JP5011188B2 - Reciprocating compressor - Google Patents

Description

  The present invention relates to a reciprocating compressor.

A reciprocating compressor that compresses gas is eccentrically attached to a rotary drive shaft of a drive source such as a motor, and a crank is attached to the crank via a bearing, and a connecting rod provided integrally with the piston is rotatably connected to the crank. There is a thing of the structure to do. In this reciprocating compressor, the piston provided at the tip of the connecting rod reciprocates while swinging in the cylinder as the crank rotates eccentrically by the rotation of the rotary drive shaft, and sucks, compresses and discharges gas. To do. In such a reciprocating compressor, the piston is formed by a disk part provided on the distal end side of the connecting rod and a separate retainer attached to the disk part, and a lip seal is sandwiched between the disk part and the retainer. The lip seal is brought into sliding contact with the inner peripheral surface of the cylinder to seal the piston and the cylinder. The lip portion of the lip seal is such that both sides of the piston swing direction (crank axis orthogonal direction) receive a pressing force due to the swing than both sides of the direction orthogonal to the swing direction (crank shaft direction). Therefore, the lip part has an elliptical shape that is long in the piston swing direction, and the thickness on both sides of the piston swing direction is the thickness on both sides in the direction perpendicular to the swing direction.
JP 7-91374 A

  In recent years, higher output is also demanded in the above-described oscillating piston type reciprocating compressor. Although the above-mentioned elliptical lip seal can extend the life against the wear, it cannot sufficiently cope with the damage caused by the high output of the compressor. In other words, when the output of the compressor is increased, the pressure of the gas applied to the lip seal increases, and the stress value generated in the lip seal increases, resulting in early breakage.

  Therefore, an object of the present invention is to provide a reciprocating compressor capable of suppressing the damage of the lip seal caused by the increase in output and extending the life of the lip seal.

  In order to achieve the above object, the present invention provides a dimensional difference in a direction perpendicular to the piston swinging direction due to a dimensional difference in outer diameter that occurs in the mounting state of the retainer that clamps the clamping part of the lip seal with the disc disk part of the piston. However, it is formed large with respect to the dimensional difference in the swing direction.

  According to the present invention, the dimensional difference in the direction perpendicular to the oscillating direction of the piston is formed to be larger than the dimensional difference in the oscillating direction due to the dimensional difference of the outer diameter generated in the mounting state of the retainer and the disk part. Therefore, the lip seal sandwiched between the retainer and the disk portion has a margin for deformation in a direction perpendicular to the swinging direction of the piston. Even if a large pressure is applied to the lip portion to cause a large deformation, the deformation can be absorbed by the above-described margin, and the generated stress can be relaxed. Accordingly, it is possible to prevent the lip seal from being damaged due to the increase in output and to extend the life of the lip seal.

A reciprocating compressor according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the reciprocating compressor 11 of this embodiment includes an electric motor 12 as a drive source, and is connected to the motor 12 at a crankcase portion 13 and driven by the motor 12 to generate compressed air. And a compressor main body 14 to be used.

  The compressor main body 14 has a cylindrical shape and is provided so as to cover a cylinder 17 disposed along a direction orthogonal to the rotation drive shaft 15 of the motor 12 and an opening opposite to the rotation drive shaft 15 of the cylinder 17. And the cylinder head 19 provided on the opposite side of the partition plate 18 from the cylinder 17. Here, although not shown, a discharge hole is formed in the partition plate 18, and a plate-like discharge valve is attached to the cylinder head 19 side so as to cover the discharge hole. Here, the rotation drive shaft 15 is disposed along the horizontal direction, and the cylinder 17 is disposed along the vertical direction.

  The compressor body 14 includes a crank member 21 that is fitted and fixed in an eccentric state to the rotary drive shaft 15 of the motor 12, a base end side that is rotatably connected to the crank member 21 via a bearing 22, and a tip end side that is a cylinder. 17 and a reciprocating member 23 provided so as to be capable of reciprocating.

  The reciprocating member 23 includes a connecting rod 24 that holds the bearing 22 on the proximal end side, and a thin disk that is provided on the distal end side of the connecting rod 24 and is reciprocally disposed in the cylinder 17. A body member 26 integrally formed with the portion 25 is provided. The reciprocating member 23 includes a thin plate-like retainer 28 disposed on the opposite side of the disk portion 25 of the main body member 26 from the connecting rod 24, and a suction hole (not shown) penetrating the retainer 28 in the thickness direction. It has a plate-like suction valve 29 that is attached to the retainer 28 so as to cover the connecting rod 24 on the opposite side, and a screw 30 that fastens the retainer 28 to the disk portion 25. The disk portion 25 and the retainer 28 of the connecting rod 24 form a piston 31 that reciprocates while swinging in the cylinder 17.

  The disc portion 25 of the main body member 26 is formed with a concave portion 34 that is recessed below the outer peripheral side in a predetermined intermediate range. As a result, an annular base portion 35 that protrudes upward with an annular outer side of the concave portion 34 is formed. It has become.

