 is provided on the outer peripheral surface 31D side of the piston ring 31, for example, by forming the C chamfered portion 32 corresponding to the maximum swing angle of the piston 14, Even when the piston 14 reaches the maximum swing angle, the piston ring 31 can be brought into surface contact with the cylinder 7. As a result, local contact with the cylinder 7 can be prevented by the C chamfered portion 32, the compression performance can be improved, and the reliability can be improved.

  Next, FIGS. 9 and 10 show a third embodiment of the present invention. The feature of this embodiment is that the outer circumference of the piston ring has an arc shape over the entire length in the reciprocating direction of the piston. It is in the structure which provides the circular arc surface part to make. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  41 is a piston ring according to the present embodiment. The piston ring 41 is mounted in the ring groove 20 in substantially the same manner as the piston ring 21 according to the first embodiment, and is excellent in wear resistance and self-lubrication, for example. The resin material, the metal material, etc. are formed in the substantially annular shape. The piston ring 41 is formed in a substantially quadrangular cross section having an upper end surface 41A, a lower end surface 41B, an inner peripheral surface 41C and an outer peripheral surface 41D. The upper end surface 41A and the lower end surface 41B are respectively in the reciprocating direction of the piston 14. The inner peripheral surface 41 </ b> C is positioned on the back side (bottom surface side) of the ring groove 20 while being positioned on both ends. Furthermore, the outer peripheral surface 41 </ b> D of the piston ring 41 protrudes from the ring groove 20 and elastically contacts the inner peripheral surface 7 </ b> A of the cylinder 7. At this time, the projecting dimension of the piston ring 41 projecting from the ring groove 20 is sufficient so that the outer peripheral surface 18A of the piston portion 18 does not contact the inner peripheral surface 7A of the cylinder 7 even when the piston 14 reciprocates while swinging. It is set to a valid value.

  Further, the piston ring 41 is inserted into the cylinder 7 together with the piston 14 in a state of being installed in the ring groove 20, and the outer peripheral surface 41 </ b> D side is in sliding contact with the inner peripheral surface 7 </ b> A of the cylinder 7. Seals between the cylinder 7 and the piston 14. At this time, an annular space is formed along the piston ring 41 between the inner peripheral surface 41 </ b> C of the piston ring 41 and the inner side of the ring groove 20.

  The outer peripheral surface 41D of the piston ring 41 forms an arcuate surface portion having an arc shape with a constant radius of curvature R2 over the entire length of the piston 14 in the reciprocating direction. For this reason, the outer diameter D1 of the piston ring 41 at both ends in the reciprocating direction of the piston 14 is set to a value smaller than the outer diameter D0 of the intermediate side. Thus, the outer peripheral surface 41D smoothly contacts the inner peripheral surface 7A of the cylinder 7 regardless of the swing angle of the piston 14.

  Thus, in the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment. In particular, in the present embodiment, the outer peripheral side of the piston ring 41 is provided with an outer peripheral surface 41D that forms an arcuate surface over an almost entire surface. For example, the outer peripheral surface 41D is a circle that matches the oscillation of the piston 14. By forming it in an arc shape, the piston ring 41 can be brought into smooth contact with the cylinder 7 regardless of the swing angle of the piston 14. As a result, local contact with the cylinder 7 can be prevented by the arc-shaped outer peripheral surface 41D, compression performance can be improved, and reliability can be improved.

  Next, FIGS. 11 to 13 show a fourth embodiment of the present invention. The feature of this embodiment is that a locking piston is provided for both the low pressure side and the high pressure side of the two-stage air compressor. In addition to being used, the piston ring is mounted on each locking piston via a ring groove. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

  Reference numeral 51 denotes a cylindrical crankcase having both axial ends open, and a bottomed cylindrical motor case 52 is disposed on the rear side of the crankcase 51. An electric motor 53 composed of a stator 53A and a rotor 53B is fixed and attached between the motor case 52 and the crankcase 51. The electric motor 53 has an output shaft 54, and the output shaft 54 is rotatably supported by the crankcase 51 and the motor case 52 via bearings 55 and 56. On the other hand, the crankshaft 51 is provided with an output shaft 54 that extends and accommodates crankshafts 70 and 90 (described later) connected to the output shaft 54.

