JP2008309124A - Scroll compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein since a temperature gradient is generated in the thickness direction of a lap of a fixed scroll, thermal expansion differs between inner and outer peripheral sides of the lap, leading to uneven contact of a lap tip part. <P>SOLUTION: Considering the temperature gradient generated in the thickness direction of the lap 12b of the fixed scroll 12, a lap upper face 12c of the fixed scroll 12 is partially lowered with respect to a portion 12f contacted with a panel board 13a of a turning scroll 13 on the outer peripheral face of the fixed scroll 12. This structure can absorb dimensional change of the lap 12b caused by thermal expansion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scroll compressor used in a cooling device such as a cooling / heating air conditioner or a refrigerator, or a heat pump type hot water supply device.

  2. Description of the Related Art Conventionally, scroll compressors used in refrigeration air conditioners and refrigerators generally form a compression chamber between the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate, and the orbiting scroll is rotated by a rotation restraint mechanism. When it is swung along a circular orbit under the constraint of the above, suction, compression, and discharge are performed by moving the compression chamber while changing the volume. The working fluid is gradually compressed along with the turning motion of the orbiting scroll, and gradually becomes a high pressure and high temperature state toward the center. As a result, the orbiting scroll and the fixed scroll are also in a high temperature state in the center, and as a result, thermal expansion occurs. When thermal expansion occurs, contact may occur locally between the orbiting scroll and the fixed scroll, which may increase input and further cause seizure. Therefore, there is a method of forming a gap between the upper surface of one lap and the bottom surface of the other wrap groove to prevent local sliding during thermal expansion (see, for example, Patent Document 1).

FIG. 6 is a cross-sectional view of a compression mechanism portion of a conventional scroll compressor described in Patent Document 1. As shown in FIG. 6, a gap is provided between the wrap upper surface 113 a of the orbiting scroll 113 and the wrap groove bottom surface 112 b of the fixed scroll 112, or the groove bottom surface 113 b of the orbiting scroll 113 and the wrap upper surface 112 a of the fixed scroll 112. Thereby, it is possible to stably minimize the gap between the top surface of the wrap and the bottom surface of the wrap groove against deformation caused by thermal expansion and pressure difference.
JP 2002-54584 A

  In the conventional configuration, the wrap height of the orbiting scroll or the fixed scroll, or the wrap groove bottom depth is set according to the temperature and pressure conditions of the compression chamber, and a gap is formed between one wrap top surface and the other wrap groove bottom surface. By forming, the dimensional change of the wrap is absorbed. However, in a scroll compressor, compression chambers are generally formed on both sides of a wrap. Since the two compression chambers have different compression phases after the working fluid is confined and the temperatures of the working fluid in the compression chambers also differ, a temperature gradient is generated in the thickness direction of the wrap. In particular, when the configuration is such that the top surface of the fixed scroll and the bottom surface of the orbiting scroll are in contact with each other, the thermal expansion of the inner surface of the fixed scroll is different from that of the outer surface. End up. That is, since the load is received locally, the surface pressure is increased, and there is a risk of causing an increase in input and further seizure. That is, if the wrap height is constant in the thickness direction, there is a problem that the performance and reliability are lowered.

  The present invention solves the above-mentioned conventional problem, and takes into account the temperature gradient in the thickness direction generated in the fixed scroll lap, and absorbs the dimensional change of the wrap due to thermal expansion, thereby providing a piece on the upper surface of the fixed scroll wrap. An object of the present invention is to provide a scroll compressor that realizes high efficiency and high reliability because it is possible to suppress the hit and prevent an increase in input and occurrence of seizure.

In order to solve the above-mentioned conventional problems, the scroll compressor of the present invention forms a compression chamber between the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate and forms a compression chamber between the two, and is regulated by the rotation restraint mechanism. As the orbiting scroll revolves along a circular orbit, the compression chamber moves toward the center while changing the volume, and in the scroll compressor that performs a series of operations of suction, compression, and discharge, the wrap upper surface of the fixed scroll is A part of the outer peripheral surface of the fixed scroll that is in contact with the end plate of the orbiting scroll is partially lowered.

  According to such a configuration, considering the temperature gradient in the thickness direction generated in the wrap of the fixed scroll, and absorbing the dimensional change of the wrap due to thermal expansion, the contact of the upper surface of the wrap of the fixed scroll is suppressed, and the input is increased. Since it is possible to prevent the occurrence of seizure, it is possible to provide a scroll compressor that achieves high efficiency and high reliability.

  The scroll compressor of the present invention takes into account the temperature gradient in the thickness direction generated in the wrap of the fixed scroll, absorbs the dimensional change of the wrap due to thermal expansion, and suppresses the per contact of the top surface of the wrap of the fixed scroll. Therefore, it is possible to provide a scroll compressor that realizes high efficiency and high reliability.

