JP2012031788A - Air compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air compressor capable of enhancing the durability of a lip ring.SOLUTION: The air compressor includes a high-pressure side cylinder 421, a high-pressure side piston 422 which is reciprocated in the high-pressure side cylinder 421 to demarcate a high-pressure side compression chamber 424 together with the high-pressure side cylinder 421, an annular lip ring 425 having a bent part which is bent toward the high-pressure side compression chamber 424 from the radial direction of the high-pressure side cylinder 421, and an abutting part which extends from the bent part and is abutted on an inner peripheral part of the high-pressure side cylinder 421 to seal a space between the high-pressure side cylinder 421 and the high-pressure side piston 422, and a support ring 426 disposed below the bent part. The support ring 426 supports the bent part to which the downward pressure is applied during the compression step.

Description

  The present invention relates to a reciprocating air compressor.

  As an air compressor that generates high-pressure compressed air that serves as power for an air tool or the like, a multistage reciprocating compressor that increases pressure in stages is generally used (see, for example, Patent Document 1). Further, as piston systems for compressing air, a reciprocating rocking type locking piston and a non-oscillating type piston rotatably provided on a compression piston pin provided at the tip of a connecting rod are known. (For example, refer to Patent Document 2). Among these, the reciprocating rocking type rocking piston has a merit that vibration and noise are small because the number of parts is small and light compared to the non-oscillating type piston.

JP 2009-185648 A JP 2009-8039 A

  However, in a reciprocating oscillation type piston, a thin plate-like lip ring for sealing between the piston and the cylinder is used. For this reason, if high pressure compressed air is generated, the lip ring may be broken due to large deformation or air leakage may occur due to wear. Therefore, it cannot be used for an air compressor that generates high pressure compressed air. .

  This invention is made | formed in view of this problem, Comprising: It aims at providing the air compressor which can improve the durability of a lip ring.

In order to achieve the above object, an air compressor according to the first aspect of the present invention includes:
A cylinder,
A piston that reciprocates within the cylinder and defines a compression chamber with the cylinder;
A bent portion that bends from the radial direction of the cylinder toward the compression chamber, a contact portion that extends from the bent portion and contacts the inner peripheral portion of the cylinder, and seals between the cylinder and the piston; An annular lip ring having
A support ring disposed on the opposite side of the bending portion from the compression chamber;
It is characterized by providing.

  The support ring may be formed with a curved surface that is in contact with the bent portion and has a curvature substantially equal to the bent portion.

  The support ring may be made of a material having a coefficient of thermal expansion substantially equal to that of the lip ring.

One end is connected to a crankshaft driven by a motor, and the other end is further provided with a connecting rod fixed to the piston,
The outer diameter of the other end of the connecting rod may be smaller than the outer diameter of the support ring.

In order to achieve the above object, an air compressor according to a second aspect of the present invention includes:
A cylinder,
A piston that reciprocates within the cylinder and defines a compression chamber with the cylinder;
A bent portion that bends from the radial direction of the cylinder toward the compression chamber, a contact portion that extends from the bent portion and contacts the inner peripheral portion of the cylinder, and seals between the cylinder and the piston; A lip ring having a support portion formed on the side of the bent portion opposite to the compression chamber;
It is characterized by providing.

  ADVANTAGE OF THE INVENTION According to this invention, the air compressor which can improve the durability of a lip ring can be provided.

1 is an external view of an air compressor according to an embodiment of the present invention. It is an external view of the air compressor which removed the cover. It is an external view of the air compressor seen from the arrow A direction of FIG. It is sectional drawing of the compressed air production | generation part in the cutting line BB of FIG. It is a principal part expanded sectional view of a 2nd step | paragraph compression apparatus. It is an external appearance perspective view of a high voltage | pressure side lip ring. It is a principal part enlarged view of FIG. It is an external appearance perspective view of a support ring. (A) is principal part sectional drawing in the conventional air compressor, (b) is principal part sectional drawing for demonstrating the waist folding state of the lip ring in the conventional air compressor. (A)-(c) is principal part sectional drawing which concerns on the modification of this embodiment.