  Further, a balance weight 57 is mounted on the output shaft 54 to be positioned in the crankcase 51 to balance the rotation, and the opening on the front end side of the crankcase 51 is closed with a cover 58. Further, a cooling fan 59 is attached to the distal end side of the output shaft 54 and is located outside the crankcase 51 to cool the compressor.

  61 is a low pressure side compression part provided in the crankcase 51, and the low pressure side compression part 61 compresses the air sucked from the outside. And the low-pressure side compression part 61 is mainly comprised from the below-mentioned cylinder 62, piston 71 grade | etc.,.

  Reference numeral 62 denotes a low-pressure side cylinder provided integrally with the crankcase 51, and the cylinder 62 is provided with a cylinder head 63. A suction chamber 64 and a discharge chamber 65 are defined in the cylinder head 63.

  A valve seat plate 66 is provided between the cylinder 62 and the cylinder head 63, and a low-pressure side compression chamber 67 is defined between the valve seat plate 66 and a piston 71 described later. The compression chamber 67 communicates with a later-described high-pressure side compression unit 81 via a pipe (not shown) and the like.

  The valve seat plate 66 is provided with a suction port 66 </ b> A that communicates the suction chamber 64 and the compression chamber 67, and a discharge port 66 </ b> B that communicates the discharge chamber 65 and the compression chamber 67. Further, the valve seat plate 66 is provided with a suction valve 68 and a discharge valve 69 at positions corresponding to the suction port 66A and the discharge port 66B, respectively.

  Reference numeral 70 denotes a crankshaft that is positioned behind the balance weight 57, which will be described later, and is fixed to the output shaft 54. A piston 71, which will be described later, is rotatably connected to the crankshaft 70.

  Reference numeral 71 denotes a low-pressure side locking piston (hereinafter referred to as a piston 71) slidably fitted into the cylinder 62, and one end of the piston 71 is rotatably connected to the crankshaft 70 via a bearing 72. A connecting portion 73, a rod-like piston rod 74 integrally formed with the connecting portion 73 and extending into the cylinder 62, and a piston portion 75 as a disk portion integrally formed with the other end of the piston rod 74. It is constituted by. The piston portion 75 is formed in a substantially disk shape with an outer diameter dimension smaller than the inner diameter dimension of the cylinder 62, and defines a compression chamber 67 between the piston seat 75 and the valve seat plate 66. ing.

  Reference numeral 76 denotes a ring groove provided to be recessed on the outer peripheral side of the piston portion 75, and the ring groove 76 is configured by an annular concave groove formed on the outer peripheral surface 75 </ b> A of the piston portion 75. The ring groove 76 is fitted with a piston ring 77 that is substantially the same as the piston ring 21 according to the first embodiment. Thus, the piston ring 77 hermetically seals between the cylinder 62 and the piston 71.

  81 is a high-pressure side compression unit provided in the crankcase 51 so as to face the low-pressure side compression unit 61, and the high-pressure side compression unit 81 again compresses the low-pressure compressed air guided from the low-pressure side compression unit 61, High pressure compressed air is obtained. The high-pressure side compression portion 81 is generally configured by a cylinder 82, a piston 91, and the like which will be described later.

  Reference numeral 82 denotes a high-pressure side cylinder provided integrally with the crankcase 51, and the cylinder 82 is provided with a cylinder head 83. A suction chamber 84 and a discharge chamber 85 are defined in the cylinder head 83.

  A valve seat plate 86 is provided between the cylinder 82 and the cylinder head 83, and a high-pressure side compression chamber 87 is defined between the valve seat plate 86 and a piston 91 described later. The compression chamber 87 is for recompressing the compressed air from the compression chamber 67 to a high pressure.