  In the first aspect of the present invention, the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate are meshed to form a compression chamber between the two, and the orbiting scroll follows the circular orbit by regulation by the rotation restraint mechanism. In a scroll compressor that performs a series of operations of suction, compression, and discharge by moving the compression chamber toward the center while changing the volume by turning, the upper surface of the fixed scroll is turned on the outer peripheral surface of the fixed scroll. This is partly lower than the part in contact with the end plate. And according to this configuration, considering the temperature gradient in the thickness direction generated in the fixed scroll wrap, by absorbing the dimensional change of the wrap due to thermal expansion, the perimeter of the fixed scroll wrap upper surface is suppressed, and the input Since increase and seizure can be prevented, a scroll compressor that realizes high efficiency and high reliability can be provided.

  In the second aspect of the present invention, in particular, a step is formed in the thickness direction of the wrap on the wrap upper surface of the fixed scroll according to the first aspect, and the inner peripheral side is made lower than the outer peripheral side of the wrap. And according to this structure, since the temperature of the compression chamber formed on the inner peripheral side is higher than that of the compression chamber formed on the outer peripheral side, the thermal expansion on the inner peripheral side of the wrap increases. Can absorb this. That is, since it is possible to avoid one-side contact in the thickness direction of the wrap, it is possible to provide a scroll compressor that achieves high efficiency and high reliability.

  In this invention of Claim 3, especially the level | step difference of Claim 2 is formed in the range of 0.001 to 0.01 times the lap height of a fixed scroll. According to this configuration, since the thermal expansion on the inner peripheral side can be sufficiently absorbed and the one-side contact in the thickness direction of the wrap can be avoided, a scroll compressor that achieves high reliability and high efficiency is provided. be able to.

  In the present invention described in claim 4, in particular, the formation width on the low step side according to claim 2 or 3 is formed in the range of 0.3 to 0.7 times the wrap thickness of the fixed scroll. is there. And according to this configuration, the thermal expansion on the inner peripheral side can be sufficiently absorbed, and at the same time, the sealing property between the compression chamber formed on the inner peripheral side and the compression chamber formed on the outer peripheral side can be secured, Performance degradation can be suppressed as much as possible. That is, it is possible to provide a scroll compressor that achieves high efficiency and high reliability.

According to the fifth aspect of the present invention, particularly in the scroll compressor according to any one of the first to fourth aspects, the working fluid is a high-pressure refrigerant, for example, carbon dioxide. In this case, particularly, the temperature gradient in the thickness direction generated in the wrap of the fixed scroll becomes large, so that the effect of the present invention appears remarkably, and a scroll compressor that achieves both high efficiency and high reliability is realized. Can do.

  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)
1 is a longitudinal sectional view of a scroll compressor according to a first embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of a compression mechanism portion of FIG. 1, FIG. 3 is a plan view of a fixed scroll, and FIG. FIG. 4 is a sectional view of a fixed scroll. Hereinafter, the operation and action of the embodiment of the scroll compressor of the present invention will be described.

  As shown in FIGS. 1 and 2, the scroll compressor of the present invention includes a main bearing member 11 of a crankshaft 4 fixed by welding or shrink fitting in a sealed container 1, and a bolt on the main bearing member 11. The scroll-type compression mechanism 2 is configured by sandwiching the orbiting scroll 13 that meshes with the fixed scroll 12 between the fixed scroll 12 and the rotation of the orbiting scroll 13 between the orbiting scroll 13 and the main bearing member 11. Then, a rotation restraint mechanism 14 such as an Oldham ring that guides the circular scroll to move is provided, and the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4 a at the upper end of the crankshaft 4, thereby causing the orbiting scroll 13 to be circular As a result, the compression chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 moves from the outer peripheral side to the center portion. Utilizing this, the refrigerant gas is sucked and compressed from the suction pipe 16 leading to the outside of the sealed container 1 and the suction port 17 on the outer peripheral portion of the fixed scroll 12, and the refrigerant gas having a predetermined pressure or higher is compressed. The reed valve 19 is pushed open from the discharge port 18 at the center of the fixed scroll 12 and discharged into the sealed container 1 repeatedly.

  On the lap upper surface 13c of the orbiting scroll 13, based on the result of measuring the temperature distribution during operation, the height of the heel gradually increases from the winding start portion as the central portion to the winding end portion as the outer peripheral portion. Is provided with a slope shape. Thereby, the dimensional change by thermal expansion can be absorbed and local sliding can be prevented.