  Hereinafter, an air compressor according to an embodiment of the present invention will be described with reference to the drawings. 1 is an external view of an air compressor 1 according to the present embodiment, FIG. 2 is an external view of the air compressor 1 with a cover 2 removed, and FIG. 3 is an air compressor viewed from the direction of arrow A in FIG. FIG. As shown in FIGS. 2 and 3, the air compressor 1 includes a drive unit 100, an air tank unit 200, a control circuit unit 300, a compressed air generation unit 400, a carrying handle 3, and a vibration isolating support rubber. It consists of feet 4.

  The drive unit 100 is configured by, for example, a direct current motor or the like, and converts the rotational motion of the direct current motor into the reciprocating motion of the piston of the compressed air generation unit 400 via the crankshaft 440 (see FIG. 4), thereby generating a compressed air generation unit. 400 is driven. The drive circuit of the drive unit 100 is controlled by the control circuit unit 300. Further, the cooling fan 110 is provided so as to sandwich the compressed air generating unit 400 together with the driving unit 100. The cooling fan 110 is attached to the rotation shaft of the drive unit 100 and cools the compressed air generation unit 400 by ventilation.

  The air tank unit 200 is composed of a pair of cylindrical air tanks 211 and 212 arranged in parallel. The air tanks 211 and 212 store the compressed air generated by the compressed air generation unit 400 and supplied through the air passage 250. The supplied compressed air has a pressure of, for example, 3.0 to 4.2 MPa in the air tanks 211 and 212. In addition, since the air tanks 211 and 212 are connected via the communication pipe and the manifold, the pressures inside the air tanks 211 and 212 are maintained substantially the same. In addition, safety valves (relief valves) are attached to the air tanks 211 and 212, and when the pressure in the air tanks 211 and 212 becomes abnormally high, a part of the compressed air inside the air tanks 211 and 212 is discharged to the outside. Prevent abnormal pressure rise. The compressed air stored in the air tanks 211 and 212 is depressurized to a predetermined pressure by the pressure reducing valves 221 and 222, and then a hose (not shown) connected to the compressed air outlet (coupler) 230 is connected. Via a pneumatic tool (not shown) such as a nail driver. Further, a pressure gauge 240 is attached in the vicinity of the coupler 230, and the pressure of the compressed air taken out from the coupler 230 can be monitored.

  The control circuit unit 300 is mainly composed of a main power switch 310, a display unit, and a circuit board on which switching elements and the like are arranged. Based on an operation signal from the main power switch 310, the control circuit unit 300 is a direct current of the driving unit 100. Controls on / off of the motor. The display unit displays, for example, a tank pressure or overload warning using an LED or the like.

  FIG. 4 is a cross-sectional view of the compressed air generation unit 400 taken along the cutting line BB in FIG. As shown in FIG. 4, the compressed air generation unit 400 includes a first-stage compression device 410, a second-stage compression device 420, a crankcase 430, and a crankshaft 440. The first stage compression device 410 and the second stage compression device 420 are arranged to face each other via the crankshaft 440. The first-stage compression device 410 includes a low-pressure side cylinder 411, a low-pressure side piston 412, a low-pressure side connecting rod 413, and the like formed from a metal material such as an aluminum alloy. The second-stage compression device 420 includes a high-pressure side cylinder 421, a high-pressure side piston 422, a high-pressure side connecting rod 423, and the like formed from a metal material such as an aluminum alloy. The low pressure side piston 412 and the high pressure side piston 422 are connected to the crankshaft 440 via a low pressure side connecting rod 413 and a high pressure side connecting rod 423, respectively. With this configuration, the rotational motion of the crankshaft 440 is converted into the reciprocating motion of the low pressure side piston 412 in the low pressure side cylinder 411 and the reciprocating motion of the high pressure side piston 422 in the high pressure side cylinder 421.

  Next, a seal structure between the low pressure side cylinder 411 and the low pressure side piston 412 in the first stage compression device 410 will be described. In the following description, among the sliding directions of the low pressure side piston 412, the low pressure side compression chamber defined by the low pressure side cylinder 411 and the low pressure side piston 412 from the crank chamber 441 in which the crankshaft 440 is accommodated. The direction toward 414 (the moving direction of the low-pressure side piston 412 during the compression process) is the upward direction, and the opposite is the downward direction.

