JP4165603B2 - Swing piston type reciprocating compressor - Google Patents

Description

  The present invention relates to an oscillating piston type reciprocating compressor used in, for example, an oxygen concentrator and a vacuum pump.

  Conventionally, as this type of oscillating piston type reciprocating compressor, as shown in FIG. 5, a cylinder 1, a piston 4 in which a head portion 2 and a rod portion 3 are integrated, and the head portion 2 described above. Some include an annular seal member 6 attached by a pressing plate 5 (for example, Japanese Patent Laid-Open No. 10-89253, FIG. 3: Patent Document 1). An eccentric shaft 8 that is eccentrically fixed to the rotating shaft 7 is fitted to the rod portion 3 via a bearing 9 so that the piston 4 swings and reciprocates as the rotating shaft 7 rotates. To compress the air.

  The top surface S of the head portion 2, that is, the sealing plane (mounting surface) S along the annular sealing member 6 is the center C of the rotating shaft 7 and the center C of the rotating shaft 7 when the piston 4 is at the bottom dead center. It is perpendicular to the reference plane R including the center E of the eccentric shaft 8.

  However, in the oscillating piston type reciprocating compressor, when the piston 4 reciprocates in the cylinder 1, the head portion 2 oscillates, that is, tilts, and the top surface S of the head portion 2, That is, since the seal plane (seal member mounting surface) S is perpendicular to the reference plane R when the piston 4 is at the bottom dead center, the seal plane S relative to the plane perpendicular to the reference plane R is used. 4, that is, the inclination angle of the head portion 2, as shown by a dashed curve L in FIG. 4, the compression stroke (the rotation angle of the rotary shaft 7 is 0 ° to 180 °) and the suction process (of the rotary shaft 7). The absolute values are equal when the rotation angle is 180 ° to 360 °. For this reason, when the load applied to the seal member 6 in the compression stroke is high (when the PV value is large), the inclination of the seal member 6 increases, and the seal member 6 contacts the inner surface of the cylinder 1 unevenly, resulting in local wear. As a result, there is a problem that the service life is shortened and a gap is formed between the cylinder 1 and the seal member 6 to reduce the compression efficiency due to air leakage.

The PV value is a numerical value representing a load on the seal member, where PV value = (sliding surface pressure of the seal member) × (sliding speed of the seal member).
Japanese Patent Laid-Open No. 10-89253 FIG.

  Therefore, the object of the present invention is to reduce the inclination of the seal member at the time of high load on the seal member so that the seal member contacts the inner surface of the cylinder uniformly, thereby preventing local wear and achieving a long life. Another object of the present invention is to provide a swing piston type reciprocating compressor capable of reducing the gap between a cylinder and a seal member, preventing air leakage and improving the compression efficiency.

In order to solve the above-mentioned problem, the swing piston type reciprocating compressor of the present invention is
A cylinder,
A piston in which a head portion and a rod portion that are reciprocally fitted to the cylinder are integrated;
A seal member attached to the head part;
An eccentric shaft that is eccentrically fixed to the rotation shaft and that is rotatably fitted to the rod portion;
When the piston is at bottom dead center, the top surface of the head portion of the piston, which is a seal plane along the seal member, is non-perpendicular to a reference plane including the center of the rotating shaft and the center of the eccentric shaft der is,
When the piston is at top dead center, the top surface of the head portion of the piston and the top surface of the cylinder chamber of the cylinder are substantially parallel .

  According to the above configuration, when the piston is at the bottom dead center, the seal plane along the seal member is non-perpendicular with respect to a reference plane including the center of the rotation shaft and the center of the eccentric shaft. The absolute value of the inclination of the seal plane relative to the plane perpendicular to the reference plane is smaller at the time of high load of the seal member having a large PV value such as the compression stroke than at the time of low load of the seal member having a small PV value such as the suction stroke. Is possible.

  Therefore, when the load on the seal member is high, the seal member can be in uniform contact with the inner surface of the cylinder to prevent local wear of the seal member and achieve a long life, and between the cylinder and the seal member. By reducing the gap, air leakage can be prevented and compression efficiency can be improved.