  The valve seat plate 86 is provided with a suction port 86 </ b> A that communicates the suction chamber 84 and the compression chamber 87, and a discharge port 86 </ b> B that communicates the discharge chamber 85 and the compression chamber 87. Further, the valve seat plate 86 is provided with a suction valve 88 and a discharge valve 89 at positions corresponding to the suction port 86A and the discharge port 86B, respectively.

  Reference numeral 90 denotes a crankshaft which is positioned on the rear side of the crankshaft 70 and fixed to the output shaft 54, and a piston 91 which will be described later is rotatably connected to the crankshaft 90.

  91 is a high-pressure side locking piston (hereinafter referred to as a piston 91) slidably fitted in the cylinder 82. The piston 91 is substantially the same as the low-pressure side piston 71 at one end side with respect to the crankshaft 90. A connecting portion 93 rotatably connected via a bearing 92, a rod-shaped piston rod 94 integrally formed with the connecting portion 93 and extending into the cylinder 82, and integrally formed on the other end side of the piston rod 94. And a piston portion 95 as a disc portion. The piston portion 95 is formed in a substantially disk shape with an outer diameter dimension smaller than the inner diameter dimension of the cylinder 82, and defines a compression chamber 87 between the valve seat plate 86 and the cylinder portion 82. ing.

  Reference numeral 96 denotes a ring groove provided in a recessed manner on the outer peripheral side of the piston portion 95, and the ring groove 96 is configured by an annular concave groove formed on the outer peripheral surface 95 </ b> A of the piston portion 95. The ring groove 96 is also provided with a piston ring 97 that is substantially the same as the piston ring 21 according to the first embodiment. Thus, the piston ring 97 hermetically seals between the cylinder 82 and the piston 91.

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

  First, the output shaft 54 is rotationally driven by the electric motor 53, and the low pressure side compression unit 61 and the high pressure side compression unit 81 are driven. Thereby, in the low pressure side compression part 61, when the crankshaft 70 rotates, the piston 71 reciprocates while swinging in the cylinder 62. As a result, on the cylinder 62 side, a compression process is repeated in which a suction stroke for sucking air from the suction chamber 64 into the compression chamber 67 and a compression stroke for compressing air in the compression chamber 67 and discharging low-pressure compressed air to the discharge chamber 65 are performed. Do the driving.

  On the other hand, the high pressure side compression unit 81 compresses and discharges the suction stroke in which the low pressure compressed air from the discharge chamber 65 of the low pressure side compression unit 61 is sucked into the compression chamber 87 from the suction chamber 84 and the air in the compression chamber 87. The compression stroke in which high-pressure compressed air is discharged into the chamber 85 is repeated.

  In this way, the reciprocating compressor compresses the low-pressure air once compressed in the compression chamber 67 of the low-pressure side compression unit 61 in the compression chamber 87 of the high-pressure side compression unit 81 and discharges it as high-pressure compressed air to the outside. To do.

  Thus, in the present embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment. In particular, in the present embodiment, piston rings 77 and 97 are attached to the pistons 71 and 91 via ring grooves 76 and 96, and the pistons 71 and 91 and the cylinders 62 and 82 are Since the gap is sealed, it is possible to seal high-pressure compressed air while preventing deformation and damage of the piston rings 77 and 97 as compared to the case of using a lip seal as in the prior art. As a result, since the locking piston 91 can be used for the high pressure side compression portion 81 in addition to the low pressure side compression portion 61 of the two-stage air compressor, for example, when the piston and the piston rod are formed as separate members In comparison, the number of parts can be reduced to reduce the manufacturing cost and the size of the apparatus.

  In the fourth embodiment, the locking pistons 71 and 91 having piston rings 77 and 97 attached to the two-stage air compressor having the low pressure side compression unit 61 and the high pressure side compression unit 81 are used. The configuration. However, the present invention is not limited to this. For example, a rocking piston having a piston ring attached to a multistage air compressor including three or more compression units may be used.

  In the fourth embodiment, the piston rings 77 and 97 are mounted on the locking pistons 71 and 91 of both the low pressure side compression portion 61 and the high pressure side compression portion 81. It is good also as a structure which attaches a lip seal to the locking piston of a compression part, and attaches a piston ring only to the locking piston of a high-pressure side compression part.