  The low-pressure side piston 412 is formed in a disk shape, and a projecting portion that projects downward in a columnar shape is formed on the lower surface thereof. Further, the upper surface of the low pressure side connecting rod 413 is formed with a recess into which the protruding portion of the low pressure side piston 412 is fitted. The protrusion of the low pressure side piston 412 fits into the recess in a state where an annular low pressure side lip ring 415 described later is inserted. The low pressure side piston 412 is fixed to the low pressure side connecting rod 413 by a bolt 416.

  The low pressure side lip ring 415 is for sealing between the low pressure side piston 412 and the low pressure side cylinder 411. The low pressure side lip ring 415 is formed in an annular shape, and its inner edge is sandwiched between the low pressure side piston 412 and the upper portion of the low pressure side connecting rod 413. The outer edge portion of the low-pressure side lip ring 415 is bent upward from the radial direction of the low-pressure side cylinder 411 and is in contact with the inner peripheral portion of the low-pressure side cylinder 411. Accordingly, when the bent portion of the low pressure side lip ring 415 receives a downward pressure due to the pressure of the compressed air during the compression process, the outer edge portion is more strongly brought into contact with the inner peripheral portion of the low pressure side cylinder 411. In this way, the low pressure side lip ring 415 seals the low pressure side compression chamber 414.

  The low-pressure lip ring 415 is made of, for example, a fluororesin such as PTFE (Polytetrafluoroethylene). Thereby, friction with the inner peripheral part of the low pressure side cylinder 411 can be made small, and slidability can be improved.

  Next, a seal structure between the high-pressure side cylinder 421 and the high-pressure side piston 422 in the second-stage compression device 420 will be described. In the following description, among the sliding directions of the high pressure side piston 422, the high pressure side compression chamber defined by the high pressure side cylinder 421 and the high pressure side piston 422 from the crank chamber 441 in which the crankshaft 440 is accommodated. The direction toward 424 (the movement direction of the high-pressure piston 422 during the compression process) is the upward direction, and the opposite is the downward direction.

  FIG. 5 shows an enlarged view of a main part of the second stage compression device 420 in FIG. The high-pressure side piston 422 is formed in a disc shape, and a projecting portion 422a that projects downward in a columnar shape is formed on the lower surface thereof. Further, the upper surface of the high pressure side connecting rod 423 is formed with a concave portion 423a into which the protruding portion 422a of the high pressure side piston 422 is fitted. Further, a stepped portion 423b in which an annular support ring 425, which will be described later, is disposed is formed outside the concave portion 423a of the high pressure side connecting rod 423. The protruding portion 422a of the high-pressure side piston 422 is inserted into an annular high-pressure side lip ring 415, which will be described later, and the support ring 426 is disposed in the stepped portion 423b of the high-pressure side connecting rod 423. 422a fits into the recess 423a of the high pressure side connecting rod 423. The high pressure side piston 422 is fixed to the high pressure side connecting rod 423 by a bolt 427.

  The high pressure side lip ring 425 is for sealing between the high pressure side piston 422 and the high pressure side cylinder 421. FIG. 6 is an external perspective view of the high-pressure lip ring 425, and FIG. 7 is an enlarged view of the main part of FIG. The high-pressure side lip ring 425 is formed in an annular shape as shown in FIGS. 6 and 7, and includes a flat plate portion 425a sandwiched between a support ring 426, a high-pressure side piston 422, and an upper surface of the high-pressure side connecting rod 423, and a flat plate. A bent portion 425b that is bent upward from the portion 425a and a contact portion 425c that extends from the bent portion 425b and contacts the inner peripheral portion of the high-pressure side cylinder 421 are integrally configured. With such a configuration, when the bent portion 425b receives a downward pressure due to the pressure of compressed air during the compression process, the contact portion 425c is more strongly contacted with the inner peripheral portion of the high-pressure side cylinder 421. In this manner, the high pressure side lip ring 425 seals the high pressure side compression chamber 424 in the same manner as the low pressure side lip ring 415.

