JP2012159088A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems of a conventional configuration that an oil amount is increased if a clearance between a piston and a cylinder is increased in a height direction in order to increase an oil amount from a piston inner face, but leakage of refrigerant gas from a compression chamber to a suction chamber is increased simultaneously, and performance is deteriorated, and that if an excessive oil amount is supplied to the compression chamber, oil discharge into a refrigerating cycle is increased, and performance of the refrigerating cycle is deteriorated.SOLUTION: As recesses 11 are configured toward the outer periphery from the upper bearing inner face 2a on the end face of an upper bearing 2, oil can be positively supplied to the compression chamber.

Description

  The present invention relates to an improvement in performance and reliability of a rotary compressor incorporated in a room air conditioner, a refrigerator, and an air conditioner.

  The piston of this type of conventional rotary compressor is configured to perform suction and compression by rotating in the cylinder as the shaft rotates (see, for example, Patent Document 1).

  FIG. 9 is a cross-sectional view of the conventional rotary compressor described in Patent Document 1 as seen from the upper bearing side. A piston 93a is inserted into the inner surface of the cylinder 91, rotates with the rotation of the shaft 92, and sucks and compresses refrigerant gas in a suction chamber 97 and a compression chamber 98 partitioned by a vane 94. In addition, a recess 96 is provided on the end surface of the upper bearing 95. In the state of the piston 93b, the recess 96 is in the inner periphery of the piston, so that oil in the inner periphery of the piston 93b is supplied, and in the piston 93a state, it is in the outer periphery of the piston 93a. For this reason, the oil accumulated in the recesses is exposed to the compression chamber. Since the oil accumulated in the inner periphery of the piston 93a is high pressure (compression pressure), it is supplied to the suction chamber 97 and the compression chamber 98 through the gap in the height direction between the piston 93a and the cylinder 91 as shown by solid line arrows. In addition, compressed refrigerant gas leaks from the compression chamber 98 to the suction chamber 97 through a gap in the height direction between the piston 93a and the cylinder 91 as indicated by a broken line arrow.

JP-A-6-74170

  However, in the configuration of Patent Document 1, the oil stored in the upper bearing recess is exposed to the compression chamber with the rotation of the piston. However, since the oil is a liquid, it is not easily diffused into the compression chamber like gas. Moreover, since the size of the depression is restricted, there is a drawback that a sufficient amount of oil cannot be obtained. In order to increase the amount of oil from the inner surface of the piston, increasing the clearance in the height direction of the piston and cylinder increases the amount of oil, but at the same time increases the leakage of refrigerant gas from the compression chamber to the suction chamber. There was a problem that performance deteriorated. In addition, when the amount of oil supplied to the compression chamber becomes too large, oil discharge into the refrigeration cycle increases, and the performance of the refrigeration cycle is degraded.

  Therefore, in order to solve the conventional problem, a rotary compressor according to a first aspect of the present invention includes a piston that is provided with an upper bearing and a lower bearing on both end surfaces of a cylinder and rotates in the cylinder, and the piston. In a rotary compressor having a driving shaft and a vane for partitioning the inside of the cylinder into a compression chamber having a suction chamber and a discharge port, and having a ring groove in the upper end surface of the piston, the upper bearing inner surface is formed on the upper bearing end surface. A depression is formed toward the outer periphery, and the angle of the existence range of the depression is the shaft rotation angle coordinate where the vane top dead center is 0 °, and the suction hole closing angle is θs, and the depression start angle is θ1. Then, if θs + 180 ° <θ1 and the end angle of the recess is θ2, then it is defined as θ2 <360 °, and the distance L from the center of the upper bearing of the recess is It is obtained by the radius of the piston Rp, the configuration defined radius of the cylinder at When Rc L <2Rp-Rc to supply the communicating oil ring groove of the piston upper surface.

  A rotary compressor according to a second aspect of the present invention is the rotary compressor according to the first aspect of the present invention, wherein a recess provided in the upper bearing end face is divided into two parts.