  Further, on the back surface 13e of the orbiting scroll 13, there is an annular seal member 78 disposed on the main bearing member 11, and the high pressure region 30 that is an inner region of the seal member 78 is formed by the seal member 78 while performing the orbiting motion, It is partitioned into a back pressure chamber 29 set at an intermediate pressure of high pressure and low pressure, which is an outer region. By applying pressure on the back surface 13e, the orbiting scroll 13 is stably pressed against the fixed scroll 12, and leakage can be reduced and the circular orbit motion can be stably performed.

  Further, the fixed scroll 12 is provided with a back pressure adjusting mechanism 9 for controlling the back pressure chamber 29 on the back surface 13e of the orbiting scroll 13 so as to always have a constant pressure.

  During operation of the compressor, a pump 25 is provided at the other downward end of the crankshaft 4 and is driven simultaneously with the scroll compressor. As a result, the pump 25 sucks up the oil 6 in the oil reservoir 20 provided at the bottom of the hermetic container 1 and supplies it to the compression mechanism 2 through the oil supply hole 26 extending vertically through the crankshaft 4. The supply pressure at this time is substantially equal to the discharge pressure of the scroll compressor, and also serves as a back pressure source for the orbiting scroll 13. As a result, the orbiting scroll 13 does not move away from the fixed scroll 12 and does not come into contact with each other, and the predetermined compression function is stably exhibited.

A part of the oil 6 supplied in this way is obtained by a supply pressure or its own weight so as to obtain a clearance, between the fitting portion between the eccentric shaft portion 4a and the orbiting scroll 13, and between the crankshaft 4 and the main bearing member 11. Then, the oil enters the bearing portion 66, lubricates the respective portions, falls, and returns to the oil sump 20. Another part of the oil 6 supplied to the high-pressure region 30 passes through an oil supply passage 54 having an opening in the high-pressure region 30, is around the outer peripheral portion of the orbiting scroll 13, and the rotation restraint mechanism 14 is located. Along with entering the pressure chamber 29 and lubricating the thrust sliding portion and the sliding portion of the rotation restraining mechanism 14, the back pressure of the orbiting scroll 13 is applied in the back pressure chamber 29.

  The back pressure chamber 29 is sealed between the high pressure region 30 and the high pressure side by an annular sealing member 78, and the pressure increases as the incoming oil fills up. 9 acts to return and enter the suction portion of the compression chamber 15.

  This approach of the oil 6 is repeated at a predetermined cycle, and the timing of this repetition is determined by a combination of the relationship between the repeated cycle of suction, compression, and discharge and the pressure setting in the back pressure adjusting mechanism 9, and the rotation with the fixed scroll 12 Intentional lubrication of the sliding portion with the scroll 13 is achieved. This intentional lubrication is always ensured by the opening of the communication path 10 into the recess 10a by the back pressure adjusting mechanism 9 as described above. The oil 6 supplied to the suction port 17 moves to the compression chamber 15 along with the orbiting motion of the orbiting scroll 13 and serves to prevent leakage between the compression chambers 15.

  Generally, in a scroll compressor, the orbiting scroll 13 and the fixed scroll 12 mesh with each other to form the compression chamber 15, but the lap 12 b of the fixed scroll 12 has two compression chambers (for example, 15 a and 15 b) formed on both sides thereof. Has been. Since these two compression chambers (15a, 15b) have different compression phases after the working fluid is confined, the temperature of the working fluid in each compression chamber is also different. Thereby, a temperature gradient is generated in the thickness direction of the wrap 12b. In particular, when the wrap upper surface 12c of the fixed scroll 12 and the lap groove bottom surface 13d of the orbiting scroll 13 are brought into contact with each other, the wrap upper surface 12c is subjected to a local load due to thermal expansion. , And there is a risk of increased input and further seizure.

  Therefore, as shown in FIG. 3, in the scroll compressor of the present embodiment, the wrap upper surface 12 c of the fixed scroll 12 is partially compared with the portion 12 f that contacts the end plate 13 a of the orbiting scroll 13 on the outer peripheral surface of the fixed scroll 12. Is formed low. In the case of lowering the entire surface, the end plate 13a of the orbiting scroll 13 and the outer peripheral surface portion 12f of the fixed scroll 12 are in contact with each other, so that stable circular locus operation can be performed, and only a part of the scroll is lowered. Since the contact area between the end plate 13a of the orbiting scroll 13 and the fixed scroll 12 increases, the surface pressure can be reduced. In any case, by absorbing the dimensional change of the wrap 12b due to thermal expansion, it is possible to suppress the one-side contact of the wrap upper surface 12c of the fixed scroll 12 and to prevent an increase in input and occurrence of seizure. Therefore, it is possible to provide a scroll compressor that achieves high efficiency and high reliability.