According to the above configuration , since the top surface of the head portion of the piston is the seal plane of the seal member, the inclination angle of the top surface of the head portion of the piston is set to a value of a seal member having a large PV value such as a compression stroke. It is possible to make it smaller at the time of high load than at the time of low load such as a suction process.

Therefore, the seal member can be in uniform contact with the inner surface of the cylinder to prevent local wear of the seal member to achieve a long life, and the gap between the cylinder and the seal member can be reduced to reduce the air. Leakage can be prevented and compression efficiency can be improved.
Further, according to the above configuration, when the piston is at the top dead center, the top surface of the head portion of the piston and the top surface of the cylinder chamber of the cylinder are substantially parallel. The dead space between the top surface of the piston head and the top surface of the cylinder chamber of the cylinder can be reduced, and the compression efficiency can be improved.

Further, according to the above configuration, when the piston is at the top dead center, the top surface of the head portion of the piston and the top surface of the cylinder chamber of the cylinder are substantially parallel. The dead space between the top surface of the piston head and the top surface of the cylinder chamber of the cylinder can be reduced, and the compression efficiency can be improved.

  In one embodiment, a part of the seal member is sandwiched and fixed between the top surface of the head portion of the piston and the pressing plate.

  According to the above embodiment, since the sealing member is attached to the top surface of the piston head portion by the pressing plate, the inclination angle of the top surface of the piston is adjusted to easily set the inclination of the sealing plane. can do.

  In one embodiment, the absolute value of the inclination angle of the seal plane with respect to a plane perpendicular to the reference plane is smaller in the compression stroke than in the suction process.

  According to the above embodiment, the absolute value of the inclination angle of the seal plane with respect to the plane perpendicular to the reference plane is smaller in the compression stroke than in the suction process. It can contact the inner surface of the cylinder almost uniformly to prevent local wear of the seal member and achieve a long life. In addition, there is less clearance between the cylinder and the seal member to prevent air leakage and compression efficiency. Can be improved.

  In one embodiment, the seal plane is perpendicular to the reference plane in the vicinity of the rotation angle of the rotation shaft where the PV value of the seal member is maximized.

  According to the embodiment, in the vicinity of the rotation angle of the rotary shaft where the PV value of the seal member is maximized, the seal plane is perpendicular to the reference plane, and the seal plane is inclined at the maximum load. Therefore, local wear of the seal member can be prevented and a long life can be achieved, and air leakage can be prevented and compression efficiency can be improved.

According to this invention, when the seal member is under a heavy load, the seal member is in contact with the inner surface of the cylinder substantially uniformly. Therefore, local wear of the seal member can be prevented and a long life can be achieved, and air leakage can be prevented. In addition, it is possible to improve the compression efficiency by reducing the dead space between the top surface of the head portion of the piston and the top surface of the cylinder chamber of the cylinder .

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  As shown in FIG. 1, a cylinder head 21 is fixed to the cylinder 1 to form a cylinder chamber 22. The cylinder 1 and the cylinder head 21 are sealed with a seal member 31. The cylinder 1 is fixed to the casing 20.

  On the other hand, a piston 14 is disposed in the casing 20 and the cylinder 1. In the piston 14, the head portion 12 and the rod portion 13 are integrated, and the head 12 is disposed in the cylinder 1 so as to be able to swing and reciprocate. A part of the annular seal member 6 is placed on the top surface S of the head part 12 of the piston 14, that is, the seal plane S, and this part is pressed against the top surface S of the head part 12 of the piston 14. The plate 5 is sandwiched and fixed. The other part of the seal member 6 protrudes from the head 12 and the pressing plate 5 and contacts the inner surface of the cylinder 1 for sealing.

  The pressing plate 5 is fixed to the head portion 12 with screws 32.

  On the other hand, the rod portion 13 of the piston 14 is fitted to an eccentric shaft 8 that is eccentrically fixed to the rotary shaft 7 via a bearing 9. As shown in FIG. 2, the rotary shaft 7 is an output shaft 7 of the motor 30, and the rotary shaft 7 is supported by a bearing 25 attached to the casing 20 and an end plate 24 fixed to the casing 20. The bearing 26 is rotatably supported.

