JP2006152929A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct degradation in efficiency caused by uneven pressure of an end plate seal face in an asymmetric scroll compressor and thereby to improve compression efficiency. <P>SOLUTION: A groove communicating with suction pressure is formed in an outer circumference of a spiral body of a fixed scroll 2. That is, in the scroll compressor, a circumferential groove communicating with a suction part of a fixed scroll end plate is formed in an outer circumferential part of the fixed scroll to surround the spiral body of the fixed scroll. Therefore, a high-performance asymmetric scroll compressor is provided so that movement of a swirl scroll 1 is stabilized and leakage from between compression chambers is reduced to significantly increase the compression efficiency. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scroll compressor used for a gas compressor such as an air compressor and a helium compressor, as well as a refrigerator and a refrigerant compressor used for freezing and air conditioning.

  Japanese Patent Laid-Open No. 56-20701 (Patent Document 1) discloses a background art relating to a so-called asymmetric scroll shape in which one has a winding angle larger than the other with respect to a shape in which the opposing scroll spirals are symmetrical.

  In the scroll compressor, when one scroll, for example, a turning scroll, is considered as a center, two compression chambers are formed on the outside and inside of the turning scroll. As shown in Patent Document 1, in the asymmetric scroll shape, the outermost chamber (maximum sealed volume) of the compression chamber formed outside the orbiting scroll is larger than the outermost chamber of the compression chamber formed inside the orbiting scroll. The orbiting scroll spiral body is formed over almost the entire outer periphery.

  FIG. 4 shows a plan view of a fixed scroll 2 having a scroll shape similar to the asymmetric scroll shape described in Patent Document 1, and FIG.

  A circle 1d formed by a dotted line shown in FIG. 4 represents an end portion of the end plate 1b of the orbiting scroll 1, and is a portion that is outside the spiral body 2a of the fixed scroll 2 and is in close contact with the end plate 1b of the orbiting scroll 1. Express. This close contact portion can be formed on the outer peripheral portion of the spiral body 2a of the fixed scroll 2, but the area varies depending on the location.

  In the asymmetric scroll shape, the innermost outer periphery of the spiral body 2 a of the fixed scroll 2 forms a compression chamber with the outer side of the orbiting scroll 1.

  During the operation of the compressor, the outer edge of the contact portion (the end plate 1 b of the orbiting scroll 1) is in an intermediate pressure state in the back pressure chamber provided on the anti-fixed scroll side of the orbiting scroll 1.

  In the case of an asymmetric scroll, the inside of the close contact portion is a pressure during compression in the compression chamber. For this reason, the contact portion of the orbiting scroll 1 serves as a seal portion that prevents leakage between the intermediate pressure and the compression chamber pressure.

JP 56-20701 A

  In the case of the asymmetric scroll shape, the outermost chamber (maximum sealed volume) of the compression chamber formed outside the orbiting scroll 1 is formed on the outer peripheral side of the orbiting spiral body. This is performed between the pressure and the pressure in the middle of compression in the compression chamber.

  In this case, the pressure in the surface of the seal portion varies depending on the location due to the fluctuation of the pressure in the compression chamber. Further, the pressure in the surface of the seal portion fluctuates during one rotation due to fluctuations in the pressure in the compression chamber during operation.

  Further, since the area of the seal portion varies depending on the location, the pressure distribution in the end surface of the orbiting scroll becomes non-uniform, and a moment is generated to tilt the orbiting scroll.

  For this reason, the orbiting scroll 1 is tilted or oscillated due to this pressure fluctuation, and there has been a problem that the compression efficiency is lowered due to the occurrence of leakage between the compression chambers or the instability of the compression operation.

  The present invention has been made to solve the problems of the prior art.

  The above-described problem is provided on the outer periphery of the fixed scroll spiral body and facing the end plate of the orbiting scroll so as to surround the fixed scroll spiral body and communicate with the suction portion of the fixed scroll end plate. Is solved.

  As a result, a groove whose pressure becomes the suction pressure is formed outside the outer periphery side compression chamber of the orbiting scroll, so that the seal pressure of the orbiting scroll end plate always becomes the suction pressure and does not change during one rotation. Further, by using the circumferential groove, the seal area does not vary depending on the place and is substantially constant.