  According to a third aspect of the present invention, there is provided a rotary compressor including an upper bearing and a lower bearing on both end faces of the cylinder, a piston that rotates in the cylinder, a shaft that drives the piston, and a suction chamber that is disposed in the cylinder. In a rotary compressor having a vane partitioning into a compression chamber in which a discharge port opens and having a ring groove on the piston upper end surface, a vertical hole is formed on the upper bearing end surface, and the angle θh of the vertical hole is the vane top dead center In the shaft rotation angle coordinate where 0 is 0 °, θs + 180 ° <θh <360 ° is defined as θs + 180 ° <θh <360 °, and the distance Lh from the center of the upper bearing is Rp, and the radius of the piston is Rp. When the radius is Rc, the lower end corner of the inner surface of the upper bearing is defined by Lh <2Rp-Rc and communicates with the hole of the upper bearing inner surface and the end surface. The ring groove of the piston upper surface provided with an oblique bore in which has a configuration for supplying communicating oil.

  Since the oil supply method of the rotary compressor of the present invention can mainly supply oil to the compression chamber instead of the suction chamber, there is little decrease in performance such that the intake refrigerant gas is warmed by the heat of the supplied oil, and the reliability is improved. Adjustment of an appropriate oil amount that can achieve both oil discharge amounts is possible because the time of supplying the ring groove on the piston upper end surface can be adjusted by changing the size of the recess on the upper bearing end surface. By increasing the amount of oil in the compression chamber, the sliding state of the contact portion between the vane tip and the piston outer peripheral portion and the contact portion between the piston end surface and the bearing end surface is improved, thereby improving the reliability.

  In addition, the sealing performance by oil against the clearance in the height direction between the piston upper end surface and the upper bearing end surface and the circumferential clearance between the piston outer periphery and the cylinder inner periphery is improved, so that leakage loss is reduced and compression efficiency is also improved. I can do it.

1 is a longitudinal sectional view of a mechanical part of a rotary compressor according to a first embodiment of the present invention. The cross-sectional view of the mechanical part seen from the lower bearing of the rotary compressor concerning Embodiment 1 of this invention The cross-sectional view of the mechanical part seen from the lower bearing which showed the plane positional relationship of the hollow of the upper bearing end surface of the rotary compressor concerning Embodiment 1 of this invention The cross-sectional view of the mechanical part seen from the lower bearing which showed the plane positional relationship of the hollow of the upper bearing end surface of the rotary compressor concerning Embodiment 1 of this invention The cross-sectional view of the mechanical part seen from the lower bearing which showed the positional relationship of two hollows of the rotary compressor upper bearing end surface concerning Embodiment 1 of this invention. The longitudinal cross-sectional view of the mechanical part seen from the lower bearing which showed the vertical cross-sectional detail figure of the vertical hole of the rotary compressor upper bearing end surface concerning Embodiment 1 of this invention, and the plane positional relationship 1 is a cross-sectional view of a mechanical part viewed from a lower bearing showing a positional relationship between a vertical cross-sectional detail view of a vertical hole on an upper bearing end face of a rotary compressor according to a first embodiment of the present invention and a plane. The characteristic view which showed the relationship between the ring groove depth of the piston upper end surface and efficiency concerning Embodiment 1 of this invention Cross section of mechanical part viewed from the upper bearing of a conventional rotary compressor

In the first aspect of the present invention, a depression is formed on the upper bearing end face from the inner surface of the upper bearing toward the outer periphery, and the existence range angle of the depression is the shaft rotation angle coordinate where the vane top dead center is 0 °, and the suction hole cutoff angle is θs. Θs + 180 ° <θ1 when the start angle of the recess is θ1, and θ2 <360 ° when the end angle of the recess is θ2, and the distance L from the center of the upper bearing is the piston radius Rp and the cylinder radius Rc Then, L <2Rp−Rc is defined, and the oil is supplied to the ring groove on the upper end surface of the piston so that the depression faces the compression chamber side. Can be supplied. Further, the amount of oil can be adjusted because the time during which the oil is supplied to the ring groove on the upper end surface of the piston can be adjusted by changing the angle θ of the depression on the upper bearing end surface.

  In the second aspect of the invention, the recess provided in the upper bearing end face of the first aspect of the invention is divided into two parts, so that at the beginning of compression, first the oil is supplied to the compression chamber to reduce leakage loss, and then the discharge process starts. It has the effect of reducing the friction between the tip of the vane and the outer periphery of the piston mainly by supplying oil for compression. Since the dent is divided into two locations, each effect can be obtained with a small amount of oil supply.