  As shown in FIG. 1, the top surface S of the head portion 12 of the piston 14, that is, the seal plane S along the annular seal member 6 is such that when the piston 14 is at the bottom dead center, the rotational shaft 7 , And a reference plane R including the center E of the eccentric shaft 8 is non-perpendicular. More specifically, when the piston 14 is at the bottom dead center, the top surface S of the head portion 12 of the piston 14, that is, the seal plane S along the annular seal member 6 is relative to the reference plane R. , 88.5 °. That is, when the piston 14 is at the bottom dead center, the top surface S (seal plane S) of the head portion 12 of the piston 14 is inclined by 1.5 ° with respect to a plane perpendicular to the reference plane R. And an inclination angle of 1.5 ° with respect to a plane perpendicular to the central axis of the cylinder 1. As a result, as shown in FIG. 4, at about 149 ° in the vicinity of the rotation angle of about 135 ° of the rotary shaft 7 at which the PV value is substantially maximum, the inclination angle with respect to the plane perpendicular to the reference plane R, that is, the piston 14 The inclination angle of the top surface S of the head portion 12 is set to zero.

  The top surface 41 of the cylinder chamber 22 of the cylinder 1 is parallel to the top surface S of the head portion 12 of the piston 14 when the piston 14 is at bottom dead center and top dead center. That is, the top surface 41 of the cylinder chamber 22 of the cylinder 1 is inclined by 1.5 ° with respect to a plane perpendicular to the central axis of the cylinder 1. As a result, when the piston 14 is at the top dead center, a dead space is not generated between the top surface 41 of the cylinder chamber 22 of the cylinder 1 and the upper surface of the pressing plate 5 to increase the compression efficiency. Yes.

  In FIG. 2, 51 is a suction port that is opened and closed by a suction valve (not shown), and 52 is a backup plate of a discharge valve of the discharge port (not shown).

  The operation of the oscillating piston type reciprocating compressor configured as described above will be described with reference to FIGS.

  In FIG. 4, the horizontal axis represents the rotation angle of the rotary shaft 7, and the right vertical axis represents the inclination angle of the top surface S of the head portion 12 of the piston 14 with respect to the plane perpendicular to the central axis of the cylinder 1. The vertical axis of represents the PV value.

  In the oscillating piston type reciprocating compressor, when the rotary shaft 7 is rotated clockwise by driving the motor 30 from the state shown in FIG. 1, the piston 14 is shown in FIGS. As described above, reciprocation is performed while swinging, and intake and compression of gas such as air is performed.

At this time, as shown by a curve M in FIG. 4, the bottom dead center (rotation angle of the rotation axis is 0 °).
At the top dead center (rotation angle 180 ° of the rotary shaft 7), the top surface S of the head portion 12 of the piston 14, that is, the seal plane S along the annular seal member 6 is perpendicular to the reference plane R. It is inclined by 1.5 ° with respect to a plane (a plane perpendicular to the central axis of the cylinder 1). Then, as the rotary shaft 7 rotates, as shown in FIGS. 3 and 4, the top surface S of the head portion 12 of the piston 14, that is, the inclination angle of the seal plane S along the annular seal member 6 (head inclination angle). ) Will change.

  As can be seen from the curve M in FIG. 4, in this embodiment, the inclination angle of the top surface S of the head portion 12 of the piston 14, that is, the absolute value of the inclination angle of the seal plane S is a conventional figure indicated by the curve L. 5 is smaller in the compression stroke than the inclination angle of the top surface S of the head portion 2 of the piston 4 and larger in the suction process.

  Thus, in the compression stroke where the PV value is large and the load on the seal member 6 is large, the absolute value of the inclination angle of the seal plane S of this embodiment (curve M in FIG. 4) is the seal plane of the conventional example of FIG. Since it becomes smaller than the absolute value of the inclination angle of S (curve L in FIG. 4), the seal member 6 comes into contact with the inner surface of the cylinder 1 substantially uniformly, thereby preventing local wear of the seal member 6 and achieving a long life. In addition, the clearance between the cylinder 1 and the seal member 6 can be reduced to prevent air leakage and improve the compression efficiency.

  In the suction process, since the PV value is generally smaller than the compression stroke and the load on the seal member 6 is relatively small, the inclination angle of the top surface S of the head portion 12 of the piston 14, that is, the seal plane. Even if the absolute value of the inclination angle of S increases, inconveniences such as local wear and leakage of the seal member 6 hardly occur.