  Moreover, in each said embodiment, it was set as the structure which forms the R chamfering part 22, the C chamfering part 32, and the circular-arc-shaped outer peripheral surface 41D in the piston rings 21, 31, and 41, respectively. However, the present invention is not limited to this, and a configuration using a piston ring 21 ′ having a substantially square cross section that is not chamfered, such as the modification shown in FIGS. 14 and 15, may be employed.

  Further, in each of the above-described embodiments, the air compressor has been described as an example of the oscillating compressor. However, the present invention may be applied to an oscillating compressor that compresses a gas other than air, a refrigerant, or the like.

It is a longitudinal section showing an air compressor by a 1st embodiment of the present invention. It is the cross-sectional view which looked at the air compressor from the arrow II-II direction in FIG. It is a cross-sectional view of the same position as in FIG. 2 showing a state where the piston has moved to the bottom dead center. FIG. 4 is an enlarged cross-sectional view of a main part showing an a part in FIG. 3 in an enlarged manner. It is a cross-sectional view which shows the piston ring in FIG. 3 alone. It is a cross-sectional view of the same position as FIG. 2 showing a state in which the piston according to the second embodiment is inclined at the maximum swing angle. It is a principal part expanded horizontal sectional view which expands and shows the b section in FIG. It is a cross-sectional view which shows the piston ring in FIG. 6 alone. It is a principal part expanded horizontal sectional view of the same position as FIG. 7 which expands and shows the piston ring etc. by 3rd Embodiment. It is a cross-sectional view which shows the piston ring in FIG. 9 alone. It is a longitudinal cross-sectional view which shows the two-stage type air compressor by 4th Embodiment. It is a fragmentary sectional view which shows the low voltage | pressure side compression part in FIG. It is a fragmentary sectional view which shows the high voltage | pressure side compression part in FIG. It is a principal part expanded horizontal sectional view of the same position as FIG. 4 which expands and shows the piston ring etc. by the modification of this invention. It is a cross-sectional view which shows the piston ring in FIG. 14 alone.

Explanation of symbols

1,51 Crankcase 4,54 Output shaft 5,70,90 Crankshaft 7,62,82 Cylinder 8,63,83 Cylinder head 11,66,86 Valve seat plate 14,71,91 Piston (locking piston)
16, 73, 93 Connecting part 17, 74, 94 Piston rod 18, 75, 95 Piston part (disk part)
19, 67, 87 Compression chamber 20, 76, 96 Ring groove 21, 31, 41, 77, 97, 21 'Piston ring 22 R chamfered portion 32 C chamfered portion 41D Outer peripheral surface (arc surface portion)

Claims (5)

A crankcase that rotatably supports the crankshaft, a cylinder that is provided on the crankcase and on which a cylinder head is mounted, and one end side is a connecting portion that is rotatably connected to the crankshaft, and the other end side swings in the cylinder. In an oscillating compressor comprising a piston that is reciprocating while moving and is a disk part that defines a compression chamber with the cylinder head,
An oscillating compressor characterized in that a ring groove located on the outer peripheral side is provided in the disk portion of the piston, and a non-lip-shaped piston ring that seals between the piston and the cylinder is attached to the ring groove. .   2. The oscillating compressor according to claim 1, wherein the piston ring is formed such that an outer diameter dimension at both ends in a reciprocating direction of the piston is smaller than an outer diameter dimension at an intermediate side.   The oscillating compressor according to claim 2, wherein an arcuate R chamfered portion is provided on both ends of the piston ring in the reciprocating direction on the outer peripheral side of the piston ring.   The oscillating compressor according to claim 2, wherein a tapered C chamfered portion is provided on both ends of the piston ring in the reciprocating direction on the outer peripheral side of the piston ring.   3. The oscillating compressor according to claim 2, wherein an arcuate surface portion having an arc shape is provided on an outer peripheral side of the piston ring over the entire length of the piston in the reciprocating direction.

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