  As a result, tilt and swing acting on the orbiting scroll can be reduced, and leakage between the compression chambers can be reduced, and compression efficiency can be improved by stabilizing the movement of the orbiting scroll.

  ADVANTAGE OF THE INVENTION According to this invention, the scroll compressor which has the highly efficient asymmetric scroll shape which remarkably improved compression efficiency can be provided by the movement of a turning scroll being stabilized and the leakage between compression chambers reducing.

  A first embodiment in which the present invention is applied to a hermetic scroll compressor will be described with reference to FIGS. 1 is a longitudinal sectional view of the compressor, FIG. 2 is an AA longitudinal sectional view of FIG. 1, and FIG. 3 is a BB sectional view of the fixed scroll 2 in FIG.

  1 to 3, the orbiting scroll 1 is composed of an orbiting side spiral body 1a and an end plate 1b, and the fixed scroll 2 is outside the fixed side spiral body 2a, end plate 2b and spiral body 2a. It is comprised from the outer peripheral part which opposes the end plate 1a.

  Each spiral body is formed by a circular involute curve, and is formed inside the compression chamber A formed outside the winding end wrap of the orbiting scroll 1 spiral body 1a by meshing the scrolls 1 and 2 with each other. The compression chamber B is different in size and has an asymmetric scroll shape whose phase is shifted by about 180 ° with respect to the rotation of the shaft.

  Next, the structure of the scroll compressor will be described. The orbiting scroll 1 has an orbiting bearing 1c on the back surface of the end plate 1b. An eccentric portion 6a of the crankshaft 6 supported by the main bearing 5a of the frame 5 is inserted into the swing bearing 1c.

  An Oldham ring 7 is disposed between the orbiting scroll 1 and the frame 5, and the orbiting scroll 1 is constrained to rotate by the Oldham ring 7 and performs the orbiting motion.

  The fixed scroll 2 has a discharge port 8 opened near the center. The winding end of the inner side curve of the fixed-side spiral body 2a is extended by about 180 ° to the vicinity of the winding end of the turning-side spiral body 1a. Therefore, when the compression chamber is formed by combining the scrolls 1 and 2, the compression chamber A formed by being confined by the outer curve of the swirl side spiral body 1a and the inner curve of the fixed side spiral body 2a, and the swirl side spiral body The compression chamber B formed by being confined by the inner curve of 1a and the outer curve of the fixed spiral body 2a is different in size and is formed with a phase shift of about 180 ° with respect to the rotation of the crankshaft.

  The differential pressure control mechanism 9a has a valve structure that controls the back pressure value, for example, opens and closes at a predetermined pressure difference, and controls the pressure in the back pressure chamber 9 including the fixed scroll 2, the orbiting scroll 1, and the frame 5. . With the adjusted pressure in the back pressure chamber 9, the orbiting scroll 1 is pressed against the fixed scroll 2, and the pressure in the compression chamber formed between the two scrolls is balanced.

  The pressure inlet side of the differential pressure control mechanism 9a communicates with the back pressure chamber 9, and the pressure outlet side communicates with a fixed outer peripheral groove 2c provided on the outer periphery of the fixed spiral body 2a.

  As shown in FIG. 2, the fixed outer peripheral groove 2c is provided on the outer periphery of the fixed spiral body 2a, and communicates with the working fluid suction port 2d. For this reason, the inside of the fixed outer peripheral groove 2c always has a suction pressure.

  The motor 10 includes a rotor and a stator, and the rotor is attached to the crankshaft 6 below the frame 5. A bearing support plate 11 is provided below the motor 10, and a sub-bearing 12 attached to the bearing support plate 11 supports the crankshaft 6 together with the main bearing.

  The suction pipe 13 is for taking in a working fluid such as refrigerant gas, and communicates with the fixed scroll 2. The discharge pipe 14 is for discharging the compressed working fluid to the outside of the compressor. Reference numeral 15 denotes a hermetically sealed case that houses the orbiting scroll 1, the fixed scroll 2, and the motor 10 in a sealed manner.