  In the above embodiment, the absolute value of the inclination angle of the seal plane S relative to the plane perpendicular to the reference plane R is smaller in the compression stroke than in the suction process. The member 6 is in contact with the inner surface of the cylinder substantially uniformly to prevent the local wear of the seal member 6 and to achieve a long service life. Further, the gap between the cylinder 1 and the seal member 6 is reduced and air leakage occurs. And the compression efficiency can be improved.

  In the above embodiment, the top surface S of the head portion 2 of the piston 4, that is, the seal plane S is relative to the reference plane R in the vicinity of the rotation angle of about 135 ° of the rotary shaft 7 at which the PV value is maximum. Since the inclination of the seal plane S with respect to the center axis of the cylinder 1 is eliminated at the maximum load at a right angle, local wear of the seal member 6 can be prevented and a long life can be achieved, and air leakage can be prevented. This can improve compression efficiency.

  Moreover, in the said embodiment, since the sealing member 6 is attached to the top | upper surface S of the head part 12 of the piston 14 with the said press board 5, the inclination | tilt angle of the top | upper surface S of the said head part 12 is adjusted, and a seal | sticker is carried out. The inclination of the plane S can be set easily.

  In the above embodiment, the top surface S of the head portion 12 of the piston 14 and the top surface 41 of the cylinder chamber 22 of the cylinder 1 are parallel, and the top surface of the holding plate 5 and the top surface of the cylinder chamber 22 of the cylinder 1 are parallel. It is possible to reduce the dead space between 41 and improve the compression efficiency.

  Moreover, in the said embodiment, although the inclination | tilt angle with respect to the plane perpendicular | vertical to the central axis of the cylinder 1 of the top surface S of the head part 12 of the piston 14 is 1.5 degrees, it is not restricted to 1.5 degrees. Of course.

  Although not shown, a crank pin of the crank shaft may be used as the eccentric shaft.

It is a longitudinal cross-sectional view of one Embodiment of the rocking | swiveling piston type reciprocating compressor of this invention. It is a sectional side view of the said embodiment. It is operation | movement explanatory drawing of the said embodiment. It is a figure which shows the relationship between the rotation angle of the said embodiment, PV value, and head inclination angle. It is a longitudinal cross-sectional view of the conventional swing piston type reciprocating compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2,12 Head part 3,13 Rod part 4,14 Piston 5 Holding plate 6 Seal member 7 Rotating shaft 8 Eccentric shaft 9, 25, 26 Bearing 21 Cylinder head 22 Cylinder chamber R Reference plane S Seal plane

Claims (4)

A cylinder (1);
A piston (14) in which a head portion (12) and a rod portion (13) which are fitted to the cylinder (1) so as to be capable of reciprocating are integrated;
A seal member (6) attached to the head portion (12);
An eccentric shaft (8) that is eccentrically fixed to the rotating shaft (7) and in which the rod portion (13) is rotatably fitted,
When the piston (14) is at the bottom dead center, the seal member with respect to a reference plane (R) including the center (C) of the rotating shaft (7) and the center (E) of the eccentric shaft (8) (6) top surface (S) is non-orthogonal der of the head portion of the sealing plane the piston (14) is (S) (12) along a is,
When the piston (14) is at top dead center, the top surface (S) of the head portion (12) of the piston (14) and the top surface (41) of the cylinder chamber (22) of the cylinder (1) Is a swing piston type reciprocating compressor characterized by being substantially parallel . In the swing piston type reciprocating compressor according to claim 1 ,
A part of the sealing member (6) is sandwiched and fixed between the top surface (S) of the head portion (12) of the piston (14) and the pressing plate (5). Oscillating piston type reciprocating compressor. The swing piston type reciprocating compressor according to claim 1 or 2 ,
An oscillating piston reciprocating compressor characterized in that an absolute value of an inclination angle of the seal plane (S) with respect to a plane perpendicular to the reference plane (R) is smaller in the compression stroke than in the suction process. . In the oscillating piston type reciprocating compressor according to any one of claims 1 to 3 ,
The seal plane (S) is perpendicular to the reference plane (R) in the vicinity of the rotation angle of the rotation shaft (7) at which the PV value of the seal member (6) is maximized. Swing piston type reciprocating compressor.

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