  In the third aspect of the present invention, a vertical hole is formed in the upper bearing end face, and the angle θh of the vertical hole is θs + 180 ° <θh <360 ° where θs is the suction hole cutoff angle in the shaft rotation angle coordinate where the vane top dead center is 0 °. The distance Lh from the upper bearing center of the vertical hole is defined as Lh <2Rp−Rc where the radius of the piston is Rp and the radius of the cylinder is Rc, and the inner surface of the upper bearing is communicated with the inner surface of the upper bearing and the vertical hole of the end face. By providing a slanted hole from the lower end corner of the cylinder and communicating with the ring groove on the upper end surface of the piston to supply oil, the oil is spotted into the compression chamber where it is needed to improve reliability and reduce the amount of oil Thus, the increase in oil discharge can be suppressed. In addition, since an oblique hole is formed from the lower end corner of the inner surface of the upper bearing, drilling is possible, so the processing cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a rotary compressor according to a first embodiment of the present invention.

  As shown in FIG. 1, an upper bearing 2 is attached to the upper portion of the cylinder 1, and a lower bearing 3 is attached to the lower portion, and a piston 5 that rotates by a shaft 4 is provided in a space surrounded by the upper bearing 2. The shaft 4 is hollow and has a centrifugal pump structure, and the oil 6 accumulated below the cylinder 1 is sucked from the lower hole 7 along with the rotation of the shaft 4 and supplied to the space 9 inside the piston from the lateral holes 8a and 8b. It is filled. Since the space 9 inside the piston is at a high pressure (discharge pressure), oil is supplied to the suction chamber and the compression chamber through a gap h between the end surface of the piston 5 and the end surface of the upper bearing 2. A ring groove 10 is formed at the center of the upper end surface of the piston 5. A recess 11 is provided on the end surface of the upper bearing 2 from the inner surface toward the outer periphery so as to communicate with the ring groove 10 on the upper end surface of the piston at a specific position. The depth of the ring-shaped ring groove 10 is set to 10 μm to 30 μm.

  FIG. 2 is a cross-sectional view of the mechanical part viewed from the lower bearing 3 of the rotary compressor according to the first embodiment of the present invention. A vane 12 is inserted into the vane groove of the cylinder 1. The cylinder 1 is provided with a suction hole 13 and a discharge notch 14. The cylinder chamber is partitioned by a vane 12 to form a suction chamber 15 and a compression chamber 16. A recess 11 (shaded portion) is provided on the end surface of the upper bearing 2 from the inner surface toward the outer periphery so as to communicate with the ring groove 10 on the upper end surface of the piston at a specific position.

  About the rotary compressor comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

First, the refrigerant gas is sucked into the suction chamber 15 through the suction hole 13. Further, the refrigerant gas in the compression chamber 16 is compressed along with the leftward rotation (in the direction of the arrow) of the piston 5 and is discharged from a discharge port (not shown) through the discharge notch 14. The oil stored in the space 9 inside the piston is once stored in the ring groove 10 formed on the upper end surface of the piston, and then passes through the gap h between the upper end surface of the piston and the upper bearing end surface to the suction chamber 15 in the direction of the arrow G1, and the arrow. Oil is supplied to the compression chambers 16 in the G2 direction. The refrigerant gas in the compression chamber 16 also leaks into the suction chamber 15 as indicated by arrows Q1 and Q2 through the gap h between the piston upper end surface and the upper bearing end surface, thereby reducing the compressor efficiency. Next, the oil flow will be described. The oil stored in the space 9 inside the piston flows into the recess 11 provided in the upper bearing end surface, and when the recess 11 and the ring groove 10 on the upper end surface of the piston overlap, the oil flows into the ring groove. 10 is supplied. Further, since the position where oil is supplied to the ring groove 10 is always set in the direction facing the compression chamber 16, the oil is mainly supplied to the compression chamber side. Furthermore, the flow rate of the refrigerant gas flows Q1 and Q2 leaking from the compression chamber 16 into the suction chamber 15 by the action of the oil accumulated in the ring groove 10 can be reduced, so that the compression efficiency can be improved. The oil supplied to the compression chamber is supplied to the outer periphery of the piston 5 where the friction is severe, the tip of the vane, the lower end surface of the piston, and the end surface of the lower bearing, thereby improving the reliability. Further, the oil supplied to the suction chamber is supplied to the circumferential gap between the outer periphery of the piston 5 and the inner circumference of the cylinder 1, and the refrigerant gas in the compression chamber 16 leaks into the suction chamber 15 from this circumferential gap. Can be reduced, and the compression efficiency can be improved.