  Next, the operation will be described. By starting the rotation of the motor 10, the crankshaft 6 rotates and the orbiting scroll 1 starts orbiting. By this operation, both scroll spiral bodies 1a, 2a mesh with each other to form compression chambers A, B.

  A working fluid such as refrigerant gas flows from the suction pipe 13 and is compressed in the compression chambers A and B. The compression chambers A and B perform a compression operation while reducing the volume in the central direction according to the rotation of the crankshaft, and are discharged from the discharge port 8 into the sealed case 15 and finally through the discharge pipe 14 to the outside of the compressor. Is discharged.

  The pressure in the back pressure chamber 9 is increased by the gas contained in the oil that lubricates the main bearing 5a and the like, and is controlled by the differential pressure control mechanism 9a so as to have a constant pressure difference with respect to the suction pressure. This pressure is intermediate between the suction pressure and the discharge pressure, and presses the orbiting scroll 1 against the fixed scroll 2.

  By this pressing, the orbiting scroll end plate 1b is in close contact with the fixed scroll 2, and the outer peripheral portion of the end plate 1b provides a seal between the intermediate pressure in the back pressure chamber 9 and the suction pressure in the fixed outer peripheral groove 2c.

  In the case of the asymmetric scroll shape, the maximum sealed space of the compression chamber A is formed on the outer peripheral side of the swirling spiral body 1a. However, by providing the fixed outer peripheral groove 2c on the outer periphery of the fixed-side spiral body 2a, the pressure seal portion by the end plate 1b is generated inside the outer edge 1d of the end plate 1b shown in FIG. Unlike the seal part of FIG. 4, it becomes a substantially circumferential shape. For this reason, there is almost no change depending on the location.

  Further, the pressure is sealed between the intermediate pressure in the back pressure chamber 9 and the suction pressure in the fixed outer peripheral groove 2c. In this case, since the pressure in the end plate 1b does not fluctuate without receiving fluctuations in the pressure in the compression chamber A, and the pressure distribution in the surface of the end plate 1b becomes uniform, an attempt is made to tilt the orbiting scroll 1. Does not occur.

  Accordingly, the motion of the orbiting scroll 2 is more stable and the pressing of the orbiting scroll 1 to the fixed scroll 2 becomes more firm, so that leakage between the compression chambers is reduced and the compression efficiency is improved.

  According to one embodiment of the present invention, by providing the fixed outer peripheral groove 2c on the outer periphery of the fixed-side spiral body 2a, the pressure seal by the orbiting scroll end plate 1b is achieved by the intermediate pressure in the back pressure chamber 9 and the fixed outer peripheral groove. 2c, the seal pressure in the end plate 1b hardly fluctuates, and the seal portion shape and the seal pressure distribution in the end plate 1b surface become uniform.

  Therefore, a moment for tilting the orbiting scroll 1 does not occur. Therefore, the motion of the orbiting scroll 2 is stabilized, the close contact between the orbiting scroll 1 and the fixed scroll 2 is ensured, and leakage between the compression chambers is reduced, so that a high-performance scroll compressor having remarkably improved compression efficiency can be obtained. Can be provided.

The longitudinal cross-sectional view of the 1st Example of this invention. AA sectional drawing of FIG. BB sectional drawing of the fixed scroll in FIG. The top view of the fixed scroll by a prior art. FIG. 5 is a BB cross-sectional view of the fixed scroll shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Turning scroll, 2 ... Fixed scroll, 5 ... Frame, 6 ... Crankshaft, 8 ... Discharge port, 10 ... Motor, 13 ... Suction pipe, 14 ... Discharge pipe, 15 ... Sealing case.

Claims (1)

An end plate and a spiral body standing on the end plate, revolving without rotating, an end plate, a spiral body standing on the end plate, and outside the spiral body Scroll compression having an asymmetric scroll shape having a fixed scroll having an outer peripheral portion facing an end plate of the orbiting scroll, wherein the winding angle of the spiral body of the fixed scroll is different from the winding angle of the spiral body of the orbiting scroll In the machine
A scroll compressor in which a circumferential groove is provided in an outer peripheral portion of the fixed scroll so as to surround a spiral body of the fixed scroll and communicate with a suction portion of the fixed scroll end plate.

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