  Further, the high-pressure side lip ring 425 is made of, for example, a fluororesin such as PTFE. Thereby, friction with the inner peripheral part of the high pressure side cylinder 421 can be reduced, and slidability can be improved.

  Further, a support ring 426 is disposed below the bent portion 425 b of the high-pressure side lip ring 425. FIG. 8 shows an external perspective view of the support ring 426. The support ring 426 is formed in an annular shape as shown in FIG. 8, and supports the high-pressure lip ring 425 (particularly the bent portion 425b) so as to suppress deformation of the high-pressure lip ring 425 due to downward pressure. Further, the support ring 426 is disposed in a stepped portion 423b formed in an annular shape on the upper portion of the high-pressure side connecting rod 423.

  Further, a curved surface 426 a that curves upward from the radial direction of the high-pressure side cylinder 421 is formed on the surface of the support ring 426 that contacts the high-pressure side lip ring 426. Specifically, the curved surface 426a has a curvature that is substantially equal to the lower surface of the bent portion 425b of the high-pressure side lip ring 425. Such a curved surface 426a contacts the lower surface of the bent portion 425b of the high-pressure side lip ring 425, so that the support ring 426 supports the bent portion 425b of the high-pressure side lip ring 425 well against the downward pressure. Can do.

  Further, as shown in FIG. 5, the outer diameter of the support ring 426 is smaller than the inner diameter of the high-pressure side cylinder 421, and a gap is formed between the outer peripheral portion of the support ring 426 and the inner peripheral portion of the high-pressure side cylinder 421. Is done. It is preferable that this gap does not have such a distance that the high-pressure side lip ring 425 can break into the gap as will be described later.

  Further, the outer diameter of the support ring 426 is larger than the outer diameter of the upper portion of the high pressure side connecting rod 423. Accordingly, when the high pressure side piston 422 and the high pressure side connecting rod 423 reciprocate in the high pressure side cylinder 421 while swinging, the support ring 426 comes into contact with the inner peripheral portion of the high pressure side cylinder 421, so that the metal high pressure side The side connecting rod 423 is prevented from contacting the inner peripheral portion of the high pressure side cylinder 421.

  Further, the radial gap between the inner peripheral portion of the support ring 426 and the stepped portion 423b is so small that the high-pressure lip ring 425 does not sink into the gap. Further, the height of the stepped portion 423b substantially matches the thickness of the support ring 426. By forming in this way, the flat plate portion 425a and the bent portion 425b of the high-pressure side lip ring 425 can be supported in a stable state.

  The support ring 426 is preferably thick enough to prevent buckling due to the radial load from the high-pressure side cylinder 421 and the frictional force during sliding. Thereby, the high pressure side lip ring 425 can be favorably supported.

  The support ring 426 is made of, for example, a fluororesin such as PTFE. Thereby, friction with the inner peripheral part of the high pressure side cylinder 421 can be reduced, and slidability can be improved. The support ring 426 is preferably made of a material having a thermal expansion coefficient substantially equal to that of the high-pressure side lip ring 425. Accordingly, even if the support ring 426 and the high-pressure side lip ring 425 expand due to heat absorbed during the compression process, the support ring 426 can continue to support the bent portion 425b of the high-pressure side lip ring 425 on the curved surface 426a.

  The operation in the compressed air generation unit 400 configured as described above will be described. First, the first stage compression device 410 compresses the external air (atmospheric pressure) sucked into the low pressure side compression chamber 414 via the inside of the crankcase 420 and compresses the second stage via the first stage piping. Compressed air is supplied to the device 420. The second stage compression device 420 compresses the compressed air supplied from the first stage compression device 410 to an allowable maximum pressure of, for example, 3.0 to 4.5 MPa in the high-pressure side compression chamber 424, and passes through the air passage 250. Then, compressed air is supplied to the air tanks 211 and 212.

  Next, operations of the high pressure side lip ring 425 and the support ring 42 according to the present embodiment will be described.