  Further, since the compression chamber 15a formed on the inner peripheral side has a higher temperature than the compression chamber 15b formed on the outer peripheral side with respect to the wrap 12b of the fixed scroll 12, thermal expansion on the inner peripheral side of the wrap 12b. Is big. Therefore, a step 35 is formed in the thickness direction of the wrap 12b on the wrap upper surface 12c of the fixed scroll 12, and the inner peripheral side is made lower than the outer peripheral side of the wrap 12b. Thereby, the local sliding in the thickness direction of the wrap 12b can be avoided, and a scroll compressor that realizes high reliability and high efficiency can be provided.

  Also, as shown in FIG. 4, by forming the step 35 in the range of 0.001 to 0.01 times the height H of the wrap 12b, the thermal expansion on the inner peripheral side can be sufficiently absorbed, and the wrap 12b Therefore, it is possible to provide a scroll compressor that achieves high reliability and high efficiency at the same time.

(Embodiment 2)
FIG. 5 is a performance characteristic diagram according to the second embodiment of the present invention. In FIG. 5, the horizontal axis represents the formation ratio on the lower side of the step 35, and the vertical axis represents the compressor efficiency. By forming the formation width on the lower side of the step 35 in the lap thickness direction in the range of 0.3 to 0.7 times the wrap thickness W of the fixed scroll, the thermal expansion on the inner peripheral side can be sufficiently absorbed. At the same time, the sealing property between the compression chamber 15a formed on the inner peripheral side and the compression chamber 15b formed on the outer peripheral side can be ensured, and the deterioration in performance can be suppressed as much as possible. When the formation ratio is small, local sliding occurs due to thermal expansion of the wrap 12b, and sliding loss increases. Under operating conditions where thermal expansion further increases, a gap is generated between the end plate 13a of the orbiting scroll 13 and the portion 12f on the outer peripheral surface of the fixed scroll 12, and the volumetric efficiency deteriorates, so the compressor efficiency tends to decrease. . On the other hand, when the formation ratio is large, the sealing performance between the compression chamber 15a formed on the inner peripheral side and the compression chamber 15b formed on the outer peripheral side is not maintained, and leakage loss increases, so that the compressor efficiency decreases. Show the trend. From the above, in order to realize high reliability and high efficiency, it is necessary to form the step 35 in the above range. More desirably, by forming the step 35 in the range of 0.4 to 0.6 times the wrap thickness W, it is possible to provide a scroll compressor that achieves higher efficiency.

  Finally, when the working fluid is a high-pressure refrigerant, for example, carbon dioxide, the temperature gradient in the thickness direction generated particularly in the wrap 12b of the fixed scroll 12 becomes large. In addition, a scroll compressor that achieves both high reliability and high reliability can be realized.

  As described above, the scroll compressor according to the present invention takes into account the temperature gradient in the thickness direction generated in the fixed scroll wrap and absorbs the dimensional change of the wrap due to thermal expansion, thereby Since it is possible to suppress the contact and prevent the increase of input and the occurrence of seizure, the working fluid is not limited to the refrigerant, and the scroll fluid machine such as an air scroll compressor, vacuum pump, scroll type expander, etc. It can also be applied to applications.

Sectional drawing of the scroll compressor in Embodiment 1 of this invention The principal part expanded sectional view of the compression mechanism part of the scroll compressor in Embodiment 1 of this invention The top view of the fixed scroll of the scroll compressor in Embodiment 1 of this invention Sectional drawing of the fixed scroll of the scroll compressor in Embodiment 1 of this invention Performance characteristic diagram in Embodiment 2 of the present invention Sectional view of the compression mechanism of a conventional scroll compressor

Explanation of symbols

12 fixed scroll 12b lap 12c lap upper surface 12f part 13 orbiting scroll 13a end plate 13b lap 14 rotation restraint mechanism 15 compression chamber 35 step H lap height W lap thickness

Claims (5)

A compression scroll is formed between both of the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate, and the orbiting scroll orbits along a circular orbit by regulation by a rotation restraint mechanism. In a scroll compressor that moves toward the center while changing the volume and performs a series of operations of suction, compression, and discharge, the upper surface of the fixed scroll is brought into contact with the end plate of the orbiting scroll at the outer peripheral surface of the fixed scroll. A scroll compressor made partially lower than the part. The scroll compressor according to claim 1, wherein a step is formed in a thickness direction of the wrap on the wrap upper surface of the fixed scroll, and an inner peripheral side is made lower than an outer peripheral side of the wrap. The scroll compressor according to claim 2, wherein the step is formed in a range of 0.001 to 0.01 times the wrap height of the fixed scroll. The scroll compressor according to claim 2 or 3, wherein a formation width on a side having a low step is formed in a range of 0.3 to 0.7 times the wrap thickness of the fixed scroll. The scroll compressor according to any one of claims 1 to 4, wherein the working fluid is a high-pressure refrigerant, for example, carbon dioxide.