  3 and 4 are cross-sectional views of the mechanical part viewed from the lower bearing 3 showing the positional relationship of the recess 11 formed on the end face of the upper bearing 2 of the present invention from the inner surface toward the outer periphery.

  FIG. 3 shows an example of a shape in which the recess 11 overlaps the ring groove 10 on the upper end surface of the piston and supplies oil in the space 9 inside the piston for a short time after the piston 5 passes the suction hole 13. FIG. 4 is a diagram showing the maximum range of the depression 11 of the present invention. The starting angle θ1 of the depression 11 is around θs + 180 °, and the end angle θ2 is around 360 °. The position of the piston when the end angle θ2 of the recess 11 and the ring groove 10 on the upper end surface of the piston communicate with each other is such that the shaft rotation angle is around 180 °. Therefore, the pressure in the compression chamber 16 has not yet reached the discharge pressure, and the oil supplied from the recess 11 to the ring groove 10 on the upper end surface of the piston is almost the discharge pressure, so that the differential pressure between the ring groove 10 and the compression chamber 16 is reached. Is secured and can flow into the compression chamber 16.

  The angle of the presence range of the depression 11 is θs + 180 ° <θ1 when the suction hole cutoff angle is θs and the depression start angle is θ1 in the rotation angle coordinate of the shaft 4 where the top dead center of the vane 12 is 0 °. When the end angle of the depression is θ2, it is defined as θ2 <360 °. The distance L from the center of the upper bearing is defined by L <2Rp−Rc where Rp is the radius of the piston and Rc is the radius of the cylinder. Due to the above positional relationship, the recess 11 and the ring groove 10 on the upper end surface of the piston overlap and the oil in the space 9 inside the piston is supplied in the direction facing the compression chamber 16 on the side opposite to the shaft 4. As a result, the oil supplied to the ring groove 10 is mainly supplied to the compression chamber 16 side and not supplied to the suction chamber 15 side. Therefore, the suction refrigerant gas is heated by the leaked oil and the compression efficiency is lowered. You can avoid doing that. Further, the oil supplied from the ring groove 10 to the compression chamber 16 side improves the sliding conditions of the piston outer periphery and the vane tip having severe sliding conditions, thereby improving the reliability. The depth of the recess 11 is set to about 0.1 to 0.5 mm.

FIG. 5 is a view showing the positional relationship between the end face of the upper bearing 2 of the present invention and the dents 11a and 11b divided into two portions formed from the inner surface toward the outer periphery. The recess 11a is located in the vicinity of the shaft rotation angle past the suction hole (θ1> θs + 180 °) where the ring groove 10 on the upper end surface of the piston and the recess 11a overlap each other, and oil is supplied to the compression chamber at the beginning of compression, and the piston outer periphery and cylinder Reduce leakage loss of refrigerant gas from the circumferential direction of the inner circumference. Further, the recess 11b is in a position where the ring groove 10 on the upper end surface of the piston and the recess 11a overlap each other until the shaft rotation angle exceeds 180 ° (θ2 <360 °), and lubricates the compression chamber until the compression chamber reaches the discharge pressure. This has the effect of reducing the friction between the tip of the vane and the outer periphery of the piston that are mainly slid. Thus, by dividing the depression into two portions 11a and 11b, the respective effects can be obtained with a smaller amount of oil supply. When the amount of oil supply is small, oil discharge into the refrigeration cycle can be suppressed and the performance of the refrigeration cycle can be improved.

  6 and 7 are detailed views of the present invention in which oil is spot-fed to the ring groove 10 on the upper end surface of the piston by making a vertical hole 17 instead of a recess in the upper bearing end surface.