  First, the operation when a high pressure is applied to a conventional lip ring that is not supported by a support ring, such as the low pressure side lip ring 415, will be described with reference to FIG. FIG. 9A is a partial cross-sectional view of the low pressure side piston 412 of the low pressure side lip ring 415 in the sliding direction. In the compression process, when a low pressure such as 0.5 to 1.5 MPa is applied to the low pressure side lip ring 415 as shown in FIG. 9A, the low pressure side lip ring 415 is lowered against the pressure. The deformation in the direction can be suppressed, and the low pressure side compression chamber 414 can be kept sealed. However, when a high pressure such as 3.0 to 4.5 MPa is applied, the low-pressure lip ring 415 is in a so-called waist-folded state as shown in FIG. 9B due to the frictional force between the high pressure and the low-pressure side cylinder 411. Since a gap is formed between the side cylinder 411 and the low pressure side lip ring 415 and the compressed air leaks, the compression ratio decreases.

  Next, the operation when high pressure is applied to the high-pressure lip ring 425 supported by the support ring 426 in the high-pressure compressor 420 will be described. As shown in FIG. 7, the high-pressure side lip ring 425 is supported by a support ring 426 disposed below at a bent portion 425b. Therefore, even if a high pressure is applied to the high-pressure side lip ring 425 in the compression process, the waist does not bend as shown in FIG. 9B, and the contact portion 425c can continue to contact the high-pressure side cylinder 421. it can. Therefore, the high pressure side lip ring 425 can continue to seal the high pressure side compression chamber 424.

  As described above, in the air compressor 1 according to the present embodiment, the support ring 426 is disposed below the bent portion 425b of the high-pressure lip ring 425, so that the high-pressure side due to the downward pressure during the compression process. The deformation of the lip ring can be suppressed, the leakage of compressed air from the gap formed by the deformation of the high pressure side lip ring can be prevented, and the high pressure side compression chamber 424 can be satisfactorily sealed.

  In the present embodiment, the support ring 426 abuts the bent portion 425b on the curved surface 426a having a curvature substantially equal to that of the bent portion 425b of the high-pressure side lip ring 425. Therefore, the bent portion 525 of the high-pressure side lip ring 425 is moved downward. It can support well against the pressure of.

  Further, in the present embodiment, the support ring 426 is made of a material having a thermal expansion coefficient substantially equal to that of the high-pressure side lip ring 425. Therefore, even if the support ring 426 expands due to heat absorbed during the compression process, the support ring 426 can perform well. 425 can continue to be supported.

  In the present embodiment, the outer diameter of the upper end of the high pressure side connecting rod 423 to which the high pressure side piston 422 is fixed is smaller than the outer diameter of the support ring 426. The support ring 426 contacts the high pressure side cylinder 421, and the high pressure side connecting rod 423 does not contact the high pressure side cylinder 421. Therefore, damage due to contact between the high-pressure side connecting rod 423 and the high-pressure side cylinder 421 that are made of metal can be prevented.

  In addition, this invention is not limited to said embodiment, A various deformation | transformation and application are possible. For example, in the above-described embodiment, the shape of the contact portion 425c of the high-pressure side lip ring 425 is formed to have substantially the same thickness in the axial cross section of the high-pressure side cylinder 421. The thickness of is not limited to this. For example, FIG. 10A shows a cross-sectional view of a high-pressure side lip ring 525 and a support ring 426 according to a modification of the present embodiment. Here, the same code | symbol is attached | subjected to the component similar to the above-mentioned embodiment, and the description is abbreviate | omitted. As shown in FIG. 10A, the contact portion 525c of the high-pressure lip ring 525 may be formed so as to become thinner toward the outside. Since the contact portion 525c of the high pressure side lip ring 525 is easily deformed by being formed in this way, even if the high pressure side piston 422 is inclined, the outside of the high pressure side lip ring 525 receives the pressure of compressed air. Therefore, it becomes easy to adhere to the inner peripheral wall of the high-pressure side cylinder 421, and it becomes easy to prevent air leakage.