  In the retainer 28, a fitting convex portion 37 that fits into the concave portion 34 of the disk portion 25 is formed on one side in the thickness direction, and as a result, the opposite side in the thickness direction has a larger diameter than the fitting convex portion 37. A flange portion 38 is formed. A mounting recess 39 is formed on the retainer 28 on the side opposite to the fitting convex portion 37, and the above-described suction valve 29 is mounted on the bottom surface of the mounting recess 39.

  The reciprocating member 23 is provided with an annular lip seal 41 held between the retainer 28 and the disk portion 25 of the main body member 26, in other words, held by the piston 31. The lip seal 41 is in sliding contact with the inner peripheral surface of the cylinder 17 to seal the gap between the cylinder 17 and the piston 31.

  The lip seal 41 is an annular seal ring made of an elastic material such as PTFE (tetrafluoroethylene resin), and the inner peripheral side engages the fitting convex part 37 of the retainer 28 and the annular base of the disk part 25. A flat plate-like annular sandwiching portion 42 sandwiched between the portion 35 and the flange portion 38 of the retainer 28, and the outer peripheral side projects outward from the sandwiching portion 42 and bends toward the retainer 28 in the thickness direction, An annular lip 43 that covers the outer peripheral side of the flange portion 38 of the retainer 28 is formed. The lip seal 41 is in sliding contact with the inner peripheral surface of the cylinder 17 at the lip portion 43. In the free state, the entire shape of the lip seal 41, the shape of the clamping portion 42, and the shape of the lip portion 43 are all circular.

  In contrast, as shown in FIG. 2, the retainer 28 has an outer shape of the flange portion 38 that is elliptical when viewed in the thickness direction. As a result, the dimensional difference in the direction perpendicular to the swing direction of the piston 31 due to the dimensional difference in the outer diameter caused by the mounting state of the disk portion 25 and the retainer 28 is formed larger than the dimensional difference in the swing direction. . When the retainer 28 is fixed to the disk portion 25 of the main body member 26 while sandwiching the sandwiching portion 42 of the lip seal 41 with the flange portion 38, the width D in the swinging direction (crank axis orthogonal direction) of the piston 31. Is positioned and fixed in a phase state that is large (that is, width D> width D1) with respect to the width D1 in the direction orthogonal to the swing direction (crankshaft direction). Here, the width D of the retainer 28 is set to be equal to or smaller than the outer diameter of the annular platform 35. Although not shown, the retainer 28 and the disk portion 25 are provided with a positioning structure portion for adjusting the phase as described above. Further, the shape of the fitting projection 37 of the retainer 28 is circular when viewed in the thickness direction in order to position the circular clamping portion 42 of the lip seal 41 in the radial direction.

  As a result, the retainer 28 has a narrow gap with the lip portion 43 of the lip seal 41 on both sides in the swing direction of the piston 31 (left and right direction in FIG. 2), and a direction orthogonal to the swing direction (up and down direction in FIG. 2). Wide on both sides.

  Here, as shown in FIG. 1, the compression chamber a is defined by the piston 31 and the lip seal 41, the cylinder 17, and the partition plate 18. It is a check valve that only allows the movement of air into the compression chamber a. Moreover, the discharge chamber b is formed by the partition plate 18 and the cylinder head 19, and the above-described discharge valve (not shown) allows only movement of air from the compression chamber a side to the discharge chamber b side. It is a check valve.

  In the reciprocating compressor 11 described above, when the rotary drive shaft 15 of the motor 12 rotates, the crank member 21 fixed to the rotary drive shaft 15 performs an eccentric rotational motion. Then, the reciprocating member 23 rotatably connected to the crank member 21 via the bearing 22 reciprocates the piston 31 and the lip seal 41 in the cylinder 17. In the intake stroke, the compression chamber a is enlarged by the movement of the piston 31 and the lip seal 41 in the direction opposite to the cylinder head 19, and the suction valve 29 is opened while the discharge valve (not shown) is closed, and the air is compressed. Introduce into a. In the subsequent compression stroke, the compression chamber a is reduced by the movement of the piston 31 and the lip seal 41 in the direction of the cylinder head 19 and the discharge valve (not shown) is opened while the suction valve 29 is closed, and compressed air is supplied from the compression chamber a. Discharge to the discharge chamber b in the cylinder head 19.

During the above operation, the piston 31 and the lip seal 41 reciprocate while swinging in the cylinder 17.
That is, when viewed along a direction orthogonal to the swinging direction of the piston 31, the connecting rod 24 is located at the center in the left-right direction at the bottom dead center where the compression chamber a is most expanded, and the piston 31 is horizontal. In this state, when the crank member 21 is rotated to perform the compression stroke, the reciprocating member 23 is raised, and the piston 31 and the lip seal 41 are moved in a direction to reduce the compression chamber a, the top dead center and the bottom dead center. The lower part of the connecting rod 24 rises while moving to one side in the left-right direction up to the middle of the point, and the lower part of the connecting rod 24 is the left-right direction at the middle between the top dead center and the bottom dead center (for example, 3 o'clock position). Located on one outside. At this time, the piston 31 is most inclined with respect to the horizontal.