  As shown in FIG. 6, a vertical hole 17 is formed in the end surface of the upper bearing 2, and an oblique hole 18 is formed through the vertical hole 17 from the lower end corner of the inner surface 2 a of the upper bearing 2. Next, the positional relationship of the vertical holes 17 on the plane will be described with reference to FIG. The angle θh of the vertical hole 17 is defined as θs + 180 ° <θh <360 °, where θs is the suction hole cutoff angle in the shaft rotation angle coordinate where the vane top dead center is 0 °, and the upper bearing of the vertical hole The distance Lh from the center is defined by Lh <2Rp−Rc, where Rp is the radius of the piston and Rc is the radius of the cylinder. The oil can be spotted into the compression chamber at a place where oil supply is required to improve the reliability, and the oil supply can be reduced to suppress the increase in oil discharge. Further, since an oblique hole is formed from the lower end corner of the inner surface of the upper bearing, drilling is possible, so that the processing cost can be reduced.

  FIG. 8 is a characteristic diagram showing efficiency (COP) when a ring groove is provided on the upper end surface of the piston and the depth of the ring groove is changed. It can be seen that the ring groove depth is effective when the depth is 10 μm to 30 μm.

  As described above, in the present embodiment, a recess is formed in the upper bearing end surface of the rotary compressor from the inner surface of the upper bearing toward the outer periphery, and the angle of the existence range of the recess is 0 ° at the vane top dead center. In the shaft rotation angle coordinates, θs + 180 ° <θ1 where θs is the suction hole closing angle and θ1 is the start angle of the recess, and θ2 <360 ° is defined as θ2 is the end angle of the recess. The distance L from the center of the upper bearing is defined as L <2Rp−Rc, where Rp is the radius of the piston and Rc is the radius of the cylinder, and oil is supplied to the ring groove on the upper end surface of the piston. Therefore, it becomes possible to supply sufficient oil to the compression chamber side. The amount of oil can be adjusted by changing the angle θ of the recess on the upper bearing end face. The oil supplied to the compression chamber is applied to the outer periphery of the piston, vane tip, piston lower end face, and lower bearing end face where friction is severe. Supplied to help improve reliability. In addition, the oil supplied to the suction chamber is supplied to the circumferential gap between the outer periphery of the piston and the inner circumference of the cylinder, and the refrigerant gas in the compression chamber can be prevented from leaking into the suction chamber from this gap. Compression efficiency can be improved.

As described above, since the rotary compressor according to the present invention can improve the compression efficiency, it can also be applied to CO ₂ compressors for hot water heaters and air compression applications.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Upper bearing 3 Lower bearing 4 Shaft 5 Piston 6 Oil 7 Lower hole 8a, 8b Side hole 9 Piston inner space 10 Ring groove 11, 11a, 11b Depression 12 Vane 13 Suction hole 14 Discharge notch 15 Suction chamber 16 Compression chamber 17 Vertical hole 18 Diagonal hole

Claims (3)

On both end faces of the cylinder, there are provided a piston that rotates with the upper and lower bearings, a shaft that drives the piston, and a vane that partitions the inside of the cylinder into a compression chamber with an inlet and a discharge port. In the rotary compressor having a ring groove on the piston upper end surface, a recess is formed on the upper bearing end surface from the inner surface of the upper bearing toward the outer periphery, and the angle of the existence range of the recess is the vane top dead center. In the shaft rotation angle coordinate set to 0 °, θs + 180 ° <θ1 when θs is the suction hole closing angle and θ1 is the start angle of the recess, and θ2 <360 ° when the end angle of the recess is θ2. The distance L from the center of the upper bearing of the recess is defined by L <2Rp−Rc where Rp is the radius of the piston and Rc is the radius of the cylinder. Rotary compressor arrangement for supplying communicating oil ring groove of the serial piston upper surface. The rotary compressor according to claim 1, wherein a recess provided in the upper bearing end face is divided into two portions. On both end faces of the cylinder, there are provided a piston that rotates with the upper and lower bearings, a shaft that drives the piston, and a vane that partitions the inside of the cylinder into a compression chamber with an inlet and a discharge port. In the rotary compressor in which a ring groove is formed on the piston upper end surface, a vertical hole is formed on the upper bearing end surface, and the angle θh of the vertical hole is sucked in the shaft rotation angle coordinate where the vane top dead center is 0 °. Θs + 180 ° <θh <360 ° is defined as θs when the hole cut-off angle is θs, and the distance Lh from the center of the upper bearing is defined as Lh <2Rp−Rc when the radius of the piston is Rp and the radius of the cylinder is Rc. An oblique hole is provided at the lower end corner of the upper bearing inner surface so that the upper bearing inner surface communicates with the hole on the end surface. Rotary compressor arrangement for supplying communicating oil groove.