  In the above embodiment, the high-pressure lip ring 425 and the support ring 426 are configured as separate parts. Such a separate part is preferable from the standpoint of easy manufacture and part replacement, but may be configured as a single part. Specifically, as shown in FIG. 10B, for example, the high-pressure side lip ring 625 includes a flat plate portion 625a, a bent portion 625b, and a contact portion 625c similar to those of the above embodiment, and a support portion 625d as an integral unit. It may be formed. The support portion 625d is formed below the bent portion 625b, and supports the bent portion 625b of the high-pressure side lip ring 625 so as to suppress deformation of the bent portion 625b of the high-pressure side lip ring 625 due to downward pressure. As described above, the high-pressure side lip ring 425 and the support ring 426 are integrally configured, so that the number of parts can be reduced.

  In the above embodiment, the outer peripheral surface of the support ring 426 is formed so as to be substantially parallel to the inner peripheral surface of the high-pressure side cylinder 421. However, the shape of the outer peripheral surface of the support ring 426 is not limited thereto. . For example, as shown in FIG. 10C, the outer peripheral surface of the support ring 726 may be formed in an arc shape that is convex in the outer diameter direction. As a result, wear of the support ring 726 can be prevented. As shown in FIG. 7, when the outer peripheral surface of the support ring 426 is substantially parallel to the inner peripheral surface of the high-pressure side cylinder 421, the support ring 426 is inclined at the same time by tilting the high-pressure side piston 422. This is because the outer peripheral upper portion 426 c and the outer peripheral lower portion 426 d strongly contact the high pressure side cylinder 421.

DESCRIPTION OF SYMBOLS 1 Air compressor 2 Cover 3 Carrying handle 4 Rubber foot 100 for vibration-proof support Drive part 110 Cooling fan 200 Air tank part 211, 212 Air tank 221, 222 Pressure reducing valve 230 Compressed air outlet (coupler)
240 Pressure gauge 250 Air passage 300 Control circuit section 310 Main power switch 400 Compressed air generating section 410 First stage compression device 411 Low pressure side cylinder 412 Low pressure side piston 413 Low pressure side connecting rod 414 Low pressure side compression chamber 415 Low pressure side lip ring 420 Two stages Eye compression device 421 High pressure side cylinder 422 High pressure side piston 422a Protruding portion 423 High pressure side connecting rod 423a Recessed portion 423b Stepped portion 424 High pressure side compression chamber 425 High pressure side lip ring 425a Flat plate portion 425b Bending portion 425c Abutting portion 426 Support ring 426a Curved surface 525 High pressure Side lip ring 525c Contact portion 625 High pressure side lip ring 625a Flat plate portion 625b Bend portion 625c Contact portion 625d Support portion 726 Support ring

Claims (5)

A cylinder,
A piston that reciprocates within the cylinder and defines a compression chamber with the cylinder;
A bent portion that bends from the radial direction of the cylinder toward the compression chamber, a contact portion that extends from the bent portion and contacts the inner peripheral portion of the cylinder, and seals between the cylinder and the piston; An annular lip ring having
A support ring disposed on the opposite side of the bending portion from the compression chamber;
An air compressor comprising: The support ring is in contact with the bent portion, and a curved surface having a curvature substantially equal to the bent portion is formed.
The air compressor according to claim 1. The support ring is made of a material having a coefficient of thermal expansion substantially equal to that of the lip ring.
The air compressor according to claim 1 or 2, characterized in that. One end is connected to a crankshaft driven by a motor, and the other end is further provided with a connecting rod fixed to the piston,
The outer diameter of the other end of the connecting rod is smaller than the outer diameter of the support ring,
The air compressor according to any one of claims 1 to 3, wherein the air compressor is provided. A cylinder,
A piston that reciprocates within the cylinder and defines a compression chamber with the cylinder;
A bent portion that bends from the radial direction of the cylinder toward the compression chamber, a contact portion that extends from the bent portion and contacts the inner peripheral portion of the cylinder, and seals between the cylinder and the piston; A lip ring having a support portion formed on the side of the bent portion opposite to the compression chamber;
An air compressor comprising:

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