  Subsequently, the lower part of the connecting rod 24 returns to the center in the left-right direction toward the top dead center, and the connecting rod 24 is located at the center in the left-right direction at the top dead center where the compression chamber a is reduced most. 31 becomes horizontal and the compression process is completed.

  When the crank member 21 rotates to perform the suction stroke from the state where the piston 31 is at the top dead center, the reciprocating member 23 moves the piston 31 and the lip seal 41 in the direction of expanding the compression chamber a. The lower part of the connecting rod 24 moves down to the middle between the upper dead center and the bottom dead center, moving downward in the left-right direction, and the lowermost part of the connecting rod 24 between the upper dead center and the lower dead center (for example, at 9 o'clock). Is located outside the other in the left-right direction. At this time, the piston 31 tilts in the opposite direction to the most horizontal.

  Subsequently, the lower part of the connecting rod 24 returns to the center in the left-right direction as it goes to the bottom dead center. At the bottom dead center where the compression chamber a is expanded most, the connecting rod 24 is located at the center in the left-right direction and the piston 31 becomes horizontal, and the suction stroke ends.

  During the movement from the bottom dead center to the top dead center in the compression stroke and the movement from the top dead center to the bottom dead center in the suction stroke, the lip seal 41 in the direction orthogonal to the swinging direction of the piston 31 is used. Both sides are pressed against the inner peripheral surface of the cylinder 17 at a position indicated by an arrow X in FIG. On the other hand, both sides of the lip seal 41 in the swinging direction of the piston 31 are pressed by the reciprocating motion of the piston 31 while swinging in addition to the pressing force and air pressure due to the tightening margin. Is pressed against the inner peripheral surface of the cylinder 17 with a force larger than that on both sides of the swing orthogonal direction. As a result, a large stress is generated in the intermediate portion (hatched portion Z shown in FIG. 2), and this stress increases as the air pressure increases, but the gap with the retainer 28 is large. When both sides of the lip seal 41 in the direction orthogonal to the swinging direction of the piston 31 follow and deform, this stress is dispersed and relaxed.

  According to the reciprocating compressor 11 of the present embodiment described above, the retainer 28 is formed large in the swinging direction of the piston 31 and small in the direction orthogonal to the swinging direction. The lip seal 41 sandwiched between the disk portions 25 has a margin for deformation in a direction perpendicular to the swinging direction of the piston 31. Therefore, even if a high pressure is applied to the lip portion 43 to deform it, it can be absorbed by the above margin, and the generated stress can be relaxed. Therefore, even if the booster is used as a booster booster or the output is increased to improve the function, the lip seal 41 can be prevented from being damaged and the life of the lip seal 41 can be extended. it can.

In addition, although illustration is abbreviate | omitted, as a lip seal, even if the lip | rip part has an elliptical shape long in the rocking | fluctuation direction of piston 31, and both the rocking | swiveling direction sides of piston 31 are thick (refer the said patent document 1). good.
In the present embodiment, the retainer 28 has been described as having an elliptical shape. However, the retainer 28 may have an elliptical shape in which a portion perpendicular to the oscillation direction on the outer periphery thereof is linearly chamfered and corners are smoothed. Good.
In the present embodiment, the cylinder and the piston are described as circular, but may be oval or oval.
Furthermore, in the present embodiment, the air compressor has been described as an example, but it goes without saying that the present invention may be used for other fluid pressurizers such as a pump.

It is a fragmentary sectional view showing the reciprocating compressor of one embodiment of the present invention. The piston and lip seal of the reciprocating compressor of one Embodiment of this invention are shown, (a) is a top view, (b) is sectional drawing which follows the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Reciprocating compressor 17 Cylinder 24 Connecting rod 25 Disk part 28 Retainer 31 Piston 41 Lip seal 42 Clamping part 43 Lip part

Claims (2)

A cylinder,
A piston that is provided on the distal end side of the connecting rod and a retainer that is attached to the disk portion and has an outer diameter equal to or smaller than the outer diameter of the disk portion and reciprocates while swinging in the cylinder;
An annular lip in which the inner peripheral side becomes an annular clamping part sandwiched between the disk part and the retainer, and the outer peripheral side protrudes outward from the sandwiching part and protrudes toward the retainer side and contacts the inner circumferential surface of the cylinder. Lip seal that became part,
In a reciprocating compressor equipped with
A dimensional difference in the direction perpendicular to the swinging direction of the piston due to a dimensional difference in outer diameter caused by the mounting state of the disk portion and the retainer is formed larger than the dimensional difference in the swinging direction. Reciprocating compressor.   The reciprocating compressor according to claim 1, wherein the retainer has an oval shape.

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